Major fixes and new features

venv/lib/python3.12/site-packages/mypy/__init__.py

@@ -0,0 +1 @@
+# This page intentionally left blank

venv/lib/python3.12/site-packages/mypy/__main__.py

@@ -0,0 +1,37 @@
+"""Mypy type checker command line tool."""
+
+from __future__ import annotations
+
+import os
+import sys
+import traceback
+
+from mypy.main import main, process_options
+from mypy.util import FancyFormatter
+
+
+def console_entry() -> None:
+    try:
+        main()
+        sys.stdout.flush()
+        sys.stderr.flush()
+    except BrokenPipeError:
+        # Python flushes standard streams on exit; redirect remaining output
+        # to devnull to avoid another BrokenPipeError at shutdown
+        devnull = os.open(os.devnull, os.O_WRONLY)
+        os.dup2(devnull, sys.stdout.fileno())
+        sys.exit(2)
+    except KeyboardInterrupt:
+        _, options = process_options(args=sys.argv[1:])
+        if options.show_traceback:
+            sys.stdout.write(traceback.format_exc())
+        formatter = FancyFormatter(sys.stdout, sys.stderr, False)
+        msg = "Interrupted\n"
+        sys.stdout.write(formatter.style(msg, color="red", bold=True))
+        sys.stdout.flush()
+        sys.stderr.flush()
+        sys.exit(2)
+
+
+if __name__ == "__main__":
+    console_entry()

venv/lib/python3.12/site-packages/mypy/api.py

@@ -0,0 +1,94 @@
+"""This module makes it possible to use mypy as part of a Python application.
+
+Since mypy still changes, the API was kept utterly simple and non-intrusive.
+It just mimics command line activation without starting a new interpreter.
+So the normal docs about the mypy command line apply.
+Changes in the command line version of mypy will be immediately usable.
+
+Just import this module and then call the 'run' function with a parameter of
+type List[str], containing what normally would have been the command line
+arguments to mypy.
+
+Function 'run' returns a Tuple[str, str, int], namely
+(<normal_report>, <error_report>, <exit_status>),
+in which <normal_report> is what mypy normally writes to sys.stdout,
+<error_report> is what mypy normally writes to sys.stderr and exit_status is
+the exit status mypy normally returns to the operating system.
+
+Any pretty formatting is left to the caller.
+
+The 'run_dmypy' function is similar, but instead mimics invocation of
+dmypy. Note that run_dmypy is not thread-safe and modifies sys.stdout
+and sys.stderr during its invocation.
+
+Note that these APIs don't support incremental generation of error
+messages.
+
+Trivial example of code using this module:
+
+import sys
+from mypy import api
+
+result = api.run(sys.argv[1:])
+
+if result[0]:
+    print('\nType checking report:\n')
+    print(result[0])  # stdout
+
+if result[1]:
+    print('\nError report:\n')
+    print(result[1])  # stderr
+
+print('\nExit status:', result[2])
+
+"""
+
+from __future__ import annotations
+
+import sys
+from io import StringIO
+from typing import Callable, TextIO
+
+
+def _run(main_wrapper: Callable[[TextIO, TextIO], None]) -> tuple[str, str, int]:
+    stdout = StringIO()
+    stderr = StringIO()
+
+    try:
+        main_wrapper(stdout, stderr)
+        exit_status = 0
+    except SystemExit as system_exit:
+        assert isinstance(system_exit.code, int)
+        exit_status = system_exit.code
+
+    return stdout.getvalue(), stderr.getvalue(), exit_status
+
+
+def run(args: list[str]) -> tuple[str, str, int]:
+    # Lazy import to avoid needing to import all of mypy to call run_dmypy
+    from mypy.main import main
+
+    return _run(
+        lambda stdout, stderr: main(args=args, stdout=stdout, stderr=stderr, clean_exit=True)
+    )
+
+
+def run_dmypy(args: list[str]) -> tuple[str, str, int]:
+    from mypy.dmypy.client import main
+
+    # A bunch of effort has been put into threading stdout and stderr
+    # through the main API to avoid the threadsafety problems of
+    # modifying sys.stdout/sys.stderr, but that hasn't been done for
+    # the dmypy client, so we just do the non-threadsafe thing.
+    def f(stdout: TextIO, stderr: TextIO) -> None:
+        old_stdout = sys.stdout
+        old_stderr = sys.stderr
+        try:
+            sys.stdout = stdout
+            sys.stderr = stderr
+            main(args)
+        finally:
+            sys.stdout = old_stdout
+            sys.stderr = old_stderr
+
+    return _run(f)

venv/lib/python3.12/site-packages/mypy/applytype.py

@@ -0,0 +1,148 @@
+from __future__ import annotations
+
+from typing import Callable, Sequence
+
+import mypy.subtypes
+from mypy.expandtype import expand_type
+from mypy.nodes import Context
+from mypy.types import (
+    AnyType,
+    CallableType,
+    ParamSpecType,
+    PartialType,
+    Type,
+    TypeVarId,
+    TypeVarLikeType,
+    TypeVarTupleType,
+    TypeVarType,
+    UninhabitedType,
+    UnpackType,
+    get_proper_type,
+)
+
+
+def get_target_type(
+    tvar: TypeVarLikeType,
+    type: Type,
+    callable: CallableType,
+    report_incompatible_typevar_value: Callable[[CallableType, Type, str, Context], None],
+    context: Context,
+    skip_unsatisfied: bool,
+) -> Type | None:
+    p_type = get_proper_type(type)
+    if isinstance(p_type, UninhabitedType) and tvar.has_default():
+        return tvar.default
+    if isinstance(tvar, ParamSpecType):
+        return type
+    if isinstance(tvar, TypeVarTupleType):
+        return type
+    assert isinstance(tvar, TypeVarType)
+    values = tvar.values
+    if values:
+        if isinstance(p_type, AnyType):
+            return type
+        if isinstance(p_type, TypeVarType) and p_type.values:
+            # Allow substituting T1 for T if every allowed value of T1
+            # is also a legal value of T.
+            if all(any(mypy.subtypes.is_same_type(v, v1) for v in values) for v1 in p_type.values):
+                return type
+        matching = []
+        for value in values:
+            if mypy.subtypes.is_subtype(type, value):
+                matching.append(value)
+        if matching:
+            best = matching[0]
+            # If there are more than one matching value, we select the narrowest
+            for match in matching[1:]:
+                if mypy.subtypes.is_subtype(match, best):
+                    best = match
+            return best
+        if skip_unsatisfied:
+            return None
+        report_incompatible_typevar_value(callable, type, tvar.name, context)
+    else:
+        upper_bound = tvar.upper_bound
+        if not mypy.subtypes.is_subtype(type, upper_bound):
+            if skip_unsatisfied:
+                return None
+            report_incompatible_typevar_value(callable, type, tvar.name, context)
+    return type
+
+
+def apply_generic_arguments(
+    callable: CallableType,
+    orig_types: Sequence[Type | None],
+    report_incompatible_typevar_value: Callable[[CallableType, Type, str, Context], None],
+    context: Context,
+    skip_unsatisfied: bool = False,
+) -> CallableType:
+    """Apply generic type arguments to a callable type.
+
+    For example, applying [int] to 'def [T] (T) -> T' results in
+    'def (int) -> int'.
+
+    Note that each type can be None; in this case, it will not be applied.
+
+    If `skip_unsatisfied` is True, then just skip the types that don't satisfy type variable
+    bound or constraints, instead of giving an error.
+    """
+    tvars = callable.variables
+    assert len(tvars) == len(orig_types)
+    # Check that inferred type variable values are compatible with allowed
+    # values and bounds.  Also, promote subtype values to allowed values.
+    # Create a map from type variable id to target type.
+    id_to_type: dict[TypeVarId, Type] = {}
+
+    for tvar, type in zip(tvars, orig_types):
+        assert not isinstance(type, PartialType), "Internal error: must never apply partial type"
+        if type is None:
+            continue
+
+        target_type = get_target_type(
+            tvar, type, callable, report_incompatible_typevar_value, context, skip_unsatisfied
+        )
+        if target_type is not None:
+            id_to_type[tvar.id] = target_type
+
+    # TODO: validate arg_kinds/arg_names for ParamSpec and TypeVarTuple replacements,
+    # not just type variable bounds above.
+    param_spec = callable.param_spec()
+    if param_spec is not None:
+        nt = id_to_type.get(param_spec.id)
+        if nt is not None:
+            # ParamSpec expansion is special-cased, so we need to always expand callable
+            # as a whole, not expanding arguments individually.
+            callable = expand_type(callable, id_to_type)
+            assert isinstance(callable, CallableType)
+            return callable.copy_modified(
+                variables=[tv for tv in tvars if tv.id not in id_to_type]
+            )
+
+    # Apply arguments to argument types.
+    var_arg = callable.var_arg()
+    if var_arg is not None and isinstance(var_arg.typ, UnpackType):
+        callable = expand_type(callable, id_to_type)
+        assert isinstance(callable, CallableType)
+        return callable.copy_modified(variables=[tv for tv in tvars if tv.id not in id_to_type])
+    else:
+        callable = callable.copy_modified(
+            arg_types=[expand_type(at, id_to_type) for at in callable.arg_types]
+        )
+
+    # Apply arguments to TypeGuard if any.
+    if callable.type_guard is not None:
+        type_guard = expand_type(callable.type_guard, id_to_type)
+    else:
+        type_guard = None
+
+    # The callable may retain some type vars if only some were applied.
+    # TODO: move apply_poly() logic from checkexpr.py here when new inference
+    # becomes universally used (i.e. in all passes + in unification).
+    # With this new logic we can actually *add* some new free variables.
+    remaining_tvars = [tv for tv in tvars if tv.id not in id_to_type]
+
+    return callable.copy_modified(
+        ret_type=expand_type(callable.ret_type, id_to_type),
+        variables=remaining_tvars,
+        type_guard=type_guard,
+    )

venv/lib/python3.12/site-packages/mypy/argmap.py

@@ -0,0 +1,247 @@
+"""Utilities for mapping between actual and formal arguments (and their types)."""
+
+from __future__ import annotations
+
+from typing import TYPE_CHECKING, Callable, Sequence
+
+from mypy import nodes
+from mypy.maptype import map_instance_to_supertype
+from mypy.types import (
+    AnyType,
+    Instance,
+    ParamSpecType,
+    TupleType,
+    Type,
+    TypedDictType,
+    TypeOfAny,
+    get_proper_type,
+)
+
+if TYPE_CHECKING:
+    from mypy.infer import ArgumentInferContext
+
+
+def map_actuals_to_formals(
+    actual_kinds: list[nodes.ArgKind],
+    actual_names: Sequence[str | None] | None,
+    formal_kinds: list[nodes.ArgKind],
+    formal_names: Sequence[str | None],
+    actual_arg_type: Callable[[int], Type],
+) -> list[list[int]]:
+    """Calculate mapping between actual (caller) args and formals.
+
+    The result contains a list of caller argument indexes mapping to each
+    callee argument index, indexed by callee index.
+
+    The caller_arg_type argument should evaluate to the type of the actual
+    argument type with the given index.
+    """
+    nformals = len(formal_kinds)
+    formal_to_actual: list[list[int]] = [[] for i in range(nformals)]
+    ambiguous_actual_kwargs: list[int] = []
+    fi = 0
+    for ai, actual_kind in enumerate(actual_kinds):
+        if actual_kind == nodes.ARG_POS:
+            if fi < nformals:
+                if not formal_kinds[fi].is_star():
+                    formal_to_actual[fi].append(ai)
+                    fi += 1
+                elif formal_kinds[fi] == nodes.ARG_STAR:
+                    formal_to_actual[fi].append(ai)
+        elif actual_kind == nodes.ARG_STAR:
+            # We need to know the actual type to map varargs.
+            actualt = get_proper_type(actual_arg_type(ai))
+            if isinstance(actualt, TupleType):
+                # A tuple actual maps to a fixed number of formals.
+                for _ in range(len(actualt.items)):
+                    if fi < nformals:
+                        if formal_kinds[fi] != nodes.ARG_STAR2:
+                            formal_to_actual[fi].append(ai)
+                        else:
+                            break
+                        if formal_kinds[fi] != nodes.ARG_STAR:
+                            fi += 1
+            else:
+                # Assume that it is an iterable (if it isn't, there will be
+                # an error later).
+                while fi < nformals:
+                    if formal_kinds[fi].is_named(star=True):
+                        break
+                    else:
+                        formal_to_actual[fi].append(ai)
+                    if formal_kinds[fi] == nodes.ARG_STAR:
+                        break
+                    fi += 1
+        elif actual_kind.is_named():
+            assert actual_names is not None, "Internal error: named kinds without names given"
+            name = actual_names[ai]
+            if name in formal_names:
+                formal_to_actual[formal_names.index(name)].append(ai)
+            elif nodes.ARG_STAR2 in formal_kinds:
+                formal_to_actual[formal_kinds.index(nodes.ARG_STAR2)].append(ai)
+        else:
+            assert actual_kind == nodes.ARG_STAR2
+            actualt = get_proper_type(actual_arg_type(ai))
+            if isinstance(actualt, TypedDictType):
+                for name in actualt.items:
+                    if name in formal_names:
+                        formal_to_actual[formal_names.index(name)].append(ai)
+                    elif nodes.ARG_STAR2 in formal_kinds:
+                        formal_to_actual[formal_kinds.index(nodes.ARG_STAR2)].append(ai)
+            else:
+                # We don't exactly know which **kwargs are provided by the
+                # caller, so we'll defer until all the other unambiguous
+                # actuals have been processed
+                ambiguous_actual_kwargs.append(ai)
+
+    if ambiguous_actual_kwargs:
+        # Assume the ambiguous kwargs will fill the remaining arguments.
+        #
+        # TODO: If there are also tuple varargs, we might be missing some potential
+        #       matches if the tuple was short enough to not match everything.
+        unmatched_formals = [
+            fi
+            for fi in range(nformals)
+            if (
+                formal_names[fi]
+                and (
+                    not formal_to_actual[fi]
+                    or actual_kinds[formal_to_actual[fi][0]] == nodes.ARG_STAR
+                )
+                and formal_kinds[fi] != nodes.ARG_STAR
+            )
+            or formal_kinds[fi] == nodes.ARG_STAR2
+        ]
+        for ai in ambiguous_actual_kwargs:
+            for fi in unmatched_formals:
+                formal_to_actual[fi].append(ai)
+
+    return formal_to_actual
+
+
+def map_formals_to_actuals(
+    actual_kinds: list[nodes.ArgKind],
+    actual_names: Sequence[str | None] | None,
+    formal_kinds: list[nodes.ArgKind],
+    formal_names: list[str | None],
+    actual_arg_type: Callable[[int], Type],
+) -> list[list[int]]:
+    """Calculate the reverse mapping of map_actuals_to_formals."""
+    formal_to_actual = map_actuals_to_formals(
+        actual_kinds, actual_names, formal_kinds, formal_names, actual_arg_type
+    )
+    # Now reverse the mapping.
+    actual_to_formal: list[list[int]] = [[] for _ in actual_kinds]
+    for formal, actuals in enumerate(formal_to_actual):
+        for actual in actuals:
+            actual_to_formal[actual].append(formal)
+    return actual_to_formal
+
+
+class ArgTypeExpander:
+    """Utility class for mapping actual argument types to formal arguments.
+
+    One of the main responsibilities is to expand caller tuple *args and TypedDict
+    **kwargs, and to keep track of which tuple/TypedDict items have already been
+    consumed.
+
+    Example:
+
+       def f(x: int, *args: str) -> None: ...
+       f(*(1, 'x', 1.1))
+
+    We'd call expand_actual_type three times:
+
+      1. The first call would provide 'int' as the actual type of 'x' (from '1').
+      2. The second call would provide 'str' as one of the actual types for '*args'.
+      2. The third call would provide 'float' as one of the actual types for '*args'.
+
+    A single instance can process all the arguments for a single call. Each call
+    needs a separate instance since instances have per-call state.
+    """
+
+    def __init__(self, context: ArgumentInferContext) -> None:
+        # Next tuple *args index to use.
+        self.tuple_index = 0
+        # Keyword arguments in TypedDict **kwargs used.
+        self.kwargs_used: set[str] = set()
+        # Type context for `*` and `**` arg kinds.
+        self.context = context
+
+    def expand_actual_type(
+        self,
+        actual_type: Type,
+        actual_kind: nodes.ArgKind,
+        formal_name: str | None,
+        formal_kind: nodes.ArgKind,
+    ) -> Type:
+        """Return the actual (caller) type(s) of a formal argument with the given kinds.
+
+        If the actual argument is a tuple *args, return the next individual tuple item that
+        maps to the formal arg.
+
+        If the actual argument is a TypedDict **kwargs, return the next matching typed dict
+        value type based on formal argument name and kind.
+
+        This is supposed to be called for each formal, in order. Call multiple times per
+        formal if multiple actuals map to a formal.
+        """
+        original_actual = actual_type
+        actual_type = get_proper_type(actual_type)
+        if actual_kind == nodes.ARG_STAR:
+            if isinstance(actual_type, Instance) and actual_type.args:
+                from mypy.subtypes import is_subtype
+
+                if is_subtype(actual_type, self.context.iterable_type):
+                    return map_instance_to_supertype(
+                        actual_type, self.context.iterable_type.type
+                    ).args[0]
+                else:
+                    # We cannot properly unpack anything other
+                    # than `Iterable` type with `*`.
+                    # Just return `Any`, other parts of code would raise
+                    # a different error for improper use.
+                    return AnyType(TypeOfAny.from_error)
+            elif isinstance(actual_type, TupleType):
+                # Get the next tuple item of a tuple *arg.
+                if self.tuple_index >= len(actual_type.items):
+                    # Exhausted a tuple -- continue to the next *args.
+                    self.tuple_index = 1
+                else:
+                    self.tuple_index += 1
+                return actual_type.items[self.tuple_index - 1]
+            elif isinstance(actual_type, ParamSpecType):
+                # ParamSpec is valid in *args but it can't be unpacked.
+                return actual_type
+            else:
+                return AnyType(TypeOfAny.from_error)
+        elif actual_kind == nodes.ARG_STAR2:
+            from mypy.subtypes import is_subtype
+
+            if isinstance(actual_type, TypedDictType):
+                if formal_kind != nodes.ARG_STAR2 and formal_name in actual_type.items:
+                    # Lookup type based on keyword argument name.
+                    assert formal_name is not None
+                else:
+                    # Pick an arbitrary item if no specified keyword is expected.
+                    formal_name = (set(actual_type.items.keys()) - self.kwargs_used).pop()
+                self.kwargs_used.add(formal_name)
+                return actual_type.items[formal_name]
+            elif (
+                isinstance(actual_type, Instance)
+                and len(actual_type.args) > 1
+                and is_subtype(actual_type, self.context.mapping_type)
+            ):
+                # Only `Mapping` type can be unpacked with `**`.
+                # Other types will produce an error somewhere else.
+                return map_instance_to_supertype(actual_type, self.context.mapping_type.type).args[
+                    1
+                ]
+            elif isinstance(actual_type, ParamSpecType):
+                # ParamSpec is valid in **kwargs but it can't be unpacked.
+                return actual_type
+            else:
+                return AnyType(TypeOfAny.from_error)
+        else:
+            # No translation for other kinds -- 1:1 mapping.
+            return original_actual

venv/lib/python3.12/site-packages/mypy/binder.py

@@ -0,0 +1,455 @@
+from __future__ import annotations
+
+from collections import defaultdict
+from contextlib import contextmanager
+from typing import DefaultDict, Iterator, List, Optional, Tuple, Union, cast
+from typing_extensions import TypeAlias as _TypeAlias
+
+from mypy.erasetype import remove_instance_last_known_values
+from mypy.join import join_simple
+from mypy.literals import Key, literal, literal_hash, subkeys
+from mypy.nodes import Expression, IndexExpr, MemberExpr, NameExpr, RefExpr, TypeInfo, Var
+from mypy.subtypes import is_same_type, is_subtype
+from mypy.types import (
+    AnyType,
+    NoneType,
+    PartialType,
+    Type,
+    TypeOfAny,
+    TypeType,
+    UnionType,
+    get_proper_type,
+)
+from mypy.typevars import fill_typevars_with_any
+
+BindableExpression: _TypeAlias = Union[IndexExpr, MemberExpr, NameExpr]
+
+
+class Frame:
+    """A Frame represents a specific point in the execution of a program.
+    It carries information about the current types of expressions at
+    that point, arising either from assignments to those expressions
+    or the result of isinstance checks. It also records whether it is
+    possible to reach that point at all.
+
+    This information is not copied into a new Frame when it is pushed
+    onto the stack, so a given Frame only has information about types
+    that were assigned in that frame.
+    """
+
+    def __init__(self, id: int, conditional_frame: bool = False) -> None:
+        self.id = id
+        self.types: dict[Key, Type] = {}
+        self.unreachable = False
+        self.conditional_frame = conditional_frame
+        self.suppress_unreachable_warnings = False
+
+    def __repr__(self) -> str:
+        return f"Frame({self.id}, {self.types}, {self.unreachable}, {self.conditional_frame})"
+
+
+Assigns = DefaultDict[Expression, List[Tuple[Type, Optional[Type]]]]
+
+
+class ConditionalTypeBinder:
+    """Keep track of conditional types of variables.
+
+    NB: Variables are tracked by literal expression, so it is possible
+    to confuse the binder; for example,
+
+    ```
+    class A:
+        a: Union[int, str] = None
+    x = A()
+    lst = [x]
+    reveal_type(x.a)      # Union[int, str]
+    x.a = 1
+    reveal_type(x.a)      # int
+    reveal_type(lst[0].a) # Union[int, str]
+    lst[0].a = 'a'
+    reveal_type(x.a)      # int
+    reveal_type(lst[0].a) # str
+    ```
+    """
+
+    # Stored assignments for situations with tuple/list lvalue and rvalue of union type.
+    # This maps an expression to a list of bound types for every item in the union type.
+    type_assignments: Assigns | None = None
+
+    def __init__(self) -> None:
+        self.next_id = 1
+
+        # The stack of frames currently used.  These map
+        # literal_hash(expr) -- literals like 'foo.bar' --
+        # to types. The last element of this list is the
+        # top-most, current frame. Each earlier element
+        # records the state as of when that frame was last
+        # on top of the stack.
+        self.frames = [Frame(self._get_id())]
+
+        # For frames higher in the stack, we record the set of
+        # Frames that can escape there, either by falling off
+        # the end of the frame or by a loop control construct
+        # or raised exception. The last element of self.frames
+        # has no corresponding element in this list.
+        self.options_on_return: list[list[Frame]] = []
+
+        # Maps literal_hash(expr) to get_declaration(expr)
+        # for every expr stored in the binder
+        self.declarations: dict[Key, Type | None] = {}
+        # Set of other keys to invalidate if a key is changed, e.g. x -> {x.a, x[0]}
+        # Whenever a new key (e.g. x.a.b) is added, we update this
+        self.dependencies: dict[Key, set[Key]] = {}
+
+        # Whether the last pop changed the newly top frame on exit
+        self.last_pop_changed = False
+
+        self.try_frames: set[int] = set()
+        self.break_frames: list[int] = []
+        self.continue_frames: list[int] = []
+
+    def _get_id(self) -> int:
+        self.next_id += 1
+        return self.next_id
+
+    def _add_dependencies(self, key: Key, value: Key | None = None) -> None:
+        if value is None:
+            value = key
+        else:
+            self.dependencies.setdefault(key, set()).add(value)
+        for elt in subkeys(key):
+            self._add_dependencies(elt, value)
+
+    def push_frame(self, conditional_frame: bool = False) -> Frame:
+        """Push a new frame into the binder."""
+        f = Frame(self._get_id(), conditional_frame)
+        self.frames.append(f)
+        self.options_on_return.append([])
+        return f
+
+    def _put(self, key: Key, type: Type, index: int = -1) -> None:
+        self.frames[index].types[key] = type
+
+    def _get(self, key: Key, index: int = -1) -> Type | None:
+        if index < 0:
+            index += len(self.frames)
+        for i in range(index, -1, -1):
+            if key in self.frames[i].types:
+                return self.frames[i].types[key]
+        return None
+
+    def put(self, expr: Expression, typ: Type) -> None:
+        if not isinstance(expr, (IndexExpr, MemberExpr, NameExpr)):
+            return
+        if not literal(expr):
+            return
+        key = literal_hash(expr)
+        assert key is not None, "Internal error: binder tried to put non-literal"
+        if key not in self.declarations:
+            self.declarations[key] = get_declaration(expr)
+            self._add_dependencies(key)
+        self._put(key, typ)
+
+    def unreachable(self) -> None:
+        self.frames[-1].unreachable = True
+
+    def suppress_unreachable_warnings(self) -> None:
+        self.frames[-1].suppress_unreachable_warnings = True
+
+    def get(self, expr: Expression) -> Type | None:
+        key = literal_hash(expr)
+        assert key is not None, "Internal error: binder tried to get non-literal"
+        return self._get(key)
+
+    def is_unreachable(self) -> bool:
+        # TODO: Copy the value of unreachable into new frames to avoid
+        # this traversal on every statement?
+        return any(f.unreachable for f in self.frames)
+
+    def is_unreachable_warning_suppressed(self) -> bool:
+        return any(f.suppress_unreachable_warnings for f in self.frames)
+
+    def cleanse(self, expr: Expression) -> None:
+        """Remove all references to a Node from the binder."""
+        key = literal_hash(expr)
+        assert key is not None, "Internal error: binder tried cleanse non-literal"
+        self._cleanse_key(key)
+
+    def _cleanse_key(self, key: Key) -> None:
+        """Remove all references to a key from the binder."""
+        for frame in self.frames:
+            if key in frame.types:
+                del frame.types[key]
+
+    def update_from_options(self, frames: list[Frame]) -> bool:
+        """Update the frame to reflect that each key will be updated
+        as in one of the frames.  Return whether any item changes.
+
+        If a key is declared as AnyType, only update it if all the
+        options are the same.
+        """
+
+        frames = [f for f in frames if not f.unreachable]
+        changed = False
+        keys = {key for f in frames for key in f.types}
+
+        for key in keys:
+            current_value = self._get(key)
+            resulting_values = [f.types.get(key, current_value) for f in frames]
+            if any(x is None for x in resulting_values):
+                # We didn't know anything about key before
+                # (current_value must be None), and we still don't
+                # know anything about key in at least one possible frame.
+                continue
+
+            type = resulting_values[0]
+            assert type is not None
+            declaration_type = get_proper_type(self.declarations.get(key))
+            if isinstance(declaration_type, AnyType):
+                # At this point resulting values can't contain None, see continue above
+                if not all(is_same_type(type, cast(Type, t)) for t in resulting_values[1:]):
+                    type = AnyType(TypeOfAny.from_another_any, source_any=declaration_type)
+            else:
+                for other in resulting_values[1:]:
+                    assert other is not None
+                    type = join_simple(self.declarations[key], type, other)
+            if current_value is None or not is_same_type(type, current_value):
+                self._put(key, type)
+                changed = True
+
+        self.frames[-1].unreachable = not frames
+
+        return changed
+
+    def pop_frame(self, can_skip: bool, fall_through: int) -> Frame:
+        """Pop a frame and return it.
+
+        See frame_context() for documentation of fall_through.
+        """
+
+        if fall_through > 0:
+            self.allow_jump(-fall_through)
+
+        result = self.frames.pop()
+        options = self.options_on_return.pop()
+
+        if can_skip:
+            options.insert(0, self.frames[-1])
+
+        self.last_pop_changed = self.update_from_options(options)
+
+        return result
+
+    @contextmanager
+    def accumulate_type_assignments(self) -> Iterator[Assigns]:
+        """Push a new map to collect assigned types in multiassign from union.
+
+        If this map is not None, actual binding is deferred until all items in
+        the union are processed (a union of collected items is later bound
+        manually by the caller).
+        """
+        old_assignments = None
+        if self.type_assignments is not None:
+            old_assignments = self.type_assignments
+        self.type_assignments = defaultdict(list)
+        yield self.type_assignments
+        self.type_assignments = old_assignments
+
+    def assign_type(
+        self, expr: Expression, type: Type, declared_type: Type | None, restrict_any: bool = False
+    ) -> None:
+        # We should erase last known value in binder, because if we are using it,
+        # it means that the target is not final, and therefore can't hold a literal.
+        type = remove_instance_last_known_values(type)
+
+        if self.type_assignments is not None:
+            # We are in a multiassign from union, defer the actual binding,
+            # just collect the types.
+            self.type_assignments[expr].append((type, declared_type))
+            return
+        if not isinstance(expr, (IndexExpr, MemberExpr, NameExpr)):
+            return None
+        if not literal(expr):
+            return
+        self.invalidate_dependencies(expr)
+
+        if declared_type is None:
+            # Not sure why this happens.  It seems to mainly happen in
+            # member initialization.
+            return
+        if not is_subtype(type, declared_type):
+            # Pretty sure this is only happens when there's a type error.
+
+            # Ideally this function wouldn't be called if the
+            # expression has a type error, though -- do other kinds of
+            # errors cause this function to get called at invalid
+            # times?
+            return
+
+        p_declared = get_proper_type(declared_type)
+        p_type = get_proper_type(type)
+        enclosing_type = get_proper_type(self.most_recent_enclosing_type(expr, type))
+        if isinstance(enclosing_type, AnyType) and not restrict_any:
+            # If x is Any and y is int, after x = y we do not infer that x is int.
+            # This could be changed.
+            # Instead, since we narrowed type from Any in a recent frame (probably an
+            # isinstance check), but now it is reassigned, we broaden back
+            # to Any (which is the most recent enclosing type)
+            self.put(expr, enclosing_type)
+        # As a special case, when assigning Any to a variable with a
+        # declared Optional type that has been narrowed to None,
+        # replace all the Nones in the declared Union type with Any.
+        # This overrides the normal behavior of ignoring Any assignments to variables
+        # in order to prevent false positives.
+        # (See discussion in #3526)
+        elif (
+            isinstance(p_type, AnyType)
+            and isinstance(p_declared, UnionType)
+            and any(isinstance(get_proper_type(item), NoneType) for item in p_declared.items)
+            and isinstance(
+                get_proper_type(self.most_recent_enclosing_type(expr, NoneType())), NoneType
+            )
+        ):
+            # Replace any Nones in the union type with Any
+            new_items = [
+                type if isinstance(get_proper_type(item), NoneType) else item
+                for item in p_declared.items
+            ]
+            self.put(expr, UnionType(new_items))
+        elif isinstance(p_type, AnyType) and not (
+            isinstance(p_declared, UnionType)
+            and any(isinstance(get_proper_type(item), AnyType) for item in p_declared.items)
+        ):
+            # Assigning an Any value doesn't affect the type to avoid false negatives, unless
+            # there is an Any item in a declared union type.
+            self.put(expr, declared_type)
+        else:
+            self.put(expr, type)
+
+        for i in self.try_frames:
+            # XXX This should probably not copy the entire frame, but
+            # just copy this variable into a single stored frame.
+            self.allow_jump(i)
+
+    def invalidate_dependencies(self, expr: BindableExpression) -> None:
+        """Invalidate knowledge of types that include expr, but not expr itself.
+
+        For example, when expr is foo.bar, invalidate foo.bar.baz.
+
+        It is overly conservative: it invalidates globally, including
+        in code paths unreachable from here.
+        """
+        key = literal_hash(expr)
+        assert key is not None
+        for dep in self.dependencies.get(key, set()):
+            self._cleanse_key(dep)
+
+    def most_recent_enclosing_type(self, expr: BindableExpression, type: Type) -> Type | None:
+        type = get_proper_type(type)
+        if isinstance(type, AnyType):
+            return get_declaration(expr)
+        key = literal_hash(expr)
+        assert key is not None
+        enclosers = [get_declaration(expr)] + [
+            f.types[key] for f in self.frames if key in f.types and is_subtype(type, f.types[key])
+        ]
+        return enclosers[-1]
+
+    def allow_jump(self, index: int) -> None:
+        # self.frames and self.options_on_return have different lengths
+        # so make sure the index is positive
+        if index < 0:
+            index += len(self.options_on_return)
+        frame = Frame(self._get_id())
+        for f in self.frames[index + 1 :]:
+            frame.types.update(f.types)
+            if f.unreachable:
+                frame.unreachable = True
+        self.options_on_return[index].append(frame)
+
+    def handle_break(self) -> None:
+        self.allow_jump(self.break_frames[-1])
+        self.unreachable()
+
+    def handle_continue(self) -> None:
+        self.allow_jump(self.continue_frames[-1])
+        self.unreachable()
+
+    @contextmanager
+    def frame_context(
+        self,
+        *,
+        can_skip: bool,
+        fall_through: int = 1,
+        break_frame: int = 0,
+        continue_frame: int = 0,
+        conditional_frame: bool = False,
+        try_frame: bool = False,
+    ) -> Iterator[Frame]:
+        """Return a context manager that pushes/pops frames on enter/exit.
+
+        If can_skip is True, control flow is allowed to bypass the
+        newly-created frame.
+
+        If fall_through > 0, then it will allow control flow that
+        falls off the end of the frame to escape to its ancestor
+        `fall_through` levels higher. Otherwise control flow ends
+        at the end of the frame.
+
+        If break_frame > 0, then 'break' statements within this frame
+        will jump out to the frame break_frame levels higher than the
+        frame created by this call to frame_context. Similarly for
+        continue_frame and 'continue' statements.
+
+        If try_frame is true, then execution is allowed to jump at any
+        point within the newly created frame (or its descendants) to
+        its parent (i.e., to the frame that was on top before this
+        call to frame_context).
+
+        After the context manager exits, self.last_pop_changed indicates
+        whether any types changed in the newly-topmost frame as a result
+        of popping this frame.
+        """
+        assert len(self.frames) > 1
+
+        if break_frame:
+            self.break_frames.append(len(self.frames) - break_frame)
+        if continue_frame:
+            self.continue_frames.append(len(self.frames) - continue_frame)
+        if try_frame:
+            self.try_frames.add(len(self.frames) - 1)
+
+        new_frame = self.push_frame(conditional_frame)
+        if try_frame:
+            # An exception may occur immediately
+            self.allow_jump(-1)
+        yield new_frame
+        self.pop_frame(can_skip, fall_through)
+
+        if break_frame:
+            self.break_frames.pop()
+        if continue_frame:
+            self.continue_frames.pop()
+        if try_frame:
+            self.try_frames.remove(len(self.frames) - 1)
+
+    @contextmanager
+    def top_frame_context(self) -> Iterator[Frame]:
+        """A variant of frame_context for use at the top level of
+        a namespace (module, function, or class).
+        """
+        assert len(self.frames) == 1
+        yield self.push_frame()
+        self.pop_frame(True, 0)
+        assert len(self.frames) == 1
+
+
+def get_declaration(expr: BindableExpression) -> Type | None:
+    if isinstance(expr, RefExpr):
+        if isinstance(expr.node, Var):
+            type = expr.node.type
+            if not isinstance(get_proper_type(type), PartialType):
+                return type
+        elif isinstance(expr.node, TypeInfo):
+            return TypeType(fill_typevars_with_any(expr.node))
+    return None

venv/lib/python3.12/site-packages/mypy/bogus_type.py

@@ -0,0 +1,27 @@
+"""A Bogus[T] type alias for marking when we subvert the type system
+
+We need this for compiling with mypyc, which inserts runtime
+typechecks that cause problems when we subvert the type system. So
+when compiling with mypyc, we turn those places into Any, while
+keeping the types around for normal typechecks.
+
+Since this causes the runtime types to be Any, this is best used
+in places where efficient access to properties is not important.
+For those cases some other technique should be used.
+"""
+
+from __future__ import annotations
+
+from typing import Any, TypeVar
+
+from mypy_extensions import FlexibleAlias
+
+T = TypeVar("T")
+
+# This won't ever be true at runtime, but we consider it true during
+# mypyc compilations.
+MYPYC = False
+if MYPYC:
+    Bogus = FlexibleAlias[T, Any]
+else:
+    Bogus = FlexibleAlias[T, T]

