132 lines
5.8 KiB
Python
132 lines
5.8 KiB
Python
"""Test cases for the constraint solver used in type inference."""
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from typing import List, Union, Tuple, Optional
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from mypy.test.helpers import Suite, assert_equal
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from mypy.constraints import SUPERTYPE_OF, SUBTYPE_OF, Constraint
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from mypy.solve import solve_constraints
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from mypy.test.typefixture import TypeFixture
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from mypy.types import Type, TypeVarType, TypeVarId
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class SolveSuite(Suite):
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def setUp(self) -> None:
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self.fx = TypeFixture()
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def test_empty_input(self) -> None:
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self.assert_solve([], [], [])
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def test_simple_supertype_constraints(self) -> None:
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self.assert_solve([self.fx.t.id],
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[self.supc(self.fx.t, self.fx.a)],
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[(self.fx.a, self.fx.o)])
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self.assert_solve([self.fx.t.id],
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[self.supc(self.fx.t, self.fx.a),
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self.supc(self.fx.t, self.fx.b)],
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[(self.fx.a, self.fx.o)])
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def test_simple_subtype_constraints(self) -> None:
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self.assert_solve([self.fx.t.id],
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[self.subc(self.fx.t, self.fx.a)],
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[self.fx.a])
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self.assert_solve([self.fx.t.id],
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[self.subc(self.fx.t, self.fx.a),
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self.subc(self.fx.t, self.fx.b)],
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[self.fx.b])
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def test_both_kinds_of_constraints(self) -> None:
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self.assert_solve([self.fx.t.id],
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[self.supc(self.fx.t, self.fx.b),
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self.subc(self.fx.t, self.fx.a)],
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[(self.fx.b, self.fx.a)])
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def test_unsatisfiable_constraints(self) -> None:
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# The constraints are impossible to satisfy.
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self.assert_solve([self.fx.t.id],
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[self.supc(self.fx.t, self.fx.a),
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self.subc(self.fx.t, self.fx.b)],
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[None])
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def test_exactly_specified_result(self) -> None:
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self.assert_solve([self.fx.t.id],
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[self.supc(self.fx.t, self.fx.b),
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self.subc(self.fx.t, self.fx.b)],
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[(self.fx.b, self.fx.b)])
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def test_multiple_variables(self) -> None:
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self.assert_solve([self.fx.t.id, self.fx.s.id],
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[self.supc(self.fx.t, self.fx.b),
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self.supc(self.fx.s, self.fx.c),
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self.subc(self.fx.t, self.fx.a)],
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[(self.fx.b, self.fx.a), (self.fx.c, self.fx.o)])
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def test_no_constraints_for_var(self) -> None:
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self.assert_solve([self.fx.t.id],
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[],
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[self.fx.uninhabited])
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self.assert_solve([self.fx.t.id, self.fx.s.id],
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[],
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[self.fx.uninhabited, self.fx.uninhabited])
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self.assert_solve([self.fx.t.id, self.fx.s.id],
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[self.supc(self.fx.s, self.fx.a)],
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[self.fx.uninhabited, (self.fx.a, self.fx.o)])
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def test_simple_constraints_with_dynamic_type(self) -> None:
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self.assert_solve([self.fx.t.id],
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[self.supc(self.fx.t, self.fx.anyt)],
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[(self.fx.anyt, self.fx.anyt)])
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self.assert_solve([self.fx.t.id],
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[self.supc(self.fx.t, self.fx.anyt),
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self.supc(self.fx.t, self.fx.anyt)],
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[(self.fx.anyt, self.fx.anyt)])
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self.assert_solve([self.fx.t.id],
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[self.supc(self.fx.t, self.fx.anyt),
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self.supc(self.fx.t, self.fx.a)],
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[(self.fx.anyt, self.fx.anyt)])
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self.assert_solve([self.fx.t.id],
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[self.subc(self.fx.t, self.fx.anyt)],
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[(self.fx.anyt, self.fx.anyt)])
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self.assert_solve([self.fx.t.id],
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[self.subc(self.fx.t, self.fx.anyt),
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self.subc(self.fx.t, self.fx.anyt)],
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[(self.fx.anyt, self.fx.anyt)])
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# self.assert_solve([self.fx.t.id],
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# [self.subc(self.fx.t, self.fx.anyt),
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# self.subc(self.fx.t, self.fx.a)],
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# [(self.fx.anyt, self.fx.anyt)])
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# TODO: figure out what this should be after changes to meet(any, X)
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def test_both_normal_and_any_types_in_results(self) -> None:
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# If one of the bounds is any, we promote the other bound to
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# any as well, since otherwise the type range does not make sense.
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self.assert_solve([self.fx.t.id],
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[self.supc(self.fx.t, self.fx.a),
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self.subc(self.fx.t, self.fx.anyt)],
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[(self.fx.anyt, self.fx.anyt)])
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self.assert_solve([self.fx.t.id],
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[self.supc(self.fx.t, self.fx.anyt),
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self.subc(self.fx.t, self.fx.a)],
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[(self.fx.anyt, self.fx.anyt)])
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def assert_solve(self,
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vars: List[TypeVarId],
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constraints: List[Constraint],
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results: List[Union[None, Type, Tuple[Type, Type]]],
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) -> None:
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res: List[Optional[Type]] = []
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for r in results:
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if isinstance(r, tuple):
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res.append(r[0])
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else:
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res.append(r)
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actual = solve_constraints(vars, constraints)
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assert_equal(str(actual), str(res))
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def supc(self, type_var: TypeVarType, bound: Type) -> Constraint:
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return Constraint(type_var.id, SUPERTYPE_OF, bound)
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def subc(self, type_var: TypeVarType, bound: Type) -> Constraint:
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return Constraint(type_var.id, SUBTYPE_OF, bound)
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