adding test case to suggestions.py

Author: Jdwashin9

mypy/suggestions.py

@@ -74,6 +74,7 @@
     TypeOfAny,
     TypeStrVisitor,
     TypeTranslator,
+    TypeVarType,
     UninhabitedType,
     UnionType,
     get_proper_type,
@@ -650,13 +651,17 @@ def extract_from_decorator(self, node: Decorator) -> FuncDef | None:
             if not isinstance(typ, FunctionLike):
                 return None
             for ct in typ.items:
-                if not (
-                    len(ct.arg_types) == 1
-                    # and isinstance(ct.arg_types[0], TypeVarType)
-                    and ct.arg_types[0] == ct.ret_type
-                ):
+                if len(ct.arg_types) != 1:
                     return None
 
+            arg_type = get_proper_type(ct.arg_types[0])
+            ret_type = get_proper_type(ct.ret_type)
+
+            if isinstance(arg_type, TypeVarType) and arg_type == ret_type:
+                continue
+
+            return None
+
         return node.func
 
     def try_type(self, func: FuncDef, typ: ProperType) -> list[str]:

mypy/test_decorator_suggestion.py

@@ -12,3 +12,8 @@ def dec(f: Callable[P, R]) -> Callable[P, R]:
 @dec
 def f() -> None:
     print("hello world")
+
+
+@dec
+def foo() -> None:
+    print()