venv/lib/python3.12/site-packages/mypy/checkpattern.py

@@ -0,0 +1,721 @@
+"""Pattern checker. This file is conceptually part of TypeChecker."""
+
+from __future__ import annotations
+
+from collections import defaultdict
+from typing import Final, NamedTuple
+
+import mypy.checker
+from mypy import message_registry
+from mypy.checkmember import analyze_member_access
+from mypy.expandtype import expand_type_by_instance
+from mypy.join import join_types
+from mypy.literals import literal_hash
+from mypy.maptype import map_instance_to_supertype
+from mypy.meet import narrow_declared_type
+from mypy.messages import MessageBuilder
+from mypy.nodes import ARG_POS, Context, Expression, NameExpr, TypeAlias, TypeInfo, Var
+from mypy.options import Options
+from mypy.patterns import (
+    AsPattern,
+    ClassPattern,
+    MappingPattern,
+    OrPattern,
+    Pattern,
+    SequencePattern,
+    SingletonPattern,
+    StarredPattern,
+    ValuePattern,
+)
+from mypy.plugin import Plugin
+from mypy.subtypes import is_subtype
+from mypy.typeops import (
+    coerce_to_literal,
+    make_simplified_union,
+    try_getting_str_literals_from_type,
+    tuple_fallback,
+)
+from mypy.types import (
+    AnyType,
+    Instance,
+    LiteralType,
+    NoneType,
+    ProperType,
+    TupleType,
+    Type,
+    TypedDictType,
+    TypeOfAny,
+    UninhabitedType,
+    UnionType,
+    get_proper_type,
+)
+from mypy.typevars import fill_typevars
+from mypy.visitor import PatternVisitor
+
+self_match_type_names: Final = [
+    "builtins.bool",
+    "builtins.bytearray",
+    "builtins.bytes",
+    "builtins.dict",
+    "builtins.float",
+    "builtins.frozenset",
+    "builtins.int",
+    "builtins.list",
+    "builtins.set",
+    "builtins.str",
+    "builtins.tuple",
+]
+
+non_sequence_match_type_names: Final = ["builtins.str", "builtins.bytes", "builtins.bytearray"]
+
+
+# For every Pattern a PatternType can be calculated. This requires recursively calculating
+# the PatternTypes of the sub-patterns first.
+# Using the data in the PatternType the match subject and captured names can be narrowed/inferred.
+class PatternType(NamedTuple):
+    type: Type  # The type the match subject can be narrowed to
+    rest_type: Type  # The remaining type if the pattern didn't match
+    captures: dict[Expression, Type]  # The variables captured by the pattern
+
+
+class PatternChecker(PatternVisitor[PatternType]):
+    """Pattern checker.
+
+    This class checks if a pattern can match a type, what the type can be narrowed to, and what
+    type capture patterns should be inferred as.
+    """
+
+    # Some services are provided by a TypeChecker instance.
+    chk: mypy.checker.TypeChecker
+    # This is shared with TypeChecker, but stored also here for convenience.
+    msg: MessageBuilder
+    # Currently unused
+    plugin: Plugin
+    # The expression being matched against the pattern
+    subject: Expression
+
+    subject_type: Type
+    # Type of the subject to check the (sub)pattern against
+    type_context: list[Type]
+    # Types that match against self instead of their __match_args__ if used as a class pattern
+    # Filled in from self_match_type_names
+    self_match_types: list[Type]
+    # Types that are sequences, but don't match sequence patterns. Filled in from
+    # non_sequence_match_type_names
+    non_sequence_match_types: list[Type]
+
+    options: Options
+
+    def __init__(
+        self, chk: mypy.checker.TypeChecker, msg: MessageBuilder, plugin: Plugin, options: Options
+    ) -> None:
+        self.chk = chk
+        self.msg = msg
+        self.plugin = plugin
+
+        self.type_context = []
+        self.self_match_types = self.generate_types_from_names(self_match_type_names)
+        self.non_sequence_match_types = self.generate_types_from_names(
+            non_sequence_match_type_names
+        )
+        self.options = options
+
+    def accept(self, o: Pattern, type_context: Type) -> PatternType:
+        self.type_context.append(type_context)
+        result = o.accept(self)
+        self.type_context.pop()
+
+        return result
+
+    def visit_as_pattern(self, o: AsPattern) -> PatternType:
+        current_type = self.type_context[-1]
+        if o.pattern is not None:
+            pattern_type = self.accept(o.pattern, current_type)
+            typ, rest_type, type_map = pattern_type
+        else:
+            typ, rest_type, type_map = current_type, UninhabitedType(), {}
+
+        if not is_uninhabited(typ) and o.name is not None:
+            typ, _ = self.chk.conditional_types_with_intersection(
+                current_type, [get_type_range(typ)], o, default=current_type
+            )
+            if not is_uninhabited(typ):
+                type_map[o.name] = typ
+
+        return PatternType(typ, rest_type, type_map)
+
+    def visit_or_pattern(self, o: OrPattern) -> PatternType:
+        current_type = self.type_context[-1]
+
+        #
+        # Check all the subpatterns
+        #
+        pattern_types = []
+        for pattern in o.patterns:
+            pattern_type = self.accept(pattern, current_type)
+            pattern_types.append(pattern_type)
+            current_type = pattern_type.rest_type
+
+        #
+        # Collect the final type
+        #
+        types = []
+        for pattern_type in pattern_types:
+            if not is_uninhabited(pattern_type.type):
+                types.append(pattern_type.type)
+
+        #
+        # Check the capture types
+        #
+        capture_types: dict[Var, list[tuple[Expression, Type]]] = defaultdict(list)
+        # Collect captures from the first subpattern
+        for expr, typ in pattern_types[0].captures.items():
+            node = get_var(expr)
+            capture_types[node].append((expr, typ))
+
+        # Check if other subpatterns capture the same names
+        for i, pattern_type in enumerate(pattern_types[1:]):
+            vars = {get_var(expr) for expr, _ in pattern_type.captures.items()}
+            if capture_types.keys() != vars:
+                self.msg.fail(message_registry.OR_PATTERN_ALTERNATIVE_NAMES, o.patterns[i])
+            for expr, typ in pattern_type.captures.items():
+                node = get_var(expr)
+                capture_types[node].append((expr, typ))
+
+        captures: dict[Expression, Type] = {}
+        for var, capture_list in capture_types.items():
+            typ = UninhabitedType()
+            for _, other in capture_list:
+                typ = join_types(typ, other)
+
+            captures[capture_list[0][0]] = typ
+
+        union_type = make_simplified_union(types)
+        return PatternType(union_type, current_type, captures)
+
+    def visit_value_pattern(self, o: ValuePattern) -> PatternType:
+        current_type = self.type_context[-1]
+        typ = self.chk.expr_checker.accept(o.expr)
+        typ = coerce_to_literal(typ)
+        narrowed_type, rest_type = self.chk.conditional_types_with_intersection(
+            current_type, [get_type_range(typ)], o, default=current_type
+        )
+        if not isinstance(get_proper_type(narrowed_type), (LiteralType, UninhabitedType)):
+            return PatternType(narrowed_type, UnionType.make_union([narrowed_type, rest_type]), {})
+        return PatternType(narrowed_type, rest_type, {})
+
+    def visit_singleton_pattern(self, o: SingletonPattern) -> PatternType:
+        current_type = self.type_context[-1]
+        value: bool | None = o.value
+        if isinstance(value, bool):
+            typ = self.chk.expr_checker.infer_literal_expr_type(value, "builtins.bool")
+        elif value is None:
+            typ = NoneType()
+        else:
+            assert False
+
+        narrowed_type, rest_type = self.chk.conditional_types_with_intersection(
+            current_type, [get_type_range(typ)], o, default=current_type
+        )
+        return PatternType(narrowed_type, rest_type, {})
+
+    def visit_sequence_pattern(self, o: SequencePattern) -> PatternType:
+        #
+        # check for existence of a starred pattern
+        #
+        current_type = get_proper_type(self.type_context[-1])
+        if not self.can_match_sequence(current_type):
+            return self.early_non_match()
+        star_positions = [i for i, p in enumerate(o.patterns) if isinstance(p, StarredPattern)]
+        star_position: int | None = None
+        if len(star_positions) == 1:
+            star_position = star_positions[0]
+        elif len(star_positions) >= 2:
+            assert False, "Parser should prevent multiple starred patterns"
+        required_patterns = len(o.patterns)
+        if star_position is not None:
+            required_patterns -= 1
+
+        #
+        # get inner types of original type
+        #
+        if isinstance(current_type, TupleType):
+            inner_types = current_type.items
+            size_diff = len(inner_types) - required_patterns
+            if size_diff < 0:
+                return self.early_non_match()
+            elif size_diff > 0 and star_position is None:
+                return self.early_non_match()
+        else:
+            inner_type = self.get_sequence_type(current_type, o)
+            if inner_type is None:
+                inner_type = self.chk.named_type("builtins.object")
+            inner_types = [inner_type] * len(o.patterns)
+
+        #
+        # match inner patterns
+        #
+        contracted_new_inner_types: list[Type] = []
+        contracted_rest_inner_types: list[Type] = []
+        captures: dict[Expression, Type] = {}
+
+        contracted_inner_types = self.contract_starred_pattern_types(
+            inner_types, star_position, required_patterns
+        )
+        for p, t in zip(o.patterns, contracted_inner_types):
+            pattern_type = self.accept(p, t)
+            typ, rest, type_map = pattern_type
+            contracted_new_inner_types.append(typ)
+            contracted_rest_inner_types.append(rest)
+            self.update_type_map(captures, type_map)
+
+        new_inner_types = self.expand_starred_pattern_types(
+            contracted_new_inner_types, star_position, len(inner_types)
+        )
+        rest_inner_types = self.expand_starred_pattern_types(
+            contracted_rest_inner_types, star_position, len(inner_types)
+        )
+
+        #
+        # Calculate new type
+        #
+        new_type: Type
+        rest_type: Type = current_type
+        if isinstance(current_type, TupleType):
+            narrowed_inner_types = []
+            inner_rest_types = []
+            for inner_type, new_inner_type in zip(inner_types, new_inner_types):
+                (
+                    narrowed_inner_type,
+                    inner_rest_type,
+                ) = self.chk.conditional_types_with_intersection(
+                    new_inner_type, [get_type_range(inner_type)], o, default=new_inner_type
+                )
+                narrowed_inner_types.append(narrowed_inner_type)
+                inner_rest_types.append(inner_rest_type)
+            if all(not is_uninhabited(typ) for typ in narrowed_inner_types):
+                new_type = TupleType(narrowed_inner_types, current_type.partial_fallback)
+            else:
+                new_type = UninhabitedType()
+
+            if all(is_uninhabited(typ) for typ in inner_rest_types):
+                # All subpatterns always match, so we can apply negative narrowing
+                rest_type = TupleType(rest_inner_types, current_type.partial_fallback)
+        else:
+            new_inner_type = UninhabitedType()
+            for typ in new_inner_types:
+                new_inner_type = join_types(new_inner_type, typ)
+            new_type = self.construct_sequence_child(current_type, new_inner_type)
+            if is_subtype(new_type, current_type):
+                new_type, _ = self.chk.conditional_types_with_intersection(
+                    current_type, [get_type_range(new_type)], o, default=current_type
+                )
+            else:
+                new_type = current_type
+        return PatternType(new_type, rest_type, captures)
+
+    def get_sequence_type(self, t: Type, context: Context) -> Type | None:
+        t = get_proper_type(t)
+        if isinstance(t, AnyType):
+            return AnyType(TypeOfAny.from_another_any, t)
+        if isinstance(t, UnionType):
+            items = [self.get_sequence_type(item, context) for item in t.items]
+            not_none_items = [item for item in items if item is not None]
+            if not_none_items:
+                return make_simplified_union(not_none_items)
+            else:
+                return None
+
+        if self.chk.type_is_iterable(t) and isinstance(t, (Instance, TupleType)):
+            if isinstance(t, TupleType):
+                t = tuple_fallback(t)
+            return self.chk.iterable_item_type(t, context)
+        else:
+            return None
+
+    def contract_starred_pattern_types(
+        self, types: list[Type], star_pos: int | None, num_patterns: int
+    ) -> list[Type]:
+        """
+        Contracts a list of types in a sequence pattern depending on the position of a starred
+        capture pattern.
+
+        For example if the sequence pattern [a, *b, c] is matched against types [bool, int, str,
+        bytes] the contracted types are [bool, Union[int, str], bytes].
+
+        If star_pos in None the types are returned unchanged.
+        """
+        if star_pos is None:
+            return types
+        new_types = types[:star_pos]
+        star_length = len(types) - num_patterns
+        new_types.append(make_simplified_union(types[star_pos : star_pos + star_length]))
+        new_types += types[star_pos + star_length :]
+
+        return new_types
+
+    def expand_starred_pattern_types(
+        self, types: list[Type], star_pos: int | None, num_types: int
+    ) -> list[Type]:
+        """Undoes the contraction done by contract_starred_pattern_types.
+
+        For example if the sequence pattern is [a, *b, c] and types [bool, int, str] are extended
+        to length 4 the result is [bool, int, int, str].
+        """
+        if star_pos is None:
+            return types
+        new_types = types[:star_pos]
+        star_length = num_types - len(types) + 1
+        new_types += [types[star_pos]] * star_length
+        new_types += types[star_pos + 1 :]
+
+        return new_types
+
+    def visit_starred_pattern(self, o: StarredPattern) -> PatternType:
+        captures: dict[Expression, Type] = {}
+        if o.capture is not None:
+            list_type = self.chk.named_generic_type("builtins.list", [self.type_context[-1]])
+            captures[o.capture] = list_type
+        return PatternType(self.type_context[-1], UninhabitedType(), captures)
+
+    def visit_mapping_pattern(self, o: MappingPattern) -> PatternType:
+        current_type = get_proper_type(self.type_context[-1])
+        can_match = True
+        captures: dict[Expression, Type] = {}
+        for key, value in zip(o.keys, o.values):
+            inner_type = self.get_mapping_item_type(o, current_type, key)
+            if inner_type is None:
+                can_match = False
+                inner_type = self.chk.named_type("builtins.object")
+            pattern_type = self.accept(value, inner_type)
+            if is_uninhabited(pattern_type.type):
+                can_match = False
+            else:
+                self.update_type_map(captures, pattern_type.captures)
+
+        if o.rest is not None:
+            mapping = self.chk.named_type("typing.Mapping")
+            if is_subtype(current_type, mapping) and isinstance(current_type, Instance):
+                mapping_inst = map_instance_to_supertype(current_type, mapping.type)
+                dict_typeinfo = self.chk.lookup_typeinfo("builtins.dict")
+                rest_type = Instance(dict_typeinfo, mapping_inst.args)
+            else:
+                object_type = self.chk.named_type("builtins.object")
+                rest_type = self.chk.named_generic_type(
+                    "builtins.dict", [object_type, object_type]
+                )
+
+            captures[o.rest] = rest_type
+
+        if can_match:
+            # We can't narrow the type here, as Mapping key is invariant.
+            new_type = self.type_context[-1]
+        else:
+            new_type = UninhabitedType()
+        return PatternType(new_type, current_type, captures)
+
+    def get_mapping_item_type(
+        self, pattern: MappingPattern, mapping_type: Type, key: Expression
+    ) -> Type | None:
+        mapping_type = get_proper_type(mapping_type)
+        if isinstance(mapping_type, TypedDictType):
+            with self.msg.filter_errors() as local_errors:
+                result: Type | None = self.chk.expr_checker.visit_typeddict_index_expr(
+                    mapping_type, key
+                )
+                has_local_errors = local_errors.has_new_errors()
+            # If we can't determine the type statically fall back to treating it as a normal
+            # mapping
+            if has_local_errors:
+                with self.msg.filter_errors() as local_errors:
+                    result = self.get_simple_mapping_item_type(pattern, mapping_type, key)
+
+                    if local_errors.has_new_errors():
+                        result = None
+        else:
+            with self.msg.filter_errors():
+                result = self.get_simple_mapping_item_type(pattern, mapping_type, key)
+        return result
+
+    def get_simple_mapping_item_type(
+        self, pattern: MappingPattern, mapping_type: Type, key: Expression
+    ) -> Type:
+        result, _ = self.chk.expr_checker.check_method_call_by_name(
+            "__getitem__", mapping_type, [key], [ARG_POS], pattern
+        )
+        return result
+
+    def visit_class_pattern(self, o: ClassPattern) -> PatternType:
+        current_type = get_proper_type(self.type_context[-1])
+
+        #
+        # Check class type
+        #
+        type_info = o.class_ref.node
+        if type_info is None:
+            return PatternType(AnyType(TypeOfAny.from_error), AnyType(TypeOfAny.from_error), {})
+        if isinstance(type_info, TypeAlias) and not type_info.no_args:
+            self.msg.fail(message_registry.CLASS_PATTERN_GENERIC_TYPE_ALIAS, o)
+            return self.early_non_match()
+        if isinstance(type_info, TypeInfo):
+            any_type = AnyType(TypeOfAny.implementation_artifact)
+            typ: Type = Instance(type_info, [any_type] * len(type_info.defn.type_vars))
+        elif isinstance(type_info, TypeAlias):
+            typ = type_info.target
+        else:
+            if isinstance(type_info, Var) and type_info.type is not None:
+                name = type_info.type.str_with_options(self.options)
+            else:
+                name = type_info.name
+            self.msg.fail(message_registry.CLASS_PATTERN_TYPE_REQUIRED.format(name), o)
+            return self.early_non_match()
+
+        new_type, rest_type = self.chk.conditional_types_with_intersection(
+            current_type, [get_type_range(typ)], o, default=current_type
+        )
+        if is_uninhabited(new_type):
+            return self.early_non_match()
+        # TODO: Do I need this?
+        narrowed_type = narrow_declared_type(current_type, new_type)
+
+        #
+        # Convert positional to keyword patterns
+        #
+        keyword_pairs: list[tuple[str | None, Pattern]] = []
+        match_arg_set: set[str] = set()
+
+        captures: dict[Expression, Type] = {}
+
+        if len(o.positionals) != 0:
+            if self.should_self_match(typ):
+                if len(o.positionals) > 1:
+                    self.msg.fail(message_registry.CLASS_PATTERN_TOO_MANY_POSITIONAL_ARGS, o)
+                pattern_type = self.accept(o.positionals[0], narrowed_type)
+                if not is_uninhabited(pattern_type.type):
+                    return PatternType(
+                        pattern_type.type,
+                        join_types(rest_type, pattern_type.rest_type),
+                        pattern_type.captures,
+                    )
+                captures = pattern_type.captures
+            else:
+                with self.msg.filter_errors() as local_errors:
+                    match_args_type = analyze_member_access(
+                        "__match_args__",
+                        typ,
+                        o,
+                        False,
+                        False,
+                        False,
+                        self.msg,
+                        original_type=typ,
+                        chk=self.chk,
+                    )
+                    has_local_errors = local_errors.has_new_errors()
+                if has_local_errors:
+                    self.msg.fail(
+                        message_registry.MISSING_MATCH_ARGS.format(
+                            typ.str_with_options(self.options)
+                        ),
+                        o,
+                    )
+                    return self.early_non_match()
+
+                proper_match_args_type = get_proper_type(match_args_type)
+                if isinstance(proper_match_args_type, TupleType):
+                    match_arg_names = get_match_arg_names(proper_match_args_type)
+
+                    if len(o.positionals) > len(match_arg_names):
+                        self.msg.fail(message_registry.CLASS_PATTERN_TOO_MANY_POSITIONAL_ARGS, o)
+                        return self.early_non_match()
+                else:
+                    match_arg_names = [None] * len(o.positionals)
+
+                for arg_name, pos in zip(match_arg_names, o.positionals):
+                    keyword_pairs.append((arg_name, pos))
+                    if arg_name is not None:
+                        match_arg_set.add(arg_name)
+
+        #
+        # Check for duplicate patterns
+        #
+        keyword_arg_set = set()
+        has_duplicates = False
+        for key, value in zip(o.keyword_keys, o.keyword_values):
+            keyword_pairs.append((key, value))
+            if key in match_arg_set:
+                self.msg.fail(
+                    message_registry.CLASS_PATTERN_KEYWORD_MATCHES_POSITIONAL.format(key), value
+                )
+                has_duplicates = True
+            elif key in keyword_arg_set:
+                self.msg.fail(
+                    message_registry.CLASS_PATTERN_DUPLICATE_KEYWORD_PATTERN.format(key), value
+                )
+                has_duplicates = True
+            keyword_arg_set.add(key)
+
+        if has_duplicates:
+            return self.early_non_match()
+
+        #
+        # Check keyword patterns
+        #
+        can_match = True
+        for keyword, pattern in keyword_pairs:
+            key_type: Type | None = None
+            with self.msg.filter_errors() as local_errors:
+                if keyword is not None:
+                    key_type = analyze_member_access(
+                        keyword,
+                        narrowed_type,
+                        pattern,
+                        False,
+                        False,
+                        False,
+                        self.msg,
+                        original_type=new_type,
+                        chk=self.chk,
+                    )
+                else:
+                    key_type = AnyType(TypeOfAny.from_error)
+                has_local_errors = local_errors.has_new_errors()
+            if has_local_errors or key_type is None:
+                key_type = AnyType(TypeOfAny.from_error)
+                self.msg.fail(
+                    message_registry.CLASS_PATTERN_UNKNOWN_KEYWORD.format(
+                        typ.str_with_options(self.options), keyword
+                    ),
+                    pattern,
+                )
+
+            inner_type, inner_rest_type, inner_captures = self.accept(pattern, key_type)
+            if is_uninhabited(inner_type):
+                can_match = False
+            else:
+                self.update_type_map(captures, inner_captures)
+                if not is_uninhabited(inner_rest_type):
+                    rest_type = current_type
+
+        if not can_match:
+            new_type = UninhabitedType()
+        return PatternType(new_type, rest_type, captures)
+
+    def should_self_match(self, typ: Type) -> bool:
+        typ = get_proper_type(typ)
+        if isinstance(typ, Instance) and typ.type.is_named_tuple:
+            return False
+        for other in self.self_match_types:
+            if is_subtype(typ, other):
+                return True
+        return False
+
+    def can_match_sequence(self, typ: ProperType) -> bool:
+        if isinstance(typ, UnionType):
+            return any(self.can_match_sequence(get_proper_type(item)) for item in typ.items)
+        for other in self.non_sequence_match_types:
+            # We have to ignore promotions, as memoryview should match, but bytes,
+            # which it can be promoted to, shouldn't
+            if is_subtype(typ, other, ignore_promotions=True):
+                return False
+        sequence = self.chk.named_type("typing.Sequence")
+        # If the static type is more general than sequence the actual type could still match
+        return is_subtype(typ, sequence) or is_subtype(sequence, typ)
+
+    def generate_types_from_names(self, type_names: list[str]) -> list[Type]:
+        types: list[Type] = []
+        for name in type_names:
+            try:
+                types.append(self.chk.named_type(name))
+            except KeyError as e:
+                # Some built in types are not defined in all test cases
+                if not name.startswith("builtins."):
+                    raise e
+        return types
+
+    def update_type_map(
+        self, original_type_map: dict[Expression, Type], extra_type_map: dict[Expression, Type]
+    ) -> None:
+        # Calculating this would not be needed if TypeMap directly used literal hashes instead of
+        # expressions, as suggested in the TODO above it's definition
+        already_captured = {literal_hash(expr) for expr in original_type_map}
+        for expr, typ in extra_type_map.items():
+            if literal_hash(expr) in already_captured:
+                node = get_var(expr)
+                self.msg.fail(
+                    message_registry.MULTIPLE_ASSIGNMENTS_IN_PATTERN.format(node.name), expr
+                )
+            else:
+                original_type_map[expr] = typ
+
+    def construct_sequence_child(self, outer_type: Type, inner_type: Type) -> Type:
+        """
+        If outer_type is a child class of typing.Sequence returns a new instance of
+        outer_type, that is a Sequence of inner_type. If outer_type is not a child class of
+        typing.Sequence just returns a Sequence of inner_type
+
+        For example:
+        construct_sequence_child(List[int], str) = List[str]
+
+        TODO: this doesn't make sense. For example if one has class S(Sequence[int], Generic[T])
+        or class T(Sequence[Tuple[T, T]]), there is no way any of those can map to Sequence[str].
+        """
+        proper_type = get_proper_type(outer_type)
+        if isinstance(proper_type, UnionType):
+            types = [
+                self.construct_sequence_child(item, inner_type)
+                for item in proper_type.items
+                if self.can_match_sequence(get_proper_type(item))
+            ]
+            return make_simplified_union(types)
+        sequence = self.chk.named_generic_type("typing.Sequence", [inner_type])
+        if is_subtype(outer_type, self.chk.named_type("typing.Sequence")):
+            proper_type = get_proper_type(outer_type)
+            if isinstance(proper_type, TupleType):
+                proper_type = tuple_fallback(proper_type)
+            assert isinstance(proper_type, Instance)
+            empty_type = fill_typevars(proper_type.type)
+            partial_type = expand_type_by_instance(empty_type, sequence)
+            return expand_type_by_instance(partial_type, proper_type)
+        else:
+            return sequence
+
+    def early_non_match(self) -> PatternType:
+        return PatternType(UninhabitedType(), self.type_context[-1], {})
+
+
+def get_match_arg_names(typ: TupleType) -> list[str | None]:
+    args: list[str | None] = []
+    for item in typ.items:
+        values = try_getting_str_literals_from_type(item)
+        if values is None or len(values) != 1:
+            args.append(None)
+        else:
+            args.append(values[0])
+    return args
+
+
+def get_var(expr: Expression) -> Var:
+    """
+    Warning: this in only true for expressions captured by a match statement.
+    Don't call it from anywhere else
+    """
+    assert isinstance(expr, NameExpr)
+    node = expr.node
+    assert isinstance(node, Var)
+    return node
+
+
+def get_type_range(typ: Type) -> mypy.checker.TypeRange:
+    typ = get_proper_type(typ)
+    if (
+        isinstance(typ, Instance)
+        and typ.last_known_value
+        and isinstance(typ.last_known_value.value, bool)
+    ):
+        typ = typ.last_known_value
+    return mypy.checker.TypeRange(typ, is_upper_bound=False)
+
+
+def is_uninhabited(typ: Type) -> bool:
+    return isinstance(get_proper_type(typ), UninhabitedType)

venv/lib/python3.12/site-packages/mypy/config_parser.py

@@ -0,0 +1,638 @@
+from __future__ import annotations
+
+import argparse
+import configparser
+import glob as fileglob
+import os
+import re
+import sys
+from io import StringIO
+
+from mypy.errorcodes import error_codes
+
+if sys.version_info >= (3, 11):
+    import tomllib
+else:
+    import tomli as tomllib
+
+from typing import (
+    Any,
+    Callable,
+    Dict,
+    Final,
+    Iterable,
+    List,
+    Mapping,
+    MutableMapping,
+    Sequence,
+    TextIO,
+    Tuple,
+    Union,
+)
+from typing_extensions import TypeAlias as _TypeAlias
+
+from mypy import defaults
+from mypy.options import PER_MODULE_OPTIONS, Options
+
+_CONFIG_VALUE_TYPES: _TypeAlias = Union[
+    str, bool, int, float, Dict[str, str], List[str], Tuple[int, int]
+]
+_INI_PARSER_CALLABLE: _TypeAlias = Callable[[Any], _CONFIG_VALUE_TYPES]
+
+
+def parse_version(v: str | float) -> tuple[int, int]:
+    m = re.match(r"\A(\d)\.(\d+)\Z", str(v))
+    if not m:
+        raise argparse.ArgumentTypeError(f"Invalid python version '{v}' (expected format: 'x.y')")
+    major, minor = int(m.group(1)), int(m.group(2))
+    if major == 2 and minor == 7:
+        pass  # Error raised elsewhere
+    elif major == 3:
+        if minor < defaults.PYTHON3_VERSION_MIN[1]:
+            msg = "Python 3.{} is not supported (must be {}.{} or higher)".format(
+                minor, *defaults.PYTHON3_VERSION_MIN
+            )
+
+            if isinstance(v, float):
+                msg += ". You may need to put quotes around your Python version"
+
+            raise argparse.ArgumentTypeError(msg)
+    else:
+        raise argparse.ArgumentTypeError(
+            f"Python major version '{major}' out of range (must be 3)"
+        )
+    return major, minor
+
+
+def try_split(v: str | Sequence[str], split_regex: str = "[,]") -> list[str]:
+    """Split and trim a str or list of str into a list of str"""
+    if isinstance(v, str):
+        return [p.strip() for p in re.split(split_regex, v)]
+
+    return [p.strip() for p in v]
+
+
+def validate_codes(codes: list[str]) -> list[str]:
+    invalid_codes = set(codes) - set(error_codes.keys())
+    if invalid_codes:
+        raise argparse.ArgumentTypeError(
+            f"Invalid error code(s): {', '.join(sorted(invalid_codes))}"
+        )
+    return codes
+
+
+def validate_package_allow_list(allow_list: list[str]) -> list[str]:
+    for p in allow_list:
+        msg = f"Invalid allow list entry: {p}"
+        if "*" in p:
+            raise argparse.ArgumentTypeError(
+                f"{msg} (entries are already prefixes so must not contain *)"
+            )
+        if "\\" in p or "/" in p:
+            raise argparse.ArgumentTypeError(
+                f"{msg} (entries must be packages like foo.bar not directories or files)"
+            )
+    return allow_list
+
+
+def expand_path(path: str) -> str:
+    """Expand the user home directory and any environment variables contained within
+    the provided path.
+    """
+
+    return os.path.expandvars(os.path.expanduser(path))
+
+
+def str_or_array_as_list(v: str | Sequence[str]) -> list[str]:
+    if isinstance(v, str):
+        return [v.strip()] if v.strip() else []
+    return [p.strip() for p in v if p.strip()]
+
+
+def split_and_match_files_list(paths: Sequence[str]) -> list[str]:
+    """Take a list of files/directories (with support for globbing through the glob library).
+
+    Where a path/glob matches no file, we still include the raw path in the resulting list.
+
+    Returns a list of file paths
+    """
+    expanded_paths = []
+
+    for path in paths:
+        path = expand_path(path.strip())
+        globbed_files = fileglob.glob(path, recursive=True)
+        if globbed_files:
+            expanded_paths.extend(globbed_files)
+        else:
+            expanded_paths.append(path)
+
+    return expanded_paths
+
+
+def split_and_match_files(paths: str) -> list[str]:
+    """Take a string representing a list of files/directories (with support for globbing
+    through the glob library).
+
+    Where a path/glob matches no file, we still include the raw path in the resulting list.
+
+    Returns a list of file paths
+    """
+
+    return split_and_match_files_list(paths.split(","))
+
+
+def check_follow_imports(choice: str) -> str:
+    choices = ["normal", "silent", "skip", "error"]
+    if choice not in choices:
+        raise argparse.ArgumentTypeError(
+            "invalid choice '{}' (choose from {})".format(
+                choice, ", ".join(f"'{x}'" for x in choices)
+            )
+        )
+    return choice
+
+
+def split_commas(value: str) -> list[str]:
+    # Uses a bit smarter technique to allow last trailing comma
+    # and to remove last `""` item from the split.
+    items = value.split(",")
+    if items and items[-1] == "":
+        items.pop(-1)
+    return items
+
+
+# For most options, the type of the default value set in options.py is
+# sufficient, and we don't have to do anything here.  This table
+# exists to specify types for values initialized to None or container
+# types.
+ini_config_types: Final[dict[str, _INI_PARSER_CALLABLE]] = {
+    "python_version": parse_version,
+    "custom_typing_module": str,
+    "custom_typeshed_dir": expand_path,
+    "mypy_path": lambda s: [expand_path(p.strip()) for p in re.split("[,:]", s)],
+    "files": split_and_match_files,
+    "quickstart_file": expand_path,
+    "junit_xml": expand_path,
+    "follow_imports": check_follow_imports,
+    "no_site_packages": bool,
+    "plugins": lambda s: [p.strip() for p in split_commas(s)],
+    "always_true": lambda s: [p.strip() for p in split_commas(s)],
+    "always_false": lambda s: [p.strip() for p in split_commas(s)],
+    "untyped_calls_exclude": lambda s: validate_package_allow_list(
+        [p.strip() for p in split_commas(s)]
+    ),
+    "enable_incomplete_feature": lambda s: [p.strip() for p in split_commas(s)],
+    "disable_error_code": lambda s: validate_codes([p.strip() for p in split_commas(s)]),
+    "enable_error_code": lambda s: validate_codes([p.strip() for p in split_commas(s)]),
+    "package_root": lambda s: [p.strip() for p in split_commas(s)],
+    "cache_dir": expand_path,
+    "python_executable": expand_path,
+    "strict": bool,
+    "exclude": lambda s: [s.strip()],
+    "packages": try_split,
+    "modules": try_split,
+}
+
+# Reuse the ini_config_types and overwrite the diff
+toml_config_types: Final[dict[str, _INI_PARSER_CALLABLE]] = ini_config_types.copy()
+toml_config_types.update(
+    {
+        "python_version": parse_version,
+        "mypy_path": lambda s: [expand_path(p) for p in try_split(s, "[,:]")],
+        "files": lambda s: split_and_match_files_list(try_split(s)),
+        "follow_imports": lambda s: check_follow_imports(str(s)),
+        "plugins": try_split,
+        "always_true": try_split,
+        "always_false": try_split,
+        "untyped_calls_exclude": lambda s: validate_package_allow_list(try_split(s)),
+        "enable_incomplete_feature": try_split,
+        "disable_error_code": lambda s: validate_codes(try_split(s)),
+        "enable_error_code": lambda s: validate_codes(try_split(s)),
+        "package_root": try_split,
+        "exclude": str_or_array_as_list,
+        "packages": try_split,
+        "modules": try_split,
+    }
+)
+
+
+def parse_config_file(
+    options: Options,
+    set_strict_flags: Callable[[], None],
+    filename: str | None,
+    stdout: TextIO | None = None,
+    stderr: TextIO | None = None,
+) -> None:
+    """Parse a config file into an Options object.
+
+    Errors are written to stderr but are not fatal.
+
+    If filename is None, fall back to default config files.
+    """
+    stdout = stdout or sys.stdout
+    stderr = stderr or sys.stderr
+
+    if filename is not None:
+        config_files: tuple[str, ...] = (filename,)
+    else:
+        config_files_iter: Iterable[str] = map(os.path.expanduser, defaults.CONFIG_FILES)
+        config_files = tuple(config_files_iter)
+
+    config_parser = configparser.RawConfigParser()
+
+    for config_file in config_files:
+        if not os.path.exists(config_file):
+            continue
+        try:
+            if is_toml(config_file):
+                with open(config_file, "rb") as f:
+                    toml_data = tomllib.load(f)
+                # Filter down to just mypy relevant toml keys
+                toml_data = toml_data.get("tool", {})
+                if "mypy" not in toml_data:
+                    continue
+                toml_data = {"mypy": toml_data["mypy"]}
+                parser: MutableMapping[str, Any] = destructure_overrides(toml_data)
+                config_types = toml_config_types
+            else:
+                config_parser.read(config_file)
+                parser = config_parser
+                config_types = ini_config_types
+        except (tomllib.TOMLDecodeError, configparser.Error, ConfigTOMLValueError) as err:
+            print(f"{config_file}: {err}", file=stderr)
+        else:
+            if config_file in defaults.SHARED_CONFIG_FILES and "mypy" not in parser:
+                continue
+            file_read = config_file
+            options.config_file = file_read
+            break
+    else:
+        return
+
+    os.environ["MYPY_CONFIG_FILE_DIR"] = os.path.dirname(os.path.abspath(config_file))
+
+    if "mypy" not in parser:
+        if filename or file_read not in defaults.SHARED_CONFIG_FILES:
+            print(f"{file_read}: No [mypy] section in config file", file=stderr)
+    else:
+        section = parser["mypy"]
+        prefix = f"{file_read}: [mypy]: "
+        updates, report_dirs = parse_section(
+            prefix, options, set_strict_flags, section, config_types, stderr
+        )
+        for k, v in updates.items():
+            setattr(options, k, v)
+        options.report_dirs.update(report_dirs)
+
+    for name, section in parser.items():
+        if name.startswith("mypy-"):
+            prefix = get_prefix(file_read, name)
+            updates, report_dirs = parse_section(
+                prefix, options, set_strict_flags, section, config_types, stderr
+            )
+            if report_dirs:
+                print(
+                    "%sPer-module sections should not specify reports (%s)"
+                    % (prefix, ", ".join(s + "_report" for s in sorted(report_dirs))),
+                    file=stderr,
+                )
+            if set(updates) - PER_MODULE_OPTIONS:
+                print(
+                    "%sPer-module sections should only specify per-module flags (%s)"
+                    % (prefix, ", ".join(sorted(set(updates) - PER_MODULE_OPTIONS))),
+                    file=stderr,
+                )
+                updates = {k: v for k, v in updates.items() if k in PER_MODULE_OPTIONS}
+
+            globs = name[5:]
+            for glob in globs.split(","):
+                # For backwards compatibility, replace (back)slashes with dots.
+                glob = glob.replace(os.sep, ".")
+                if os.altsep:
+                    glob = glob.replace(os.altsep, ".")
+
+                if any(c in glob for c in "?[]!") or any(
+                    "*" in x and x != "*" for x in glob.split(".")
+                ):
+                    print(
+                        "%sPatterns must be fully-qualified module names, optionally "
+                        "with '*' in some components (e.g spam.*.eggs.*)" % prefix,
+                        file=stderr,
+                    )
+                else:
+                    options.per_module_options[glob] = updates
+
+
+def get_prefix(file_read: str, name: str) -> str:
+    if is_toml(file_read):
+        module_name_str = 'module = "%s"' % "-".join(name.split("-")[1:])
+    else:
+        module_name_str = name
+
+    return f"{file_read}: [{module_name_str}]: "
+
+
+def is_toml(filename: str) -> bool:
+    return filename.lower().endswith(".toml")
+
+
+def destructure_overrides(toml_data: dict[str, Any]) -> dict[str, Any]:
+    """Take the new [[tool.mypy.overrides]] section array in the pyproject.toml file,
+    and convert it back to a flatter structure that the existing config_parser can handle.
+
+    E.g. the following pyproject.toml file:
+
+        [[tool.mypy.overrides]]
+        module = [
+            "a.b",
+            "b.*"
+        ]
+        disallow_untyped_defs = true
+
+        [[tool.mypy.overrides]]
+        module = 'c'
+        disallow_untyped_defs = false
+
+    Would map to the following config dict that it would have gotten from parsing an equivalent
+    ini file:
+
+        {
+            "mypy-a.b": {
+                disallow_untyped_defs = true,
+            },
+            "mypy-b.*": {
+                disallow_untyped_defs = true,
+            },
+            "mypy-c": {
+                disallow_untyped_defs: false,
+            },
+        }
+    """
+    if "overrides" not in toml_data["mypy"]:
+        return toml_data
+
+    if not isinstance(toml_data["mypy"]["overrides"], list):
+        raise ConfigTOMLValueError(
+            "tool.mypy.overrides sections must be an array. Please make "
+            "sure you are using double brackets like so: [[tool.mypy.overrides]]"
+        )
+
+    result = toml_data.copy()
+    for override in result["mypy"]["overrides"]:
+        if "module" not in override:
+            raise ConfigTOMLValueError(
+                "toml config file contains a [[tool.mypy.overrides]] "
+                "section, but no module to override was specified."
+            )
+
+        if isinstance(override["module"], str):
+            modules = [override["module"]]
+        elif isinstance(override["module"], list):
+            modules = override["module"]
+        else:
+            raise ConfigTOMLValueError(
+                "toml config file contains a [[tool.mypy.overrides]] "
+                "section with a module value that is not a string or a list of "
+                "strings"
+            )
+
+        for module in modules:
+            module_overrides = override.copy()
+            del module_overrides["module"]
+            old_config_name = f"mypy-{module}"
+            if old_config_name not in result:
+                result[old_config_name] = module_overrides
+            else:
+                for new_key, new_value in module_overrides.items():
+                    if (
+                        new_key in result[old_config_name]
+                        and result[old_config_name][new_key] != new_value
+                    ):
+                        raise ConfigTOMLValueError(
+                            "toml config file contains "
+                            "[[tool.mypy.overrides]] sections with conflicting "
+                            "values. Module '%s' has two different values for '%s'"
+                            % (module, new_key)
+                        )
+                    result[old_config_name][new_key] = new_value
+
+    del result["mypy"]["overrides"]
+    return result
+
+
+def parse_section(
+    prefix: str,
+    template: Options,
+    set_strict_flags: Callable[[], None],
+    section: Mapping[str, Any],
+    config_types: dict[str, Any],
+    stderr: TextIO = sys.stderr,
+) -> tuple[dict[str, object], dict[str, str]]:
+    """Parse one section of a config file.
+
+    Returns a dict of option values encountered, and a dict of report directories.
+    """
+    results: dict[str, object] = {}
+    report_dirs: dict[str, str] = {}
+    for key in section:
+        invert = False
+        options_key = key
+        if key in config_types:
+            ct = config_types[key]
+        else:
+            dv = None
+            # We have to keep new_semantic_analyzer in Options
+            # for plugin compatibility but it is not a valid option anymore.
+            assert hasattr(template, "new_semantic_analyzer")
+            if key != "new_semantic_analyzer":
+                dv = getattr(template, key, None)
+            if dv is None:
+                if key.endswith("_report"):
+                    report_type = key[:-7].replace("_", "-")
+                    if report_type in defaults.REPORTER_NAMES:
+                        report_dirs[report_type] = str(section[key])
+                    else:
+                        print(f"{prefix}Unrecognized report type: {key}", file=stderr)
+                    continue
+                if key.startswith("x_"):
+                    pass  # Don't complain about `x_blah` flags
+                elif key.startswith("no_") and hasattr(template, key[3:]):
+                    options_key = key[3:]
+                    invert = True
+                elif key.startswith("allow") and hasattr(template, "dis" + key):
+                    options_key = "dis" + key
+                    invert = True
+                elif key.startswith("disallow") and hasattr(template, key[3:]):
+                    options_key = key[3:]
+                    invert = True
+                elif key.startswith("show_") and hasattr(template, "hide_" + key[5:]):
+                    options_key = "hide_" + key[5:]
+                    invert = True
+                elif key == "strict":
+                    pass  # Special handling below
+                else:
+                    print(f"{prefix}Unrecognized option: {key} = {section[key]}", file=stderr)
+                if invert:
+                    dv = getattr(template, options_key, None)
+                else:
+                    continue
+            ct = type(dv)
+        v: Any = None
+        try:
+            if ct is bool:
+                if isinstance(section, dict):
+                    v = convert_to_boolean(section.get(key))
+                else:
+                    v = section.getboolean(key)  # type: ignore[attr-defined]  # Until better stub
+                if invert:
+                    v = not v
+            elif callable(ct):
+                if invert:
+                    print(f"{prefix}Can not invert non-boolean key {options_key}", file=stderr)
+                    continue
+                try:
+                    v = ct(section.get(key))
+                except argparse.ArgumentTypeError as err:
+                    print(f"{prefix}{key}: {err}", file=stderr)
+                    continue
+            else:
+                print(f"{prefix}Don't know what type {key} should have", file=stderr)
+                continue
+        except ValueError as err:
+            print(f"{prefix}{key}: {err}", file=stderr)
+            continue
+        if key == "strict":
+            if v:
+                set_strict_flags()
+            continue
+        results[options_key] = v
+
+    # These two flags act as per-module overrides, so store the empty defaults.
+    if "disable_error_code" not in results:
+        results["disable_error_code"] = []
+    if "enable_error_code" not in results:
+        results["enable_error_code"] = []
+
+    return results, report_dirs
+
+
+def convert_to_boolean(value: Any | None) -> bool:
+    """Return a boolean value translating from other types if necessary."""
+    if isinstance(value, bool):
+        return value
+    if not isinstance(value, str):
+        value = str(value)
+    if value.lower() not in configparser.RawConfigParser.BOOLEAN_STATES:
+        raise ValueError(f"Not a boolean: {value}")
+    return configparser.RawConfigParser.BOOLEAN_STATES[value.lower()]
+
+
+def split_directive(s: str) -> tuple[list[str], list[str]]:
+    """Split s on commas, except during quoted sections.
+
+    Returns the parts and a list of error messages."""
+    parts = []
+    cur: list[str] = []
+    errors = []
+    i = 0
+    while i < len(s):
+        if s[i] == ",":
+            parts.append("".join(cur).strip())
+            cur = []
+        elif s[i] == '"':
+            i += 1
+            while i < len(s) and s[i] != '"':
+                cur.append(s[i])
+                i += 1
+            if i == len(s):
+                errors.append("Unterminated quote in configuration comment")
+                cur.clear()
+        else:
+            cur.append(s[i])
+        i += 1
+    if cur:
+        parts.append("".join(cur).strip())
+
+    return parts, errors
+
+
+def mypy_comments_to_config_map(line: str, template: Options) -> tuple[dict[str, str], list[str]]:
+    """Rewrite the mypy comment syntax into ini file syntax."""
+    options = {}
+    entries, errors = split_directive(line)
+    for entry in entries:
+        if "=" not in entry:
+            name = entry
+            value = None
+        else:
+            name, value = (x.strip() for x in entry.split("=", 1))
+
+        name = name.replace("-", "_")
+        if value is None:
+            value = "True"
+        options[name] = value
+
+    return options, errors
+
+
+def parse_mypy_comments(
+    args: list[tuple[int, str]], template: Options
+) -> tuple[dict[str, object], list[tuple[int, str]]]:
+    """Parse a collection of inline mypy: configuration comments.
+
+    Returns a dictionary of options to be applied and a list of error messages
+    generated.
+    """
+
+    errors: list[tuple[int, str]] = []
+    sections = {}
+
+    for lineno, line in args:
+        # In order to easily match the behavior for bools, we abuse configparser.
+        # Oddly, the only way to get the SectionProxy object with the getboolean
+        # method is to create a config parser.
+        parser = configparser.RawConfigParser()
+        options, parse_errors = mypy_comments_to_config_map(line, template)
+        parser["dummy"] = options
+        errors.extend((lineno, x) for x in parse_errors)
+
+        stderr = StringIO()
+        strict_found = False
+
+        def set_strict_flags() -> None:
+            nonlocal strict_found
+            strict_found = True
+
+        new_sections, reports = parse_section(
+            "", template, set_strict_flags, parser["dummy"], ini_config_types, stderr=stderr
+        )
+        errors.extend((lineno, x) for x in stderr.getvalue().strip().split("\n") if x)
+        if reports:
+            errors.append((lineno, "Reports not supported in inline configuration"))
+        if strict_found:
+            errors.append(
+                (
+                    lineno,
+                    'Setting "strict" not supported in inline configuration: specify it in '
+                    "a configuration file instead, or set individual inline flags "
+                    '(see "mypy -h" for the list of flags enabled in strict mode)',
+                )
+            )
+
+        sections.update(new_sections)
+
+    return sections, errors
+
+
+def get_config_module_names(filename: str | None, modules: list[str]) -> str:
+    if not filename or not modules:
+        return ""
+
+    if not is_toml(filename):
+        return ", ".join(f"[mypy-{module}]" for module in modules)
+
+    return "module = ['%s']" % ("', '".join(sorted(modules)))
+
+
+class ConfigTOMLValueError(ValueError):
+    pass

