Major fixes and new features

venv/lib/python3.12/site-packages/mypy/test/testconstraints.py

@@ -0,0 +1,158 @@
+from __future__ import annotations
+
+from mypy.constraints import SUBTYPE_OF, SUPERTYPE_OF, Constraint, infer_constraints
+from mypy.test.helpers import Suite
+from mypy.test.typefixture import TypeFixture
+from mypy.types import Instance, TupleType, UnpackType
+
+
+class ConstraintsSuite(Suite):
+    def setUp(self) -> None:
+        self.fx = TypeFixture()
+
+    def test_no_type_variables(self) -> None:
+        assert not infer_constraints(self.fx.o, self.fx.o, SUBTYPE_OF)
+
+    def test_basic_type_variable(self) -> None:
+        fx = self.fx
+        for direction in [SUBTYPE_OF, SUPERTYPE_OF]:
+            assert infer_constraints(fx.gt, fx.ga, direction) == [
+                Constraint(type_var=fx.t, op=direction, target=fx.a)
+            ]
+
+    def test_basic_type_var_tuple_subtype(self) -> None:
+        fx = self.fx
+        assert infer_constraints(
+            Instance(fx.gvi, [UnpackType(fx.ts)]), Instance(fx.gvi, [fx.a, fx.b]), SUBTYPE_OF
+        ) == [
+            Constraint(type_var=fx.ts, op=SUBTYPE_OF, target=TupleType([fx.a, fx.b], fx.std_tuple))
+        ]
+
+    def test_basic_type_var_tuple(self) -> None:
+        fx = self.fx
+        assert infer_constraints(
+            Instance(fx.gvi, [UnpackType(fx.ts)]), Instance(fx.gvi, [fx.a, fx.b]), SUPERTYPE_OF
+        ) == [
+            Constraint(
+                type_var=fx.ts, op=SUPERTYPE_OF, target=TupleType([fx.a, fx.b], fx.std_tuple)
+            )
+        ]
+
+    def test_type_var_tuple_with_prefix_and_suffix(self) -> None:
+        fx = self.fx
+        assert set(
+            infer_constraints(
+                Instance(fx.gv2i, [fx.t, UnpackType(fx.ts), fx.s]),
+                Instance(fx.gv2i, [fx.a, fx.b, fx.c, fx.d]),
+                SUPERTYPE_OF,
+            )
+        ) == {
+            Constraint(type_var=fx.t, op=SUPERTYPE_OF, target=fx.a),
+            Constraint(
+                type_var=fx.ts, op=SUPERTYPE_OF, target=TupleType([fx.b, fx.c], fx.std_tuple)
+            ),
+            Constraint(type_var=fx.s, op=SUPERTYPE_OF, target=fx.d),
+        }
+
+    def test_unpack_homogenous_tuple(self) -> None:
+        fx = self.fx
+        assert set(
+            infer_constraints(
+                Instance(fx.gvi, [UnpackType(Instance(fx.std_tuplei, [fx.t]))]),
+                Instance(fx.gvi, [fx.a, fx.b]),
+                SUPERTYPE_OF,
+            )
+        ) == {
+            Constraint(type_var=fx.t, op=SUPERTYPE_OF, target=fx.a),
+            Constraint(type_var=fx.t, op=SUPERTYPE_OF, target=fx.b),
+        }
+
+    def test_unpack_homogenous_tuple_with_prefix_and_suffix(self) -> None:
+        fx = self.fx
+        assert set(
+            infer_constraints(
+                Instance(fx.gv2i, [fx.t, UnpackType(Instance(fx.std_tuplei, [fx.s])), fx.u]),
+                Instance(fx.gv2i, [fx.a, fx.b, fx.c, fx.d]),
+                SUPERTYPE_OF,
+            )
+        ) == {
+            Constraint(type_var=fx.t, op=SUPERTYPE_OF, target=fx.a),
+            Constraint(type_var=fx.s, op=SUPERTYPE_OF, target=fx.b),
+            Constraint(type_var=fx.s, op=SUPERTYPE_OF, target=fx.c),
+            Constraint(type_var=fx.u, op=SUPERTYPE_OF, target=fx.d),
+        }
+
+    def test_unpack_tuple(self) -> None:
+        fx = self.fx
+        assert set(
+            infer_constraints(
+                Instance(
+                    fx.gvi,
+                    [
+                        UnpackType(
+                            TupleType([fx.t, fx.s], fallback=Instance(fx.std_tuplei, [fx.o]))
+                        )
+                    ],
+                ),
+                Instance(fx.gvi, [fx.a, fx.b]),
+                SUPERTYPE_OF,
+            )
+        ) == {
+            Constraint(type_var=fx.t, op=SUPERTYPE_OF, target=fx.a),
+            Constraint(type_var=fx.s, op=SUPERTYPE_OF, target=fx.b),
+        }
+
+    def test_unpack_with_prefix_and_suffix(self) -> None:
+        fx = self.fx
+        assert set(
+            infer_constraints(
+                Instance(
+                    fx.gv2i,
+                    [
+                        fx.u,
+                        UnpackType(
+                            TupleType([fx.t, fx.s], fallback=Instance(fx.std_tuplei, [fx.o]))
+                        ),
+                        fx.u,
+                    ],
+                ),
+                Instance(fx.gv2i, [fx.a, fx.b, fx.c, fx.d]),
+                SUPERTYPE_OF,
+            )
+        ) == {
+            Constraint(type_var=fx.u, op=SUPERTYPE_OF, target=fx.a),
+            Constraint(type_var=fx.t, op=SUPERTYPE_OF, target=fx.b),
+            Constraint(type_var=fx.s, op=SUPERTYPE_OF, target=fx.c),
+            Constraint(type_var=fx.u, op=SUPERTYPE_OF, target=fx.d),
+        }
+
+    def test_unpack_tuple_length_non_match(self) -> None:
+        fx = self.fx
+        assert set(
+            infer_constraints(
+                Instance(
+                    fx.gv2i,
+                    [
+                        fx.u,
+                        UnpackType(
+                            TupleType([fx.t, fx.s], fallback=Instance(fx.std_tuplei, [fx.o]))
+                        ),
+                        fx.u,
+                    ],
+                ),
+                Instance(fx.gv2i, [fx.a, fx.b, fx.d]),
+                SUPERTYPE_OF,
+            )
+            # We still get constraints on the prefix/suffix in this case.
+        ) == {
+            Constraint(type_var=fx.u, op=SUPERTYPE_OF, target=fx.a),
+            Constraint(type_var=fx.u, op=SUPERTYPE_OF, target=fx.d),
+        }
+
+    def test_var_length_tuple_with_fixed_length_tuple(self) -> None:
+        fx = self.fx
+        assert not infer_constraints(
+            TupleType([fx.t, fx.s], fallback=Instance(fx.std_tuplei, [fx.o])),
+            Instance(fx.std_tuplei, [fx.a]),
+            SUPERTYPE_OF,
+        )