avoid narrowing type(x) to type(y: Any)

Author: hauntsaninja

mypy/checker.py

@@ -6782,6 +6782,13 @@ def narrow_type_by_identity_equality(
                 expr = operands[j]
 
                 current_type_range = self.get_isinstance_type(expr)
+                if current_type_range is not None:
+                    target_type = get_proper_type(
+                        make_simplified_union([tr.item for tr in current_type_range])
+                    )
+                    if isinstance(target_type, AnyType):
+                        # Avoid widening to Any for checks like `type(x) is type(y: Any)`.
+                        continue
                 if_map, else_map = conditional_types_to_typemaps(
                     expr_in_type_expr,
                     *self.conditional_types_with_intersection(

test-data/unit/check-narrowing.test

@@ -3068,6 +3068,16 @@ if type(x) == type(y) == int:
     reveal_type(y) # N: Revealed type is "builtins.int"
     reveal_type(x) # N: Revealed type is "builtins.int"
 
+[case testTypeEqualsCheckDoesNotWidenToAny]
+# flags: --strict-equality --warn-unreachable
+from typing import Any
+
+x: str
+y: Any
+if type(y) is type(x):
+    reveal_type(x) # N: Revealed type is "builtins.str"
+    reveal_type(y) # N: Revealed type is "builtins.str"
+
 [case testTypeEqualsCheckUsingIs]
 # flags: --strict-equality --warn-unreachable
 from typing import Any