venv/lib/python3.12/site-packages/mypy/constant_fold.py

@@ -0,0 +1,187 @@
+"""Constant folding of expressions.
+
+For example, 3 + 5 can be constant folded into 8.
+"""
+
+from __future__ import annotations
+
+from typing import Final, Union
+
+from mypy.nodes import (
+    ComplexExpr,
+    Expression,
+    FloatExpr,
+    IntExpr,
+    NameExpr,
+    OpExpr,
+    StrExpr,
+    UnaryExpr,
+    Var,
+)
+
+# All possible result types of constant folding
+ConstantValue = Union[int, bool, float, complex, str]
+CONST_TYPES: Final = (int, bool, float, complex, str)
+
+
+def constant_fold_expr(expr: Expression, cur_mod_id: str) -> ConstantValue | None:
+    """Return the constant value of an expression for supported operations.
+
+    Among other things, support int arithmetic and string
+    concatenation. For example, the expression 3 + 5 has the constant
+    value 8.
+
+    Also bind simple references to final constants defined in the
+    current module (cur_mod_id). Binding to references is best effort
+    -- we don't bind references to other modules. Mypyc trusts these
+    to be correct in compiled modules, so that it can replace a
+    constant expression (or a reference to one) with the statically
+    computed value. We don't want to infer constant values based on
+    stubs, in particular, as these might not match the implementation
+    (due to version skew, for example).
+
+    Return None if unsuccessful.
+    """
+    if isinstance(expr, IntExpr):
+        return expr.value
+    if isinstance(expr, StrExpr):
+        return expr.value
+    if isinstance(expr, FloatExpr):
+        return expr.value
+    if isinstance(expr, ComplexExpr):
+        return expr.value
+    elif isinstance(expr, NameExpr):
+        if expr.name == "True":
+            return True
+        elif expr.name == "False":
+            return False
+        node = expr.node
+        if (
+            isinstance(node, Var)
+            and node.is_final
+            and node.fullname.rsplit(".", 1)[0] == cur_mod_id
+        ):
+            value = node.final_value
+            if isinstance(value, (CONST_TYPES)):
+                return value
+    elif isinstance(expr, OpExpr):
+        left = constant_fold_expr(expr.left, cur_mod_id)
+        right = constant_fold_expr(expr.right, cur_mod_id)
+        if left is not None and right is not None:
+            return constant_fold_binary_op(expr.op, left, right)
+    elif isinstance(expr, UnaryExpr):
+        value = constant_fold_expr(expr.expr, cur_mod_id)
+        if value is not None:
+            return constant_fold_unary_op(expr.op, value)
+    return None
+
+
+def constant_fold_binary_op(
+    op: str, left: ConstantValue, right: ConstantValue
+) -> ConstantValue | None:
+    if isinstance(left, int) and isinstance(right, int):
+        return constant_fold_binary_int_op(op, left, right)
+
+    # Float and mixed int/float arithmetic.
+    if isinstance(left, float) and isinstance(right, float):
+        return constant_fold_binary_float_op(op, left, right)
+    elif isinstance(left, float) and isinstance(right, int):
+        return constant_fold_binary_float_op(op, left, right)
+    elif isinstance(left, int) and isinstance(right, float):
+        return constant_fold_binary_float_op(op, left, right)
+
+    # String concatenation and multiplication.
+    if op == "+" and isinstance(left, str) and isinstance(right, str):
+        return left + right
+    elif op == "*" and isinstance(left, str) and isinstance(right, int):
+        return left * right
+    elif op == "*" and isinstance(left, int) and isinstance(right, str):
+        return left * right
+
+    # Complex construction.
+    if op == "+" and isinstance(left, (int, float)) and isinstance(right, complex):
+        return left + right
+    elif op == "+" and isinstance(left, complex) and isinstance(right, (int, float)):
+        return left + right
+    elif op == "-" and isinstance(left, (int, float)) and isinstance(right, complex):
+        return left - right
+    elif op == "-" and isinstance(left, complex) and isinstance(right, (int, float)):
+        return left - right
+
+    return None
+
+
+def constant_fold_binary_int_op(op: str, left: int, right: int) -> int | float | None:
+    if op == "+":
+        return left + right
+    if op == "-":
+        return left - right
+    elif op == "*":
+        return left * right
+    elif op == "/":
+        if right != 0:
+            return left / right
+    elif op == "//":
+        if right != 0:
+            return left // right
+    elif op == "%":
+        if right != 0:
+            return left % right
+    elif op == "&":
+        return left & right
+    elif op == "|":
+        return left | right
+    elif op == "^":
+        return left ^ right
+    elif op == "<<":
+        if right >= 0:
+            return left << right
+    elif op == ">>":
+        if right >= 0:
+            return left >> right
+    elif op == "**":
+        if right >= 0:
+            ret = left**right
+            assert isinstance(ret, int)
+            return ret
+    return None
+
+
+def constant_fold_binary_float_op(op: str, left: int | float, right: int | float) -> float | None:
+    assert not (isinstance(left, int) and isinstance(right, int)), (op, left, right)
+    if op == "+":
+        return left + right
+    elif op == "-":
+        return left - right
+    elif op == "*":
+        return left * right
+    elif op == "/":
+        if right != 0:
+            return left / right
+    elif op == "//":
+        if right != 0:
+            return left // right
+    elif op == "%":
+        if right != 0:
+            return left % right
+    elif op == "**":
+        if (left < 0 and isinstance(right, int)) or left > 0:
+            try:
+                ret = left**right
+            except OverflowError:
+                return None
+            else:
+                assert isinstance(ret, float), ret
+                return ret
+
+    return None
+
+
+def constant_fold_unary_op(op: str, value: ConstantValue) -> int | float | None:
+    if op == "-" and isinstance(value, (int, float)):
+        return -value
+    elif op == "~" and isinstance(value, int):
+        return ~value
+    elif op == "+" and isinstance(value, (int, float)):
+        return value
+    return None

venv/lib/python3.12/site-packages/mypy/copytype.py

@@ -0,0 +1,133 @@
+from __future__ import annotations
+
+from typing import Any, cast
+
+from mypy.types import (
+    AnyType,
+    CallableType,
+    DeletedType,
+    ErasedType,
+    Instance,
+    LiteralType,
+    NoneType,
+    Overloaded,
+    Parameters,
+    ParamSpecType,
+    PartialType,
+    ProperType,
+    TupleType,
+    TypeAliasType,
+    TypedDictType,
+    TypeType,
+    TypeVarTupleType,
+    TypeVarType,
+    UnboundType,
+    UninhabitedType,
+    UnionType,
+    UnpackType,
+)
+
+# type_visitor needs to be imported after types
+from mypy.type_visitor import TypeVisitor  # ruff: isort: skip
+
+
+def copy_type(t: ProperType) -> ProperType:
+    """Create a shallow copy of a type.
+
+    This can be used to mutate the copy with truthiness information.
+
+    Classes compiled with mypyc don't support copy.copy(), so we need
+    a custom implementation.
+    """
+    return t.accept(TypeShallowCopier())
+
+
+class TypeShallowCopier(TypeVisitor[ProperType]):
+    def visit_unbound_type(self, t: UnboundType) -> ProperType:
+        return t
+
+    def visit_any(self, t: AnyType) -> ProperType:
+        return self.copy_common(t, AnyType(t.type_of_any, t.source_any, t.missing_import_name))
+
+    def visit_none_type(self, t: NoneType) -> ProperType:
+        return self.copy_common(t, NoneType())
+
+    def visit_uninhabited_type(self, t: UninhabitedType) -> ProperType:
+        dup = UninhabitedType(t.is_noreturn)
+        dup.ambiguous = t.ambiguous
+        return self.copy_common(t, dup)
+
+    def visit_erased_type(self, t: ErasedType) -> ProperType:
+        return self.copy_common(t, ErasedType())
+
+    def visit_deleted_type(self, t: DeletedType) -> ProperType:
+        return self.copy_common(t, DeletedType(t.source))
+
+    def visit_instance(self, t: Instance) -> ProperType:
+        dup = Instance(t.type, t.args, last_known_value=t.last_known_value)
+        dup.invalid = t.invalid
+        return self.copy_common(t, dup)
+
+    def visit_type_var(self, t: TypeVarType) -> ProperType:
+        return self.copy_common(t, t.copy_modified())
+
+    def visit_param_spec(self, t: ParamSpecType) -> ProperType:
+        dup = ParamSpecType(
+            t.name, t.fullname, t.id, t.flavor, t.upper_bound, t.default, prefix=t.prefix
+        )
+        return self.copy_common(t, dup)
+
+    def visit_parameters(self, t: Parameters) -> ProperType:
+        dup = Parameters(
+            t.arg_types,
+            t.arg_kinds,
+            t.arg_names,
+            variables=t.variables,
+            is_ellipsis_args=t.is_ellipsis_args,
+        )
+        return self.copy_common(t, dup)
+
+    def visit_type_var_tuple(self, t: TypeVarTupleType) -> ProperType:
+        dup = TypeVarTupleType(
+            t.name, t.fullname, t.id, t.upper_bound, t.tuple_fallback, t.default
+        )
+        return self.copy_common(t, dup)
+
+    def visit_unpack_type(self, t: UnpackType) -> ProperType:
+        dup = UnpackType(t.type)
+        return self.copy_common(t, dup)
+
+    def visit_partial_type(self, t: PartialType) -> ProperType:
+        return self.copy_common(t, PartialType(t.type, t.var, t.value_type))
+
+    def visit_callable_type(self, t: CallableType) -> ProperType:
+        return self.copy_common(t, t.copy_modified())
+
+    def visit_tuple_type(self, t: TupleType) -> ProperType:
+        return self.copy_common(t, TupleType(t.items, t.partial_fallback, implicit=t.implicit))
+
+    def visit_typeddict_type(self, t: TypedDictType) -> ProperType:
+        return self.copy_common(t, TypedDictType(t.items, t.required_keys, t.fallback))
+
+    def visit_literal_type(self, t: LiteralType) -> ProperType:
+        return self.copy_common(t, LiteralType(value=t.value, fallback=t.fallback))
+
+    def visit_union_type(self, t: UnionType) -> ProperType:
+        return self.copy_common(t, UnionType(t.items))
+
+    def visit_overloaded(self, t: Overloaded) -> ProperType:
+        return self.copy_common(t, Overloaded(items=t.items))
+
+    def visit_type_type(self, t: TypeType) -> ProperType:
+        # Use cast since the type annotations in TypeType are imprecise.
+        return self.copy_common(t, TypeType(cast(Any, t.item)))
+
+    def visit_type_alias_type(self, t: TypeAliasType) -> ProperType:
+        assert False, "only ProperTypes supported"
+
+    def copy_common(self, t: ProperType, t2: ProperType) -> ProperType:
+        t2.line = t.line
+        t2.column = t.column
+        t2.can_be_false = t.can_be_false
+        t2.can_be_true = t.can_be_true
+        return t2

venv/lib/python3.12/site-packages/mypy/defaults.py

@@ -0,0 +1,46 @@
+from __future__ import annotations
+
+import os
+from typing import Final
+
+# Earliest fully supported Python 3.x version. Used as the default Python
+# version in tests. Mypy wheels should be built starting with this version,
+# and CI tests should be run on this version (and later versions).
+PYTHON3_VERSION: Final = (3, 8)
+
+# Earliest Python 3.x version supported via --python-version 3.x. To run
+# mypy, at least version PYTHON3_VERSION is needed.
+PYTHON3_VERSION_MIN: Final = (3, 7)  # Keep in sync with typeshed's python support
+
+CACHE_DIR: Final = ".mypy_cache"
+CONFIG_FILE: Final = ["mypy.ini", ".mypy.ini"]
+PYPROJECT_CONFIG_FILES: Final = ["pyproject.toml"]
+SHARED_CONFIG_FILES: Final = ["setup.cfg"]
+USER_CONFIG_FILES: Final = ["~/.config/mypy/config", "~/.mypy.ini"]
+if os.environ.get("XDG_CONFIG_HOME"):
+    USER_CONFIG_FILES.insert(0, os.path.join(os.environ["XDG_CONFIG_HOME"], "mypy/config"))
+
+CONFIG_FILES: Final = (
+    CONFIG_FILE + PYPROJECT_CONFIG_FILES + SHARED_CONFIG_FILES + USER_CONFIG_FILES
+)
+
+# This must include all reporters defined in mypy.report. This is defined here
+# to make reporter names available without importing mypy.report -- this speeds
+# up startup.
+REPORTER_NAMES: Final = [
+    "linecount",
+    "any-exprs",
+    "linecoverage",
+    "memory-xml",
+    "cobertura-xml",
+    "xml",
+    "xslt-html",
+    "xslt-txt",
+    "html",
+    "txt",
+    "lineprecision",
+]
+
+# Threshold after which we sometimes filter out most errors to avoid very
+# verbose output. The default is to show all errors.
+MANY_ERRORS_THRESHOLD: Final = -1

venv/lib/python3.12/site-packages/mypy/dmypy/__main__.py

@@ -0,0 +1,6 @@
+from __future__ import annotations
+
+from mypy.dmypy.client import console_entry
+
+if __name__ == "__main__":
+    console_entry()

venv/lib/python3.12/site-packages/mypy/dmypy/client.py

@@ -0,0 +1,748 @@
+"""Client for mypy daemon mode.
+
+This manages a daemon process which keeps useful state in memory
+rather than having to read it back from disk on each run.
+"""
+
+from __future__ import annotations
+
+import argparse
+import base64
+import json
+import os
+import pickle
+import sys
+import time
+import traceback
+from typing import Any, Callable, Mapping, NoReturn
+
+from mypy.dmypy_os import alive, kill
+from mypy.dmypy_util import DEFAULT_STATUS_FILE, receive
+from mypy.ipc import IPCClient, IPCException
+from mypy.util import check_python_version, get_terminal_width, should_force_color
+from mypy.version import __version__
+
+# Argument parser.  Subparsers are tied to action functions by the
+# @action(subparse) decorator.
+
+
+class AugmentedHelpFormatter(argparse.RawDescriptionHelpFormatter):
+    def __init__(self, prog: str) -> None:
+        super().__init__(prog=prog, max_help_position=30)
+
+
+parser = argparse.ArgumentParser(
+    prog="dmypy", description="Client for mypy daemon mode", fromfile_prefix_chars="@"
+)
+parser.set_defaults(action=None)
+parser.add_argument(
+    "--status-file", default=DEFAULT_STATUS_FILE, help="status file to retrieve daemon details"
+)
+parser.add_argument(
+    "-V",
+    "--version",
+    action="version",
+    version="%(prog)s " + __version__,
+    help="Show program's version number and exit",
+)
+subparsers = parser.add_subparsers()
+
+start_parser = p = subparsers.add_parser("start", help="Start daemon")
+p.add_argument("--log-file", metavar="FILE", type=str, help="Direct daemon stdout/stderr to FILE")
+p.add_argument(
+    "--timeout", metavar="TIMEOUT", type=int, help="Server shutdown timeout (in seconds)"
+)
+p.add_argument(
+    "flags", metavar="FLAG", nargs="*", type=str, help="Regular mypy flags (precede with --)"
+)
+
+restart_parser = p = subparsers.add_parser(
+    "restart", help="Restart daemon (stop or kill followed by start)"
+)
+p.add_argument("--log-file", metavar="FILE", type=str, help="Direct daemon stdout/stderr to FILE")
+p.add_argument(
+    "--timeout", metavar="TIMEOUT", type=int, help="Server shutdown timeout (in seconds)"
+)
+p.add_argument(
+    "flags", metavar="FLAG", nargs="*", type=str, help="Regular mypy flags (precede with --)"
+)
+
+status_parser = p = subparsers.add_parser("status", help="Show daemon status")
+p.add_argument("-v", "--verbose", action="store_true", help="Print detailed status")
+p.add_argument("--fswatcher-dump-file", help="Collect information about the current file state")
+
+stop_parser = p = subparsers.add_parser("stop", help="Stop daemon (asks it politely to go away)")
+
+kill_parser = p = subparsers.add_parser("kill", help="Kill daemon (kills the process)")
+
+check_parser = p = subparsers.add_parser(
+    "check", formatter_class=AugmentedHelpFormatter, help="Check some files (requires daemon)"
+)
+p.add_argument("-v", "--verbose", action="store_true", help="Print detailed status")
+p.add_argument("-q", "--quiet", action="store_true", help=argparse.SUPPRESS)  # Deprecated
+p.add_argument("--junit-xml", help="Write junit.xml to the given file")
+p.add_argument("--perf-stats-file", help="write performance information to the given file")
+p.add_argument("files", metavar="FILE", nargs="+", help="File (or directory) to check")
+p.add_argument(
+    "--export-types",
+    action="store_true",
+    help="Store types of all expressions in a shared location (useful for inspections)",
+)
+
+run_parser = p = subparsers.add_parser(
+    "run",
+    formatter_class=AugmentedHelpFormatter,
+    help="Check some files, [re]starting daemon if necessary",
+)
+p.add_argument("-v", "--verbose", action="store_true", help="Print detailed status")
+p.add_argument("--junit-xml", help="Write junit.xml to the given file")
+p.add_argument("--perf-stats-file", help="write performance information to the given file")
+p.add_argument(
+    "--timeout", metavar="TIMEOUT", type=int, help="Server shutdown timeout (in seconds)"
+)
+p.add_argument("--log-file", metavar="FILE", type=str, help="Direct daemon stdout/stderr to FILE")
+p.add_argument(
+    "--export-types",
+    action="store_true",
+    help="Store types of all expressions in a shared location (useful for inspections)",
+)
+p.add_argument(
+    "flags",
+    metavar="ARG",
+    nargs="*",
+    type=str,
+    help="Regular mypy flags and files (precede with --)",
+)
+
+recheck_parser = p = subparsers.add_parser(
+    "recheck",
+    formatter_class=AugmentedHelpFormatter,
+    help="Re-check the previous list of files, with optional modifications (requires daemon)",
+)
+p.add_argument("-v", "--verbose", action="store_true", help="Print detailed status")
+p.add_argument("-q", "--quiet", action="store_true", help=argparse.SUPPRESS)  # Deprecated
+p.add_argument("--junit-xml", help="Write junit.xml to the given file")
+p.add_argument("--perf-stats-file", help="write performance information to the given file")
+p.add_argument(
+    "--export-types",
+    action="store_true",
+    help="Store types of all expressions in a shared location (useful for inspections)",
+)
+p.add_argument(
+    "--update",
+    metavar="FILE",
+    nargs="*",
+    help="Files in the run to add or check again (default: all from previous run)",
+)
+p.add_argument("--remove", metavar="FILE", nargs="*", help="Files to remove from the run")
+
+suggest_parser = p = subparsers.add_parser(
+    "suggest", help="Suggest a signature or show call sites for a specific function"
+)
+p.add_argument(
+    "function",
+    metavar="FUNCTION",
+    type=str,
+    help="Function specified as '[package.]module.[class.]function'",
+)
+p.add_argument(
+    "--json",
+    action="store_true",
+    help="Produce json that pyannotate can use to apply a suggestion",
+)
+p.add_argument(
+    "--no-errors", action="store_true", help="Only produce suggestions that cause no errors"
+)
+p.add_argument(
+    "--no-any", action="store_true", help="Only produce suggestions that don't contain Any"
+)
+p.add_argument(
+    "--flex-any",
+    type=float,
+    help="Allow anys in types if they go above a certain score (scores are from 0-1)",
+)
+p.add_argument(
+    "--callsites", action="store_true", help="Find callsites instead of suggesting a type"
+)
+p.add_argument(
+    "--use-fixme",
+    metavar="NAME",
+    type=str,
+    help="A dummy name to use instead of Any for types that can't be inferred",
+)
+p.add_argument(
+    "--max-guesses",
+    type=int,
+    help="Set the maximum number of types to try for a function (default 64)",
+)
+
+inspect_parser = p = subparsers.add_parser(
+    "inspect", help="Locate and statically inspect expression(s)"
+)
+p.add_argument(
+    "location",
+    metavar="LOCATION",
+    type=str,
+    help="Location specified as path/to/file.py:line:column[:end_line:end_column]."
+    " If position is given (i.e. only line and column), this will return all"
+    " enclosing expressions",
+)
+p.add_argument(
+    "--show",
+    metavar="INSPECTION",
+    type=str,
+    default="type",
+    choices=["type", "attrs", "definition"],
+    help="What kind of inspection to run",
+)
+p.add_argument(
+    "--verbose",
+    "-v",
+    action="count",
+    default=0,
+    help="Increase verbosity of the type string representation (can be repeated)",
+)
+p.add_argument(
+    "--limit",
+    metavar="NUM",
+    type=int,
+    default=0,
+    help="Return at most NUM innermost expressions (if position is given); 0 means no limit",
+)
+p.add_argument(
+    "--include-span",
+    action="store_true",
+    help="Prepend each inspection result with the span of corresponding expression"
+    ' (e.g. 1:2:3:4:"int")',
+)
+p.add_argument(
+    "--include-kind",
+    action="store_true",
+    help="Prepend each inspection result with the kind of corresponding expression"
+    ' (e.g. NameExpr:"int")',
+)
+p.add_argument(
+    "--include-object-attrs",
+    action="store_true",
+    help='Include attributes of "object" in "attrs" inspection',
+)
+p.add_argument(
+    "--union-attrs",
+    action="store_true",
+    help="Include attributes valid for some of possible expression types"
+    " (by default an intersection is returned)",
+)
+p.add_argument(
+    "--force-reload",
+    action="store_true",
+    help="Re-parse and re-type-check file before inspection (may be slow)",
+)
+
+hang_parser = p = subparsers.add_parser("hang", help="Hang for 100 seconds")
+
+daemon_parser = p = subparsers.add_parser("daemon", help="Run daemon in foreground")
+p.add_argument(
+    "--timeout", metavar="TIMEOUT", type=int, help="Server shutdown timeout (in seconds)"
+)
+p.add_argument("--log-file", metavar="FILE", type=str, help="Direct daemon stdout/stderr to FILE")
+p.add_argument(
+    "flags", metavar="FLAG", nargs="*", type=str, help="Regular mypy flags (precede with --)"
+)
+p.add_argument("--options-data", help=argparse.SUPPRESS)
+help_parser = p = subparsers.add_parser("help")
+
+del p
+
+
+class BadStatus(Exception):
+    """Exception raised when there is something wrong with the status file.
+
+    For example:
+    - No status file found
+    - Status file malformed
+    - Process whose pid is in the status file does not exist
+    """
+
+
+def main(argv: list[str]) -> None:
+    """The code is top-down."""
+    check_python_version("dmypy")
+    args = parser.parse_args(argv)
+    if not args.action:
+        parser.print_usage()
+    else:
+        try:
+            args.action(args)
+        except BadStatus as err:
+            fail(err.args[0])
+        except Exception:
+            # We do this explicitly to avoid exceptions percolating up
+            # through mypy.api invocations
+            traceback.print_exc()
+            sys.exit(2)
+
+
+def fail(msg: str) -> NoReturn:
+    print(msg, file=sys.stderr)
+    sys.exit(2)
+
+
+ActionFunction = Callable[[argparse.Namespace], None]
+
+
+def action(subparser: argparse.ArgumentParser) -> Callable[[ActionFunction], ActionFunction]:
+    """Decorator to tie an action function to a subparser."""
+
+    def register(func: ActionFunction) -> ActionFunction:
+        subparser.set_defaults(action=func)
+        return func
+
+    return register
+
+
+# Action functions (run in client from command line).
+
+
+@action(start_parser)
+def do_start(args: argparse.Namespace) -> None:
+    """Start daemon (it must not already be running).
+
+    This is where mypy flags are set from the command line.
+
+    Setting flags is a bit awkward; you have to use e.g.:
+
+      dmypy start -- --strict
+
+    since we don't want to duplicate mypy's huge list of flags.
+    """
+    try:
+        get_status(args.status_file)
+    except BadStatus:
+        # Bad or missing status file or dead process; good to start.
+        pass
+    else:
+        fail("Daemon is still alive")
+    start_server(args)
+
+
+@action(restart_parser)
+def do_restart(args: argparse.Namespace) -> None:
+    """Restart daemon (it may or may not be running; but not hanging).
+
+    We first try to stop it politely if it's running.  This also sets
+    mypy flags from the command line (see do_start()).
+    """
+    restart_server(args)
+
+
+def restart_server(args: argparse.Namespace, allow_sources: bool = False) -> None:
+    """Restart daemon (it may or may not be running; but not hanging)."""
+    try:
+        do_stop(args)
+    except BadStatus:
+        # Bad or missing status file or dead process; good to start.
+        pass
+    start_server(args, allow_sources)
+
+
+def start_server(args: argparse.Namespace, allow_sources: bool = False) -> None:
+    """Start the server from command arguments and wait for it."""
+    # Lazy import so this import doesn't slow down other commands.
+    from mypy.dmypy_server import daemonize, process_start_options
+
+    start_options = process_start_options(args.flags, allow_sources)
+    if daemonize(start_options, args.status_file, timeout=args.timeout, log_file=args.log_file):
+        sys.exit(2)
+    wait_for_server(args.status_file)
+
+
+def wait_for_server(status_file: str, timeout: float = 5.0) -> None:
+    """Wait until the server is up.
+
+    Exit if it doesn't happen within the timeout.
+    """
+    endtime = time.time() + timeout
+    while time.time() < endtime:
+        try:
+            data = read_status(status_file)
+        except BadStatus:
+            # If the file isn't there yet, retry later.
+            time.sleep(0.1)
+            continue
+        # If the file's content is bogus or the process is dead, fail.
+        check_status(data)
+        print("Daemon started")
+        return
+    fail("Timed out waiting for daemon to start")
+
+
+@action(run_parser)
+def do_run(args: argparse.Namespace) -> None:
+    """Do a check, starting (or restarting) the daemon as necessary
+
+    Restarts the daemon if the running daemon reports that it is
+    required (due to a configuration change, for example).
+
+    Setting flags is a bit awkward; you have to use e.g.:
+
+      dmypy run -- --strict a.py b.py ...
+
+    since we don't want to duplicate mypy's huge list of flags.
+    (The -- is only necessary if flags are specified.)
+    """
+    if not is_running(args.status_file):
+        # Bad or missing status file or dead process; good to start.
+        start_server(args, allow_sources=True)
+    t0 = time.time()
+    response = request(
+        args.status_file,
+        "run",
+        version=__version__,
+        args=args.flags,
+        export_types=args.export_types,
+    )
+    # If the daemon signals that a restart is necessary, do it
+    if "restart" in response:
+        print(f"Restarting: {response['restart']}")
+        restart_server(args, allow_sources=True)
+        response = request(
+            args.status_file,
+            "run",
+            version=__version__,
+            args=args.flags,
+            export_types=args.export_types,
+        )
+
+    t1 = time.time()
+    response["roundtrip_time"] = t1 - t0
+    check_output(response, args.verbose, args.junit_xml, args.perf_stats_file)
+
+
+@action(status_parser)
+def do_status(args: argparse.Namespace) -> None:
+    """Print daemon status.
+
+    This verifies that it is responsive to requests.
+    """
+    status = read_status(args.status_file)
+    if args.verbose:
+        show_stats(status)
+    # Both check_status() and request() may raise BadStatus,
+    # which will be handled by main().
+    check_status(status)
+    response = request(
+        args.status_file, "status", fswatcher_dump_file=args.fswatcher_dump_file, timeout=5
+    )
+    if args.verbose or "error" in response:
+        show_stats(response)
+    if "error" in response:
+        fail(f"Daemon is stuck; consider {sys.argv[0]} kill")
+    print("Daemon is up and running")
+
+
+@action(stop_parser)
+def do_stop(args: argparse.Namespace) -> None:
+    """Stop daemon via a 'stop' request."""
+    # May raise BadStatus, which will be handled by main().
+    response = request(args.status_file, "stop", timeout=5)
+    if "error" in response:
+        show_stats(response)
+        fail(f"Daemon is stuck; consider {sys.argv[0]} kill")
+    else:
+        print("Daemon stopped")
+
+
+@action(kill_parser)
+def do_kill(args: argparse.Namespace) -> None:
+    """Kill daemon process with SIGKILL."""
+    pid, _ = get_status(args.status_file)
+    try:
+        kill(pid)
+    except OSError as err:
+        fail(str(err))
+    else:
+        print("Daemon killed")
+
+
+@action(check_parser)
+def do_check(args: argparse.Namespace) -> None:
+    """Ask the daemon to check a list of files."""
+    t0 = time.time()
+    response = request(args.status_file, "check", files=args.files, export_types=args.export_types)
+    t1 = time.time()
+    response["roundtrip_time"] = t1 - t0
+    check_output(response, args.verbose, args.junit_xml, args.perf_stats_file)
+
+
+@action(recheck_parser)
+def do_recheck(args: argparse.Namespace) -> None:
+    """Ask the daemon to recheck the previous list of files, with optional modifications.
+
+    If at least one of --remove or --update is given, the server will
+    update the list of files to check accordingly and assume that any other files
+    are unchanged.  If none of these flags are given, the server will call stat()
+    on each file last checked to determine its status.
+
+    Files given in --update ought to exist.  Files given in --remove need not exist;
+    if they don't they will be ignored.
+    The lists may be empty but oughtn't contain duplicates or overlap.
+
+    NOTE: The list of files is lost when the daemon is restarted.
+    """
+    t0 = time.time()
+    if args.remove is not None or args.update is not None:
+        response = request(
+            args.status_file,
+            "recheck",
+            export_types=args.export_types,
+            remove=args.remove,
+            update=args.update,
+        )
+    else:
+        response = request(args.status_file, "recheck", export_types=args.export_types)
+    t1 = time.time()
+    response["roundtrip_time"] = t1 - t0
+    check_output(response, args.verbose, args.junit_xml, args.perf_stats_file)
+
+
+@action(suggest_parser)
+def do_suggest(args: argparse.Namespace) -> None:
+    """Ask the daemon for a suggested signature.
+
+    This just prints whatever the daemon reports as output.
+    For now it may be closer to a list of call sites.
+    """
+    response = request(
+        args.status_file,
+        "suggest",
+        function=args.function,
+        json=args.json,
+        callsites=args.callsites,
+        no_errors=args.no_errors,
+        no_any=args.no_any,
+        flex_any=args.flex_any,
+        use_fixme=args.use_fixme,
+        max_guesses=args.max_guesses,
+    )
+    check_output(response, verbose=False, junit_xml=None, perf_stats_file=None)
+
+
+@action(inspect_parser)
+def do_inspect(args: argparse.Namespace) -> None:
+    """Ask daemon to print the type of an expression."""
+    response = request(
+        args.status_file,
+        "inspect",
+        show=args.show,
+        location=args.location,
+        verbosity=args.verbose,
+        limit=args.limit,
+        include_span=args.include_span,
+        include_kind=args.include_kind,
+        include_object_attrs=args.include_object_attrs,
+        union_attrs=args.union_attrs,
+        force_reload=args.force_reload,
+    )
+    check_output(response, verbose=False, junit_xml=None, perf_stats_file=None)
+
+
+def check_output(
+    response: dict[str, Any], verbose: bool, junit_xml: str | None, perf_stats_file: str | None
+) -> None:
+    """Print the output from a check or recheck command.
+
+    Call sys.exit() unless the status code is zero.
+    """
+    if "error" in response:
+        fail(response["error"])
+    try:
+        out, err, status_code = response["out"], response["err"], response["status"]
+    except KeyError:
+        fail(f"Response: {str(response)}")
+    sys.stdout.write(out)
+    sys.stdout.flush()
+    sys.stderr.write(err)
+    sys.stderr.flush()
+    if verbose:
+        show_stats(response)
+    if junit_xml:
+        # Lazy import so this import doesn't slow things down when not writing junit
+        from mypy.util import write_junit_xml
+
+        messages = (out + err).splitlines()
+        write_junit_xml(
+            response["roundtrip_time"],
+            bool(err),
+            messages,
+            junit_xml,
+            response["python_version"],
+            response["platform"],
+        )
+    if perf_stats_file:
+        telemetry = response.get("stats", {})
+        with open(perf_stats_file, "w") as f:
+            json.dump(telemetry, f)
+
+    if status_code:
+        sys.exit(status_code)
+
+
+def show_stats(response: Mapping[str, object]) -> None:
+    for key, value in sorted(response.items()):
+        if key in ("out", "err", "stdout", "stderr"):
+            # Special case text output to display just 40 characters of text
+            value = repr(value)[1:-1]
+            if len(value) > 50:
+                value = f"{value[:40]} ... {len(value)-40} more characters"
+            print("%-24s: %s" % (key, value))
+            continue
+        print("%-24s: %10s" % (key, "%.3f" % value if isinstance(value, float) else value))
+
+
+@action(hang_parser)
+def do_hang(args: argparse.Namespace) -> None:
+    """Hang for 100 seconds, as a debug hack."""
+    print(request(args.status_file, "hang", timeout=1))
+
+
+@action(daemon_parser)
+def do_daemon(args: argparse.Namespace) -> None:
+    """Serve requests in the foreground."""
+    # Lazy import so this import doesn't slow down other commands.
+    from mypy.dmypy_server import Server, process_start_options
+
+    if args.log_file:
+        sys.stdout = sys.stderr = open(args.log_file, "a", buffering=1)
+        fd = sys.stdout.fileno()
+        os.dup2(fd, 2)
+        os.dup2(fd, 1)
+
+    if args.options_data:
+        from mypy.options import Options
+
+        options_dict = pickle.loads(base64.b64decode(args.options_data))
+        options_obj = Options()
+        options = options_obj.apply_changes(options_dict)
+    else:
+        options = process_start_options(args.flags, allow_sources=False)
+
+    Server(options, args.status_file, timeout=args.timeout).serve()
+
+
+@action(help_parser)
+def do_help(args: argparse.Namespace) -> None:
+    """Print full help (same as dmypy --help)."""
+    parser.print_help()
+
+
+# Client-side infrastructure.
+
+
+def request(
+    status_file: str, command: str, *, timeout: int | None = None, **kwds: object
+) -> dict[str, Any]:
+    """Send a request to the daemon.
+
+    Return the JSON dict with the response.
+
+    Raise BadStatus if there is something wrong with the status file
+    or if the process whose pid is in the status file has died.
+
+    Return {'error': <message>} if an IPC operation or receive()
+    raised OSError.  This covers cases such as connection refused or
+    closed prematurely as well as invalid JSON received.
+    """
+    response: dict[str, str] = {}
+    args = dict(kwds)
+    args["command"] = command
+    # Tell the server whether this request was initiated from a human-facing terminal,
+    # so that it can format the type checking output accordingly.
+    args["is_tty"] = sys.stdout.isatty() or should_force_color()
+    args["terminal_width"] = get_terminal_width()
+    bdata = json.dumps(args).encode("utf8")
+    _, name = get_status(status_file)
+    try:
+        with IPCClient(name, timeout) as client:
+            client.write(bdata)
+            response = receive(client)
+    except (OSError, IPCException) as err:
+        return {"error": str(err)}
+    # TODO: Other errors, e.g. ValueError, UnicodeError
+    else:
+        # Display debugging output written to stdout/stderr in the server process for convenience.
+        # This should not be confused with "out" and "err" fields in the response.
+        # Those fields hold the output of the "check" command, and are handled in check_output().
+        stdout = response.get("stdout")
+        if stdout:
+            sys.stdout.write(stdout)
+        stderr = response.get("stderr")
+        if stderr:
+            print("-" * 79)
+            print("stderr:")
+            sys.stdout.write(stderr)
+        return response
+
+
+def get_status(status_file: str) -> tuple[int, str]:
+    """Read status file and check if the process is alive.
+
+    Return (pid, connection_name) on success.
+
+    Raise BadStatus if something's wrong.
+    """
+    data = read_status(status_file)
+    return check_status(data)
+
+
+def check_status(data: dict[str, Any]) -> tuple[int, str]:
+    """Check if the process is alive.
+
+    Return (pid, connection_name) on success.
+
+    Raise BadStatus if something's wrong.
+    """
+    if "pid" not in data:
+        raise BadStatus("Invalid status file (no pid field)")
+    pid = data["pid"]
+    if not isinstance(pid, int):
+        raise BadStatus("pid field is not an int")
+    if not alive(pid):
+        raise BadStatus("Daemon has died")
+    if "connection_name" not in data:
+        raise BadStatus("Invalid status file (no connection_name field)")
+    connection_name = data["connection_name"]
+    if not isinstance(connection_name, str):
+        raise BadStatus("connection_name field is not a string")
+    return pid, connection_name
+
+
+def read_status(status_file: str) -> dict[str, object]:
+    """Read status file.
+
+    Raise BadStatus if the status file doesn't exist or contains
+    invalid JSON or the JSON is not a dict.
+    """
+    if not os.path.isfile(status_file):
+        raise BadStatus("No status file found")
+    with open(status_file) as f:
+        try:
+            data = json.load(f)
+        except Exception as e:
+            raise BadStatus("Malformed status file (not JSON)") from e
+    if not isinstance(data, dict):
+        raise BadStatus("Invalid status file (not a dict)")
+    return data
+
+
+def is_running(status_file: str) -> bool:
+    """Check if the server is running cleanly"""
+    try:
+        get_status(status_file)
+    except BadStatus:
+        return False
+    return True
+
+
+# Run main().
+def console_entry() -> None:
+    main(sys.argv[1:])

venv/lib/python3.12/site-packages/mypy/dmypy_os.py

@@ -0,0 +1,42 @@
+from __future__ import annotations
+
+import sys
+from typing import Any, Callable
+
+if sys.platform == "win32":
+    import ctypes
+    import subprocess
+    from ctypes.wintypes import DWORD, HANDLE
+
+    PROCESS_QUERY_LIMITED_INFORMATION = ctypes.c_ulong(0x1000)
+
+    kernel32 = ctypes.windll.kernel32
+    OpenProcess: Callable[[DWORD, int, int], HANDLE] = kernel32.OpenProcess
+    GetExitCodeProcess: Callable[[HANDLE, Any], int] = kernel32.GetExitCodeProcess
+else:
+    import os
+    import signal
+
+
+def alive(pid: int) -> bool:
+    """Is the process alive?"""
+    if sys.platform == "win32":
+        # why can't anything be easy...
+        status = DWORD()
+        handle = OpenProcess(PROCESS_QUERY_LIMITED_INFORMATION, 0, pid)
+        GetExitCodeProcess(handle, ctypes.byref(status))
+        return status.value == 259  # STILL_ACTIVE
+    else:
+        try:
+            os.kill(pid, 0)
+        except OSError:
+            return False
+        return True
+
+
+def kill(pid: int) -> None:
+    """Kill the process."""
+    if sys.platform == "win32":
+        subprocess.check_output(f"taskkill /pid {pid} /f /t")
+    else:
+        os.kill(pid, signal.SIGKILL)

