diff --git a/fastapi/dependencies/utils.py b/fastapi/dependencies/utils.py
index 72b0b14f0b..40e6957b8b 100644
--- a/fastapi/dependencies/utils.py
+++ b/fastapi/dependencies/utils.py
@@ -254,19 +254,6 @@ def get_typed_annotation(annotation: Any, globalns: dict[str, Any]) -> Any:
     return annotation
 
 
-def _resolve_forward_ref_lenient(
-    fwd_ref: ForwardRef,
-    globalns: dict[str, Any],
-) -> Any:
-    class _LenientNamespace(dict):
-        def __missing__(self, key: str) -> Any:
-            return Any
-
-    localns = _LenientNamespace(globalns)
-    result = fwd_ref._evaluate(globalns, localns, set())
-    return result
-
-
 def _resolve_forward_ref_lenient(
     fwd_ref: ForwardRef,
     globalns: dict[str, Any],
@@ -277,11 +264,11 @@ def _resolve_forward_ref_lenient(
 
     localns = _LenientNamespace(globalns)
     if sys.version_info >= (3, 13):
-        result = fwd_ref._evaluate(
-            globalns, localns, recursive_guard=set(), type_params=()
+        result = fwd_ref.evaluate(
+            globalns, localns, recursive_guard=frozenset(), type_params=()
         )
     else:
-        result = fwd_ref._evaluate(globalns, localns, recursive_guard=set())
+        result = fwd_ref.evaluate(globalns, localns, recursive_guard=frozenset())
     return result
 
 
diff --git a/tests/test_annotated_forward_ref.py b/tests/test_annotated_forward_ref.py
index 8b9a483eaa..ceb7636aa7 100644
--- a/tests/test_annotated_forward_ref.py
+++ b/tests/test_annotated_forward_ref.py
@@ -20,7 +20,7 @@ async def read_root(potato: Annotated[Potato, Depends(get_potato)]):
     return {"color": potato.color, "size": potato.size}
 
 
-from dataclasses import dataclass
+from dataclasses import dataclass  # noqa: E402
 
 
 @dataclass