Make sure we consistently use the same dict class for types.

rchen152 · rchen152 · commit d18fe8c6ad85 · 2024-01-23T14:11:17.000-08:00
We have a `dict` special builtin that is used to implement `dict(...)` calls,
but it was sneaking into ParameterizedClass base classes as well.

PiperOrigin-RevId: 600882569
diff --git a/pytype/overlays/special_builtins.py b/pytype/overlays/special_builtins.py
@@ -781,6 +781,11 @@ def call(self, node, func, args, alias_map=None):
     else:
       return super().call(node, func, args, alias_map)
 
+  def get_special_attribute(self, node, name, valself):
+    # For doing something like getting the __getitem__ attribute to subscript
+    # dict, we want to use the real dict type.
+    return self.ctx.convert.dict_type.get_special_attribute(node, name, valself)
+
 
 class Type(BuiltinClass, mixin.HasSlots):
 
diff --git a/pytype/tests/test_typevar2.py b/pytype/tests/test_typevar2.py
@@ -1057,6 +1057,23 @@ def f(x: T) -> T:
       f("oops")  # wrong-arg-types
     """)
 
+  @test_utils.skipBeforePy((3, 9), "subscripting builtins.dict is new in 3.9")
+  def test_builtin_dict_constraint(self):
+    with self.DepTree([("foo.pyi", """
+      from typing import TypeVar
+      T = TypeVar('T', int, dict[str, int])
+      class C:
+        def f(self, x: T) -> T: ...
+    """)]):
+      self.Check("""
+        import foo
+        from typing import TypeVar
+        T = TypeVar('T', int, dict[str, int])
+        class C(foo.C):
+          def f(self, x: T) -> T:
+            return x
+      """)
+
 
 if __name__ == "__main__":
   test_base.main()