venv/lib/python3.12/site-packages/mypy/dmypy_util.py

@@ -0,0 +1,31 @@
+"""Shared code between dmypy.py and dmypy_server.py.
+
+This should be pretty lightweight and not depend on other mypy code (other than ipc).
+"""
+
+from __future__ import annotations
+
+import json
+from typing import Any, Final
+
+from mypy.ipc import IPCBase
+
+DEFAULT_STATUS_FILE: Final = ".dmypy.json"
+
+
+def receive(connection: IPCBase) -> Any:
+    """Receive JSON data from a connection until EOF.
+
+    Raise OSError if the data received is not valid JSON or if it is
+    not a dict.
+    """
+    bdata = connection.read()
+    if not bdata:
+        raise OSError("No data received")
+    try:
+        data = json.loads(bdata.decode("utf8"))
+    except Exception as e:
+        raise OSError("Data received is not valid JSON") from e
+    if not isinstance(data, dict):
+        raise OSError(f"Data received is not a dict ({type(data)})")
+    return data

venv/lib/python3.12/site-packages/mypy/erasetype.py

@@ -0,0 +1,233 @@
+from __future__ import annotations
+
+from typing import Callable, Container, cast
+
+from mypy.nodes import ARG_STAR, ARG_STAR2
+from mypy.types import (
+    AnyType,
+    CallableType,
+    DeletedType,
+    ErasedType,
+    Instance,
+    LiteralType,
+    NoneType,
+    Overloaded,
+    Parameters,
+    ParamSpecType,
+    PartialType,
+    ProperType,
+    TupleType,
+    Type,
+    TypeAliasType,
+    TypedDictType,
+    TypeOfAny,
+    TypeTranslator,
+    TypeType,
+    TypeVarId,
+    TypeVarTupleType,
+    TypeVarType,
+    TypeVisitor,
+    UnboundType,
+    UninhabitedType,
+    UnionType,
+    UnpackType,
+    get_proper_type,
+    get_proper_types,
+)
+
+
+def erase_type(typ: Type) -> ProperType:
+    """Erase any type variables from a type.
+
+    Also replace tuple types with the corresponding concrete types.
+
+    Examples:
+      A -> A
+      B[X] -> B[Any]
+      Tuple[A, B] -> tuple
+      Callable[[A1, A2, ...], R] -> Callable[..., Any]
+      Type[X] -> Type[Any]
+    """
+    typ = get_proper_type(typ)
+    return typ.accept(EraseTypeVisitor())
+
+
+class EraseTypeVisitor(TypeVisitor[ProperType]):
+    def visit_unbound_type(self, t: UnboundType) -> ProperType:
+        # TODO: replace with an assert after UnboundType can't leak from semantic analysis.
+        return AnyType(TypeOfAny.from_error)
+
+    def visit_any(self, t: AnyType) -> ProperType:
+        return t
+
+    def visit_none_type(self, t: NoneType) -> ProperType:
+        return t
+
+    def visit_uninhabited_type(self, t: UninhabitedType) -> ProperType:
+        return t
+
+    def visit_erased_type(self, t: ErasedType) -> ProperType:
+        return t
+
+    def visit_partial_type(self, t: PartialType) -> ProperType:
+        # Should not get here.
+        raise RuntimeError("Cannot erase partial types")
+
+    def visit_deleted_type(self, t: DeletedType) -> ProperType:
+        return t
+
+    def visit_instance(self, t: Instance) -> ProperType:
+        return Instance(t.type, [AnyType(TypeOfAny.special_form)] * len(t.args), t.line)
+
+    def visit_type_var(self, t: TypeVarType) -> ProperType:
+        return AnyType(TypeOfAny.special_form)
+
+    def visit_param_spec(self, t: ParamSpecType) -> ProperType:
+        return AnyType(TypeOfAny.special_form)
+
+    def visit_parameters(self, t: Parameters) -> ProperType:
+        raise RuntimeError("Parameters should have been bound to a class")
+
+    def visit_type_var_tuple(self, t: TypeVarTupleType) -> ProperType:
+        return AnyType(TypeOfAny.special_form)
+
+    def visit_unpack_type(self, t: UnpackType) -> ProperType:
+        return AnyType(TypeOfAny.special_form)
+
+    def visit_callable_type(self, t: CallableType) -> ProperType:
+        # We must preserve the fallback type for overload resolution to work.
+        any_type = AnyType(TypeOfAny.special_form)
+        return CallableType(
+            arg_types=[any_type, any_type],
+            arg_kinds=[ARG_STAR, ARG_STAR2],
+            arg_names=[None, None],
+            ret_type=any_type,
+            fallback=t.fallback,
+            is_ellipsis_args=True,
+            implicit=True,
+        )
+
+    def visit_overloaded(self, t: Overloaded) -> ProperType:
+        return t.fallback.accept(self)
+
+    def visit_tuple_type(self, t: TupleType) -> ProperType:
+        return t.partial_fallback.accept(self)
+
+    def visit_typeddict_type(self, t: TypedDictType) -> ProperType:
+        return t.fallback.accept(self)
+
+    def visit_literal_type(self, t: LiteralType) -> ProperType:
+        # The fallback for literal types should always be either
+        # something like int or str, or an enum class -- types that
+        # don't contain any TypeVars. So there's no need to visit it.
+        return t
+
+    def visit_union_type(self, t: UnionType) -> ProperType:
+        erased_items = [erase_type(item) for item in t.items]
+        from mypy.typeops import make_simplified_union
+
+        return make_simplified_union(erased_items)
+
+    def visit_type_type(self, t: TypeType) -> ProperType:
+        return TypeType.make_normalized(t.item.accept(self), line=t.line)
+
+    def visit_type_alias_type(self, t: TypeAliasType) -> ProperType:
+        raise RuntimeError("Type aliases should be expanded before accepting this visitor")
+
+
+def erase_typevars(t: Type, ids_to_erase: Container[TypeVarId] | None = None) -> Type:
+    """Replace all type variables in a type with any,
+    or just the ones in the provided collection.
+    """
+
+    def erase_id(id: TypeVarId) -> bool:
+        if ids_to_erase is None:
+            return True
+        return id in ids_to_erase
+
+    return t.accept(TypeVarEraser(erase_id, AnyType(TypeOfAny.special_form)))
+
+
+def replace_meta_vars(t: Type, target_type: Type) -> Type:
+    """Replace unification variables in a type with the target type."""
+    return t.accept(TypeVarEraser(lambda id: id.is_meta_var(), target_type))
+
+
+class TypeVarEraser(TypeTranslator):
+    """Implementation of type erasure"""
+
+    def __init__(self, erase_id: Callable[[TypeVarId], bool], replacement: Type) -> None:
+        self.erase_id = erase_id
+        self.replacement = replacement
+
+    def visit_type_var(self, t: TypeVarType) -> Type:
+        if self.erase_id(t.id):
+            return self.replacement
+        return t
+
+    def visit_type_var_tuple(self, t: TypeVarTupleType) -> Type:
+        if self.erase_id(t.id):
+            return self.replacement
+        return t
+
+    def visit_param_spec(self, t: ParamSpecType) -> Type:
+        if self.erase_id(t.id):
+            return self.replacement
+        return t
+
+    def visit_type_alias_type(self, t: TypeAliasType) -> Type:
+        # Type alias target can't contain bound type variables (not bound by the type
+        # alias itself), so it is safe to just erase the arguments.
+        return t.copy_modified(args=[a.accept(self) for a in t.args])
+
+
+def remove_instance_last_known_values(t: Type) -> Type:
+    return t.accept(LastKnownValueEraser())
+
+
+class LastKnownValueEraser(TypeTranslator):
+    """Removes the Literal[...] type that may be associated with any
+    Instance types."""
+
+    def visit_instance(self, t: Instance) -> Type:
+        if not t.last_known_value and not t.args:
+            return t
+        return t.copy_modified(args=[a.accept(self) for a in t.args], last_known_value=None)
+
+    def visit_type_alias_type(self, t: TypeAliasType) -> Type:
+        # Type aliases can't contain literal values, because they are
+        # always constructed as explicit types.
+        return t
+
+    def visit_union_type(self, t: UnionType) -> Type:
+        new = cast(UnionType, super().visit_union_type(t))
+        # Erasure can result in many duplicate items; merge them.
+        # Call make_simplified_union only on lists of instance types
+        # that all have the same fullname, to avoid simplifying too
+        # much.
+        instances = [item for item in new.items if isinstance(get_proper_type(item), Instance)]
+        # Avoid merge in simple cases such as optional types.
+        if len(instances) > 1:
+            instances_by_name: dict[str, list[Instance]] = {}
+            p_new_items = get_proper_types(new.items)
+            for p_item in p_new_items:
+                if isinstance(p_item, Instance) and not p_item.args:
+                    instances_by_name.setdefault(p_item.type.fullname, []).append(p_item)
+            merged: list[Type] = []
+            for item in new.items:
+                orig_item = item
+                item = get_proper_type(item)
+                if isinstance(item, Instance) and not item.args:
+                    types = instances_by_name.get(item.type.fullname)
+                    if types is not None:
+                        if len(types) == 1:
+                            merged.append(item)
+                        else:
+                            from mypy.typeops import make_simplified_union
+
+                            merged.append(make_simplified_union(types))
+                            del instances_by_name[item.type.fullname]
+                else:
+                    merged.append(orig_item)
+            return UnionType.make_union(merged)
+        return new

venv/lib/python3.12/site-packages/mypy/errorcodes.py

@@ -0,0 +1,263 @@
+"""Classification of possible errors mypy can detect.
+
+These can be used for filtering specific errors.
+"""
+
+from __future__ import annotations
+
+from collections import defaultdict
+from typing import Final
+
+from mypy_extensions import mypyc_attr
+
+error_codes: dict[str, ErrorCode] = {}
+sub_code_map: dict[str, set[str]] = defaultdict(set)
+
+
+@mypyc_attr(allow_interpreted_subclasses=True)
+class ErrorCode:
+    def __init__(
+        self,
+        code: str,
+        description: str,
+        category: str,
+        default_enabled: bool = True,
+        sub_code_of: ErrorCode | None = None,
+    ) -> None:
+        self.code = code
+        self.description = description
+        self.category = category
+        self.default_enabled = default_enabled
+        self.sub_code_of = sub_code_of
+        if sub_code_of is not None:
+            assert sub_code_of.sub_code_of is None, "Nested subcategories are not supported"
+            sub_code_map[sub_code_of.code].add(code)
+        error_codes[code] = self
+
+    def __str__(self) -> str:
+        return f"<ErrorCode {self.code}>"
+
+    def __eq__(self, other: object) -> bool:
+        if not isinstance(other, ErrorCode):
+            return False
+        return self.code == other.code
+
+    def __hash__(self) -> int:
+        return hash((self.code,))
+
+
+ATTR_DEFINED: Final = ErrorCode("attr-defined", "Check that attribute exists", "General")
+NAME_DEFINED: Final = ErrorCode("name-defined", "Check that name is defined", "General")
+CALL_ARG: Final[ErrorCode] = ErrorCode(
+    "call-arg", "Check number, names and kinds of arguments in calls", "General"
+)
+ARG_TYPE: Final = ErrorCode("arg-type", "Check argument types in calls", "General")
+CALL_OVERLOAD: Final = ErrorCode(
+    "call-overload", "Check that an overload variant matches arguments", "General"
+)
+VALID_TYPE: Final[ErrorCode] = ErrorCode(
+    "valid-type", "Check that type (annotation) is valid", "General"
+)
+VAR_ANNOTATED: Final = ErrorCode(
+    "var-annotated", "Require variable annotation if type can't be inferred", "General"
+)
+OVERRIDE: Final = ErrorCode(
+    "override", "Check that method override is compatible with base class", "General"
+)
+RETURN: Final[ErrorCode] = ErrorCode(
+    "return", "Check that function always returns a value", "General"
+)
+RETURN_VALUE: Final[ErrorCode] = ErrorCode(
+    "return-value", "Check that return value is compatible with signature", "General"
+)
+ASSIGNMENT: Final[ErrorCode] = ErrorCode(
+    "assignment", "Check that assigned value is compatible with target", "General"
+)
+METHOD_ASSIGN: Final[ErrorCode] = ErrorCode(
+    "method-assign",
+    "Check that assignment target is not a method",
+    "General",
+    sub_code_of=ASSIGNMENT,
+)
+TYPE_ARG: Final = ErrorCode("type-arg", "Check that generic type arguments are present", "General")
+TYPE_VAR: Final = ErrorCode("type-var", "Check that type variable values are valid", "General")
+UNION_ATTR: Final = ErrorCode(
+    "union-attr", "Check that attribute exists in each item of a union", "General"
+)
+INDEX: Final = ErrorCode("index", "Check indexing operations", "General")
+OPERATOR: Final = ErrorCode("operator", "Check that operator is valid for operands", "General")
+LIST_ITEM: Final = ErrorCode(
+    "list-item", "Check list items in a list expression [item, ...]", "General"
+)
+DICT_ITEM: Final = ErrorCode(
+    "dict-item", "Check dict items in a dict expression {key: value, ...}", "General"
+)
+TYPEDDICT_ITEM: Final = ErrorCode(
+    "typeddict-item", "Check items when constructing TypedDict", "General"
+)
+TYPEDDICT_UNKNOWN_KEY: Final = ErrorCode(
+    "typeddict-unknown-key",
+    "Check unknown keys when constructing TypedDict",
+    "General",
+    sub_code_of=TYPEDDICT_ITEM,
+)
+HAS_TYPE: Final = ErrorCode(
+    "has-type", "Check that type of reference can be determined", "General"
+)
+IMPORT: Final = ErrorCode(
+    "import", "Require that imported module can be found or has stubs", "General"
+)
+IMPORT_NOT_FOUND: Final = ErrorCode(
+    "import-not-found", "Require that imported module can be found", "General", sub_code_of=IMPORT
+)
+IMPORT_UNTYPED: Final = ErrorCode(
+    "import-untyped", "Require that imported module has stubs", "General", sub_code_of=IMPORT
+)
+NO_REDEF: Final = ErrorCode("no-redef", "Check that each name is defined once", "General")
+FUNC_RETURNS_VALUE: Final = ErrorCode(
+    "func-returns-value", "Check that called function returns a value in value context", "General"
+)
+ABSTRACT: Final = ErrorCode(
+    "abstract", "Prevent instantiation of classes with abstract attributes", "General"
+)
+TYPE_ABSTRACT: Final = ErrorCode(
+    "type-abstract", "Require only concrete classes where Type[...] is expected", "General"
+)
+VALID_NEWTYPE: Final = ErrorCode(
+    "valid-newtype", "Check that argument 2 to NewType is valid", "General"
+)
+STRING_FORMATTING: Final = ErrorCode(
+    "str-format", "Check that string formatting/interpolation is type-safe", "General"
+)
+STR_BYTES_PY3: Final = ErrorCode(
+    "str-bytes-safe", "Warn about implicit coercions related to bytes and string types", "General"
+)
+EXIT_RETURN: Final = ErrorCode(
+    "exit-return", "Warn about too general return type for '__exit__'", "General"
+)
+LITERAL_REQ: Final = ErrorCode("literal-required", "Check that value is a literal", "General")
+UNUSED_COROUTINE: Final = ErrorCode(
+    "unused-coroutine", "Ensure that all coroutines are used", "General"
+)
+# TODO: why do we need the explicit type here? Without it mypyc CI builds fail with
+# mypy/message_registry.py:37: error: Cannot determine type of "EMPTY_BODY"  [has-type]
+EMPTY_BODY: Final[ErrorCode] = ErrorCode(
+    "empty-body",
+    "A dedicated error code to opt out return errors for empty/trivial bodies",
+    "General",
+)
+SAFE_SUPER: Final = ErrorCode(
+    "safe-super", "Warn about calls to abstract methods with empty/trivial bodies", "General"
+)
+TOP_LEVEL_AWAIT: Final = ErrorCode(
+    "top-level-await", "Warn about top level await expressions", "General"
+)
+AWAIT_NOT_ASYNC: Final = ErrorCode(
+    "await-not-async", 'Warn about "await" outside coroutine ("async def")', "General"
+)
+# These error codes aren't enabled by default.
+NO_UNTYPED_DEF: Final[ErrorCode] = ErrorCode(
+    "no-untyped-def", "Check that every function has an annotation", "General"
+)
+NO_UNTYPED_CALL: Final = ErrorCode(
+    "no-untyped-call",
+    "Disallow calling functions without type annotations from annotated functions",
+    "General",
+)
+REDUNDANT_CAST: Final = ErrorCode(
+    "redundant-cast", "Check that cast changes type of expression", "General"
+)
+ASSERT_TYPE: Final = ErrorCode("assert-type", "Check that assert_type() call succeeds", "General")
+COMPARISON_OVERLAP: Final = ErrorCode(
+    "comparison-overlap", "Check that types in comparisons and 'in' expressions overlap", "General"
+)
+NO_ANY_UNIMPORTED: Final = ErrorCode(
+    "no-any-unimported", 'Reject "Any" types from unfollowed imports', "General"
+)
+NO_ANY_RETURN: Final = ErrorCode(
+    "no-any-return",
+    'Reject returning value with "Any" type if return type is not "Any"',
+    "General",
+)
+UNREACHABLE: Final = ErrorCode(
+    "unreachable", "Warn about unreachable statements or expressions", "General"
+)
+ANNOTATION_UNCHECKED = ErrorCode(
+    "annotation-unchecked", "Notify about type annotations in unchecked functions", "General"
+)
+POSSIBLY_UNDEFINED: Final[ErrorCode] = ErrorCode(
+    "possibly-undefined",
+    "Warn about variables that are defined only in some execution paths",
+    "General",
+    default_enabled=False,
+)
+REDUNDANT_EXPR: Final = ErrorCode(
+    "redundant-expr", "Warn about redundant expressions", "General", default_enabled=False
+)
+TRUTHY_BOOL: Final[ErrorCode] = ErrorCode(
+    "truthy-bool",
+    "Warn about expressions that could always evaluate to true in boolean contexts",
+    "General",
+    default_enabled=False,
+)
+TRUTHY_FUNCTION: Final[ErrorCode] = ErrorCode(
+    "truthy-function",
+    "Warn about function that always evaluate to true in boolean contexts",
+    "General",
+)
+TRUTHY_ITERABLE: Final[ErrorCode] = ErrorCode(
+    "truthy-iterable",
+    "Warn about Iterable expressions that could always evaluate to true in boolean contexts",
+    "General",
+    default_enabled=False,
+)
+NAME_MATCH: Final = ErrorCode(
+    "name-match", "Check that type definition has consistent naming", "General"
+)
+NO_OVERLOAD_IMPL: Final = ErrorCode(
+    "no-overload-impl",
+    "Check that overloaded functions outside stub files have an implementation",
+    "General",
+)
+IGNORE_WITHOUT_CODE: Final = ErrorCode(
+    "ignore-without-code",
+    "Warn about '# type: ignore' comments which do not have error codes",
+    "General",
+    default_enabled=False,
+)
+UNUSED_AWAITABLE: Final = ErrorCode(
+    "unused-awaitable",
+    "Ensure that all awaitable values are used",
+    "General",
+    default_enabled=False,
+)
+REDUNDANT_SELF_TYPE = ErrorCode(
+    "redundant-self",
+    "Warn about redundant Self type annotations on method first argument",
+    "General",
+    default_enabled=False,
+)
+USED_BEFORE_DEF: Final[ErrorCode] = ErrorCode(
+    "used-before-def", "Warn about variables that are used before they are defined", "General"
+)
+UNUSED_IGNORE: Final = ErrorCode(
+    "unused-ignore", "Ensure that all type ignores are used", "General", default_enabled=False
+)
+EXPLICIT_OVERRIDE_REQUIRED: Final = ErrorCode(
+    "explicit-override",
+    "Require @override decorator if method is overriding a base class method",
+    "General",
+    default_enabled=False,
+)
+
+
+# Syntax errors are often blocking.
+SYNTAX: Final[ErrorCode] = ErrorCode("syntax", "Report syntax errors", "General")
+
+# This is an internal marker code for a whole-file ignore. It is not intended to
+# be user-visible.
+FILE: Final = ErrorCode("file", "Internal marker for a whole file being ignored", "General")
+del error_codes[FILE.code]
+
+# This is a catch-all for remaining uncategorized errors.
+MISC: Final = ErrorCode("misc", "Miscellaneous other checks", "General")

venv/lib/python3.12/site-packages/mypy/evalexpr.py

@@ -0,0 +1,204 @@
+"""
+
+Evaluate an expression.
+
+Used by stubtest; in a separate file because things break if we don't
+put it in a mypyc-compiled file.
+
+"""
+import ast
+from typing import Final
+
+import mypy.nodes
+from mypy.visitor import ExpressionVisitor
+
+UNKNOWN = object()
+
+
+class _NodeEvaluator(ExpressionVisitor[object]):
+    def visit_int_expr(self, o: mypy.nodes.IntExpr) -> int:
+        return o.value
+
+    def visit_str_expr(self, o: mypy.nodes.StrExpr) -> str:
+        return o.value
+
+    def visit_bytes_expr(self, o: mypy.nodes.BytesExpr) -> object:
+        # The value of a BytesExpr is a string created from the repr()
+        # of the bytes object. Get the original bytes back.
+        try:
+            return ast.literal_eval(f"b'{o.value}'")
+        except SyntaxError:
+            return ast.literal_eval(f'b"{o.value}"')
+
+    def visit_float_expr(self, o: mypy.nodes.FloatExpr) -> float:
+        return o.value
+
+    def visit_complex_expr(self, o: mypy.nodes.ComplexExpr) -> object:
+        return o.value
+
+    def visit_ellipsis(self, o: mypy.nodes.EllipsisExpr) -> object:
+        return Ellipsis
+
+    def visit_star_expr(self, o: mypy.nodes.StarExpr) -> object:
+        return UNKNOWN
+
+    def visit_name_expr(self, o: mypy.nodes.NameExpr) -> object:
+        if o.name == "True":
+            return True
+        elif o.name == "False":
+            return False
+        elif o.name == "None":
+            return None
+        # TODO: Handle more names by figuring out a way to hook into the
+        # symbol table.
+        return UNKNOWN
+
+    def visit_member_expr(self, o: mypy.nodes.MemberExpr) -> object:
+        return UNKNOWN
+
+    def visit_yield_from_expr(self, o: mypy.nodes.YieldFromExpr) -> object:
+        return UNKNOWN
+
+    def visit_yield_expr(self, o: mypy.nodes.YieldExpr) -> object:
+        return UNKNOWN
+
+    def visit_call_expr(self, o: mypy.nodes.CallExpr) -> object:
+        return UNKNOWN
+
+    def visit_op_expr(self, o: mypy.nodes.OpExpr) -> object:
+        return UNKNOWN
+
+    def visit_comparison_expr(self, o: mypy.nodes.ComparisonExpr) -> object:
+        return UNKNOWN
+
+    def visit_cast_expr(self, o: mypy.nodes.CastExpr) -> object:
+        return o.expr.accept(self)
+
+    def visit_assert_type_expr(self, o: mypy.nodes.AssertTypeExpr) -> object:
+        return o.expr.accept(self)
+
+    def visit_reveal_expr(self, o: mypy.nodes.RevealExpr) -> object:
+        return UNKNOWN
+
+    def visit_super_expr(self, o: mypy.nodes.SuperExpr) -> object:
+        return UNKNOWN
+
+    def visit_unary_expr(self, o: mypy.nodes.UnaryExpr) -> object:
+        operand = o.expr.accept(self)
+        if operand is UNKNOWN:
+            return UNKNOWN
+        if o.op == "-":
+            if isinstance(operand, (int, float, complex)):
+                return -operand
+        elif o.op == "+":
+            if isinstance(operand, (int, float, complex)):
+                return +operand
+        elif o.op == "~":
+            if isinstance(operand, int):
+                return ~operand
+        elif o.op == "not":
+            if isinstance(operand, (bool, int, float, str, bytes)):
+                return not operand
+        return UNKNOWN
+
+    def visit_assignment_expr(self, o: mypy.nodes.AssignmentExpr) -> object:
+        return o.value.accept(self)
+
+    def visit_list_expr(self, o: mypy.nodes.ListExpr) -> object:
+        items = [item.accept(self) for item in o.items]
+        if all(item is not UNKNOWN for item in items):
+            return items
+        return UNKNOWN
+
+    def visit_dict_expr(self, o: mypy.nodes.DictExpr) -> object:
+        items = [
+            (UNKNOWN if key is None else key.accept(self), value.accept(self))
+            for key, value in o.items
+        ]
+        if all(key is not UNKNOWN and value is not None for key, value in items):
+            return dict(items)
+        return UNKNOWN
+
+    def visit_tuple_expr(self, o: mypy.nodes.TupleExpr) -> object:
+        items = [item.accept(self) for item in o.items]
+        if all(item is not UNKNOWN for item in items):
+            return tuple(items)
+        return UNKNOWN
+
+    def visit_set_expr(self, o: mypy.nodes.SetExpr) -> object:
+        items = [item.accept(self) for item in o.items]
+        if all(item is not UNKNOWN for item in items):
+            return set(items)
+        return UNKNOWN
+
+    def visit_index_expr(self, o: mypy.nodes.IndexExpr) -> object:
+        return UNKNOWN
+
+    def visit_type_application(self, o: mypy.nodes.TypeApplication) -> object:
+        return UNKNOWN
+
+    def visit_lambda_expr(self, o: mypy.nodes.LambdaExpr) -> object:
+        return UNKNOWN
+
+    def visit_list_comprehension(self, o: mypy.nodes.ListComprehension) -> object:
+        return UNKNOWN
+
+    def visit_set_comprehension(self, o: mypy.nodes.SetComprehension) -> object:
+        return UNKNOWN
+
+    def visit_dictionary_comprehension(self, o: mypy.nodes.DictionaryComprehension) -> object:
+        return UNKNOWN
+
+    def visit_generator_expr(self, o: mypy.nodes.GeneratorExpr) -> object:
+        return UNKNOWN
+
+    def visit_slice_expr(self, o: mypy.nodes.SliceExpr) -> object:
+        return UNKNOWN
+
+    def visit_conditional_expr(self, o: mypy.nodes.ConditionalExpr) -> object:
+        return UNKNOWN
+
+    def visit_type_var_expr(self, o: mypy.nodes.TypeVarExpr) -> object:
+        return UNKNOWN
+
+    def visit_paramspec_expr(self, o: mypy.nodes.ParamSpecExpr) -> object:
+        return UNKNOWN
+
+    def visit_type_var_tuple_expr(self, o: mypy.nodes.TypeVarTupleExpr) -> object:
+        return UNKNOWN
+
+    def visit_type_alias_expr(self, o: mypy.nodes.TypeAliasExpr) -> object:
+        return UNKNOWN
+
+    def visit_namedtuple_expr(self, o: mypy.nodes.NamedTupleExpr) -> object:
+        return UNKNOWN
+
+    def visit_enum_call_expr(self, o: mypy.nodes.EnumCallExpr) -> object:
+        return UNKNOWN
+
+    def visit_typeddict_expr(self, o: mypy.nodes.TypedDictExpr) -> object:
+        return UNKNOWN
+
+    def visit_newtype_expr(self, o: mypy.nodes.NewTypeExpr) -> object:
+        return UNKNOWN
+
+    def visit__promote_expr(self, o: mypy.nodes.PromoteExpr) -> object:
+        return UNKNOWN
+
+    def visit_await_expr(self, o: mypy.nodes.AwaitExpr) -> object:
+        return UNKNOWN
+
+    def visit_temp_node(self, o: mypy.nodes.TempNode) -> object:
+        return UNKNOWN
+
+
+_evaluator: Final = _NodeEvaluator()
+
+
+def evaluate_expression(expr: mypy.nodes.Expression) -> object:
+    """Evaluate an expression at runtime.
+
+    Return the result of the expression, or UNKNOWN if the expression cannot be
+    evaluated.
+    """
+    return expr.accept(_evaluator)

venv/lib/python3.12/site-packages/mypy/expandtype.py

@@ -0,0 +1,516 @@
+from __future__ import annotations
+
+from typing import Final, Iterable, Mapping, Sequence, TypeVar, cast, overload
+
+from mypy.nodes import ARG_STAR, Var
+from mypy.state import state
+from mypy.types import (
+    ANY_STRATEGY,
+    AnyType,
+    BoolTypeQuery,
+    CallableType,
+    DeletedType,
+    ErasedType,
+    FunctionLike,
+    Instance,
+    LiteralType,
+    NoneType,
+    Overloaded,
+    Parameters,
+    ParamSpecFlavor,
+    ParamSpecType,
+    PartialType,
+    ProperType,
+    TrivialSyntheticTypeTranslator,
+    TupleType,
+    Type,
+    TypeAliasType,
+    TypedDictType,
+    TypeType,
+    TypeVarId,
+    TypeVarLikeType,
+    TypeVarTupleType,
+    TypeVarType,
+    UnboundType,
+    UninhabitedType,
+    UnionType,
+    UnpackType,
+    flatten_nested_unions,
+    get_proper_type,
+    split_with_prefix_and_suffix,
+)
+from mypy.typevartuples import split_with_instance
+
+# Solving the import cycle:
+import mypy.type_visitor  # ruff: isort: skip
+
+# WARNING: these functions should never (directly or indirectly) depend on
+# is_subtype(), meet_types(), join_types() etc.
+# TODO: add a static dependency test for this.
+
+
+@overload
+def expand_type(typ: CallableType, env: Mapping[TypeVarId, Type]) -> CallableType:
+    ...
+
+
+@overload
+def expand_type(typ: ProperType, env: Mapping[TypeVarId, Type]) -> ProperType:
+    ...
+
+
+@overload
+def expand_type(typ: Type, env: Mapping[TypeVarId, Type]) -> Type:
+    ...
+
+
+def expand_type(typ: Type, env: Mapping[TypeVarId, Type]) -> Type:
+    """Substitute any type variable references in a type given by a type
+    environment.
+    """
+    return typ.accept(ExpandTypeVisitor(env))
+
+
+@overload
+def expand_type_by_instance(typ: CallableType, instance: Instance) -> CallableType:
+    ...
+
+
+@overload
+def expand_type_by_instance(typ: ProperType, instance: Instance) -> ProperType:
+    ...
+
+
+@overload
+def expand_type_by_instance(typ: Type, instance: Instance) -> Type:
+    ...
+
+
+def expand_type_by_instance(typ: Type, instance: Instance) -> Type:
+    """Substitute type variables in type using values from an Instance.
+    Type variables are considered to be bound by the class declaration."""
+    if not instance.args:
+        return typ
+    else:
+        variables: dict[TypeVarId, Type] = {}
+        if instance.type.has_type_var_tuple_type:
+            assert instance.type.type_var_tuple_prefix is not None
+            assert instance.type.type_var_tuple_suffix is not None
+
+            args_prefix, args_middle, args_suffix = split_with_instance(instance)
+            tvars_prefix, tvars_middle, tvars_suffix = split_with_prefix_and_suffix(
+                tuple(instance.type.defn.type_vars),
+                instance.type.type_var_tuple_prefix,
+                instance.type.type_var_tuple_suffix,
+            )
+            tvar = tvars_middle[0]
+            assert isinstance(tvar, TypeVarTupleType)
+            variables = {tvar.id: TupleType(list(args_middle), tvar.tuple_fallback)}
+            instance_args = args_prefix + args_suffix
+            tvars = tvars_prefix + tvars_suffix
+        else:
+            tvars = tuple(instance.type.defn.type_vars)
+            instance_args = instance.args
+
+        for binder, arg in zip(tvars, instance_args):
+            assert isinstance(binder, TypeVarLikeType)
+            variables[binder.id] = arg
+
+        return expand_type(typ, variables)
+
+
+F = TypeVar("F", bound=FunctionLike)
+
+
+def freshen_function_type_vars(callee: F) -> F:
+    """Substitute fresh type variables for generic function type variables."""
+    if isinstance(callee, CallableType):
+        if not callee.is_generic():
+            return cast(F, callee)
+        tvs = []
+        tvmap: dict[TypeVarId, Type] = {}
+        for v in callee.variables:
+            tv = v.new_unification_variable(v)
+            tvs.append(tv)
+            tvmap[v.id] = tv
+        fresh = expand_type(callee, tvmap).copy_modified(variables=tvs)
+        return cast(F, fresh)
+    else:
+        assert isinstance(callee, Overloaded)
+        fresh_overload = Overloaded([freshen_function_type_vars(item) for item in callee.items])
+        return cast(F, fresh_overload)
+
+
+class HasGenericCallable(BoolTypeQuery):
+    def __init__(self) -> None:
+        super().__init__(ANY_STRATEGY)
+
+    def visit_callable_type(self, t: CallableType) -> bool:
+        return t.is_generic() or super().visit_callable_type(t)
+
+
+# Share a singleton since this is performance sensitive
+has_generic_callable: Final = HasGenericCallable()
+
+
+T = TypeVar("T", bound=Type)
+
+
+def freshen_all_functions_type_vars(t: T) -> T:
+    result: Type
+    has_generic_callable.reset()
+    if not t.accept(has_generic_callable):
+        return t  # Fast path to avoid expensive freshening
+    else:
+        result = t.accept(FreshenCallableVisitor())
+        assert isinstance(result, type(t))
+        return result
+
+
+class FreshenCallableVisitor(mypy.type_visitor.TypeTranslator):
+    def visit_callable_type(self, t: CallableType) -> Type:
+        result = super().visit_callable_type(t)
+        assert isinstance(result, ProperType) and isinstance(result, CallableType)
+        return freshen_function_type_vars(result)
+
+    def visit_type_alias_type(self, t: TypeAliasType) -> Type:
+        # Same as for ExpandTypeVisitor
+        return t.copy_modified(args=[arg.accept(self) for arg in t.args])
+
+
+class ExpandTypeVisitor(TrivialSyntheticTypeTranslator):
+    """Visitor that substitutes type variables with values."""
+
+    variables: Mapping[TypeVarId, Type]  # TypeVar id -> TypeVar value
+
+    def __init__(self, variables: Mapping[TypeVarId, Type]) -> None:
+        self.variables = variables
+
+    def visit_unbound_type(self, t: UnboundType) -> Type:
+        return t
+
+    def visit_any(self, t: AnyType) -> Type:
+        return t
+
+    def visit_none_type(self, t: NoneType) -> Type:
+        return t
+
+    def visit_uninhabited_type(self, t: UninhabitedType) -> Type:
+        return t
+
+    def visit_deleted_type(self, t: DeletedType) -> Type:
+        return t
+
+    def visit_erased_type(self, t: ErasedType) -> Type:
+        # This may happen during type inference if some function argument
+        # type is a generic callable, and its erased form will appear in inferred
+        # constraints, then solver may check subtyping between them, which will trigger
+        # unify_generic_callables(), this is why we can get here. Another example is
+        # when inferring type of lambda in generic context, the lambda body contains
+        # a generic method in generic class.
+        return t
+
+    def visit_instance(self, t: Instance) -> Type:
+        args = self.expand_types_with_unpack(list(t.args))
+        if isinstance(args, list):
+            return t.copy_modified(args=args)
+        else:
+            return args
+
+    def visit_type_var(self, t: TypeVarType) -> Type:
+        # Normally upper bounds can't contain other type variables, the only exception is
+        # special type variable Self`0 <: C[T, S], where C is the class where Self is used.
+        if t.id.raw_id == 0:
+            t = t.copy_modified(upper_bound=t.upper_bound.accept(self))
+        repl = self.variables.get(t.id, t)
+        if isinstance(repl, ProperType) and isinstance(repl, Instance):
+            # TODO: do we really need to do this?
+            # If I try to remove this special-casing ~40 tests fail on reveal_type().
+            return repl.copy_modified(last_known_value=None)
+        return repl
+
+    def visit_param_spec(self, t: ParamSpecType) -> Type:
+        # Set prefix to something empty, so we don't duplicate it below.
+        repl = self.variables.get(t.id, t.copy_modified(prefix=Parameters([], [], [])))
+        if isinstance(repl, ParamSpecType):
+            return repl.copy_modified(
+                flavor=t.flavor,
+                prefix=t.prefix.copy_modified(
+                    arg_types=self.expand_types(t.prefix.arg_types) + repl.prefix.arg_types,
+                    arg_kinds=t.prefix.arg_kinds + repl.prefix.arg_kinds,
+                    arg_names=t.prefix.arg_names + repl.prefix.arg_names,
+                ),
+            )
+        elif isinstance(repl, Parameters):
+            assert t.flavor == ParamSpecFlavor.BARE
+            return Parameters(
+                self.expand_types(t.prefix.arg_types) + repl.arg_types,
+                t.prefix.arg_kinds + repl.arg_kinds,
+                t.prefix.arg_names + repl.arg_names,
+                variables=[*t.prefix.variables, *repl.variables],
+            )
+        else:
+            # TODO: replace this with "assert False"
+            return repl
+
+    def visit_type_var_tuple(self, t: TypeVarTupleType) -> Type:
+        # Sometimes solver may need to expand a type variable with (a copy of) itself
+        # (usually together with other TypeVars, but it is hard to filter out TypeVarTuples).
+        repl = self.variables.get(t.id, t)
+        if isinstance(repl, TypeVarTupleType):
+            return repl
+        raise NotImplementedError
+
+    def visit_unpack_type(self, t: UnpackType) -> Type:
+        # It is impossible to reasonably implement visit_unpack_type, because
+        # unpacking inherently expands to something more like a list of types.
+        #
+        # Relevant sections that can call unpack should call expand_unpack()
+        # instead.
+        # However, if the item is a variadic tuple, we can simply carry it over.
+        # In particular, if we expand A[*tuple[T, ...]] with substitutions {T: str},
+        # it is hard to assert this without getting proper type. Another important
+        # example is non-normalized types when called from semanal.py.
+        return UnpackType(t.type.accept(self))
+
+    def expand_unpack(self, t: UnpackType) -> list[Type]:
+        assert isinstance(t.type, TypeVarTupleType)
+        repl = get_proper_type(self.variables.get(t.type.id, t.type))
+        if isinstance(repl, TupleType):
+            return repl.items
+        elif (
+            isinstance(repl, Instance)
+            and repl.type.fullname == "builtins.tuple"
+            or isinstance(repl, TypeVarTupleType)
+        ):
+            return [UnpackType(typ=repl)]
+        elif isinstance(repl, (AnyType, UninhabitedType)):
+            # Replace *Ts = Any with *Ts = *tuple[Any, ...] and some for <nothing>.
+            # These types may appear here as a result of user error or failed inference.
+            return [UnpackType(t.type.tuple_fallback.copy_modified(args=[repl]))]
+        else:
+            raise RuntimeError(f"Invalid type replacement to expand: {repl}")
+
+    def visit_parameters(self, t: Parameters) -> Type:
+        return t.copy_modified(arg_types=self.expand_types(t.arg_types))
+
+    def interpolate_args_for_unpack(self, t: CallableType, var_arg: UnpackType) -> list[Type]:
+        star_index = t.arg_kinds.index(ARG_STAR)
+        prefix = self.expand_types(t.arg_types[:star_index])
+        suffix = self.expand_types(t.arg_types[star_index + 1 :])
+
+        var_arg_type = get_proper_type(var_arg.type)
+        # We have something like Unpack[Tuple[Unpack[Ts], X1, X2]]
+        if isinstance(var_arg_type, TupleType):
+            expanded_tuple = var_arg_type.accept(self)
+            assert isinstance(expanded_tuple, ProperType) and isinstance(expanded_tuple, TupleType)
+            expanded_items = expanded_tuple.items
+            fallback = var_arg_type.partial_fallback
+        else:
+            # We have plain Unpack[Ts]
+            assert isinstance(var_arg_type, TypeVarTupleType)
+            fallback = var_arg_type.tuple_fallback
+            expanded_items = self.expand_unpack(var_arg)
+        new_unpack = UnpackType(TupleType(expanded_items, fallback))
+        return prefix + [new_unpack] + suffix
+
+    def visit_callable_type(self, t: CallableType) -> CallableType:
+        param_spec = t.param_spec()
+        if param_spec is not None:
+            repl = self.variables.get(param_spec.id)
+            # If a ParamSpec in a callable type is substituted with a
+            # callable type, we can't use normal substitution logic,
+            # since ParamSpec is actually split into two components
+            # *P.args and **P.kwargs in the original type. Instead, we
+            # must expand both of them with all the argument types,
+            # kinds and names in the replacement. The return type in
+            # the replacement is ignored.
+            if isinstance(repl, Parameters):
+                # We need to expand both the types in the prefix and the ParamSpec itself
+                return t.copy_modified(
+                    arg_types=self.expand_types(t.arg_types[:-2]) + repl.arg_types,
+                    arg_kinds=t.arg_kinds[:-2] + repl.arg_kinds,
+                    arg_names=t.arg_names[:-2] + repl.arg_names,
+                    ret_type=t.ret_type.accept(self),
+                    type_guard=(t.type_guard.accept(self) if t.type_guard is not None else None),
+                    imprecise_arg_kinds=(t.imprecise_arg_kinds or repl.imprecise_arg_kinds),
+                    variables=[*repl.variables, *t.variables],
+                )
+            elif isinstance(repl, ParamSpecType):
+                # We're substituting one ParamSpec for another; this can mean that the prefix
+                # changes, e.g. substitute Concatenate[int, P] in place of Q.
+                prefix = repl.prefix
+                clean_repl = repl.copy_modified(prefix=Parameters([], [], []))
+                return t.copy_modified(
+                    arg_types=self.expand_types(t.arg_types[:-2])
+                    + prefix.arg_types
+                    + [
+                        clean_repl.with_flavor(ParamSpecFlavor.ARGS),
+                        clean_repl.with_flavor(ParamSpecFlavor.KWARGS),
+                    ],
+                    arg_kinds=t.arg_kinds[:-2] + prefix.arg_kinds + t.arg_kinds[-2:],
+                    arg_names=t.arg_names[:-2] + prefix.arg_names + t.arg_names[-2:],
+                    ret_type=t.ret_type.accept(self),
+                    from_concatenate=t.from_concatenate or bool(repl.prefix.arg_types),
+                    imprecise_arg_kinds=(t.imprecise_arg_kinds or prefix.imprecise_arg_kinds),
+                )
+
+        var_arg = t.var_arg()
+        needs_normalization = False
+        if var_arg is not None and isinstance(var_arg.typ, UnpackType):
+            needs_normalization = True
+            arg_types = self.interpolate_args_for_unpack(t, var_arg.typ)
+        else:
+            arg_types = self.expand_types(t.arg_types)
+        expanded = t.copy_modified(
+            arg_types=arg_types,
+            ret_type=t.ret_type.accept(self),
+            type_guard=(t.type_guard.accept(self) if t.type_guard is not None else None),
+        )
+        if needs_normalization:
+            return expanded.with_normalized_var_args()
+        return expanded
+
+    def visit_overloaded(self, t: Overloaded) -> Type:
+        items: list[CallableType] = []
+        for item in t.items:
+            new_item = item.accept(self)
+            assert isinstance(new_item, ProperType)
+            assert isinstance(new_item, CallableType)
+            items.append(new_item)
+        return Overloaded(items)
+
+    def expand_types_with_unpack(
+        self, typs: Sequence[Type]
+    ) -> list[Type] | AnyType | UninhabitedType:
+        """Expands a list of types that has an unpack.
+
+        In corner cases, this can return a type rather than a list, in which case this
+        indicates use of Any or some error occurred earlier. In this case callers should
+        simply propagate the resulting type.
+        """
+        items: list[Type] = []
+        for item in typs:
+            if isinstance(item, UnpackType) and isinstance(item.type, TypeVarTupleType):
+                items.extend(self.expand_unpack(item))
+            else:
+                items.append(item.accept(self))
+        return items
+
+    def visit_tuple_type(self, t: TupleType) -> Type:
+        items = self.expand_types_with_unpack(t.items)
+        if isinstance(items, list):
+            if len(items) == 1:
+                # Normalize Tuple[*Tuple[X, ...]] -> Tuple[X, ...]
+                item = items[0]
+                if isinstance(item, UnpackType):
+                    unpacked = get_proper_type(item.type)
+                    if isinstance(unpacked, Instance):
+                        assert unpacked.type.fullname == "builtins.tuple"
+                        if t.partial_fallback.type.fullname != "builtins.tuple":
+                            # If it is a subtype (like named tuple) we need to preserve it,
+                            # this essentially mimics the logic in tuple_fallback().
+                            return t.partial_fallback.accept(self)
+                        return unpacked
+            fallback = t.partial_fallback.accept(self)
+            assert isinstance(fallback, ProperType) and isinstance(fallback, Instance)
+            return t.copy_modified(items=items, fallback=fallback)
+        else:
+            return items
+
+    def visit_typeddict_type(self, t: TypedDictType) -> Type:
+        fallback = t.fallback.accept(self)
+        assert isinstance(fallback, ProperType) and isinstance(fallback, Instance)
+        return t.copy_modified(item_types=self.expand_types(t.items.values()), fallback=fallback)
+
+    def visit_literal_type(self, t: LiteralType) -> Type:
+        # TODO: Verify this implementation is correct
+        return t
+
+    def visit_union_type(self, t: UnionType) -> Type:
+        expanded = self.expand_types(t.items)
+        # After substituting for type variables in t.items, some resulting types
+        # might be subtypes of others, however calling  make_simplified_union()
+        # can cause recursion, so we just remove strict duplicates.
+        simplified = UnionType.make_union(
+            remove_trivial(flatten_nested_unions(expanded)), t.line, t.column
+        )
+        # This call to get_proper_type() is unfortunate but is required to preserve
+        # the invariant that ProperType will stay ProperType after applying expand_type(),
+        # otherwise a single item union of a type alias will break it. Note this should not
+        # cause infinite recursion since pathological aliases like A = Union[A, B] are
+        # banned at the semantic analysis level.
+        return get_proper_type(simplified)
+
+    def visit_partial_type(self, t: PartialType) -> Type:
+        return t
+
+    def visit_type_type(self, t: TypeType) -> Type:
+        # TODO: Verify that the new item type is valid (instance or
+        # union of instances or Any).  Sadly we can't report errors
+        # here yet.
+        item = t.item.accept(self)
+        return TypeType.make_normalized(item)
+
+    def visit_type_alias_type(self, t: TypeAliasType) -> Type:
+        # Target of the type alias cannot contain type variables (not bound by the type
+        # alias itself), so we just expand the arguments.
+        args = self.expand_types_with_unpack(t.args)
+        if isinstance(args, list):
+            # TODO: normalize if target is Tuple, and args are [*tuple[X, ...]]?
+            return t.copy_modified(args=args)
+        else:
+            return args
+
+    def expand_types(self, types: Iterable[Type]) -> list[Type]:
+        a: list[Type] = []
+        for t in types:
+            a.append(t.accept(self))
+        return a
+
+
+@overload
+def expand_self_type(var: Var, typ: ProperType, replacement: ProperType) -> ProperType:
+    ...
+
+
+@overload
+def expand_self_type(var: Var, typ: Type, replacement: Type) -> Type:
+    ...
+
+
+def expand_self_type(var: Var, typ: Type, replacement: Type) -> Type:
+    """Expand appearances of Self type in a variable type."""
+    if var.info.self_type is not None and not var.is_property:
+        return expand_type(typ, {var.info.self_type.id: replacement})
+    return typ
+
+
+def remove_trivial(types: Iterable[Type]) -> list[Type]:
+    """Make trivial simplifications on a list of types without calling is_subtype().
+
+    This makes following simplifications:
+        * Remove bottom types (taking into account strict optional setting)
+        * Remove everything else if there is an `object`
+        * Remove strict duplicate types
+    """
+    removed_none = False
+    new_types = []
+    all_types = set()
+    for t in types:
+        p_t = get_proper_type(t)
+        if isinstance(p_t, UninhabitedType):
+            continue
+        if isinstance(p_t, NoneType) and not state.strict_optional:
+            removed_none = True
+            continue
+        if isinstance(p_t, Instance) and p_t.type.fullname == "builtins.object":
+            return [p_t]
+        if p_t not in all_types:
+            new_types.append(t)
+            all_types.add(p_t)
+    if new_types:
+        return new_types
+    if removed_none:
+        return [NoneType()]
+    return [UninhabitedType()]

