Method visit_dictionary_comprehension

mypy/checkexpr.py:5935–5969

Type check a dictionary comprehension.

(self, e: DictionaryComprehension)

            return self.check_call(constructor, [gen.left_expr], [nodes.ARG_POS], gen)[0]

    def visit_dictionary_comprehension(self, e: DictionaryComprehension) -> Type:
        """Type check a dictionary comprehension."""
        with self.chk.binder.frame_context(can_skip=True, fall_through=0):
            self.check_for_comp(e)

            # Infer the type of the list comprehension by using a synthetic generic
            # callable type.
            ktdef = TypeVarType(
                "KT",
                "KT",
                id=TypeVarId(-1, namespace="<dict>"),
                values=[],
                upper_bound=self.object_type(),
                default=AnyType(TypeOfAny.from_omitted_generics),
            )
            vtdef = TypeVarType(
                "VT",
                "VT",
                id=TypeVarId(-2, namespace="<dict>"),
                values=[],
                upper_bound=self.object_type(),
                default=AnyType(TypeOfAny.from_omitted_generics),
            )
            constructor = CallableType(
                [ktdef, vtdef],
                [nodes.ARG_POS, nodes.ARG_POS],
                [None, None],
                self.chk.named_generic_type("builtins.dict", [ktdef, vtdef]),
                self.chk.named_type("builtins.function"),
                name="<dictionary-comprehension>",
                variables=[ktdef, vtdef],
            )
            return self.check_call(
                constructor, [e.key, e.value], [nodes.ARG_POS, nodes.ARG_POS], e
            )[0]

    def check_for_comp(self, e: GeneratorExpr | DictionaryComprehension) -> None:
        """Check the for_comp part of comprehensions. That is the part from 'for':