venv/lib/python3.12/site-packages/mypy/exprtotype.py

@@ -0,0 +1,201 @@
+"""Translate an Expression to a Type value."""
+
+from __future__ import annotations
+
+from mypy.fastparse import parse_type_string
+from mypy.nodes import (
+    BytesExpr,
+    CallExpr,
+    ComplexExpr,
+    EllipsisExpr,
+    Expression,
+    FloatExpr,
+    IndexExpr,
+    IntExpr,
+    ListExpr,
+    MemberExpr,
+    NameExpr,
+    OpExpr,
+    RefExpr,
+    StarExpr,
+    StrExpr,
+    TupleExpr,
+    UnaryExpr,
+    get_member_expr_fullname,
+)
+from mypy.options import Options
+from mypy.types import (
+    ANNOTATED_TYPE_NAMES,
+    AnyType,
+    CallableArgument,
+    EllipsisType,
+    ProperType,
+    RawExpressionType,
+    Type,
+    TypeList,
+    TypeOfAny,
+    UnboundType,
+    UnionType,
+    UnpackType,
+)
+
+
+class TypeTranslationError(Exception):
+    """Exception raised when an expression is not valid as a type."""
+
+
+def _extract_argument_name(expr: Expression) -> str | None:
+    if isinstance(expr, NameExpr) and expr.name == "None":
+        return None
+    elif isinstance(expr, StrExpr):
+        return expr.value
+    else:
+        raise TypeTranslationError()
+
+
+def expr_to_unanalyzed_type(
+    expr: Expression,
+    options: Options | None = None,
+    allow_new_syntax: bool = False,
+    _parent: Expression | None = None,
+    allow_unpack: bool = False,
+) -> ProperType:
+    """Translate an expression to the corresponding type.
+
+    The result is not semantically analyzed. It can be UnboundType or TypeList.
+    Raise TypeTranslationError if the expression cannot represent a type.
+
+    If allow_new_syntax is True, allow all type syntax independent of the target
+    Python version (used in stubs).
+    """
+    # The `parent` parameter is used in recursive calls to provide context for
+    # understanding whether an CallableArgument is ok.
+    name: str | None = None
+    if isinstance(expr, NameExpr):
+        name = expr.name
+        if name == "True":
+            return RawExpressionType(True, "builtins.bool", line=expr.line, column=expr.column)
+        elif name == "False":
+            return RawExpressionType(False, "builtins.bool", line=expr.line, column=expr.column)
+        else:
+            return UnboundType(name, line=expr.line, column=expr.column)
+    elif isinstance(expr, MemberExpr):
+        fullname = get_member_expr_fullname(expr)
+        if fullname:
+            return UnboundType(fullname, line=expr.line, column=expr.column)
+        else:
+            raise TypeTranslationError()
+    elif isinstance(expr, IndexExpr):
+        base = expr_to_unanalyzed_type(expr.base, options, allow_new_syntax, expr)
+        if isinstance(base, UnboundType):
+            if base.args:
+                raise TypeTranslationError()
+            if isinstance(expr.index, TupleExpr):
+                args = expr.index.items
+            else:
+                args = [expr.index]
+
+            if isinstance(expr.base, RefExpr) and expr.base.fullname in ANNOTATED_TYPE_NAMES:
+                # TODO: this is not the optimal solution as we are basically getting rid
+                # of the Annotation definition and only returning the type information,
+                # losing all the annotations.
+
+                return expr_to_unanalyzed_type(args[0], options, allow_new_syntax, expr)
+            else:
+                base.args = tuple(
+                    expr_to_unanalyzed_type(arg, options, allow_new_syntax, expr) for arg in args
+                )
+            if not base.args:
+                base.empty_tuple_index = True
+            return base
+        else:
+            raise TypeTranslationError()
+    elif (
+        isinstance(expr, OpExpr)
+        and expr.op == "|"
+        and ((options and options.python_version >= (3, 10)) or allow_new_syntax)
+    ):
+        return UnionType(
+            [
+                expr_to_unanalyzed_type(expr.left, options, allow_new_syntax),
+                expr_to_unanalyzed_type(expr.right, options, allow_new_syntax),
+            ]
+        )
+    elif isinstance(expr, CallExpr) and isinstance(_parent, ListExpr):
+        c = expr.callee
+        names = []
+        # Go through the dotted member expr chain to get the full arg
+        # constructor name to look up
+        while True:
+            if isinstance(c, NameExpr):
+                names.append(c.name)
+                break
+            elif isinstance(c, MemberExpr):
+                names.append(c.name)
+                c = c.expr
+            else:
+                raise TypeTranslationError()
+        arg_const = ".".join(reversed(names))
+
+        # Go through the constructor args to get its name and type.
+        name = None
+        default_type = AnyType(TypeOfAny.unannotated)
+        typ: Type = default_type
+        for i, arg in enumerate(expr.args):
+            if expr.arg_names[i] is not None:
+                if expr.arg_names[i] == "name":
+                    if name is not None:
+                        # Two names
+                        raise TypeTranslationError()
+                    name = _extract_argument_name(arg)
+                    continue
+                elif expr.arg_names[i] == "type":
+                    if typ is not default_type:
+                        # Two types
+                        raise TypeTranslationError()
+                    typ = expr_to_unanalyzed_type(arg, options, allow_new_syntax, expr)
+                    continue
+                else:
+                    raise TypeTranslationError()
+            elif i == 0:
+                typ = expr_to_unanalyzed_type(arg, options, allow_new_syntax, expr)
+            elif i == 1:
+                name = _extract_argument_name(arg)
+            else:
+                raise TypeTranslationError()
+        return CallableArgument(typ, name, arg_const, expr.line, expr.column)
+    elif isinstance(expr, ListExpr):
+        return TypeList(
+            [
+                expr_to_unanalyzed_type(t, options, allow_new_syntax, expr, allow_unpack=True)
+                for t in expr.items
+            ],
+            line=expr.line,
+            column=expr.column,
+        )
+    elif isinstance(expr, StrExpr):
+        return parse_type_string(expr.value, "builtins.str", expr.line, expr.column)
+    elif isinstance(expr, BytesExpr):
+        return parse_type_string(expr.value, "builtins.bytes", expr.line, expr.column)
+    elif isinstance(expr, UnaryExpr):
+        typ = expr_to_unanalyzed_type(expr.expr, options, allow_new_syntax)
+        if isinstance(typ, RawExpressionType):
+            if isinstance(typ.literal_value, int) and expr.op == "-":
+                typ.literal_value *= -1
+                return typ
+        raise TypeTranslationError()
+    elif isinstance(expr, IntExpr):
+        return RawExpressionType(expr.value, "builtins.int", line=expr.line, column=expr.column)
+    elif isinstance(expr, FloatExpr):
+        # Floats are not valid parameters for RawExpressionType , so we just
+        # pass in 'None' for now. We'll report the appropriate error at a later stage.
+        return RawExpressionType(None, "builtins.float", line=expr.line, column=expr.column)
+    elif isinstance(expr, ComplexExpr):
+        # Same thing as above with complex numbers.
+        return RawExpressionType(None, "builtins.complex", line=expr.line, column=expr.column)
+    elif isinstance(expr, EllipsisExpr):
+        return EllipsisType(expr.line)
+    elif allow_unpack and isinstance(expr, StarExpr):
+        return UnpackType(expr_to_unanalyzed_type(expr.expr, options, allow_new_syntax))
+    else:
+        raise TypeTranslationError()

venv/lib/python3.12/site-packages/mypy/find_sources.py

@@ -0,0 +1,243 @@
+"""Routines for finding the sources that mypy will check"""
+
+from __future__ import annotations
+
+import functools
+import os
+from typing import Final, Sequence
+
+from mypy.fscache import FileSystemCache
+from mypy.modulefinder import PYTHON_EXTENSIONS, BuildSource, matches_exclude, mypy_path
+from mypy.options import Options
+
+PY_EXTENSIONS: Final = tuple(PYTHON_EXTENSIONS)
+
+
+class InvalidSourceList(Exception):
+    """Exception indicating a problem in the list of sources given to mypy."""
+
+
+def create_source_list(
+    paths: Sequence[str],
+    options: Options,
+    fscache: FileSystemCache | None = None,
+    allow_empty_dir: bool = False,
+) -> list[BuildSource]:
+    """From a list of source files/directories, makes a list of BuildSources.
+
+    Raises InvalidSourceList on errors.
+    """
+    fscache = fscache or FileSystemCache()
+    finder = SourceFinder(fscache, options)
+
+    sources = []
+    for path in paths:
+        path = os.path.normpath(path)
+        if path.endswith(PY_EXTENSIONS):
+            # Can raise InvalidSourceList if a directory doesn't have a valid module name.
+            name, base_dir = finder.crawl_up(path)
+            sources.append(BuildSource(path, name, None, base_dir))
+        elif fscache.isdir(path):
+            sub_sources = finder.find_sources_in_dir(path)
+            if not sub_sources and not allow_empty_dir:
+                raise InvalidSourceList(f"There are no .py[i] files in directory '{path}'")
+            sources.extend(sub_sources)
+        else:
+            mod = os.path.basename(path) if options.scripts_are_modules else None
+            sources.append(BuildSource(path, mod, None))
+    return sources
+
+
+def keyfunc(name: str) -> tuple[bool, int, str]:
+    """Determines sort order for directory listing.
+
+    The desirable properties are:
+    1) foo < foo.pyi < foo.py
+    2) __init__.py[i] < foo
+    """
+    base, suffix = os.path.splitext(name)
+    for i, ext in enumerate(PY_EXTENSIONS):
+        if suffix == ext:
+            return (base != "__init__", i, base)
+    return (base != "__init__", -1, name)
+
+
+def normalise_package_base(root: str) -> str:
+    if not root:
+        root = os.curdir
+    root = os.path.abspath(root)
+    if root.endswith(os.sep):
+        root = root[:-1]
+    return root
+
+
+def get_explicit_package_bases(options: Options) -> list[str] | None:
+    """Returns explicit package bases to use if the option is enabled, or None if disabled.
+
+    We currently use MYPYPATH and the current directory as the package bases. In the future,
+    when --namespace-packages is the default could also use the values passed with the
+    --package-root flag, see #9632.
+
+    Values returned are normalised so we can use simple string comparisons in
+    SourceFinder.is_explicit_package_base
+    """
+    if not options.explicit_package_bases:
+        return None
+    roots = mypy_path() + options.mypy_path + [os.getcwd()]
+    return [normalise_package_base(root) for root in roots]
+
+
+class SourceFinder:
+    def __init__(self, fscache: FileSystemCache, options: Options) -> None:
+        self.fscache = fscache
+        self.explicit_package_bases = get_explicit_package_bases(options)
+        self.namespace_packages = options.namespace_packages
+        self.exclude = options.exclude
+        self.verbosity = options.verbosity
+
+    def is_explicit_package_base(self, path: str) -> bool:
+        assert self.explicit_package_bases
+        return normalise_package_base(path) in self.explicit_package_bases
+
+    def find_sources_in_dir(self, path: str) -> list[BuildSource]:
+        sources = []
+
+        seen: set[str] = set()
+        names = sorted(self.fscache.listdir(path), key=keyfunc)
+        for name in names:
+            # Skip certain names altogether
+            if name in ("__pycache__", "site-packages", "node_modules") or name.startswith("."):
+                continue
+            subpath = os.path.join(path, name)
+
+            if matches_exclude(subpath, self.exclude, self.fscache, self.verbosity >= 2):
+                continue
+
+            if self.fscache.isdir(subpath):
+                sub_sources = self.find_sources_in_dir(subpath)
+                if sub_sources:
+                    seen.add(name)
+                    sources.extend(sub_sources)
+            else:
+                stem, suffix = os.path.splitext(name)
+                if stem not in seen and suffix in PY_EXTENSIONS:
+                    seen.add(stem)
+                    module, base_dir = self.crawl_up(subpath)
+                    sources.append(BuildSource(subpath, module, None, base_dir))
+
+        return sources
+
+    def crawl_up(self, path: str) -> tuple[str, str]:
+        """Given a .py[i] filename, return module and base directory.
+
+        For example, given "xxx/yyy/foo/bar.py", we might return something like:
+        ("foo.bar", "xxx/yyy")
+
+        If namespace packages is off, we crawl upwards until we find a directory without
+        an __init__.py
+
+        If namespace packages is on, we crawl upwards until the nearest explicit base directory.
+        Failing that, we return one past the highest directory containing an __init__.py
+
+        We won't crawl past directories with invalid package names.
+        The base directory returned is an absolute path.
+        """
+        path = os.path.abspath(path)
+        parent, filename = os.path.split(path)
+
+        module_name = strip_py(filename) or filename
+
+        parent_module, base_dir = self.crawl_up_dir(parent)
+        if module_name == "__init__":
+            return parent_module, base_dir
+
+        # Note that module_name might not actually be a valid identifier, but that's okay
+        # Ignoring this possibility sidesteps some search path confusion
+        module = module_join(parent_module, module_name)
+        return module, base_dir
+
+    def crawl_up_dir(self, dir: str) -> tuple[str, str]:
+        return self._crawl_up_helper(dir) or ("", dir)
+
+    @functools.lru_cache  # noqa: B019
+    def _crawl_up_helper(self, dir: str) -> tuple[str, str] | None:
+        """Given a directory, maybe returns module and base directory.
+
+        We return a non-None value if we were able to find something clearly intended as a base
+        directory (as adjudicated by being an explicit base directory or by containing a package
+        with __init__.py).
+
+        This distinction is necessary for namespace packages, so that we know when to treat
+        ourselves as a subpackage.
+        """
+        # stop crawling if we're an explicit base directory
+        if self.explicit_package_bases is not None and self.is_explicit_package_base(dir):
+            return "", dir
+
+        parent, name = os.path.split(dir)
+        if name.endswith("-stubs"):
+            name = name[:-6]  # PEP-561 stub-only directory
+
+        # recurse if there's an __init__.py
+        init_file = self.get_init_file(dir)
+        if init_file is not None:
+            if not name.isidentifier():
+                # in most cases the directory name is invalid, we'll just stop crawling upwards
+                # but if there's an __init__.py in the directory, something is messed up
+                raise InvalidSourceList(f"{name} is not a valid Python package name")
+            # we're definitely a package, so we always return a non-None value
+            mod_prefix, base_dir = self.crawl_up_dir(parent)
+            return module_join(mod_prefix, name), base_dir
+
+        # stop crawling if we're out of path components or our name is an invalid identifier
+        if not name or not parent or not name.isidentifier():
+            return None
+
+        # stop crawling if namespace packages is off (since we don't have an __init__.py)
+        if not self.namespace_packages:
+            return None
+
+        # at this point: namespace packages is on, we don't have an __init__.py and we're not an
+        # explicit base directory
+        result = self._crawl_up_helper(parent)
+        if result is None:
+            # we're not an explicit base directory and we don't have an __init__.py
+            # and none of our parents are either, so return
+            return None
+        # one of our parents was an explicit base directory or had an __init__.py, so we're
+        # definitely a subpackage! chain our name to the module.
+        mod_prefix, base_dir = result
+        return module_join(mod_prefix, name), base_dir
+
+    def get_init_file(self, dir: str) -> str | None:
+        """Check whether a directory contains a file named __init__.py[i].
+
+        If so, return the file's name (with dir prefixed).  If not, return None.
+
+        This prefers .pyi over .py (because of the ordering of PY_EXTENSIONS).
+        """
+        for ext in PY_EXTENSIONS:
+            f = os.path.join(dir, "__init__" + ext)
+            if self.fscache.isfile(f):
+                return f
+            if ext == ".py" and self.fscache.init_under_package_root(f):
+                return f
+        return None
+
+
+def module_join(parent: str, child: str) -> str:
+    """Join module ids, accounting for a possibly empty parent."""
+    if parent:
+        return parent + "." + child
+    return child
+
+
+def strip_py(arg: str) -> str | None:
+    """Strip a trailing .py or .pyi suffix.
+
+    Return None if no such suffix is found.
+    """
+    for ext in PY_EXTENSIONS:
+        if arg.endswith(ext):
+            return arg[: -len(ext)]
+    return None

venv/lib/python3.12/site-packages/mypy/fixup.py

@@ -0,0 +1,410 @@
+"""Fix up various things after deserialization."""
+
+from __future__ import annotations
+
+from typing import Any, Final
+
+from mypy.lookup import lookup_fully_qualified
+from mypy.nodes import (
+    Block,
+    ClassDef,
+    Decorator,
+    FuncDef,
+    MypyFile,
+    OverloadedFuncDef,
+    ParamSpecExpr,
+    SymbolTable,
+    TypeAlias,
+    TypeInfo,
+    TypeVarExpr,
+    TypeVarTupleExpr,
+    Var,
+)
+from mypy.types import (
+    NOT_READY,
+    AnyType,
+    CallableType,
+    Instance,
+    LiteralType,
+    Overloaded,
+    Parameters,
+    ParamSpecType,
+    TupleType,
+    TypeAliasType,
+    TypedDictType,
+    TypeOfAny,
+    TypeType,
+    TypeVarTupleType,
+    TypeVarType,
+    TypeVisitor,
+    UnboundType,
+    UnionType,
+    UnpackType,
+)
+from mypy.visitor import NodeVisitor
+
+
+# N.B: we do a allow_missing fixup when fixing up a fine-grained
+# incremental cache load (since there may be cross-refs into deleted
+# modules)
+def fixup_module(tree: MypyFile, modules: dict[str, MypyFile], allow_missing: bool) -> None:
+    node_fixer = NodeFixer(modules, allow_missing)
+    node_fixer.visit_symbol_table(tree.names, tree.fullname)
+
+
+# TODO: Fix up .info when deserializing, i.e. much earlier.
+class NodeFixer(NodeVisitor[None]):
+    current_info: TypeInfo | None = None
+
+    def __init__(self, modules: dict[str, MypyFile], allow_missing: bool) -> None:
+        self.modules = modules
+        self.allow_missing = allow_missing
+        self.type_fixer = TypeFixer(self.modules, allow_missing)
+
+    # NOTE: This method isn't (yet) part of the NodeVisitor API.
+    def visit_type_info(self, info: TypeInfo) -> None:
+        save_info = self.current_info
+        try:
+            self.current_info = info
+            if info.defn:
+                info.defn.accept(self)
+            if info.names:
+                self.visit_symbol_table(info.names, info.fullname)
+            if info.bases:
+                for base in info.bases:
+                    base.accept(self.type_fixer)
+            if info._promote:
+                for p in info._promote:
+                    p.accept(self.type_fixer)
+            if info.tuple_type:
+                info.tuple_type.accept(self.type_fixer)
+                info.update_tuple_type(info.tuple_type)
+                if info.special_alias:
+                    info.special_alias.alias_tvars = list(info.defn.type_vars)
+            if info.typeddict_type:
+                info.typeddict_type.accept(self.type_fixer)
+                info.update_typeddict_type(info.typeddict_type)
+                if info.special_alias:
+                    info.special_alias.alias_tvars = list(info.defn.type_vars)
+            if info.declared_metaclass:
+                info.declared_metaclass.accept(self.type_fixer)
+            if info.metaclass_type:
+                info.metaclass_type.accept(self.type_fixer)
+            if info.alt_promote:
+                info.alt_promote.accept(self.type_fixer)
+                instance = Instance(info, [])
+                # Hack: We may also need to add a backwards promotion (from int to native int),
+                # since it might not be serialized.
+                if instance not in info.alt_promote.type._promote:
+                    info.alt_promote.type._promote.append(instance)
+            if info._mro_refs:
+                info.mro = [
+                    lookup_fully_qualified_typeinfo(
+                        self.modules, name, allow_missing=self.allow_missing
+                    )
+                    for name in info._mro_refs
+                ]
+                info._mro_refs = None
+        finally:
+            self.current_info = save_info
+
+    # NOTE: This method *definitely* isn't part of the NodeVisitor API.
+    def visit_symbol_table(self, symtab: SymbolTable, table_fullname: str) -> None:
+        # Copy the items because we may mutate symtab.
+        for key, value in list(symtab.items()):
+            cross_ref = value.cross_ref
+            if cross_ref is not None:  # Fix up cross-reference.
+                value.cross_ref = None
+                if cross_ref in self.modules:
+                    value.node = self.modules[cross_ref]
+                else:
+                    stnode = lookup_fully_qualified(
+                        cross_ref, self.modules, raise_on_missing=not self.allow_missing
+                    )
+                    if stnode is not None:
+                        assert stnode.node is not None, (table_fullname + "." + key, cross_ref)
+                        value.node = stnode.node
+                    elif not self.allow_missing:
+                        assert False, f"Could not find cross-ref {cross_ref}"
+                    else:
+                        # We have a missing crossref in allow missing mode, need to put something
+                        value.node = missing_info(self.modules)
+            else:
+                if isinstance(value.node, TypeInfo):
+                    # TypeInfo has no accept().  TODO: Add it?
+                    self.visit_type_info(value.node)
+                elif value.node is not None:
+                    value.node.accept(self)
+                else:
+                    assert False, f"Unexpected empty node {key!r}: {value}"
+
+    def visit_func_def(self, func: FuncDef) -> None:
+        if self.current_info is not None:
+            func.info = self.current_info
+        if func.type is not None:
+            func.type.accept(self.type_fixer)
+
+    def visit_overloaded_func_def(self, o: OverloadedFuncDef) -> None:
+        if self.current_info is not None:
+            o.info = self.current_info
+        if o.type:
+            o.type.accept(self.type_fixer)
+        for item in o.items:
+            item.accept(self)
+        if o.impl:
+            o.impl.accept(self)
+
+    def visit_decorator(self, d: Decorator) -> None:
+        if self.current_info is not None:
+            d.var.info = self.current_info
+        if d.func:
+            d.func.accept(self)
+        if d.var:
+            d.var.accept(self)
+        for node in d.decorators:
+            node.accept(self)
+
+    def visit_class_def(self, c: ClassDef) -> None:
+        for v in c.type_vars:
+            if isinstance(v, TypeVarType):
+                for value in v.values:
+                    value.accept(self.type_fixer)
+            v.upper_bound.accept(self.type_fixer)
+            v.default.accept(self.type_fixer)
+
+    def visit_type_var_expr(self, tv: TypeVarExpr) -> None:
+        for value in tv.values:
+            value.accept(self.type_fixer)
+        tv.upper_bound.accept(self.type_fixer)
+        tv.default.accept(self.type_fixer)
+
+    def visit_paramspec_expr(self, p: ParamSpecExpr) -> None:
+        p.upper_bound.accept(self.type_fixer)
+        p.default.accept(self.type_fixer)
+
+    def visit_type_var_tuple_expr(self, tv: TypeVarTupleExpr) -> None:
+        tv.upper_bound.accept(self.type_fixer)
+        tv.default.accept(self.type_fixer)
+
+    def visit_var(self, v: Var) -> None:
+        if self.current_info is not None:
+            v.info = self.current_info
+        if v.type is not None:
+            v.type.accept(self.type_fixer)
+
+    def visit_type_alias(self, a: TypeAlias) -> None:
+        a.target.accept(self.type_fixer)
+        for v in a.alias_tvars:
+            v.accept(self.type_fixer)
+
+
+class TypeFixer(TypeVisitor[None]):
+    def __init__(self, modules: dict[str, MypyFile], allow_missing: bool) -> None:
+        self.modules = modules
+        self.allow_missing = allow_missing
+
+    def visit_instance(self, inst: Instance) -> None:
+        # TODO: Combine Instances that are exactly the same?
+        type_ref = inst.type_ref
+        if type_ref is None:
+            return  # We've already been here.
+        inst.type_ref = None
+        inst.type = lookup_fully_qualified_typeinfo(
+            self.modules, type_ref, allow_missing=self.allow_missing
+        )
+        # TODO: Is this needed or redundant?
+        # Also fix up the bases, just in case.
+        for base in inst.type.bases:
+            if base.type is NOT_READY:
+                base.accept(self)
+        for a in inst.args:
+            a.accept(self)
+        if inst.last_known_value is not None:
+            inst.last_known_value.accept(self)
+
+    def visit_type_alias_type(self, t: TypeAliasType) -> None:
+        type_ref = t.type_ref
+        if type_ref is None:
+            return  # We've already been here.
+        t.type_ref = None
+        t.alias = lookup_fully_qualified_alias(
+            self.modules, type_ref, allow_missing=self.allow_missing
+        )
+        for a in t.args:
+            a.accept(self)
+
+    def visit_any(self, o: Any) -> None:
+        pass  # Nothing to descend into.
+
+    def visit_callable_type(self, ct: CallableType) -> None:
+        if ct.fallback:
+            ct.fallback.accept(self)
+        for argt in ct.arg_types:
+            # argt may be None, e.g. for __self in NamedTuple constructors.
+            if argt is not None:
+                argt.accept(self)
+        if ct.ret_type is not None:
+            ct.ret_type.accept(self)
+        for v in ct.variables:
+            v.accept(self)
+        for arg in ct.bound_args:
+            if arg:
+                arg.accept(self)
+        if ct.type_guard is not None:
+            ct.type_guard.accept(self)
+
+    def visit_overloaded(self, t: Overloaded) -> None:
+        for ct in t.items:
+            ct.accept(self)
+
+    def visit_erased_type(self, o: Any) -> None:
+        # This type should exist only temporarily during type inference
+        raise RuntimeError("Shouldn't get here", o)
+
+    def visit_deleted_type(self, o: Any) -> None:
+        pass  # Nothing to descend into.
+
+    def visit_none_type(self, o: Any) -> None:
+        pass  # Nothing to descend into.
+
+    def visit_uninhabited_type(self, o: Any) -> None:
+        pass  # Nothing to descend into.
+
+    def visit_partial_type(self, o: Any) -> None:
+        raise RuntimeError("Shouldn't get here", o)
+
+    def visit_tuple_type(self, tt: TupleType) -> None:
+        if tt.items:
+            for it in tt.items:
+                it.accept(self)
+        if tt.partial_fallback is not None:
+            tt.partial_fallback.accept(self)
+
+    def visit_typeddict_type(self, tdt: TypedDictType) -> None:
+        if tdt.items:
+            for it in tdt.items.values():
+                it.accept(self)
+        if tdt.fallback is not None:
+            if tdt.fallback.type_ref is not None:
+                if (
+                    lookup_fully_qualified(
+                        tdt.fallback.type_ref,
+                        self.modules,
+                        raise_on_missing=not self.allow_missing,
+                    )
+                    is None
+                ):
+                    # We reject fake TypeInfos for TypedDict fallbacks because
+                    # the latter are used in type checking and must be valid.
+                    tdt.fallback.type_ref = "typing._TypedDict"
+            tdt.fallback.accept(self)
+
+    def visit_literal_type(self, lt: LiteralType) -> None:
+        lt.fallback.accept(self)
+
+    def visit_type_var(self, tvt: TypeVarType) -> None:
+        if tvt.values:
+            for vt in tvt.values:
+                vt.accept(self)
+        tvt.upper_bound.accept(self)
+        tvt.default.accept(self)
+
+    def visit_param_spec(self, p: ParamSpecType) -> None:
+        p.upper_bound.accept(self)
+        p.default.accept(self)
+
+    def visit_type_var_tuple(self, t: TypeVarTupleType) -> None:
+        t.upper_bound.accept(self)
+        t.default.accept(self)
+
+    def visit_unpack_type(self, u: UnpackType) -> None:
+        u.type.accept(self)
+
+    def visit_parameters(self, p: Parameters) -> None:
+        for argt in p.arg_types:
+            if argt is not None:
+                argt.accept(self)
+        for var in p.variables:
+            var.accept(self)
+
+    def visit_unbound_type(self, o: UnboundType) -> None:
+        for a in o.args:
+            a.accept(self)
+
+    def visit_union_type(self, ut: UnionType) -> None:
+        if ut.items:
+            for it in ut.items:
+                it.accept(self)
+
+    def visit_void(self, o: Any) -> None:
+        pass  # Nothing to descend into.
+
+    def visit_type_type(self, t: TypeType) -> None:
+        t.item.accept(self)
+
+
+def lookup_fully_qualified_typeinfo(
+    modules: dict[str, MypyFile], name: str, *, allow_missing: bool
+) -> TypeInfo:
+    stnode = lookup_fully_qualified(name, modules, raise_on_missing=not allow_missing)
+    node = stnode.node if stnode else None
+    if isinstance(node, TypeInfo):
+        return node
+    else:
+        # Looks like a missing TypeInfo during an initial daemon load, put something there
+        assert (
+            allow_missing
+        ), "Should never get here in normal mode, got {}:{} instead of TypeInfo".format(
+            type(node).__name__, node.fullname if node else ""
+        )
+        return missing_info(modules)
+
+
+def lookup_fully_qualified_alias(
+    modules: dict[str, MypyFile], name: str, *, allow_missing: bool
+) -> TypeAlias:
+    stnode = lookup_fully_qualified(name, modules, raise_on_missing=not allow_missing)
+    node = stnode.node if stnode else None
+    if isinstance(node, TypeAlias):
+        return node
+    elif isinstance(node, TypeInfo):
+        if node.special_alias:
+            # Already fixed up.
+            return node.special_alias
+        if node.tuple_type:
+            alias = TypeAlias.from_tuple_type(node)
+        elif node.typeddict_type:
+            alias = TypeAlias.from_typeddict_type(node)
+        else:
+            assert allow_missing
+            return missing_alias()
+        node.special_alias = alias
+        return alias
+    else:
+        # Looks like a missing TypeAlias during an initial daemon load, put something there
+        assert (
+            allow_missing
+        ), "Should never get here in normal mode, got {}:{} instead of TypeAlias".format(
+            type(node).__name__, node.fullname if node else ""
+        )
+        return missing_alias()
+
+
+_SUGGESTION: Final = "<missing {}: *should* have gone away during fine-grained update>"
+
+
+def missing_info(modules: dict[str, MypyFile]) -> TypeInfo:
+    suggestion = _SUGGESTION.format("info")
+    dummy_def = ClassDef(suggestion, Block([]))
+    dummy_def.fullname = suggestion
+
+    info = TypeInfo(SymbolTable(), dummy_def, "<missing>")
+    obj_type = lookup_fully_qualified_typeinfo(modules, "builtins.object", allow_missing=False)
+    info.bases = [Instance(obj_type, [])]
+    info.mro = [info, obj_type]
+    return info
+
+
+def missing_alias() -> TypeAlias:
+    suggestion = _SUGGESTION.format("alias")
+    return TypeAlias(AnyType(TypeOfAny.special_form), suggestion, line=-1, column=-1)

venv/lib/python3.12/site-packages/mypy/freetree.py

@@ -0,0 +1,23 @@
+"""Generic node traverser visitor"""
+
+from __future__ import annotations
+
+from mypy.nodes import Block, MypyFile
+from mypy.traverser import TraverserVisitor
+
+
+class TreeFreer(TraverserVisitor):
+    def visit_block(self, block: Block) -> None:
+        super().visit_block(block)
+        block.body.clear()
+
+
+def free_tree(tree: MypyFile) -> None:
+    """Free all the ASTs associated with a module.
+
+    This needs to be done recursively, since symbol tables contain
+    references to definitions, so those won't be freed but we want their
+    contents to be.
+    """
+    tree.accept(TreeFreer())
+    tree.defs.clear()

venv/lib/python3.12/site-packages/mypy/fscache.py

@@ -0,0 +1,309 @@
+"""Interface for accessing the file system with automatic caching.
+
+The idea is to cache the results of any file system state reads during
+a single transaction. This has two main benefits:
+
+* This avoids redundant syscalls, as we won't perform the same OS
+  operations multiple times.
+
+* This makes it easier to reason about concurrent FS updates, as different
+  operations targeting the same paths can't report different state during
+  a transaction.
+
+Note that this only deals with reading state, not writing.
+
+Properties maintained by the API:
+
+* The contents of the file are always from the same or later time compared
+  to the reported mtime of the file, even if mtime is queried after reading
+  a file.
+
+* Repeating an operation produces the same result as the first one during
+  a transaction.
+
+* Call flush() to start a new transaction (flush the caches).
+
+The API is a bit limited. It's easy to add new cached operations, however.
+You should perform all file system reads through the API to actually take
+advantage of the benefits.
+"""
+
+from __future__ import annotations
+
+import os
+import stat
+
+from mypy_extensions import mypyc_attr
+
+from mypy.util import hash_digest
+
+
+@mypyc_attr(allow_interpreted_subclasses=True)  # for tests
+class FileSystemCache:
+    def __init__(self) -> None:
+        # The package root is not flushed with the caches.
+        # It is set by set_package_root() below.
+        self.package_root: list[str] = []
+        self.flush()
+
+    def set_package_root(self, package_root: list[str]) -> None:
+        self.package_root = package_root
+
+    def flush(self) -> None:
+        """Start another transaction and empty all caches."""
+        self.stat_cache: dict[str, os.stat_result] = {}
+        self.stat_error_cache: dict[str, OSError] = {}
+        self.listdir_cache: dict[str, list[str]] = {}
+        self.listdir_error_cache: dict[str, OSError] = {}
+        self.isfile_case_cache: dict[str, bool] = {}
+        self.exists_case_cache: dict[str, bool] = {}
+        self.read_cache: dict[str, bytes] = {}
+        self.read_error_cache: dict[str, Exception] = {}
+        self.hash_cache: dict[str, str] = {}
+        self.fake_package_cache: set[str] = set()
+
+    def stat(self, path: str) -> os.stat_result:
+        if path in self.stat_cache:
+            return self.stat_cache[path]
+        if path in self.stat_error_cache:
+            raise copy_os_error(self.stat_error_cache[path])
+        try:
+            st = os.stat(path)
+        except OSError as err:
+            if self.init_under_package_root(path):
+                try:
+                    return self._fake_init(path)
+                except OSError:
+                    pass
+            # Take a copy to get rid of associated traceback and frame objects.
+            # Just assigning to __traceback__ doesn't free them.
+            self.stat_error_cache[path] = copy_os_error(err)
+            raise err
+        self.stat_cache[path] = st
+        return st
+
+    def init_under_package_root(self, path: str) -> bool:
+        """Is this path an __init__.py under a package root?
+
+        This is used to detect packages that don't contain __init__.py
+        files, which is needed to support Bazel.  The function should
+        only be called for non-existing files.
+
+        It will return True if it refers to a __init__.py file that
+        Bazel would create, so that at runtime Python would think the
+        directory containing it is a package.  For this to work you
+        must pass one or more package roots using the --package-root
+        flag.
+
+        As an exceptional case, any directory that is a package root
+        itself will not be considered to contain a __init__.py file.
+        This is different from the rules Bazel itself applies, but is
+        necessary for mypy to properly distinguish packages from other
+        directories.
+
+        See https://docs.bazel.build/versions/master/be/python.html,
+        where this behavior is described under legacy_create_init.
+        """
+        if not self.package_root:
+            return False
+        dirname, basename = os.path.split(path)
+        if basename != "__init__.py":
+            return False
+        if not os.path.basename(dirname).isidentifier():
+            # Can't put an __init__.py in a place that's not an identifier
+            return False
+        try:
+            st = self.stat(dirname)
+        except OSError:
+            return False
+        else:
+            if not stat.S_ISDIR(st.st_mode):
+                return False
+        ok = False
+        drive, path = os.path.splitdrive(path)  # Ignore Windows drive name
+        if os.path.isabs(path):
+            path = os.path.relpath(path)
+        path = os.path.normpath(path)
+        for root in self.package_root:
+            if path.startswith(root):
+                if path == root + basename:
+                    # A package root itself is never a package.
+                    ok = False
+                    break
+                else:
+                    ok = True
+        return ok
+
+    def _fake_init(self, path: str) -> os.stat_result:
+        """Prime the cache with a fake __init__.py file.
+
+        This makes code that looks for path believe an empty file by
+        that name exists.  Should only be called after
+        init_under_package_root() returns True.
+        """
+        dirname, basename = os.path.split(path)
+        assert basename == "__init__.py", path
+        assert not os.path.exists(path), path  # Not cached!
+        dirname = os.path.normpath(dirname)
+        st = self.stat(dirname)  # May raise OSError
+        # Get stat result as a list so we can modify it.
+        seq: list[float] = list(st)
+        seq[stat.ST_MODE] = stat.S_IFREG | 0o444
+        seq[stat.ST_INO] = 1
+        seq[stat.ST_NLINK] = 1
+        seq[stat.ST_SIZE] = 0
+        st = os.stat_result(seq)
+        self.stat_cache[path] = st
+        # Make listdir() and read() also pretend this file exists.
+        self.fake_package_cache.add(dirname)
+        return st
+
+    def listdir(self, path: str) -> list[str]:
+        path = os.path.normpath(path)
+        if path in self.listdir_cache:
+            res = self.listdir_cache[path]
+            # Check the fake cache.
+            if path in self.fake_package_cache and "__init__.py" not in res:
+                res.append("__init__.py")  # Updates the result as well as the cache
+            return res
+        if path in self.listdir_error_cache:
+            raise copy_os_error(self.listdir_error_cache[path])
+        try:
+            results = os.listdir(path)
+        except OSError as err:
+            # Like above, take a copy to reduce memory use.
+            self.listdir_error_cache[path] = copy_os_error(err)
+            raise err
+        self.listdir_cache[path] = results
+        # Check the fake cache.
+        if path in self.fake_package_cache and "__init__.py" not in results:
+            results.append("__init__.py")
+        return results
+
+    def isfile(self, path: str) -> bool:
+        try:
+            st = self.stat(path)
+        except OSError:
+            return False
+        return stat.S_ISREG(st.st_mode)
+
+    def isfile_case(self, path: str, prefix: str) -> bool:
+        """Return whether path exists and is a file.
+
+        On case-insensitive filesystems (like Mac or Windows) this returns
+        False if the case of path's last component does not exactly match
+        the case found in the filesystem.
+
+        We check also the case of other path components up to prefix.
+        For example, if path is 'user-stubs/pack/mod.pyi' and prefix is 'user-stubs',
+        we check that the case of 'pack' and 'mod.py' matches exactly, 'user-stubs' will be
+        case insensitive on case insensitive filesystems.
+
+        The caller must ensure that prefix is a valid file system prefix of path.
+        """
+        if not self.isfile(path):
+            # Fast path
+            return False
+        if path in self.isfile_case_cache:
+            return self.isfile_case_cache[path]
+        head, tail = os.path.split(path)
+        if not tail:
+            self.isfile_case_cache[path] = False
+            return False
+        try:
+            names = self.listdir(head)
+            # This allows one to check file name case sensitively in
+            # case-insensitive filesystems.
+            res = tail in names
+        except OSError:
+            res = False
+        if res:
+            # Also recursively check the other path components in case sensitive way.
+            res = self.exists_case(head, prefix)
+        self.isfile_case_cache[path] = res
+        return res
+
+    def exists_case(self, path: str, prefix: str) -> bool:
+        """Return whether path exists - checking path components in case sensitive
+        fashion, up to prefix.
+        """
+        if path in self.exists_case_cache:
+            return self.exists_case_cache[path]
+        head, tail = os.path.split(path)
+        if not head.startswith(prefix) or not tail:
+            # Only perform the check for paths under prefix.
+            self.exists_case_cache[path] = True
+            return True
+        try:
+            names = self.listdir(head)
+            # This allows one to check file name case sensitively in
+            # case-insensitive filesystems.
+            res = tail in names
+        except OSError:
+            res = False
+        if res:
+            # Also recursively check other path components.
+            res = self.exists_case(head, prefix)
+        self.exists_case_cache[path] = res
+        return res
+
+    def isdir(self, path: str) -> bool:
+        try:
+            st = self.stat(path)
+        except OSError:
+            return False
+        return stat.S_ISDIR(st.st_mode)
+
+    def exists(self, path: str) -> bool:
+        try:
+            self.stat(path)
+        except FileNotFoundError:
+            return False
+        return True
+
+    def read(self, path: str) -> bytes:
+        if path in self.read_cache:
+            return self.read_cache[path]
+        if path in self.read_error_cache:
+            raise self.read_error_cache[path]
+
+        # Need to stat first so that the contents of file are from no
+        # earlier instant than the mtime reported by self.stat().
+        self.stat(path)
+
+        dirname, basename = os.path.split(path)
+        dirname = os.path.normpath(dirname)
+        # Check the fake cache.
+        if basename == "__init__.py" and dirname in self.fake_package_cache:
+            data = b""
+        else:
+            try:
+                with open(path, "rb") as f:
+                    data = f.read()
+            except OSError as err:
+                self.read_error_cache[path] = err
+                raise
+
+        self.read_cache[path] = data
+        self.hash_cache[path] = hash_digest(data)
+        return data
+
+    def hash_digest(self, path: str) -> str:
+        if path not in self.hash_cache:
+            self.read(path)
+        return self.hash_cache[path]
+
+    def samefile(self, f1: str, f2: str) -> bool:
+        s1 = self.stat(f1)
+        s2 = self.stat(f2)
+        return os.path.samestat(s1, s2)
+
+
+def copy_os_error(e: OSError) -> OSError:
+    new = OSError(*e.args)
+    new.errno = e.errno
+    new.strerror = e.strerror
+    new.filename = e.filename
+    if e.filename2:
+        new.filename2 = e.filename2
+    return new

venv/lib/python3.12/site-packages/mypy/fswatcher.py

@@ -0,0 +1,106 @@
+"""Watch parts of the file system for changes."""
+
+from __future__ import annotations
+
+from typing import AbstractSet, Iterable, NamedTuple
+
+from mypy.fscache import FileSystemCache
+
+
+class FileData(NamedTuple):
+    st_mtime: float
+    st_size: int
+    hash: str
+
+
+class FileSystemWatcher:
+    """Watcher for file system changes among specific paths.
+
+    All file system access is performed using FileSystemCache. We
+    detect changed files by stat()ing them all and comparing hashes
+    of potentially changed files. If a file has both size and mtime
+    unmodified, the file is assumed to be unchanged.
+
+    An important goal of this class is to make it easier to eventually
+    use file system events to detect file changes.
+
+    Note: This class doesn't flush the file system cache. If you don't
+    manually flush it, changes won't be seen.
+    """
+
+    # TODO: Watching directories?
+    # TODO: Handle non-files
+
+    def __init__(self, fs: FileSystemCache) -> None:
+        self.fs = fs
+        self._paths: set[str] = set()
+        self._file_data: dict[str, FileData | None] = {}
+
+    def dump_file_data(self) -> dict[str, tuple[float, int, str]]:
+        return {k: v for k, v in self._file_data.items() if v is not None}
+
+    def set_file_data(self, path: str, data: FileData) -> None:
+        self._file_data[path] = data
+
+    def add_watched_paths(self, paths: Iterable[str]) -> None:
+        for path in paths:
+            if path not in self._paths:
+                # By storing None this path will get reported as changed by
+                # find_changed if it exists.
+                self._file_data[path] = None
+        self._paths |= set(paths)
+
+    def remove_watched_paths(self, paths: Iterable[str]) -> None:
+        for path in paths:
+            if path in self._file_data:
+                del self._file_data[path]
+        self._paths -= set(paths)
+
+    def _update(self, path: str) -> None:
+        st = self.fs.stat(path)
+        hash_digest = self.fs.hash_digest(path)
+        self._file_data[path] = FileData(st.st_mtime, st.st_size, hash_digest)
+
+    def _find_changed(self, paths: Iterable[str]) -> AbstractSet[str]:
+        changed = set()
+        for path in paths:
+            old = self._file_data[path]
+            try:
+                st = self.fs.stat(path)
+            except FileNotFoundError:
+                if old is not None:
+                    # File was deleted.
+                    changed.add(path)
+                    self._file_data[path] = None
+            else:
+                if old is None:
+                    # File is new.
+                    changed.add(path)
+                    self._update(path)
+                # Round mtimes down, to match the mtimes we write to meta files
+                elif st.st_size != old.st_size or int(st.st_mtime) != int(old.st_mtime):
+                    # Only look for changes if size or mtime has changed as an
+                    # optimization, since calculating hash is expensive.
+                    new_hash = self.fs.hash_digest(path)
+                    self._update(path)
+                    if st.st_size != old.st_size or new_hash != old.hash:
+                        # Changed file.
+                        changed.add(path)
+        return changed
+
+    def find_changed(self) -> AbstractSet[str]:
+        """Return paths that have changes since the last call, in the watched set."""
+        return self._find_changed(self._paths)
+
+    def update_changed(self, remove: list[str], update: list[str]) -> AbstractSet[str]:
+        """Alternative to find_changed() given explicit changes.
+
+        This only calls self.fs.stat() on added or updated files, not
+        on all files.  It believes all other files are unchanged!
+
+        Implies add_watched_paths() for add and update, and
+        remove_watched_paths() for remove.
+        """
+        self.remove_watched_paths(remove)
+        self.add_watched_paths(update)
+        return self._find_changed(update)

venv/lib/python3.12/site-packages/mypy/gclogger.py

@@ -0,0 +1,47 @@
+from __future__ import annotations
+
+import gc
+import time
+from typing import Mapping
+
+
+class GcLogger:
+    """Context manager to log GC stats and overall time."""
+
+    def __enter__(self) -> GcLogger:
+        self.gc_start_time: float | None = None
+        self.gc_time = 0.0
+        self.gc_calls = 0
+        self.gc_collected = 0
+        self.gc_uncollectable = 0
+        gc.callbacks.append(self.gc_callback)
+        self.start_time = time.time()
+        return self
+
+    def gc_callback(self, phase: str, info: Mapping[str, int]) -> None:
+        if phase == "start":
+            assert self.gc_start_time is None, "Start phase out of sequence"
+            self.gc_start_time = time.time()
+        elif phase == "stop":
+            assert self.gc_start_time is not None, "Stop phase out of sequence"
+            self.gc_calls += 1
+            self.gc_time += time.time() - self.gc_start_time
+            self.gc_start_time = None
+            self.gc_collected += info["collected"]
+            self.gc_uncollectable += info["uncollectable"]
+        else:
+            assert False, f"Unrecognized gc phase ({phase!r})"
+
+    def __exit__(self, *args: object) -> None:
+        while self.gc_callback in gc.callbacks:
+            gc.callbacks.remove(self.gc_callback)
+
+    def get_stats(self) -> Mapping[str, float]:
+        end_time = time.time()
+        result = {}
+        result["gc_time"] = self.gc_time
+        result["gc_calls"] = self.gc_calls
+        result["gc_collected"] = self.gc_collected
+        result["gc_uncollectable"] = self.gc_uncollectable
+        result["build_time"] = end_time - self.start_time
+        return result

venv/lib/python3.12/site-packages/mypy/git.py

@@ -0,0 +1,34 @@
+"""Git utilities."""
+
+# Used also from setup.py, so don't pull in anything additional here (like mypy or typing):
+from __future__ import annotations
+
+import os
+import subprocess
+
+
+def is_git_repo(dir: str) -> bool:
+    """Is the given directory version-controlled with git?"""
+    return os.path.exists(os.path.join(dir, ".git"))
+
+
+def have_git() -> bool:
+    """Can we run the git executable?"""
+    try:
+        subprocess.check_output(["git", "--help"])
+        return True
+    except subprocess.CalledProcessError:
+        return False
+    except OSError:
+        return False
+
+
+def git_revision(dir: str) -> bytes:
+    """Get the SHA-1 of the HEAD of a git repository."""
+    return subprocess.check_output(["git", "rev-parse", "HEAD"], cwd=dir).strip()
+
+
+def is_dirty(dir: str) -> bool:
+    """Check whether a git repository has uncommitted changes."""
+    output = subprocess.check_output(["git", "status", "-uno", "--porcelain"], cwd=dir)
+    return output.strip() != b""

venv/lib/python3.12/site-packages/mypy/graph_utils.py

@@ -0,0 +1,112 @@
+"""Helpers for manipulations with graphs."""
+
+from __future__ import annotations
+
+from typing import AbstractSet, Iterable, Iterator, TypeVar
+
+T = TypeVar("T")
+
+
+def strongly_connected_components(
+    vertices: AbstractSet[T], edges: dict[T, list[T]]
+) -> Iterator[set[T]]:
+    """Compute Strongly Connected Components of a directed graph.
+
+    Args:
+      vertices: the labels for the vertices
+      edges: for each vertex, gives the target vertices of its outgoing edges
+
+    Returns:
+      An iterator yielding strongly connected components, each
+      represented as a set of vertices.  Each input vertex will occur
+      exactly once; vertices not part of a SCC are returned as
+      singleton sets.
+
+    From https://code.activestate.com/recipes/578507/.
+    """
+    identified: set[T] = set()
+    stack: list[T] = []
+    index: dict[T, int] = {}
+    boundaries: list[int] = []
+
+    def dfs(v: T) -> Iterator[set[T]]:
+        index[v] = len(stack)
+        stack.append(v)
+        boundaries.append(index[v])
+
+        for w in edges[v]:
+            if w not in index:
+                yield from dfs(w)
+            elif w not in identified:
+                while index[w] < boundaries[-1]:
+                    boundaries.pop()
+
+        if boundaries[-1] == index[v]:
+            boundaries.pop()
+            scc = set(stack[index[v] :])
+            del stack[index[v] :]
+            identified.update(scc)
+            yield scc
+
+    for v in vertices:
+        if v not in index:
+            yield from dfs(v)
+
+
+def prepare_sccs(
+    sccs: list[set[T]], edges: dict[T, list[T]]
+) -> dict[AbstractSet[T], set[AbstractSet[T]]]:
+    """Use original edges to organize SCCs in a graph by dependencies between them."""
+    sccsmap = {v: frozenset(scc) for scc in sccs for v in scc}
+    data: dict[AbstractSet[T], set[AbstractSet[T]]] = {}
+    for scc in sccs:
+        deps: set[AbstractSet[T]] = set()
+        for v in scc:
+            deps.update(sccsmap[x] for x in edges[v])
+        data[frozenset(scc)] = deps
+    return data
+
+
+def topsort(data: dict[T, set[T]]) -> Iterable[set[T]]:
+    """Topological sort.
+
+    Args:
+      data: A map from vertices to all vertices that it has an edge
+            connecting it to.  NOTE: This data structure
+            is modified in place -- for normalization purposes,
+            self-dependencies are removed and entries representing
+            orphans are added.
+
+    Returns:
+      An iterator yielding sets of vertices that have an equivalent
+      ordering.
+
+    Example:
+      Suppose the input has the following structure:
+
+        {A: {B, C}, B: {D}, C: {D}}
+
+      This is normalized to:
+
+        {A: {B, C}, B: {D}, C: {D}, D: {}}
+
+      The algorithm will yield the following values:
+
+        {D}
+        {B, C}
+        {A}
+
+    From https://code.activestate.com/recipes/577413/.
+    """
+    # TODO: Use a faster algorithm?
+    for k, v in data.items():
+        v.discard(k)  # Ignore self dependencies.
+    for item in set.union(*data.values()) - set(data.keys()):
+        data[item] = set()
+    while True:
+        ready = {item for item, dep in data.items() if not dep}
+        if not ready:
+            break
+        yield ready
+        data = {item: (dep - ready) for item, dep in data.items() if item not in ready}
+    assert not data, f"A cyclic dependency exists amongst {data!r}"

venv/lib/python3.12/site-packages/mypy/indirection.py

@@ -0,0 +1,121 @@
+from __future__ import annotations
+
+from typing import Iterable, Set
+
+import mypy.types as types
+from mypy.types import TypeVisitor
+from mypy.util import split_module_names
+
+
+def extract_module_names(type_name: str | None) -> list[str]:
+    """Returns the module names of a fully qualified type name."""
+    if type_name is not None:
+        # Discard the first one, which is just the qualified name of the type
+        possible_module_names = split_module_names(type_name)
+        return possible_module_names[1:]
+    else:
+        return []
+
+
+class TypeIndirectionVisitor(TypeVisitor[Set[str]]):
+    """Returns all module references within a particular type."""
+
+    def __init__(self) -> None:
+        self.cache: dict[types.Type, set[str]] = {}
+        self.seen_aliases: set[types.TypeAliasType] = set()
+
+    def find_modules(self, typs: Iterable[types.Type]) -> set[str]:
+        self.seen_aliases.clear()
+        return self._visit(typs)
+
+    def _visit(self, typ_or_typs: types.Type | Iterable[types.Type]) -> set[str]:
+        typs = [typ_or_typs] if isinstance(typ_or_typs, types.Type) else typ_or_typs
+        output: set[str] = set()
+        for typ in typs:
+            if isinstance(typ, types.TypeAliasType):
+                # Avoid infinite recursion for recursive type aliases.
+                if typ in self.seen_aliases:
+                    continue
+                self.seen_aliases.add(typ)
+            if typ in self.cache:
+                modules = self.cache[typ]
+            else:
+                modules = typ.accept(self)
+                self.cache[typ] = set(modules)
+            output.update(modules)
+        return output
+
+    def visit_unbound_type(self, t: types.UnboundType) -> set[str]:
+        return self._visit(t.args)
+
+    def visit_any(self, t: types.AnyType) -> set[str]:
+        return set()
+
+    def visit_none_type(self, t: types.NoneType) -> set[str]:
+        return set()
+
+    def visit_uninhabited_type(self, t: types.UninhabitedType) -> set[str]:
+        return set()
+
+    def visit_erased_type(self, t: types.ErasedType) -> set[str]:
+        return set()
+
+    def visit_deleted_type(self, t: types.DeletedType) -> set[str]:
+        return set()
+
+    def visit_type_var(self, t: types.TypeVarType) -> set[str]:
+        return self._visit(t.values) | self._visit(t.upper_bound) | self._visit(t.default)
+
+    def visit_param_spec(self, t: types.ParamSpecType) -> set[str]:
+        return self._visit(t.upper_bound) | self._visit(t.default)
+
+    def visit_type_var_tuple(self, t: types.TypeVarTupleType) -> set[str]:
+        return self._visit(t.upper_bound) | self._visit(t.default)
+
+    def visit_unpack_type(self, t: types.UnpackType) -> set[str]:
+        return t.type.accept(self)
+
+    def visit_parameters(self, t: types.Parameters) -> set[str]:
+        return self._visit(t.arg_types)
+
+    def visit_instance(self, t: types.Instance) -> set[str]:
+        out = self._visit(t.args)
+        if t.type:
+            # Uses of a class depend on everything in the MRO,
+            # as changes to classes in the MRO can add types to methods,
+            # change property types, change the MRO itself, etc.
+            for s in t.type.mro:
+                out.update(split_module_names(s.module_name))
+            if t.type.metaclass_type is not None:
+                out.update(split_module_names(t.type.metaclass_type.type.module_name))
+        return out
+
+    def visit_callable_type(self, t: types.CallableType) -> set[str]:
+        out = self._visit(t.arg_types) | self._visit(t.ret_type)
+        if t.definition is not None:
+            out.update(extract_module_names(t.definition.fullname))
+        return out
+
+    def visit_overloaded(self, t: types.Overloaded) -> set[str]:
+        return self._visit(t.items) | self._visit(t.fallback)
+
+    def visit_tuple_type(self, t: types.TupleType) -> set[str]:
+        return self._visit(t.items) | self._visit(t.partial_fallback)
+
+    def visit_typeddict_type(self, t: types.TypedDictType) -> set[str]:
+        return self._visit(t.items.values()) | self._visit(t.fallback)
+
+    def visit_literal_type(self, t: types.LiteralType) -> set[str]:
+        return self._visit(t.fallback)
+
+    def visit_union_type(self, t: types.UnionType) -> set[str]:
+        return self._visit(t.items)
+
+    def visit_partial_type(self, t: types.PartialType) -> set[str]:
+        return set()
+
+    def visit_type_type(self, t: types.TypeType) -> set[str]:
+        return self._visit(t.item)
+
+    def visit_type_alias_type(self, t: types.TypeAliasType) -> set[str]:
+        return self._visit(types.get_proper_type(t))

venv/lib/python3.12/site-packages/mypy/infer.py

@@ -0,0 +1,71 @@
+"""Utilities for type argument inference."""
+
+from __future__ import annotations
+
+from typing import NamedTuple, Sequence
+
+from mypy.constraints import (
+    SUBTYPE_OF,
+    SUPERTYPE_OF,
+    infer_constraints,
+    infer_constraints_for_callable,
+)
+from mypy.nodes import ArgKind
+from mypy.solve import solve_constraints
+from mypy.types import CallableType, Instance, Type, TypeVarLikeType
+
+
+class ArgumentInferContext(NamedTuple):
+    """Type argument inference context.
+
+    We need this because we pass around ``Mapping`` and ``Iterable`` types.
+    These types are only known by ``TypeChecker`` itself.
+    It is required for ``*`` and ``**`` argument inference.
+
+    https://github.com/python/mypy/issues/11144
+    """
+
+    mapping_type: Instance
+    iterable_type: Instance
+
+
+def infer_function_type_arguments(
+    callee_type: CallableType,
+    arg_types: Sequence[Type | None],
+    arg_kinds: list[ArgKind],
+    arg_names: Sequence[str | None] | None,
+    formal_to_actual: list[list[int]],
+    context: ArgumentInferContext,
+    strict: bool = True,
+    allow_polymorphic: bool = False,
+) -> tuple[list[Type | None], list[TypeVarLikeType]]:
+    """Infer the type arguments of a generic function.
+
+    Return an array of lower bound types for the type variables -1 (at
+    index 0), -2 (at index 1), etc. A lower bound is None if a value
+    could not be inferred.
+
+    Arguments:
+      callee_type: the target generic function
+      arg_types: argument types at the call site (each optional; if None,
+                 we are not considering this argument in the current pass)
+      arg_kinds: nodes.ARG_* values for arg_types
+      formal_to_actual: mapping from formal to actual variable indices
+    """
+    # Infer constraints.
+    constraints = infer_constraints_for_callable(
+        callee_type, arg_types, arg_kinds, arg_names, formal_to_actual, context
+    )
+
+    # Solve constraints.
+    type_vars = callee_type.variables
+    return solve_constraints(type_vars, constraints, strict, allow_polymorphic)
+
+
+def infer_type_arguments(
+    type_vars: Sequence[TypeVarLikeType], template: Type, actual: Type, is_supertype: bool = False
+) -> list[Type | None]:
+    # Like infer_function_type_arguments, but only match a single type
+    # against a generic type.
+    constraints = infer_constraints(template, actual, SUPERTYPE_OF if is_supertype else SUBTYPE_OF)
+    return solve_constraints(type_vars, constraints)[0]

venv/lib/python3.12/site-packages/mypy/inspections.py

@@ -0,0 +1,625 @@
+from __future__ import annotations
+
+import os
+from collections import defaultdict
+from functools import cmp_to_key
+from typing import Callable
+
+from mypy.build import State
+from mypy.find_sources import InvalidSourceList, SourceFinder
+from mypy.messages import format_type
+from mypy.modulefinder import PYTHON_EXTENSIONS
+from mypy.nodes import (
+    LDEF,
+    Decorator,
+    Expression,
+    FuncBase,
+    MemberExpr,
+    MypyFile,
+    Node,
+    OverloadedFuncDef,
+    RefExpr,
+    SymbolNode,
+    TypeInfo,
+    Var,
+)
+from mypy.server.update import FineGrainedBuildManager
+from mypy.traverser import ExtendedTraverserVisitor
+from mypy.typeops import tuple_fallback
+from mypy.types import (
+    FunctionLike,
+    Instance,
+    LiteralType,
+    ProperType,
+    TupleType,
+    TypedDictType,
+    TypeVarType,
+    UnionType,
+    get_proper_type,
+)
+from mypy.typevars import fill_typevars_with_any
+
+
+def node_starts_after(o: Node, line: int, column: int) -> bool:
+    return o.line > line or o.line == line and o.column > column
+
+
+def node_ends_before(o: Node, line: int, column: int) -> bool:
+    # Unfortunately, end positions for some statements are a mess,
+    # e.g. overloaded functions, so we return False when we don't know.
+    if o.end_line is not None and o.end_column is not None:
+        if o.end_line < line or o.end_line == line and o.end_column < column:
+            return True
+    return False
+
+
+def expr_span(expr: Expression) -> str:
+    """Format expression span as in mypy error messages."""
+    return f"{expr.line}:{expr.column + 1}:{expr.end_line}:{expr.end_column}"
+
+
+def get_instance_fallback(typ: ProperType) -> list[Instance]:
+    """Returns the Instance fallback for this type if one exists or None."""
+    if isinstance(typ, Instance):
+        return [typ]
+    elif isinstance(typ, TupleType):
+        return [tuple_fallback(typ)]
+    elif isinstance(typ, TypedDictType):
+        return [typ.fallback]
+    elif isinstance(typ, FunctionLike):
+        return [typ.fallback]
+    elif isinstance(typ, LiteralType):
+        return [typ.fallback]
+    elif isinstance(typ, TypeVarType):
+        if typ.values:
+            res = []
+            for t in typ.values:
+                res.extend(get_instance_fallback(get_proper_type(t)))
+            return res
+        return get_instance_fallback(get_proper_type(typ.upper_bound))
+    elif isinstance(typ, UnionType):
+        res = []
+        for t in typ.items:
+            res.extend(get_instance_fallback(get_proper_type(t)))
+        return res
+    return []
+
+
+def find_node(name: str, info: TypeInfo) -> Var | FuncBase | None:
+    """Find the node defining member 'name' in given TypeInfo."""
+    # TODO: this code shares some logic with checkmember.py
+    method = info.get_method(name)
+    if method:
+        if isinstance(method, Decorator):
+            return method.var
+        if method.is_property:
+            assert isinstance(method, OverloadedFuncDef)
+            dec = method.items[0]
+            assert isinstance(dec, Decorator)
+            return dec.var
+        return method
+    else:
+        # don't have such method, maybe variable?
+        node = info.get(name)
+        v = node.node if node else None
+        if isinstance(v, Var):
+            return v
+    return None
+
+
+def find_module_by_fullname(fullname: str, modules: dict[str, State]) -> State | None:
+    """Find module by a node fullname.
+
+    This logic mimics the one we use in fixup, so should be good enough.
+    """
+    head = fullname
+    # Special case: a module symbol is considered to be defined in itself, not in enclosing
+    # package, since this is what users want when clicking go to definition on a module.
+    if head in modules:
+        return modules[head]
+    while True:
+        if "." not in head:
+            return None
+        head, tail = head.rsplit(".", maxsplit=1)
+        mod = modules.get(head)
+        if mod is not None:
+            return mod
+
+
+class SearchVisitor(ExtendedTraverserVisitor):
+    """Visitor looking for an expression whose span matches given one exactly."""
+
+    def __init__(self, line: int, column: int, end_line: int, end_column: int) -> None:
+        self.line = line
+        self.column = column
+        self.end_line = end_line
+        self.end_column = end_column
+        self.result: Expression | None = None
+
+    def visit(self, o: Node) -> bool:
+        if node_starts_after(o, self.line, self.column):
+            return False
+        if node_ends_before(o, self.end_line, self.end_column):
+            return False
+        if (
+            o.line == self.line
+            and o.end_line == self.end_line
+            and o.column == self.column
+            and o.end_column == self.end_column
+        ):
+            if isinstance(o, Expression):
+                self.result = o
+        return self.result is None
+
+
+def find_by_location(
+    tree: MypyFile, line: int, column: int, end_line: int, end_column: int
+) -> Expression | None:
+    """Find an expression matching given span, or None if not found."""
+    if end_line < line:
+        raise ValueError('"end_line" must not be before "line"')
+    if end_line == line and end_column <= column:
+        raise ValueError('"end_column" must be after "column"')
+    visitor = SearchVisitor(line, column, end_line, end_column)
+    tree.accept(visitor)
+    return visitor.result
+
+
+class SearchAllVisitor(ExtendedTraverserVisitor):
+    """Visitor looking for all expressions whose spans enclose given position."""
+
+    def __init__(self, line: int, column: int) -> None:
+        self.line = line
+        self.column = column
+        self.result: list[Expression] = []
+
+    def visit(self, o: Node) -> bool:
+        if node_starts_after(o, self.line, self.column):
+            return False
+        if node_ends_before(o, self.line, self.column):
+            return False
+        if isinstance(o, Expression):
+            self.result.append(o)
+        return True
+
+
+def find_all_by_location(tree: MypyFile, line: int, column: int) -> list[Expression]:
+    """Find all expressions enclosing given position starting from innermost."""
+    visitor = SearchAllVisitor(line, column)
+    tree.accept(visitor)
+    return list(reversed(visitor.result))
+
+
+class InspectionEngine:
+    """Engine for locating and statically inspecting expressions."""
+
+    def __init__(
+        self,
+        fg_manager: FineGrainedBuildManager,
+        *,
+        verbosity: int = 0,
+        limit: int = 0,
+        include_span: bool = False,
+        include_kind: bool = False,
+        include_object_attrs: bool = False,
+        union_attrs: bool = False,
+        force_reload: bool = False,
+    ) -> None:
+        self.fg_manager = fg_manager
+        self.finder = SourceFinder(
+            self.fg_manager.manager.fscache, self.fg_manager.manager.options
+        )
+        self.verbosity = verbosity
+        self.limit = limit
+        self.include_span = include_span
+        self.include_kind = include_kind
+        self.include_object_attrs = include_object_attrs
+        self.union_attrs = union_attrs
+        self.force_reload = force_reload
+        # Module for which inspection was requested.
+        self.module: State | None = None
+
+    def parse_location(self, location: str) -> tuple[str, list[int]]:
+        if location.count(":") not in [2, 4]:
+            raise ValueError("Format should be file:line:column[:end_line:end_column]")
+        parts = location.split(":")
+        module, *rest = parts
+        return module, [int(p) for p in rest]
+
+    def reload_module(self, state: State) -> None:
+        """Reload given module while temporary exporting types."""
+        old = self.fg_manager.manager.options.export_types
+        self.fg_manager.manager.options.export_types = True
+        try:
+            self.fg_manager.flush_cache()
+            assert state.path is not None
+            self.fg_manager.update([(state.id, state.path)], [])
+        finally:
+            self.fg_manager.manager.options.export_types = old
+
+    def expr_type(self, expression: Expression) -> tuple[str, bool]:
+        """Format type for an expression using current options.
+
+        If type is known, second item returned is True. If type is not known, an error
+        message is returned instead, and second item returned is False.
+        """
+        expr_type = self.fg_manager.manager.all_types.get(expression)
+        if expr_type is None:
+            return self.missing_type(expression), False
+
+        type_str = format_type(
+            expr_type, self.fg_manager.manager.options, verbosity=self.verbosity
+        )
+        return self.add_prefixes(type_str, expression), True
+
+    def object_type(self) -> Instance:
+        builtins = self.fg_manager.graph["builtins"].tree
+        assert builtins is not None
+        object_node = builtins.names["object"].node
+        assert isinstance(object_node, TypeInfo)
+        return Instance(object_node, [])
+
+    def collect_attrs(self, instances: list[Instance]) -> dict[TypeInfo, list[str]]:
+        """Collect attributes from all union/typevar variants."""
+
+        def item_attrs(attr_dict: dict[TypeInfo, list[str]]) -> set[str]:
+            attrs = set()
+            for base in attr_dict:
+                attrs |= set(attr_dict[base])
+            return attrs
+
+        def cmp_types(x: TypeInfo, y: TypeInfo) -> int:
+            if x in y.mro:
+                return 1
+            if y in x.mro:
+                return -1
+            return 0
+
+        # First gather all attributes for every union variant.
+        assert instances
+        all_attrs = []
+        for instance in instances:
+            attrs = {}
+            mro = instance.type.mro
+            if not self.include_object_attrs:
+                mro = mro[:-1]
+            for base in mro:
+                attrs[base] = sorted(base.names)
+            all_attrs.append(attrs)
+
+        # Find attributes valid for all variants in a union or type variable.
+        intersection = item_attrs(all_attrs[0])
+        for item in all_attrs[1:]:
+            intersection &= item_attrs(item)
+
+        # Combine attributes from all variants into a single dict while
+        # also removing invalid attributes (unless using --union-attrs).
+        combined_attrs = defaultdict(list)
+        for item in all_attrs:
+            for base in item:
+                if base in combined_attrs:
+                    continue
+                for name in item[base]:
+                    if self.union_attrs or name in intersection:
+                        combined_attrs[base].append(name)
+
+        # Sort bases by MRO, unrelated will appear in the order they appeared as union variants.
+        sorted_bases = sorted(combined_attrs.keys(), key=cmp_to_key(cmp_types))
+        result = {}
+        for base in sorted_bases:
+            if not combined_attrs[base]:
+                # Skip bases where everytihng was filtered out.
+                continue
+            result[base] = combined_attrs[base]
+        return result
+
+    def _fill_from_dict(
+        self, attrs_strs: list[str], attrs_dict: dict[TypeInfo, list[str]]
+    ) -> None:
+        for base in attrs_dict:
+            cls_name = base.name if self.verbosity < 1 else base.fullname
+            attrs = [f'"{attr}"' for attr in attrs_dict[base]]
+            attrs_strs.append(f'"{cls_name}": [{", ".join(attrs)}]')
+
+    def expr_attrs(self, expression: Expression) -> tuple[str, bool]:
+        """Format attributes that are valid for a given expression.
+
+        If expression type is not an Instance, try using fallback. Attributes are
+        returned as a JSON (ordered by MRO) that maps base class name to list of
+        attributes. Attributes may appear in multiple bases if overridden (we simply
+        follow usual mypy logic for creating new Vars etc).
+        """
+        expr_type = self.fg_manager.manager.all_types.get(expression)
+        if expr_type is None:
+            return self.missing_type(expression), False
+
+        expr_type = get_proper_type(expr_type)
+        instances = get_instance_fallback(expr_type)
+        if not instances:
+            # Everything is an object in Python.
+            instances = [self.object_type()]
+
+        attrs_dict = self.collect_attrs(instances)
+
+        # Special case: modules have names apart from those from ModuleType.
+        if isinstance(expression, RefExpr) and isinstance(expression.node, MypyFile):
+            node = expression.node
+            names = sorted(node.names)
+            if "__builtins__" in names:
+                # This is just to make tests stable. No one will really need ths name.
+                names.remove("__builtins__")
+            mod_dict = {f'"<{node.fullname}>"': [f'"{name}"' for name in names]}
+        else:
+            mod_dict = {}
+
+        # Special case: for class callables, prepend with the class attributes.
+        # TODO: also handle cases when such callable appears in a union.
+        if isinstance(expr_type, FunctionLike) and expr_type.is_type_obj():
+            template = fill_typevars_with_any(expr_type.type_object())
+            class_dict = self.collect_attrs(get_instance_fallback(template))
+        else:
+            class_dict = {}
+
+        # We don't use JSON dump to be sure keys order is always preserved.
+        base_attrs = []
+        if mod_dict:
+            for mod in mod_dict:
+                base_attrs.append(f'{mod}: [{", ".join(mod_dict[mod])}]')
+        self._fill_from_dict(base_attrs, class_dict)
+        self._fill_from_dict(base_attrs, attrs_dict)
+        return self.add_prefixes(f'{{{", ".join(base_attrs)}}}', expression), True
+
+    def format_node(self, module: State, node: FuncBase | SymbolNode) -> str:
+        return f"{module.path}:{node.line}:{node.column + 1}:{node.name}"
+
+    def collect_nodes(self, expression: RefExpr) -> list[FuncBase | SymbolNode]:
+        """Collect nodes that can be referred to by an expression.
+
+        Note: it can be more than one for example in case of a union attribute.
+        """
+        node: FuncBase | SymbolNode | None = expression.node
+        nodes: list[FuncBase | SymbolNode]
+        if node is None:
+            # Tricky case: instance attribute
+            if isinstance(expression, MemberExpr) and expression.kind is None:
+                base_type = self.fg_manager.manager.all_types.get(expression.expr)
+                if base_type is None:
+                    return []
+
+                # Now we use the base type to figure out where the attribute is defined.
+                base_type = get_proper_type(base_type)
+                instances = get_instance_fallback(base_type)
+                nodes = []
+                for instance in instances:
+                    node = find_node(expression.name, instance.type)
+                    if node:
+                        nodes.append(node)
+                if not nodes:
+                    # Try checking class namespace if attribute is on a class object.
+                    if isinstance(base_type, FunctionLike) and base_type.is_type_obj():
+                        instances = get_instance_fallback(
+                            fill_typevars_with_any(base_type.type_object())
+                        )
+                        for instance in instances:
+                            node = find_node(expression.name, instance.type)
+                            if node:
+                                nodes.append(node)
+                    else:
+                        # Still no luck, give up.
+                        return []
+            else:
+                return []
+        else:
+            # Easy case: a module-level definition
+            nodes = [node]
+        return nodes
+
+    def modules_for_nodes(
+        self, nodes: list[FuncBase | SymbolNode], expression: RefExpr
+    ) -> tuple[dict[FuncBase | SymbolNode, State], bool]:
+        """Gather modules where given nodes where defined.
+
+        Also check if they need to be refreshed (cached nodes may have
+        lines/columns missing).
+        """
+        modules = {}
+        reload_needed = False
+        for node in nodes:
+            module = find_module_by_fullname(node.fullname, self.fg_manager.graph)
+            if not module:
+                if expression.kind == LDEF and self.module:
+                    module = self.module
+                else:
+                    continue
+            modules[node] = module
+            if not module.tree or module.tree.is_cache_skeleton or self.force_reload:
+                reload_needed |= not module.tree or module.tree.is_cache_skeleton
+                self.reload_module(module)
+        return modules, reload_needed
+
+    def expression_def(self, expression: Expression) -> tuple[str, bool]:
+        """Find and format definition location for an expression.
+
+        If it is not a RefExpr, it is effectively skipped by returning an
+        empty result.
+        """
+        if not isinstance(expression, RefExpr):
+            # If there are no suitable matches at all, we return error later.
+            return "", True
+
+        nodes = self.collect_nodes(expression)
+
+        if not nodes:
+            return self.missing_node(expression), False
+
+        modules, reload_needed = self.modules_for_nodes(nodes, expression)
+        if reload_needed:
+            # TODO: line/column are not stored in cache for vast majority of symbol nodes.
+            # Adding them will make thing faster, but will have visible memory impact.
+            nodes = self.collect_nodes(expression)
+            modules, reload_needed = self.modules_for_nodes(nodes, expression)
+            assert not reload_needed
+
+        result = []
+        for node in modules:
+            result.append(self.format_node(modules[node], node))
+
+        if not result:
+            return self.missing_node(expression), False
+
+        return self.add_prefixes(", ".join(result), expression), True
+
+    def missing_type(self, expression: Expression) -> str:
+        alt_suggestion = ""
+        if not self.force_reload:
+            alt_suggestion = " or try --force-reload"
+        return (
+            f'No known type available for "{type(expression).__name__}"'
+            f" (maybe unreachable{alt_suggestion})"
+        )
+
+    def missing_node(self, expression: Expression) -> str:
+        return (
+            f'Cannot find definition for "{type(expression).__name__}"'
+            f" at {expr_span(expression)}"
+        )
+
+    def add_prefixes(self, result: str, expression: Expression) -> str:
+        prefixes = []
+        if self.include_kind:
+            prefixes.append(f"{type(expression).__name__}")
+        if self.include_span:
+            prefixes.append(expr_span(expression))
+        if prefixes:
+            prefix = ":".join(prefixes) + " -> "
+        else:
+            prefix = ""
+        return prefix + result
+
+    def run_inspection_by_exact_location(
+        self,
+        tree: MypyFile,
+        line: int,
+        column: int,
+        end_line: int,
+        end_column: int,
+        method: Callable[[Expression], tuple[str, bool]],
+    ) -> dict[str, object]:
+        """Get type of an expression matching a span.
+
+        Type or error is returned as a standard daemon response dict.
+        """
+        try:
+            expression = find_by_location(tree, line, column - 1, end_line, end_column)
+        except ValueError as err:
+            return {"error": str(err)}
+
+        if expression is None:
+            span = f"{line}:{column}:{end_line}:{end_column}"
+            return {"out": f"Can't find expression at span {span}", "err": "", "status": 1}
+
+        inspection_str, success = method(expression)
+        return {"out": inspection_str, "err": "", "status": 0 if success else 1}
+
+    def run_inspection_by_position(
+        self,
+        tree: MypyFile,
+        line: int,
+        column: int,
+        method: Callable[[Expression], tuple[str, bool]],
+    ) -> dict[str, object]:
+        """Get types of all expressions enclosing a position.
+
+        Types and/or errors are returned as a standard daemon response dict.
+        """
+        expressions = find_all_by_location(tree, line, column - 1)
+        if not expressions:
+            position = f"{line}:{column}"
+            return {
+                "out": f"Can't find any expressions at position {position}",
+                "err": "",
+                "status": 1,
+            }
+
+        inspection_strs = []
+        status = 0
+        for expression in expressions:
+            inspection_str, success = method(expression)
+            if not success:
+                status = 1
+            if inspection_str:
+                inspection_strs.append(inspection_str)
+        if self.limit:
+            inspection_strs = inspection_strs[: self.limit]
+        return {"out": "\n".join(inspection_strs), "err": "", "status": status}
+
+    def find_module(self, file: str) -> tuple[State | None, dict[str, object]]:
+        """Find module by path, or return a suitable error message.
+
+        Note we don't use exceptions to simplify handling 1 vs 2 statuses.
+        """
+        if not any(file.endswith(ext) for ext in PYTHON_EXTENSIONS):
+            return None, {"error": "Source file is not a Python file"}
+
+        try:
+            module, _ = self.finder.crawl_up(os.path.normpath(file))
+        except InvalidSourceList:
+            return None, {"error": "Invalid source file name: " + file}
+
+        state = self.fg_manager.graph.get(module)
+        self.module = state
+        return (
+            state,
+            {"out": f"Unknown module: {module}", "err": "", "status": 1} if state is None else {},
+        )
+
+    def run_inspection(
+        self, location: str, method: Callable[[Expression], tuple[str, bool]]
+    ) -> dict[str, object]:
+        """Top-level logic to inspect expression(s) at a location.
+
+        This can be re-used by various simple inspections.
+        """
+        try:
+            file, pos = self.parse_location(location)
+        except ValueError as err:
+            return {"error": str(err)}
+
+        state, err_dict = self.find_module(file)
+        if state is None:
+            assert err_dict
+            return err_dict
+
+        # Force reloading to load from cache, account for any edits, etc.
+        if not state.tree or state.tree.is_cache_skeleton or self.force_reload:
+            self.reload_module(state)
+        assert state.tree is not None
+
+        if len(pos) == 4:
+            # Full span, return an exact match only.
+            line, column, end_line, end_column = pos
+            return self.run_inspection_by_exact_location(
+                state.tree, line, column, end_line, end_column, method
+            )
+        assert len(pos) == 2
+        # Inexact location, return all expressions.
+        line, column = pos
+        return self.run_inspection_by_position(state.tree, line, column, method)
+
+    def get_type(self, location: str) -> dict[str, object]:
+        """Get types of expression(s) at a location."""
+        return self.run_inspection(location, self.expr_type)
+
+    def get_attrs(self, location: str) -> dict[str, object]:
+        """Get attributes of expression(s) at a location."""
+        return self.run_inspection(location, self.expr_attrs)
+
+    def get_definition(self, location: str) -> dict[str, object]:
+        """Get symbol definitions of expression(s) at a location."""
+        result = self.run_inspection(location, self.expression_def)
+        if "out" in result and not result["out"]:
+            # None of the expressions found turns out to be a RefExpr.
+            _, location = location.split(":", maxsplit=1)
+            result["out"] = f"No name or member expressions at {location}"
+            result["status"] = 1
+        return result

venv/lib/python3.12/site-packages/mypy/ipc.py

@@ -0,0 +1,268 @@
+"""Cross platform abstractions for inter-process communication
+
+On Unix, this uses AF_UNIX sockets.
+On Windows, this uses NamedPipes.
+"""
+
+from __future__ import annotations
+
+import base64
+import os
+import shutil
+import sys
+import tempfile
+from types import TracebackType
+from typing import Callable, Final
+
+if sys.platform == "win32":
+    # This may be private, but it is needed for IPC on Windows, and is basically stable
+    import ctypes
+
+    import _winapi
+
+    _IPCHandle = int
+
+    kernel32 = ctypes.windll.kernel32
+    DisconnectNamedPipe: Callable[[_IPCHandle], int] = kernel32.DisconnectNamedPipe
+    FlushFileBuffers: Callable[[_IPCHandle], int] = kernel32.FlushFileBuffers
+else:
+    import socket
+
+    _IPCHandle = socket.socket
+
+
+class IPCException(Exception):
+    """Exception for IPC issues."""
+
+
+class IPCBase:
+    """Base class for communication between the dmypy client and server.
+
+    This contains logic shared between the client and server, such as reading
+    and writing.
+    """
+
+    connection: _IPCHandle
+
+    def __init__(self, name: str, timeout: float | None) -> None:
+        self.name = name
+        self.timeout = timeout
+
+    def read(self, size: int = 100000) -> bytes:
+        """Read bytes from an IPC connection until its empty."""
+        bdata = bytearray()
+        if sys.platform == "win32":
+            while True:
+                ov, err = _winapi.ReadFile(self.connection, size, overlapped=True)
+                try:
+                    if err == _winapi.ERROR_IO_PENDING:
+                        timeout = int(self.timeout * 1000) if self.timeout else _winapi.INFINITE
+                        res = _winapi.WaitForSingleObject(ov.event, timeout)
+                        if res != _winapi.WAIT_OBJECT_0:
+                            raise IPCException(f"Bad result from I/O wait: {res}")
+                except BaseException:
+                    ov.cancel()
+                    raise
+                _, err = ov.GetOverlappedResult(True)
+                more = ov.getbuffer()
+                if more:
+                    bdata.extend(more)
+                if err == 0:
+                    # we are done!
+                    break
+                elif err == _winapi.ERROR_MORE_DATA:
+                    # read again
+                    continue
+                elif err == _winapi.ERROR_OPERATION_ABORTED:
+                    raise IPCException("ReadFile operation aborted.")
+        else:
+            while True:
+                more = self.connection.recv(size)
+                if not more:
+                    break
+                bdata.extend(more)
+        return bytes(bdata)
+
+    def write(self, data: bytes) -> None:
+        """Write bytes to an IPC connection."""
+        if sys.platform == "win32":
+            try:
+                ov, err = _winapi.WriteFile(self.connection, data, overlapped=True)
+                try:
+                    if err == _winapi.ERROR_IO_PENDING:
+                        timeout = int(self.timeout * 1000) if self.timeout else _winapi.INFINITE
+                        res = _winapi.WaitForSingleObject(ov.event, timeout)
+                        if res != _winapi.WAIT_OBJECT_0:
+                            raise IPCException(f"Bad result from I/O wait: {res}")
+                    elif err != 0:
+                        raise IPCException(f"Failed writing to pipe with error: {err}")
+                except BaseException:
+                    ov.cancel()
+                    raise
+                bytes_written, err = ov.GetOverlappedResult(True)
+                assert err == 0, err
+                assert bytes_written == len(data)
+            except OSError as e:
+                raise IPCException(f"Failed to write with error: {e.winerror}") from e
+        else:
+            self.connection.sendall(data)
+            self.connection.shutdown(socket.SHUT_WR)
+
+    def close(self) -> None:
+        if sys.platform == "win32":
+            if self.connection != _winapi.NULL:
+                _winapi.CloseHandle(self.connection)
+        else:
+            self.connection.close()
+
+
+class IPCClient(IPCBase):
+    """The client side of an IPC connection."""
+
+    def __init__(self, name: str, timeout: float | None) -> None:
+        super().__init__(name, timeout)
+        if sys.platform == "win32":
+            timeout = int(self.timeout * 1000) if self.timeout else _winapi.NMPWAIT_WAIT_FOREVER
+            try:
+                _winapi.WaitNamedPipe(self.name, timeout)
+            except FileNotFoundError as e:
+                raise IPCException(f"The NamedPipe at {self.name} was not found.") from e
+            except OSError as e:
+                if e.winerror == _winapi.ERROR_SEM_TIMEOUT:
+                    raise IPCException("Timed out waiting for connection.") from e
+                else:
+                    raise
+            try:
+                self.connection = _winapi.CreateFile(
+                    self.name,
+                    _winapi.GENERIC_READ | _winapi.GENERIC_WRITE,
+                    0,
+                    _winapi.NULL,
+                    _winapi.OPEN_EXISTING,
+                    _winapi.FILE_FLAG_OVERLAPPED,
+                    _winapi.NULL,
+                )
+            except OSError as e:
+                if e.winerror == _winapi.ERROR_PIPE_BUSY:
+                    raise IPCException("The connection is busy.") from e
+                else:
+                    raise
+            _winapi.SetNamedPipeHandleState(
+                self.connection, _winapi.PIPE_READMODE_MESSAGE, None, None
+            )
+        else:
+            self.connection = socket.socket(socket.AF_UNIX)
+            self.connection.settimeout(timeout)
+            self.connection.connect(name)
+
+    def __enter__(self) -> IPCClient:
+        return self
+
+    def __exit__(
+        self,
+        exc_ty: type[BaseException] | None = None,
+        exc_val: BaseException | None = None,
+        exc_tb: TracebackType | None = None,
+    ) -> None:
+        self.close()
+
+
+class IPCServer(IPCBase):
+    BUFFER_SIZE: Final = 2**16
+
+    def __init__(self, name: str, timeout: float | None = None) -> None:
+        if sys.platform == "win32":
+            name = r"\\.\pipe\{}-{}.pipe".format(
+                name, base64.urlsafe_b64encode(os.urandom(6)).decode()
+            )
+        else:
+            name = f"{name}.sock"
+        super().__init__(name, timeout)
+        if sys.platform == "win32":
+            self.connection = _winapi.CreateNamedPipe(
+                self.name,
+                _winapi.PIPE_ACCESS_DUPLEX
+                | _winapi.FILE_FLAG_FIRST_PIPE_INSTANCE
+                | _winapi.FILE_FLAG_OVERLAPPED,
+                _winapi.PIPE_READMODE_MESSAGE
+                | _winapi.PIPE_TYPE_MESSAGE
+                | _winapi.PIPE_WAIT
+                | 0x8,  # PIPE_REJECT_REMOTE_CLIENTS
+                1,  # one instance
+                self.BUFFER_SIZE,
+                self.BUFFER_SIZE,
+                _winapi.NMPWAIT_WAIT_FOREVER,
+                0,  # Use default security descriptor
+            )
+            if self.connection == -1:  # INVALID_HANDLE_VALUE
+                err = _winapi.GetLastError()
+                raise IPCException(f"Invalid handle to pipe: {err}")
+        else:
+            self.sock_directory = tempfile.mkdtemp()
+            sockfile = os.path.join(self.sock_directory, self.name)
+            self.sock = socket.socket(socket.AF_UNIX)
+            self.sock.bind(sockfile)
+            self.sock.listen(1)
+            if timeout is not None:
+                self.sock.settimeout(timeout)
+
+    def __enter__(self) -> IPCServer:
+        if sys.platform == "win32":
+            # NOTE: It is theoretically possible that this will hang forever if the
+            # client never connects, though this can be "solved" by killing the server
+            try:
+                ov = _winapi.ConnectNamedPipe(self.connection, overlapped=True)
+            except OSError as e:
+                # Don't raise if the client already exists, or the client already connected
+                if e.winerror not in (_winapi.ERROR_PIPE_CONNECTED, _winapi.ERROR_NO_DATA):
+                    raise
+            else:
+                try:
+                    timeout = int(self.timeout * 1000) if self.timeout else _winapi.INFINITE
+                    res = _winapi.WaitForSingleObject(ov.event, timeout)
+                    assert res == _winapi.WAIT_OBJECT_0
+                except BaseException:
+                    ov.cancel()
+                    _winapi.CloseHandle(self.connection)
+                    raise
+                _, err = ov.GetOverlappedResult(True)
+                assert err == 0
+        else:
+            try:
+                self.connection, _ = self.sock.accept()
+            except socket.timeout as e:
+                raise IPCException("The socket timed out") from e
+        return self
+
+    def __exit__(
+        self,
+        exc_ty: type[BaseException] | None = None,
+        exc_val: BaseException | None = None,
+        exc_tb: TracebackType | None = None,
+    ) -> None:
+        if sys.platform == "win32":
+            try:
+                # Wait for the client to finish reading the last write before disconnecting
+                if not FlushFileBuffers(self.connection):
+                    raise IPCException(
+                        "Failed to flush NamedPipe buffer, maybe the client hung up?"
+                    )
+            finally:
+                DisconnectNamedPipe(self.connection)
+        else:
+            self.close()
+
+    def cleanup(self) -> None:
+        if sys.platform == "win32":
+            self.close()
+        else:
+            shutil.rmtree(self.sock_directory)
+
+    @property
+    def connection_name(self) -> str:
+        if sys.platform == "win32":
+            return self.name
+        else:
+            name = self.sock.getsockname()
+            assert isinstance(name, str)
+            return name

venv/lib/python3.12/site-packages/mypy/join.py

@@ -0,0 +1,688 @@
+"""Calculation of the least upper bound types (joins)."""
+
+from __future__ import annotations
+
+from typing import overload
+
+import mypy.typeops
+from mypy.maptype import map_instance_to_supertype
+from mypy.nodes import CONTRAVARIANT, COVARIANT, INVARIANT
+from mypy.state import state
+from mypy.subtypes import (
+    SubtypeContext,
+    find_member,
+    is_equivalent,
+    is_proper_subtype,
+    is_protocol_implementation,
+    is_subtype,
+)
+from mypy.types import (
+    AnyType,
+    CallableType,
+    DeletedType,
+    ErasedType,
+    FunctionLike,
+    Instance,
+    LiteralType,
+    NoneType,
+    Overloaded,
+    Parameters,
+    ParamSpecType,
+    PartialType,
+    ProperType,
+    TupleType,
+    Type,
+    TypeAliasType,
+    TypedDictType,
+    TypeOfAny,
+    TypeType,
+    TypeVarTupleType,
+    TypeVarType,
+    TypeVisitor,
+    UnboundType,
+    UninhabitedType,
+    UnionType,
+    UnpackType,
+    get_proper_type,
+    get_proper_types,
+)
+
+
+class InstanceJoiner:
+    def __init__(self) -> None:
+        self.seen_instances: list[tuple[Instance, Instance]] = []
+
+    def join_instances(self, t: Instance, s: Instance) -> ProperType:
+        if (t, s) in self.seen_instances or (s, t) in self.seen_instances:
+            return object_from_instance(t)
+
+        self.seen_instances.append((t, s))
+
+        # Calculate the join of two instance types
+        if t.type == s.type:
+            # Simplest case: join two types with the same base type (but
+            # potentially different arguments).
+
+            # Combine type arguments.
+            args: list[Type] = []
+            # N.B: We use zip instead of indexing because the lengths might have
+            # mismatches during daemon reprocessing.
+            for ta, sa, type_var in zip(t.args, s.args, t.type.defn.type_vars):
+                ta_proper = get_proper_type(ta)
+                sa_proper = get_proper_type(sa)
+                new_type: Type | None = None
+                if isinstance(ta_proper, AnyType):
+                    new_type = AnyType(TypeOfAny.from_another_any, ta_proper)
+                elif isinstance(sa_proper, AnyType):
+                    new_type = AnyType(TypeOfAny.from_another_any, sa_proper)
+                elif isinstance(type_var, TypeVarType):
+                    if type_var.variance == COVARIANT:
+                        new_type = join_types(ta, sa, self)
+                        if len(type_var.values) != 0 and new_type not in type_var.values:
+                            self.seen_instances.pop()
+                            return object_from_instance(t)
+                        if not is_subtype(new_type, type_var.upper_bound):
+                            self.seen_instances.pop()
+                            return object_from_instance(t)
+                    # TODO: contravariant case should use meet but pass seen instances as
+                    # an argument to keep track of recursive checks.
+                    elif type_var.variance in (INVARIANT, CONTRAVARIANT):
+                        if not is_equivalent(ta, sa):
+                            self.seen_instances.pop()
+                            return object_from_instance(t)
+                        # If the types are different but equivalent, then an Any is involved
+                        # so using a join in the contravariant case is also OK.
+                        new_type = join_types(ta, sa, self)
+                else:
+                    # ParamSpec type variables behave the same, independent of variance
+                    if not is_equivalent(ta, sa):
+                        return get_proper_type(type_var.upper_bound)
+                    new_type = join_types(ta, sa, self)
+                assert new_type is not None
+                args.append(new_type)
+            result: ProperType = Instance(t.type, args)
+        elif t.type.bases and is_proper_subtype(
+            t, s, subtype_context=SubtypeContext(ignore_type_params=True)
+        ):
+            result = self.join_instances_via_supertype(t, s)
+        else:
+            # Now t is not a subtype of s, and t != s. Now s could be a subtype
+            # of t; alternatively, we need to find a common supertype. This works
+            # in of the both cases.
+            result = self.join_instances_via_supertype(s, t)
+
+        self.seen_instances.pop()
+        return result
+
+    def join_instances_via_supertype(self, t: Instance, s: Instance) -> ProperType:
+        # Give preference to joins via duck typing relationship, so that
+        # join(int, float) == float, for example.
+        for p in t.type._promote:
+            if is_subtype(p, s):
+                return join_types(p, s, self)
+        for p in s.type._promote:
+            if is_subtype(p, t):
+                return join_types(t, p, self)
+
+        # Compute the "best" supertype of t when joined with s.
+        # The definition of "best" may evolve; for now it is the one with
+        # the longest MRO.  Ties are broken by using the earlier base.
+        best: ProperType | None = None
+        for base in t.type.bases:
+            mapped = map_instance_to_supertype(t, base.type)
+            res = self.join_instances(mapped, s)
+            if best is None or is_better(res, best):
+                best = res
+        assert best is not None
+        for promote in t.type._promote:
+            if isinstance(promote, Instance):
+                res = self.join_instances(promote, s)
+                if is_better(res, best):
+                    best = res
+        return best
+
+
+def join_simple(declaration: Type | None, s: Type, t: Type) -> ProperType:
+    """Return a simple least upper bound given the declared type.
+
+    This function should be only used by binder, and should not recurse.
+    For all other uses, use `join_types()`.
+    """
+    declaration = get_proper_type(declaration)
+    s = get_proper_type(s)
+    t = get_proper_type(t)
+
+    if (s.can_be_true, s.can_be_false) != (t.can_be_true, t.can_be_false):
+        # if types are restricted in different ways, use the more general versions
+        s = mypy.typeops.true_or_false(s)
+        t = mypy.typeops.true_or_false(t)
+
+    if isinstance(s, AnyType):
+        return s
+
+    if isinstance(s, ErasedType):
+        return t
+
+    if is_proper_subtype(s, t, ignore_promotions=True):
+        return t
+
+    if is_proper_subtype(t, s, ignore_promotions=True):
+        return s
+
+    if isinstance(declaration, UnionType):
+        return mypy.typeops.make_simplified_union([s, t])
+
+    if isinstance(s, NoneType) and not isinstance(t, NoneType):
+        s, t = t, s
+
+    if isinstance(s, UninhabitedType) and not isinstance(t, UninhabitedType):
+        s, t = t, s
+
+    # Meets/joins require callable type normalization.
+    s, t = normalize_callables(s, t)
+
+    if isinstance(s, UnionType) and not isinstance(t, UnionType):
+        s, t = t, s
+
+    value = t.accept(TypeJoinVisitor(s))
+    if declaration is None or is_subtype(value, declaration):
+        return value
+
+    return declaration
+
+
+def trivial_join(s: Type, t: Type) -> Type:
+    """Return one of types (expanded) if it is a supertype of other, otherwise top type."""
+    if is_subtype(s, t):
+        return t
+    elif is_subtype(t, s):
+        return s
+    else:
+        return object_or_any_from_type(get_proper_type(t))
+
+
+@overload
+def join_types(
+    s: ProperType, t: ProperType, instance_joiner: InstanceJoiner | None = None
+) -> ProperType:
+    ...
+
+
+@overload
+def join_types(s: Type, t: Type, instance_joiner: InstanceJoiner | None = None) -> Type:
+    ...
+
+
+def join_types(s: Type, t: Type, instance_joiner: InstanceJoiner | None = None) -> Type:
+    """Return the least upper bound of s and t.
+
+    For example, the join of 'int' and 'object' is 'object'.
+    """
+    if mypy.typeops.is_recursive_pair(s, t):
+        # This case can trigger an infinite recursion, general support for this will be
+        # tricky so we use a trivial join (like for protocols).
+        return trivial_join(s, t)
+    s = get_proper_type(s)
+    t = get_proper_type(t)
+
+    if (s.can_be_true, s.can_be_false) != (t.can_be_true, t.can_be_false):
+        # if types are restricted in different ways, use the more general versions
+        s = mypy.typeops.true_or_false(s)
+        t = mypy.typeops.true_or_false(t)
+
+    if isinstance(s, UnionType) and not isinstance(t, UnionType):
+        s, t = t, s
+
+    if isinstance(s, AnyType):
+        return s
+
+    if isinstance(s, ErasedType):
+        return t
+
+    if isinstance(s, NoneType) and not isinstance(t, NoneType):
+        s, t = t, s
+
+    if isinstance(s, UninhabitedType) and not isinstance(t, UninhabitedType):
+        s, t = t, s
+
+    # Meets/joins require callable type normalization.
+    s, t = normalize_callables(s, t)
+
+    # Use a visitor to handle non-trivial cases.
+    return t.accept(TypeJoinVisitor(s, instance_joiner))
+
+
+class TypeJoinVisitor(TypeVisitor[ProperType]):
+    """Implementation of the least upper bound algorithm.
+
+    Attributes:
+      s: The other (left) type operand.
+    """
+
+    def __init__(self, s: ProperType, instance_joiner: InstanceJoiner | None = None) -> None:
+        self.s = s
+        self.instance_joiner = instance_joiner
+
+    def visit_unbound_type(self, t: UnboundType) -> ProperType:
+        return AnyType(TypeOfAny.special_form)
+
+    def visit_union_type(self, t: UnionType) -> ProperType:
+        if is_proper_subtype(self.s, t):
+            return t
+        else:
+            return mypy.typeops.make_simplified_union([self.s, t])
+
+    def visit_any(self, t: AnyType) -> ProperType:
+        return t
+
+    def visit_none_type(self, t: NoneType) -> ProperType:
+        if state.strict_optional:
+            if isinstance(self.s, (NoneType, UninhabitedType)):
+                return t
+            elif isinstance(self.s, UnboundType):
+                return AnyType(TypeOfAny.special_form)
+            else:
+                return mypy.typeops.make_simplified_union([self.s, t])
+        else:
+            return self.s
+
+    def visit_uninhabited_type(self, t: UninhabitedType) -> ProperType:
+        return self.s
+
+    def visit_deleted_type(self, t: DeletedType) -> ProperType:
+        return self.s
+
+    def visit_erased_type(self, t: ErasedType) -> ProperType:
+        return self.s
+
+    def visit_type_var(self, t: TypeVarType) -> ProperType:
+        if isinstance(self.s, TypeVarType) and self.s.id == t.id:
+            return self.s
+        else:
+            return self.default(self.s)
+
+    def visit_param_spec(self, t: ParamSpecType) -> ProperType:
+        if self.s == t:
+            return t
+        return self.default(self.s)
+
+    def visit_type_var_tuple(self, t: TypeVarTupleType) -> ProperType:
+        if self.s == t:
+            return t
+        return self.default(self.s)
+
+    def visit_unpack_type(self, t: UnpackType) -> UnpackType:
+        raise NotImplementedError
+
+    def visit_parameters(self, t: Parameters) -> ProperType:
+        if isinstance(self.s, Parameters):
+            if len(t.arg_types) != len(self.s.arg_types):
+                return self.default(self.s)
+            return t.copy_modified(
+                # Note that since during constraint inference we already treat whole ParamSpec as
+                # contravariant, we should join individual items, not meet them like for Callables
+                arg_types=[join_types(s_a, t_a) for s_a, t_a in zip(self.s.arg_types, t.arg_types)]
+            )
+        else:
+            return self.default(self.s)
+
+    def visit_instance(self, t: Instance) -> ProperType:
+        if isinstance(self.s, Instance):
+            if self.instance_joiner is None:
+                self.instance_joiner = InstanceJoiner()
+            nominal = self.instance_joiner.join_instances(t, self.s)
+            structural: Instance | None = None
+            if t.type.is_protocol and is_protocol_implementation(self.s, t):
+                structural = t
+            elif self.s.type.is_protocol and is_protocol_implementation(t, self.s):
+                structural = self.s
+            # Structural join is preferred in the case where we have found both
+            # structural and nominal and they have same MRO length (see two comments
+            # in join_instances_via_supertype). Otherwise, just return the nominal join.
+            if not structural or is_better(nominal, structural):
+                return nominal
+            return structural
+        elif isinstance(self.s, FunctionLike):
+            if t.type.is_protocol:
+                call = unpack_callback_protocol(t)
+                if call:
+                    return join_types(call, self.s)
+            return join_types(t, self.s.fallback)
+        elif isinstance(self.s, TypeType):
+            return join_types(t, self.s)
+        elif isinstance(self.s, TypedDictType):
+            return join_types(t, self.s)
+        elif isinstance(self.s, TupleType):
+            return join_types(t, self.s)
+        elif isinstance(self.s, LiteralType):
+            return join_types(t, self.s)
+        else:
+            return self.default(self.s)
+
+    def visit_callable_type(self, t: CallableType) -> ProperType:
+        if isinstance(self.s, CallableType) and is_similar_callables(t, self.s):
+            if is_equivalent(t, self.s):
+                return combine_similar_callables(t, self.s)
+            result = join_similar_callables(t, self.s)
+            # We set the from_type_type flag to suppress error when a collection of
+            # concrete class objects gets inferred as their common abstract superclass.
+            if not (
+                (t.is_type_obj() and t.type_object().is_abstract)
+                or (self.s.is_type_obj() and self.s.type_object().is_abstract)
+            ):
+                result.from_type_type = True
+            if any(
+                isinstance(tp, (NoneType, UninhabitedType))
+                for tp in get_proper_types(result.arg_types)
+            ):
+                # We don't want to return unusable Callable, attempt fallback instead.
+                return join_types(t.fallback, self.s)
+            return result
+        elif isinstance(self.s, Overloaded):
+            # Switch the order of arguments to that we'll get to visit_overloaded.
+            return join_types(t, self.s)
+        elif isinstance(self.s, Instance) and self.s.type.is_protocol:
+            call = unpack_callback_protocol(self.s)
+            if call:
+                return join_types(t, call)
+        return join_types(t.fallback, self.s)
+
+    def visit_overloaded(self, t: Overloaded) -> ProperType:
+        # This is more complex than most other cases. Here are some
+        # examples that illustrate how this works.
+        #
+        # First let's define a concise notation:
+        #  - Cn are callable types (for n in 1, 2, ...)
+        #  - Ov(C1, C2, ...) is an overloaded type with items C1, C2, ...
+        #  - Callable[[T, ...], S] is written as [T, ...] -> S.
+        #
+        # We want some basic properties to hold (assume Cn are all
+        # unrelated via Any-similarity):
+        #
+        #   join(Ov(C1, C2), C1) == C1
+        #   join(Ov(C1, C2), Ov(C1, C2)) == Ov(C1, C2)
+        #   join(Ov(C1, C2), Ov(C1, C3)) == C1
+        #   join(Ov(C2, C2), C3) == join of fallback types
+        #
+        # The presence of Any types makes things more interesting. The join is the
+        # most general type we can get with respect to Any:
+        #
+        #   join(Ov([int] -> int, [str] -> str), [Any] -> str) == Any -> str
+        #
+        # We could use a simplification step that removes redundancies, but that's not
+        # implemented right now. Consider this example, where we get a redundancy:
+        #
+        #   join(Ov([int, Any] -> Any, [str, Any] -> Any), [Any, int] -> Any) ==
+        #       Ov([Any, int] -> Any, [Any, int] -> Any)
+        #
+        # TODO: Consider more cases of callable subtyping.
+        result: list[CallableType] = []
+        s = self.s
+        if isinstance(s, FunctionLike):
+            # The interesting case where both types are function types.
+            for t_item in t.items:
+                for s_item in s.items:
+                    if is_similar_callables(t_item, s_item):
+                        if is_equivalent(t_item, s_item):
+                            result.append(combine_similar_callables(t_item, s_item))
+                        elif is_subtype(t_item, s_item):
+                            result.append(s_item)
+            if result:
+                # TODO: Simplify redundancies from the result.
+                if len(result) == 1:
+                    return result[0]
+                else:
+                    return Overloaded(result)
+            return join_types(t.fallback, s.fallback)
+        elif isinstance(s, Instance) and s.type.is_protocol:
+            call = unpack_callback_protocol(s)
+            if call:
+                return join_types(t, call)
+        return join_types(t.fallback, s)
+
+    def visit_tuple_type(self, t: TupleType) -> ProperType:
+        # When given two fixed-length tuples:
+        # * If they have the same length, join their subtypes item-wise:
+        #   Tuple[int, bool] + Tuple[bool, bool] becomes Tuple[int, bool]
+        # * If lengths do not match, return a variadic tuple:
+        #   Tuple[bool, int] + Tuple[bool] becomes Tuple[int, ...]
+        #
+        # Otherwise, `t` is a fixed-length tuple but `self.s` is NOT:
+        # * Joining with a variadic tuple returns variadic tuple:
+        #   Tuple[int, bool] + Tuple[bool, ...] becomes Tuple[int, ...]
+        # * Joining with any Sequence also returns a Sequence:
+        #   Tuple[int, bool] + List[bool] becomes Sequence[int]
+        if isinstance(self.s, TupleType) and self.s.length() == t.length():
+            if self.instance_joiner is None:
+                self.instance_joiner = InstanceJoiner()
+            fallback = self.instance_joiner.join_instances(
+                mypy.typeops.tuple_fallback(self.s), mypy.typeops.tuple_fallback(t)
+            )
+            assert isinstance(fallback, Instance)
+            if self.s.length() == t.length():
+                items: list[Type] = []
+                for i in range(t.length()):
+                    items.append(join_types(t.items[i], self.s.items[i]))
+                return TupleType(items, fallback)
+            else:
+                return fallback
+        else:
+            return join_types(self.s, mypy.typeops.tuple_fallback(t))
+
+    def visit_typeddict_type(self, t: TypedDictType) -> ProperType:
+        if isinstance(self.s, TypedDictType):
+            items = {
+                item_name: s_item_type
+                for (item_name, s_item_type, t_item_type) in self.s.zip(t)
+                if (
+                    is_equivalent(s_item_type, t_item_type)
+                    and (item_name in t.required_keys) == (item_name in self.s.required_keys)
+                )
+            }
+            fallback = self.s.create_anonymous_fallback()
+            # We need to filter by items.keys() since some required keys present in both t and
+            # self.s might be missing from the join if the types are incompatible.
+            required_keys = set(items.keys()) & t.required_keys & self.s.required_keys
+            return TypedDictType(items, required_keys, fallback)
+        elif isinstance(self.s, Instance):
+            return join_types(self.s, t.fallback)
+        else:
+            return self.default(self.s)
+
+    def visit_literal_type(self, t: LiteralType) -> ProperType:
+        if isinstance(self.s, LiteralType):
+            if t == self.s:
+                return t
+            if self.s.fallback.type.is_enum and t.fallback.type.is_enum:
+                return mypy.typeops.make_simplified_union([self.s, t])
+            return join_types(self.s.fallback, t.fallback)
+        else:
+            return join_types(self.s, t.fallback)
+
+    def visit_partial_type(self, t: PartialType) -> ProperType:
+        # We only have partial information so we can't decide the join result. We should
+        # never get here.
+        assert False, "Internal error"
+
+    def visit_type_type(self, t: TypeType) -> ProperType:
+        if isinstance(self.s, TypeType):
+            return TypeType.make_normalized(join_types(t.item, self.s.item), line=t.line)
+        elif isinstance(self.s, Instance) and self.s.type.fullname == "builtins.type":
+            return self.s
+        else:
+            return self.default(self.s)
+
+    def visit_type_alias_type(self, t: TypeAliasType) -> ProperType:
+        assert False, f"This should be never called, got {t}"
+
+    def default(self, typ: Type) -> ProperType:
+        typ = get_proper_type(typ)
+        if isinstance(typ, Instance):
+            return object_from_instance(typ)
+        elif isinstance(typ, UnboundType):
+            return AnyType(TypeOfAny.special_form)
+        elif isinstance(typ, TupleType):
+            return self.default(mypy.typeops.tuple_fallback(typ))
+        elif isinstance(typ, TypedDictType):
+            return self.default(typ.fallback)
+        elif isinstance(typ, FunctionLike):
+            return self.default(typ.fallback)
+        elif isinstance(typ, TypeVarType):
+            return self.default(typ.upper_bound)
+        elif isinstance(typ, ParamSpecType):
+            return self.default(typ.upper_bound)
+        else:
+            return AnyType(TypeOfAny.special_form)
+
+
+def is_better(t: Type, s: Type) -> bool:
+    # Given two possible results from join_instances_via_supertype(),
+    # indicate whether t is the better one.
+    t = get_proper_type(t)
+    s = get_proper_type(s)
+
+    if isinstance(t, Instance):
+        if not isinstance(s, Instance):
+            return True
+        # Use len(mro) as a proxy for the better choice.
+        if len(t.type.mro) > len(s.type.mro):
+            return True
+    return False
+
+
+def normalize_callables(s: ProperType, t: ProperType) -> tuple[ProperType, ProperType]:
+    if isinstance(s, (CallableType, Overloaded)):
+        s = s.with_unpacked_kwargs()
+    if isinstance(t, (CallableType, Overloaded)):
+        t = t.with_unpacked_kwargs()
+    return s, t
+
+
+def is_similar_callables(t: CallableType, s: CallableType) -> bool:
+    """Return True if t and s have identical numbers of
+    arguments, default arguments and varargs.
+    """
+    return (
+        len(t.arg_types) == len(s.arg_types)
+        and t.min_args == s.min_args
+        and t.is_var_arg == s.is_var_arg
+    )
+
+
+def join_similar_callables(t: CallableType, s: CallableType) -> CallableType:
+    from mypy.meet import meet_types
+
+    arg_types: list[Type] = []
+    for i in range(len(t.arg_types)):
+        arg_types.append(meet_types(t.arg_types[i], s.arg_types[i]))
+    # TODO in combine_similar_callables also applies here (names and kinds; user metaclasses)
+    # The fallback type can be either 'function', 'type', or some user-provided metaclass.
+    # The result should always use 'function' as a fallback if either operands are using it.
+    if t.fallback.type.fullname == "builtins.function":
+        fallback = t.fallback
+    else:
+        fallback = s.fallback
+    return t.copy_modified(
+        arg_types=arg_types,
+        arg_names=combine_arg_names(t, s),
+        ret_type=join_types(t.ret_type, s.ret_type),
+        fallback=fallback,
+        name=None,
+    )
+
+
+def combine_similar_callables(t: CallableType, s: CallableType) -> CallableType:
+    arg_types: list[Type] = []
+    for i in range(len(t.arg_types)):
+        arg_types.append(join_types(t.arg_types[i], s.arg_types[i]))
+    # TODO kinds and argument names
+    # TODO what should happen if one fallback is 'type' and the other is a user-provided metaclass?
+    # The fallback type can be either 'function', 'type', or some user-provided metaclass.
+    # The result should always use 'function' as a fallback if either operands are using it.
+    if t.fallback.type.fullname == "builtins.function":
+        fallback = t.fallback
+    else:
+        fallback = s.fallback
+    return t.copy_modified(
+        arg_types=arg_types,
+        arg_names=combine_arg_names(t, s),
+        ret_type=join_types(t.ret_type, s.ret_type),
+        fallback=fallback,
+        name=None,
+    )
+
+
+def combine_arg_names(t: CallableType, s: CallableType) -> list[str | None]:
+    """Produces a list of argument names compatible with both callables.
+
+    For example, suppose 't' and 's' have the following signatures:
+
+    - t: (a: int, b: str, X: str) -> None
+    - s: (a: int, b: str, Y: str) -> None
+
+    This function would return ["a", "b", None]. This information
+    is then used above to compute the join of t and s, which results
+    in a signature of (a: int, b: str, str) -> None.
+
+    Note that the third argument's name is omitted and 't' and 's'
+    are both valid subtypes of this inferred signature.
+
+    Precondition: is_similar_types(t, s) is true.
+    """
+    num_args = len(t.arg_types)
+    new_names = []
+    for i in range(num_args):
+        t_name = t.arg_names[i]
+        s_name = s.arg_names[i]
+        if t_name == s_name or t.arg_kinds[i].is_named() or s.arg_kinds[i].is_named():
+            new_names.append(t_name)
+        else:
+            new_names.append(None)
+    return new_names
+
+
+def object_from_instance(instance: Instance) -> Instance:
+    """Construct the type 'builtins.object' from an instance type."""
+    # Use the fact that 'object' is always the last class in the mro.
+    res = Instance(instance.type.mro[-1], [])
+    return res
+
+
+def object_or_any_from_type(typ: ProperType) -> ProperType:
+    # Similar to object_from_instance() but tries hard for all types.
+    # TODO: find a better way to get object, or make this more reliable.
+    if isinstance(typ, Instance):
+        return object_from_instance(typ)
+    elif isinstance(typ, (CallableType, TypedDictType, LiteralType)):
+        return object_from_instance(typ.fallback)
+    elif isinstance(typ, TupleType):
+        return object_from_instance(typ.partial_fallback)
+    elif isinstance(typ, TypeType):
+        return object_or_any_from_type(typ.item)
+    elif isinstance(typ, TypeVarType) and isinstance(typ.upper_bound, ProperType):
+        return object_or_any_from_type(typ.upper_bound)
+    elif isinstance(typ, UnionType):
+        for item in typ.items:
+            if isinstance(item, ProperType):
+                candidate = object_or_any_from_type(item)
+                if isinstance(candidate, Instance):
+                    return candidate
+    return AnyType(TypeOfAny.implementation_artifact)
+
+
+def join_type_list(types: list[Type]) -> Type:
+    if not types:
+        # This is a little arbitrary but reasonable. Any empty tuple should be compatible
+        # with all variable length tuples, and this makes it possible.
+        return UninhabitedType()
+    joined = types[0]
+    for t in types[1:]:
+        joined = join_types(joined, t)
+    return joined
+
+
+def unpack_callback_protocol(t: Instance) -> ProperType | None:
+    assert t.type.is_protocol
+    if t.type.protocol_members == ["__call__"]:
+        return get_proper_type(find_member("__call__", t, t, is_operator=True))
+    return None

venv/lib/python3.12/site-packages/mypy/literals.py

@@ -0,0 +1,306 @@
+from __future__ import annotations
+
+from typing import Any, Final, Iterable, Optional, Tuple
+from typing_extensions import TypeAlias as _TypeAlias
+
+from mypy.nodes import (
+    LITERAL_NO,
+    LITERAL_TYPE,
+    LITERAL_YES,
+    AssertTypeExpr,
+    AssignmentExpr,
+    AwaitExpr,
+    BytesExpr,
+    CallExpr,
+    CastExpr,
+    ComparisonExpr,
+    ComplexExpr,
+    ConditionalExpr,
+    DictExpr,
+    DictionaryComprehension,
+    EllipsisExpr,
+    EnumCallExpr,
+    Expression,
+    FloatExpr,
+    GeneratorExpr,
+    IndexExpr,
+    IntExpr,
+    LambdaExpr,
+    ListComprehension,
+    ListExpr,
+    MemberExpr,
+    NamedTupleExpr,
+    NameExpr,
+    NewTypeExpr,
+    OpExpr,
+    ParamSpecExpr,
+    PromoteExpr,
+    RevealExpr,
+    SetComprehension,
+    SetExpr,
+    SliceExpr,
+    StarExpr,
+    StrExpr,
+    SuperExpr,
+    TempNode,
+    TupleExpr,
+    TypeAliasExpr,
+    TypeApplication,
+    TypedDictExpr,
+    TypeVarExpr,
+    TypeVarTupleExpr,
+    UnaryExpr,
+    Var,
+    YieldExpr,
+    YieldFromExpr,
+)
+from mypy.visitor import ExpressionVisitor
+
+# [Note Literals and literal_hash]
+# ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+#
+# Mypy uses the term "literal" to refer to any expression built out of
+# the following:
+#
+# * Plain literal expressions, like `1` (integer, float, string, etc.)
+#
+# * Compound literal expressions, like `(lit1, lit2)` (list, dict,
+#   set, or tuple)
+#
+# * Operator expressions, like `lit1 + lit2`
+#
+# * Variable references, like `x`
+#
+# * Member references, like `lit.m`
+#
+# * Index expressions, like `lit[0]`
+#
+# A typical "literal" looks like `x[(i,j+1)].m`.
+#
+# An expression that is a literal has a `literal_hash`, with the
+# following properties.
+#
+# * `literal_hash` is a Key: a tuple containing basic data types and
+#   possibly other Keys. So it can be used as a key in a dictionary
+#   that will be compared by value (as opposed to the Node itself,
+#   which is compared by identity).
+#
+# * Two expressions have equal `literal_hash`es if and only if they
+#   are syntactically equal expressions. (NB: Actually, we also
+#   identify as equal expressions like `3` and `3.0`; is this a good
+#   idea?)
+#
+# * The elements of `literal_hash` that are tuples are exactly the
+#   subexpressions of the original expression (e.g. the base and index
+#   of an index expression, or the operands of an operator expression).
+
+
+def literal(e: Expression) -> int:
+    if isinstance(e, ComparisonExpr):
+        return min(literal(o) for o in e.operands)
+
+    elif isinstance(e, OpExpr):
+        return min(literal(e.left), literal(e.right))
+
+    elif isinstance(e, (MemberExpr, UnaryExpr, StarExpr)):
+        return literal(e.expr)
+
+    elif isinstance(e, AssignmentExpr):
+        return literal(e.target)
+
+    elif isinstance(e, IndexExpr):
+        if literal(e.index) == LITERAL_YES:
+            return literal(e.base)
+        else:
+            return LITERAL_NO
+
+    elif isinstance(e, NameExpr):
+        if isinstance(e.node, Var) and e.node.is_final and e.node.final_value is not None:
+            return LITERAL_YES
+        return LITERAL_TYPE
+
+    if isinstance(e, (IntExpr, FloatExpr, ComplexExpr, StrExpr, BytesExpr)):
+        return LITERAL_YES
+
+    if literal_hash(e):
+        return LITERAL_YES
+
+    return LITERAL_NO
+
+
+Key: _TypeAlias = Tuple[Any, ...]
+
+
+def subkeys(key: Key) -> Iterable[Key]:
+    return [elt for elt in key if isinstance(elt, tuple)]
+
+
+def literal_hash(e: Expression) -> Key | None:
+    return e.accept(_hasher)
+
+
+def extract_var_from_literal_hash(key: Key) -> Var | None:
+    """If key refers to a Var node, return it.
+
+    Return None otherwise.
+    """
+    if len(key) == 2 and key[0] == "Var" and isinstance(key[1], Var):
+        return key[1]
+    return None
+
+
+class _Hasher(ExpressionVisitor[Optional[Key]]):
+    def visit_int_expr(self, e: IntExpr) -> Key:
+        return ("Literal", e.value)
+
+    def visit_str_expr(self, e: StrExpr) -> Key:
+        return ("Literal", e.value)
+
+    def visit_bytes_expr(self, e: BytesExpr) -> Key:
+        return ("Literal", e.value)
+
+    def visit_float_expr(self, e: FloatExpr) -> Key:
+        return ("Literal", e.value)
+
+    def visit_complex_expr(self, e: ComplexExpr) -> Key:
+        return ("Literal", e.value)
+
+    def visit_star_expr(self, e: StarExpr) -> Key:
+        return ("Star", literal_hash(e.expr))
+
+    def visit_name_expr(self, e: NameExpr) -> Key:
+        if isinstance(e.node, Var) and e.node.is_final and e.node.final_value is not None:
+            return ("Literal", e.node.final_value)
+        # N.B: We use the node itself as the key, and not the name,
+        # because using the name causes issues when there is shadowing
+        # (for example, in list comprehensions).
+        return ("Var", e.node)
+
+    def visit_member_expr(self, e: MemberExpr) -> Key:
+        return ("Member", literal_hash(e.expr), e.name)
+
+    def visit_op_expr(self, e: OpExpr) -> Key:
+        return ("Binary", e.op, literal_hash(e.left), literal_hash(e.right))
+
+    def visit_comparison_expr(self, e: ComparisonExpr) -> Key:
+        rest: tuple[str | Key | None, ...] = tuple(e.operators)
+        rest += tuple(literal_hash(o) for o in e.operands)
+        return ("Comparison",) + rest
+
+    def visit_unary_expr(self, e: UnaryExpr) -> Key:
+        return ("Unary", e.op, literal_hash(e.expr))
+
+    def seq_expr(self, e: ListExpr | TupleExpr | SetExpr, name: str) -> Key | None:
+        if all(literal(x) == LITERAL_YES for x in e.items):
+            rest: tuple[Key | None, ...] = tuple(literal_hash(x) for x in e.items)
+            return (name,) + rest
+        return None
+
+    def visit_list_expr(self, e: ListExpr) -> Key | None:
+        return self.seq_expr(e, "List")
+
+    def visit_dict_expr(self, e: DictExpr) -> Key | None:
+        if all(a and literal(a) == literal(b) == LITERAL_YES for a, b in e.items):
+            rest: tuple[Key | None, ...] = tuple(
+                (literal_hash(a) if a else None, literal_hash(b)) for a, b in e.items
+            )
+            return ("Dict",) + rest
+        return None
+
+    def visit_tuple_expr(self, e: TupleExpr) -> Key | None:
+        return self.seq_expr(e, "Tuple")
+
+    def visit_set_expr(self, e: SetExpr) -> Key | None:
+        return self.seq_expr(e, "Set")
+
+    def visit_index_expr(self, e: IndexExpr) -> Key | None:
+        if literal(e.index) == LITERAL_YES:
+            return ("Index", literal_hash(e.base), literal_hash(e.index))
+        return None
+
+    def visit_assignment_expr(self, e: AssignmentExpr) -> Key | None:
+        return literal_hash(e.target)
+
+    def visit_call_expr(self, e: CallExpr) -> None:
+        return None
+
+    def visit_slice_expr(self, e: SliceExpr) -> None:
+        return None
+
+    def visit_cast_expr(self, e: CastExpr) -> None:
+        return None
+
+    def visit_assert_type_expr(self, e: AssertTypeExpr) -> None:
+        return None
+
+    def visit_conditional_expr(self, e: ConditionalExpr) -> None:
+        return None
+
+    def visit_ellipsis(self, e: EllipsisExpr) -> None:
+        return None
+
+    def visit_yield_from_expr(self, e: YieldFromExpr) -> None:
+        return None
+
+    def visit_yield_expr(self, e: YieldExpr) -> None:
+        return None
+
+    def visit_reveal_expr(self, e: RevealExpr) -> None:
+        return None
+
+    def visit_super_expr(self, e: SuperExpr) -> None:
+        return None
+
+    def visit_type_application(self, e: TypeApplication) -> None:
+        return None
+
+    def visit_lambda_expr(self, e: LambdaExpr) -> None:
+        return None
+
+    def visit_list_comprehension(self, e: ListComprehension) -> None:
+        return None
+
+    def visit_set_comprehension(self, e: SetComprehension) -> None:
+        return None
+
+    def visit_dictionary_comprehension(self, e: DictionaryComprehension) -> None:
+        return None
+
+    def visit_generator_expr(self, e: GeneratorExpr) -> None:
+        return None
+
+    def visit_type_var_expr(self, e: TypeVarExpr) -> None:
+        return None
+
+    def visit_paramspec_expr(self, e: ParamSpecExpr) -> None:
+        return None
+
+    def visit_type_var_tuple_expr(self, e: TypeVarTupleExpr) -> None:
+        return None
+
+    def visit_type_alias_expr(self, e: TypeAliasExpr) -> None:
+        return None
+
+    def visit_namedtuple_expr(self, e: NamedTupleExpr) -> None:
+        return None
+
+    def visit_enum_call_expr(self, e: EnumCallExpr) -> None:
+        return None
+
+    def visit_typeddict_expr(self, e: TypedDictExpr) -> None:
+        return None
+
+    def visit_newtype_expr(self, e: NewTypeExpr) -> None:
+        return None
+
+    def visit__promote_expr(self, e: PromoteExpr) -> None:
+        return None
+
+    def visit_await_expr(self, e: AwaitExpr) -> None:
+        return None
+
+    def visit_temp_node(self, e: TempNode) -> None:
+        return None
+
+
+_hasher: Final = _Hasher()

venv/lib/python3.12/site-packages/mypy/lookup.py

@@ -0,0 +1,61 @@
+"""
+This is a module for various lookup functions:
+functions that will find a semantic node by its name.
+"""
+
+from __future__ import annotations
+
+from mypy.nodes import MypyFile, SymbolTableNode, TypeInfo
+
+# TODO: gradually move existing lookup functions to this module.
+
+
+def lookup_fully_qualified(
+    name: str, modules: dict[str, MypyFile], *, raise_on_missing: bool = False
+) -> SymbolTableNode | None:
+    """Find a symbol using it fully qualified name.
+
+    The algorithm has two steps: first we try splitting the name on '.' to find
+    the module, then iteratively look for each next chunk after a '.' (e.g. for
+    nested classes).
+
+    This function should *not* be used to find a module. Those should be looked
+    in the modules dictionary.
+    """
+    head = name
+    rest = []
+    # 1. Find a module tree in modules dictionary.
+    while True:
+        if "." not in head:
+            if raise_on_missing:
+                assert "." in head, f"Cannot find module for {name}"
+            return None
+        head, tail = head.rsplit(".", maxsplit=1)
+        rest.append(tail)
+        mod = modules.get(head)
+        if mod is not None:
+            break
+    names = mod.names
+    # 2. Find the symbol in the module tree.
+    if not rest:
+        # Looks like a module, don't use this to avoid confusions.
+        if raise_on_missing:
+            assert rest, f"Cannot find {name}, got a module symbol"
+        return None
+    while True:
+        key = rest.pop()
+        if key not in names:
+            if raise_on_missing:
+                assert key in names, f"Cannot find component {key!r} for {name!r}"
+            return None
+        stnode = names[key]
+        if not rest:
+            return stnode
+        node = stnode.node
+        # In fine-grained mode, could be a cross-reference to a deleted module
+        # or a Var made up for a missing module.
+        if not isinstance(node, TypeInfo):
+            if raise_on_missing:
+                assert node, f"Cannot find {name}"
+            return None
+        names = node.names

venv/lib/python3.12/site-packages/mypy/maptype.py

@@ -0,0 +1,117 @@
+from __future__ import annotations
+
+from mypy.expandtype import expand_type
+from mypy.nodes import TypeInfo
+from mypy.types import AnyType, Instance, TupleType, Type, TypeOfAny, TypeVarId, has_type_vars
+
+
+def map_instance_to_supertype(instance: Instance, superclass: TypeInfo) -> Instance:
+    """Produce a supertype of `instance` that is an Instance
+    of `superclass`, mapping type arguments up the chain of bases.
+
+    If `superclass` is not a nominal superclass of `instance.type`,
+    then all type arguments are mapped to 'Any'.
+    """
+    if instance.type == superclass:
+        # Fast path: `instance` already belongs to `superclass`.
+        return instance
+
+    if superclass.fullname == "builtins.tuple" and instance.type.tuple_type:
+        if has_type_vars(instance.type.tuple_type):
+            # We special case mapping generic tuple types to tuple base, because for
+            # such tuples fallback can't be calculated before applying type arguments.
+            alias = instance.type.special_alias
+            assert alias is not None
+            if not alias._is_recursive:
+                # Unfortunately we can't support this for generic recursive tuples.
+                # If we skip this special casing we will fall back to tuple[Any, ...].
+                env = instance_to_type_environment(instance)
+                tuple_type = expand_type(instance.type.tuple_type, env)
+                if isinstance(tuple_type, TupleType):
+                    # Make the import here to avoid cyclic imports.
+                    import mypy.typeops
+
+                    return mypy.typeops.tuple_fallback(tuple_type)
+
+    if not superclass.type_vars:
+        # Fast path: `superclass` has no type variables to map to.
+        return Instance(superclass, [])
+
+    return map_instance_to_supertypes(instance, superclass)[0]
+
+
+def map_instance_to_supertypes(instance: Instance, supertype: TypeInfo) -> list[Instance]:
+    # FIX: Currently we should only have one supertype per interface, so no
+    #      need to return an array
+    result: list[Instance] = []
+    for path in class_derivation_paths(instance.type, supertype):
+        types = [instance]
+        for sup in path:
+            a: list[Instance] = []
+            for t in types:
+                a.extend(map_instance_to_direct_supertypes(t, sup))
+            types = a
+        result.extend(types)
+    if result:
+        return result
+    else:
+        # Nothing. Presumably due to an error. Construct a dummy using Any.
+        any_type = AnyType(TypeOfAny.from_error)
+        return [Instance(supertype, [any_type] * len(supertype.type_vars))]
+
+
+def class_derivation_paths(typ: TypeInfo, supertype: TypeInfo) -> list[list[TypeInfo]]:
+    """Return an array of non-empty paths of direct base classes from
+    type to supertype.  Return [] if no such path could be found.
+
+      InterfaceImplementationPaths(A, B) == [[B]] if A inherits B
+      InterfaceImplementationPaths(A, C) == [[B, C]] if A inherits B and
+                                                        B inherits C
+    """
+    # FIX: Currently we might only ever have a single path, so this could be
+    #      simplified
+    result: list[list[TypeInfo]] = []
+
+    for base in typ.bases:
+        btype = base.type
+        if btype == supertype:
+            result.append([btype])
+        else:
+            # Try constructing a longer path via the base class.
+            for path in class_derivation_paths(btype, supertype):
+                result.append([btype] + path)
+
+    return result
+
+
+def map_instance_to_direct_supertypes(instance: Instance, supertype: TypeInfo) -> list[Instance]:
+    # FIX: There should only be one supertypes, always.
+    typ = instance.type
+    result: list[Instance] = []
+
+    for b in typ.bases:
+        if b.type == supertype:
+            env = instance_to_type_environment(instance)
+            t = expand_type(b, env)
+            assert isinstance(t, Instance)
+            result.append(t)
+
+    if result:
+        return result
+    else:
+        # Relationship with the supertype not specified explicitly. Use dynamic
+        # type arguments implicitly.
+        any_type = AnyType(TypeOfAny.unannotated)
+        return [Instance(supertype, [any_type] * len(supertype.type_vars))]
+
+
+def instance_to_type_environment(instance: Instance) -> dict[TypeVarId, Type]:
+    """Given an Instance, produce the resulting type environment for type
+    variables bound by the Instance's class definition.
+
+    An Instance is a type application of a class (a TypeInfo) to its
+    required number of type arguments.  So this environment consists
+    of the class's type variables mapped to the Instance's actual
+    arguments.  The type variables are mapped by their `id`.
+    """
+    return {binder.id: arg for binder, arg in zip(instance.type.defn.type_vars, instance.args)}

venv/lib/python3.12/site-packages/mypy/memprofile.py

@@ -0,0 +1,121 @@
+"""Utility for dumping memory usage stats.
+
+This is tailored to mypy and knows (a little) about which list objects are
+owned by particular AST nodes, etc.
+"""
+
+from __future__ import annotations
+
+import gc
+import sys
+from collections import defaultdict
+from typing import Dict, Iterable, cast
+
+from mypy.nodes import FakeInfo, Node
+from mypy.types import Type
+from mypy.util import get_class_descriptors
+
+
+def collect_memory_stats() -> tuple[dict[str, int], dict[str, int]]:
+    """Return stats about memory use.
+
+    Return a tuple with these items:
+      - Dict from object kind to number of instances of that kind
+      - Dict from object kind to total bytes used by all instances of that kind
+    """
+    objs = gc.get_objects()
+    find_recursive_objects(objs)
+
+    inferred = {}
+    for obj in objs:
+        if type(obj) is FakeInfo:
+            # Processing these would cause a crash.
+            continue
+        n = type(obj).__name__
+        if hasattr(obj, "__dict__"):
+            # Keep track of which class a particular __dict__ is associated with.
+            inferred[id(obj.__dict__)] = f"{n} (__dict__)"
+        if isinstance(obj, (Node, Type)):  # type: ignore[misc]
+            if hasattr(obj, "__dict__"):
+                for x in obj.__dict__.values():
+                    if isinstance(x, list):
+                        # Keep track of which node a list is associated with.
+                        inferred[id(x)] = f"{n} (list)"
+                    if isinstance(x, tuple):
+                        # Keep track of which node a list is associated with.
+                        inferred[id(x)] = f"{n} (tuple)"
+
+            for k in get_class_descriptors(type(obj)):
+                x = getattr(obj, k, None)
+                if isinstance(x, list):
+                    inferred[id(x)] = f"{n} (list)"
+                if isinstance(x, tuple):
+                    inferred[id(x)] = f"{n} (tuple)"
+
+    freqs: dict[str, int] = {}
+    memuse: dict[str, int] = {}
+    for obj in objs:
+        if id(obj) in inferred:
+            name = inferred[id(obj)]
+        else:
+            name = type(obj).__name__
+        freqs[name] = freqs.get(name, 0) + 1
+        memuse[name] = memuse.get(name, 0) + sys.getsizeof(obj)
+
+    return freqs, memuse
+
+
+def print_memory_profile(run_gc: bool = True) -> None:
+    if not sys.platform.startswith("win"):
+        import resource
+
+        system_memuse = resource.getrusage(resource.RUSAGE_SELF).ru_maxrss
+    else:
+        system_memuse = -1  # TODO: Support this on Windows
+    if run_gc:
+        gc.collect()
+    freqs, memuse = collect_memory_stats()
+    print("%7s  %7s  %7s  %s" % ("Freq", "Size(k)", "AvgSize", "Type"))
+    print("-------------------------------------------")
+    totalmem = 0
+    i = 0
+    for n, mem in sorted(memuse.items(), key=lambda x: -x[1]):
+        f = freqs[n]
+        if i < 50:
+            print("%7d  %7d  %7.0f  %s" % (f, mem // 1024, mem / f, n))
+        i += 1
+        totalmem += mem
+    print()
+    print("Mem usage RSS   ", system_memuse // 1024)
+    print("Total reachable ", totalmem // 1024)
+
+
+def find_recursive_objects(objs: list[object]) -> None:
+    """Find additional objects referenced by objs and append them to objs.
+
+    We use this since gc.get_objects() does not return objects without pointers
+    in them such as strings.
+    """
+    seen = {id(o) for o in objs}
+
+    def visit(o: object) -> None:
+        if id(o) not in seen:
+            objs.append(o)
+            seen.add(id(o))
+
+    for obj in objs.copy():
+        if type(obj) is FakeInfo:
+            # Processing these would cause a crash.
+            continue
+        if type(obj) in (dict, defaultdict):
+            for key, val in cast(Dict[object, object], obj).items():
+                visit(key)
+                visit(val)
+        if type(obj) in (list, tuple, set):
+            for x in cast(Iterable[object], obj):
+                visit(x)
+        if hasattr(obj, "__slots__"):
+            for base in type.mro(type(obj)):
+                for slot in getattr(base, "__slots__", ()):
+                    if hasattr(obj, slot):
+                        visit(getattr(obj, slot))

venv/lib/python3.12/site-packages/mypy/message_registry.py

@@ -0,0 +1,319 @@
+"""Message constants for generating error messages during type checking.
+
+Literal messages should be defined as constants in this module so they won't get out of sync
+if used in more than one place, and so that they can be easily introspected. These messages are
+ultimately consumed by messages.MessageBuilder.fail(). For more non-trivial message generation,
+add a method to MessageBuilder and call this instead.
+"""
+
+from __future__ import annotations
+
+from typing import Final, NamedTuple
+
+from mypy import errorcodes as codes
+
+
+class ErrorMessage(NamedTuple):
+    value: str
+    code: codes.ErrorCode | None = None
+
+    def format(self, *args: object, **kwargs: object) -> ErrorMessage:
+        return ErrorMessage(self.value.format(*args, **kwargs), code=self.code)
+
+    def with_additional_msg(self, info: str) -> ErrorMessage:
+        return ErrorMessage(self.value + info, code=self.code)
+
+
+# Invalid types
+INVALID_TYPE_RAW_ENUM_VALUE: Final = ErrorMessage(
+    "Invalid type: try using Literal[{}.{}] instead?", codes.VALID_TYPE
+)
+
+# Type checker error message constants
+NO_RETURN_VALUE_EXPECTED: Final = ErrorMessage("No return value expected", codes.RETURN_VALUE)
+MISSING_RETURN_STATEMENT: Final = ErrorMessage("Missing return statement", codes.RETURN)
+EMPTY_BODY_ABSTRACT: Final = ErrorMessage(
+    "If the method is meant to be abstract, use @abc.abstractmethod", codes.EMPTY_BODY
+)
+INVALID_IMPLICIT_RETURN: Final = ErrorMessage("Implicit return in function which does not return")
+INCOMPATIBLE_RETURN_VALUE_TYPE: Final = ErrorMessage(
+    "Incompatible return value type", codes.RETURN_VALUE
+)
+RETURN_VALUE_EXPECTED: Final = ErrorMessage("Return value expected", codes.RETURN_VALUE)
+NO_RETURN_EXPECTED: Final = ErrorMessage("Return statement in function which does not return")
+INVALID_EXCEPTION: Final = ErrorMessage("Exception must be derived from BaseException")
+INVALID_EXCEPTION_TYPE: Final = ErrorMessage(
+    "Exception type must be derived from BaseException (or be a tuple of exception classes)"
+)
+INVALID_EXCEPTION_GROUP: Final = ErrorMessage(
+    "Exception type in except* cannot derive from BaseExceptionGroup"
+)
+RETURN_IN_ASYNC_GENERATOR: Final = ErrorMessage(
+    '"return" with value in async generator is not allowed'
+)
+INVALID_RETURN_TYPE_FOR_GENERATOR: Final = ErrorMessage(
+    'The return type of a generator function should be "Generator"' " or one of its supertypes"
+)
+INVALID_RETURN_TYPE_FOR_ASYNC_GENERATOR: Final = ErrorMessage(
+    'The return type of an async generator function should be "AsyncGenerator" or one of its '
+    "supertypes"
+)
+YIELD_VALUE_EXPECTED: Final = ErrorMessage("Yield value expected")
+INCOMPATIBLE_TYPES: Final = ErrorMessage("Incompatible types")
+INCOMPATIBLE_TYPES_IN_ASSIGNMENT: Final = ErrorMessage(
+    "Incompatible types in assignment", code=codes.ASSIGNMENT
+)
+INCOMPATIBLE_TYPES_IN_AWAIT: Final = ErrorMessage('Incompatible types in "await"')
+INCOMPATIBLE_REDEFINITION: Final = ErrorMessage("Incompatible redefinition")
+INCOMPATIBLE_TYPES_IN_ASYNC_WITH_AENTER: Final = (
+    'Incompatible types in "async with" for "__aenter__"'
+)
+INCOMPATIBLE_TYPES_IN_ASYNC_WITH_AEXIT: Final = (
+    'Incompatible types in "async with" for "__aexit__"'
+)
+INCOMPATIBLE_TYPES_IN_ASYNC_FOR: Final = 'Incompatible types in "async for"'
+INVALID_TYPE_FOR_SLOTS: Final = 'Invalid type for "__slots__"'
+
+ASYNC_FOR_OUTSIDE_COROUTINE: Final = '"async for" outside async function'
+ASYNC_WITH_OUTSIDE_COROUTINE: Final = '"async with" outside async function'
+
+INCOMPATIBLE_TYPES_IN_YIELD: Final = ErrorMessage('Incompatible types in "yield"')
+INCOMPATIBLE_TYPES_IN_YIELD_FROM: Final = ErrorMessage('Incompatible types in "yield from"')
+INCOMPATIBLE_TYPES_IN_STR_INTERPOLATION: Final = "Incompatible types in string interpolation"
+INCOMPATIBLE_TYPES_IN_CAPTURE: Final = ErrorMessage("Incompatible types in capture pattern")
+MUST_HAVE_NONE_RETURN_TYPE: Final = ErrorMessage('The return type of "{}" must be None')
+TUPLE_INDEX_OUT_OF_RANGE: Final = ErrorMessage("Tuple index out of range")
+INVALID_SLICE_INDEX: Final = ErrorMessage("Slice index must be an integer, SupportsIndex or None")
+CANNOT_INFER_LAMBDA_TYPE: Final = ErrorMessage("Cannot infer type of lambda")
+CANNOT_ACCESS_INIT: Final = (
+    'Accessing "__init__" on an instance is unsound, since instance.__init__ could be from'
+    " an incompatible subclass"
+)
+NON_INSTANCE_NEW_TYPE: Final = ErrorMessage('"__new__" must return a class instance (got {})')
+INVALID_NEW_TYPE: Final = ErrorMessage('Incompatible return type for "__new__"')
+BAD_CONSTRUCTOR_TYPE: Final = ErrorMessage("Unsupported decorated constructor type")
+CANNOT_ASSIGN_TO_METHOD: Final = "Cannot assign to a method"
+CANNOT_ASSIGN_TO_TYPE: Final = "Cannot assign to a type"
+INCONSISTENT_ABSTRACT_OVERLOAD: Final = ErrorMessage(
+    "Overloaded method has both abstract and non-abstract variants"
+)
+MULTIPLE_OVERLOADS_REQUIRED: Final = ErrorMessage("Single overload definition, multiple required")
+READ_ONLY_PROPERTY_OVERRIDES_READ_WRITE: Final = ErrorMessage(
+    "Read-only property cannot override read-write property"
+)
+FORMAT_REQUIRES_MAPPING: Final = "Format requires a mapping"
+RETURN_TYPE_CANNOT_BE_CONTRAVARIANT: Final = ErrorMessage(
+    "Cannot use a contravariant type variable as return type"
+)
+FUNCTION_PARAMETER_CANNOT_BE_COVARIANT: Final = ErrorMessage(
+    "Cannot use a covariant type variable as a parameter"
+)
+INCOMPATIBLE_IMPORT_OF: Final = ErrorMessage('Incompatible import of "{}"', code=codes.ASSIGNMENT)
+FUNCTION_TYPE_EXPECTED: Final = ErrorMessage(
+    "Function is missing a type annotation", codes.NO_UNTYPED_DEF
+)
+ONLY_CLASS_APPLICATION: Final = ErrorMessage(
+    "Type application is only supported for generic classes"
+)
+RETURN_TYPE_EXPECTED: Final = ErrorMessage(
+    "Function is missing a return type annotation", codes.NO_UNTYPED_DEF
+)
+ARGUMENT_TYPE_EXPECTED: Final = ErrorMessage(
+    "Function is missing a type annotation for one or more arguments", codes.NO_UNTYPED_DEF
+)
+KEYWORD_ARGUMENT_REQUIRES_STR_KEY_TYPE: Final = ErrorMessage(
+    'Keyword argument only valid with "str" key type in call to "dict"'
+)
+ALL_MUST_BE_SEQ_STR: Final = ErrorMessage("Type of __all__ must be {}, not {}")
+INVALID_TYPEDDICT_ARGS: Final = ErrorMessage(
+    "Expected keyword arguments, {...}, or dict(...) in TypedDict constructor"
+)
+TYPEDDICT_KEY_MUST_BE_STRING_LITERAL: Final = ErrorMessage(
+    "Expected TypedDict key to be string literal"
+)
+MALFORMED_ASSERT: Final = ErrorMessage("Assertion is always true, perhaps remove parentheses?")
+DUPLICATE_TYPE_SIGNATURES: Final = ErrorMessage("Function has duplicate type signatures")
+DESCRIPTOR_SET_NOT_CALLABLE: Final = ErrorMessage("{}.__set__ is not callable")
+DESCRIPTOR_GET_NOT_CALLABLE: Final = "{}.__get__ is not callable"
+MODULE_LEVEL_GETATTRIBUTE: Final = ErrorMessage(
+    "__getattribute__ is not valid at the module level"
+)
+CLASS_VAR_CONFLICTS_SLOTS: Final = '"{}" in __slots__ conflicts with class variable access'
+NAME_NOT_IN_SLOTS: Final = ErrorMessage(
+    'Trying to assign name "{}" that is not in "__slots__" of type "{}"'
+)
+TYPE_ALWAYS_TRUE: Final = ErrorMessage(
+    "{} which does not implement __bool__ or __len__ "
+    "so it could always be true in boolean context",
+    code=codes.TRUTHY_BOOL,
+)
+TYPE_ALWAYS_TRUE_UNIONTYPE: Final = ErrorMessage(
+    "{} of which no members implement __bool__ or __len__ "
+    "so it could always be true in boolean context",
+    code=codes.TRUTHY_BOOL,
+)
+FUNCTION_ALWAYS_TRUE: Final = ErrorMessage(
+    "Function {} could always be true in boolean context", code=codes.TRUTHY_FUNCTION
+)
+ITERABLE_ALWAYS_TRUE: Final = ErrorMessage(
+    "{} which can always be true in boolean context. Consider using {} instead.",
+    code=codes.TRUTHY_ITERABLE,
+)
+NOT_CALLABLE: Final = "{} not callable"
+TYPE_MUST_BE_USED: Final = "Value of type {} must be used"
+
+# Generic
+GENERIC_INSTANCE_VAR_CLASS_ACCESS: Final = (
+    "Access to generic instance variables via class is ambiguous"
+)
+GENERIC_CLASS_VAR_ACCESS: Final = "Access to generic class variables is ambiguous"
+BARE_GENERIC: Final = "Missing type parameters for generic type {}"
+IMPLICIT_GENERIC_ANY_BUILTIN: Final = (
+    'Implicit generic "Any". Use "{}" and specify generic parameters'
+)
+INVALID_UNPACK: Final = "{} cannot be unpacked (must be tuple or TypeVarTuple)"
+INVALID_UNPACK_POSITION: Final = "Unpack is only valid in a variadic position"
+
+# TypeVar
+INCOMPATIBLE_TYPEVAR_VALUE: Final = 'Value of type variable "{}" of {} cannot be {}'
+CANNOT_USE_TYPEVAR_AS_EXPRESSION: Final = 'Type variable "{}.{}" cannot be used as an expression'
+INVALID_TYPEVAR_AS_TYPEARG: Final = 'Type variable "{}" not valid as type argument value for "{}"'
+INVALID_TYPEVAR_ARG_BOUND: Final = 'Type argument {} of "{}" must be a subtype of {}'
+INVALID_TYPEVAR_ARG_VALUE: Final = 'Invalid type argument value for "{}"'
+TYPEVAR_VARIANCE_DEF: Final = 'TypeVar "{}" may only be a literal bool'
+TYPEVAR_ARG_MUST_BE_TYPE: Final = '{} "{}" must be a type'
+TYPEVAR_UNEXPECTED_ARGUMENT: Final = 'Unexpected argument to "TypeVar()"'
+UNBOUND_TYPEVAR: Final = (
+    "A function returning TypeVar should receive at least "
+    "one argument containing the same TypeVar"
+)
+
+# Super
+TOO_MANY_ARGS_FOR_SUPER: Final = ErrorMessage('Too many arguments for "super"')
+SUPER_WITH_SINGLE_ARG_NOT_SUPPORTED: Final = ErrorMessage(
+    '"super" with a single argument not supported'
+)
+UNSUPPORTED_ARG_1_FOR_SUPER: Final = ErrorMessage('Unsupported argument 1 for "super"')
+UNSUPPORTED_ARG_2_FOR_SUPER: Final = ErrorMessage('Unsupported argument 2 for "super"')
+SUPER_VARARGS_NOT_SUPPORTED: Final = ErrorMessage('Varargs not supported with "super"')
+SUPER_POSITIONAL_ARGS_REQUIRED: Final = ErrorMessage('"super" only accepts positional arguments')
+SUPER_ARG_2_NOT_INSTANCE_OF_ARG_1: Final = ErrorMessage(
+    'Argument 2 for "super" not an instance of argument 1'
+)
+TARGET_CLASS_HAS_NO_BASE_CLASS: Final = ErrorMessage("Target class has no base class")
+SUPER_OUTSIDE_OF_METHOD_NOT_SUPPORTED: Final = ErrorMessage(
+    "super() outside of a method is not supported"
+)
+SUPER_ENCLOSING_POSITIONAL_ARGS_REQUIRED: Final = ErrorMessage(
+    "super() requires one or more positional arguments in enclosing function"
+)
+
+# Self-type
+MISSING_OR_INVALID_SELF_TYPE: Final = ErrorMessage(
+    "Self argument missing for a non-static method (or an invalid type for self)"
+)
+ERASED_SELF_TYPE_NOT_SUPERTYPE: Final = ErrorMessage(
+    'The erased type of self "{}" is not a supertype of its class "{}"'
+)
+
+# Final
+CANNOT_INHERIT_FROM_FINAL: Final = ErrorMessage('Cannot inherit from final class "{}"')
+DEPENDENT_FINAL_IN_CLASS_BODY: Final = ErrorMessage(
+    "Final name declared in class body cannot depend on type variables"
+)
+CANNOT_ACCESS_FINAL_INSTANCE_ATTR: Final = (
+    'Cannot access final instance attribute "{}" on class object'
+)
+CANNOT_MAKE_DELETABLE_FINAL: Final = ErrorMessage("Deletable attribute cannot be final")
+
+# Enum
+ENUM_MEMBERS_ATTR_WILL_BE_OVERRIDEN: Final = ErrorMessage(
+    'Assigned "__members__" will be overridden by "Enum" internally'
+)
+
+# ClassVar
+CANNOT_OVERRIDE_INSTANCE_VAR: Final = ErrorMessage(
+    'Cannot override instance variable (previously declared on base class "{}") with class '
+    "variable"
+)
+CANNOT_OVERRIDE_CLASS_VAR: Final = ErrorMessage(
+    'Cannot override class variable (previously declared on base class "{}") with instance '
+    "variable"
+)
+CLASS_VAR_WITH_TYPEVARS: Final = "ClassVar cannot contain type variables"
+CLASS_VAR_WITH_GENERIC_SELF: Final = "ClassVar cannot contain Self type in generic classes"
+CLASS_VAR_OUTSIDE_OF_CLASS: Final = "ClassVar can only be used for assignments in class body"
+
+# Protocol
+RUNTIME_PROTOCOL_EXPECTED: Final = ErrorMessage(
+    "Only @runtime_checkable protocols can be used with instance and class checks"
+)
+CANNOT_INSTANTIATE_PROTOCOL: Final = ErrorMessage('Cannot instantiate protocol class "{}"')
+TOO_MANY_UNION_COMBINATIONS: Final = ErrorMessage(
+    "Not all union combinations were tried because there are too many unions"
+)
+
+CONTIGUOUS_ITERABLE_EXPECTED: Final = ErrorMessage("Contiguous iterable with same type expected")
+ITERABLE_TYPE_EXPECTED: Final = ErrorMessage("Invalid type '{}' for *expr (iterable expected)")
+TYPE_GUARD_POS_ARG_REQUIRED: Final = ErrorMessage("Type guard requires positional argument")
+
+# Match Statement
+MISSING_MATCH_ARGS: Final = 'Class "{}" doesn\'t define "__match_args__"'
+OR_PATTERN_ALTERNATIVE_NAMES: Final = "Alternative patterns bind different names"
+CLASS_PATTERN_GENERIC_TYPE_ALIAS: Final = (
+    "Class pattern class must not be a type alias with type parameters"
+)
+CLASS_PATTERN_TYPE_REQUIRED: Final = 'Expected type in class pattern; found "{}"'
+CLASS_PATTERN_TOO_MANY_POSITIONAL_ARGS: Final = "Too many positional patterns for class pattern"
+CLASS_PATTERN_KEYWORD_MATCHES_POSITIONAL: Final = (
+    'Keyword "{}" already matches a positional pattern'
+)
+CLASS_PATTERN_DUPLICATE_KEYWORD_PATTERN: Final = 'Duplicate keyword pattern "{}"'
+CLASS_PATTERN_UNKNOWN_KEYWORD: Final = 'Class "{}" has no attribute "{}"'
+CLASS_PATTERN_CLASS_OR_STATIC_METHOD: Final = "Cannot have both classmethod and staticmethod"
+MULTIPLE_ASSIGNMENTS_IN_PATTERN: Final = 'Multiple assignments to name "{}" in pattern'
+CANNOT_MODIFY_MATCH_ARGS: Final = 'Cannot assign to "__match_args__"'
+
+DATACLASS_FIELD_ALIAS_MUST_BE_LITERAL: Final = (
+    '"alias" argument to dataclass field must be a string literal'
+)
+DATACLASS_POST_INIT_MUST_BE_A_FUNCTION: Final = '"__post_init__" method must be an instance method'
+
+# fastparse
+FAILED_TO_MERGE_OVERLOADS: Final = ErrorMessage(
+    "Condition can't be inferred, unable to merge overloads"
+)
+TYPE_IGNORE_WITH_ERRCODE_ON_MODULE: Final = ErrorMessage(
+    "type ignore with error code is not supported for modules; "
+    'use `# mypy: disable-error-code="{}"`',
+    codes.SYNTAX,
+)
+INVALID_TYPE_IGNORE: Final = ErrorMessage('Invalid "type: ignore" comment', codes.SYNTAX)
+TYPE_COMMENT_SYNTAX_ERROR_VALUE: Final = ErrorMessage(
+    'Syntax error in type comment "{}"', codes.SYNTAX
+)
+ELLIPSIS_WITH_OTHER_TYPEARGS: Final = ErrorMessage(
+    "Ellipses cannot accompany other argument types in function type signature", codes.SYNTAX
+)
+TYPE_SIGNATURE_TOO_MANY_ARGS: Final = ErrorMessage(
+    "Type signature has too many arguments", codes.SYNTAX
+)
+TYPE_SIGNATURE_TOO_FEW_ARGS: Final = ErrorMessage(
+    "Type signature has too few arguments", codes.SYNTAX
+)
+ARG_CONSTRUCTOR_NAME_EXPECTED: Final = ErrorMessage("Expected arg constructor name", codes.SYNTAX)
+ARG_CONSTRUCTOR_TOO_MANY_ARGS: Final = ErrorMessage(
+    "Too many arguments for argument constructor", codes.SYNTAX
+)
+MULTIPLE_VALUES_FOR_NAME_KWARG: Final = ErrorMessage(
+    '"{}" gets multiple values for keyword argument "name"', codes.SYNTAX
+)
+MULTIPLE_VALUES_FOR_TYPE_KWARG: Final = ErrorMessage(
+    '"{}" gets multiple values for keyword argument "type"', codes.SYNTAX
+)
+ARG_CONSTRUCTOR_UNEXPECTED_ARG: Final = ErrorMessage(
+    'Unexpected argument "{}" for argument constructor', codes.SYNTAX
+)
+ARG_NAME_EXPECTED_STRING_LITERAL: Final = ErrorMessage(
+    "Expected string literal for argument name, got {}", codes.SYNTAX
+)