Fixed NameError when a decorated method references an imported name

Fixes #362.

docs/versionhistory.rst

@@ -5,8 +5,11 @@ This library adheres to `Semantic Versioning 2.0 <https://semver.org/#semantic-v
 
 **UNRELEASED**
 
-- Fix handling of ``typing_extensions.Literal`` on Python 3.8 and 3.9
-  when ``typing_extensions>=4.6.0`` is installed.
+- Fixed handling of ``typing_extensions.Literal`` on Python 3.8 and 3.9 when
+  ``typing_extensions>=4.6.0`` is installed
+  (`#363 <https://github.com/agronholm/typeguard/issues/363>`_; PR by Alex Waygood)
+- Fixed ``NameError`` when generated type checking code references an imported name from
+  a method (`#362 <https://github.com/agronholm/typeguard/issues/362>`_)
 
 **4.0.0** (2023-05-12)
 

src/typeguard/_transformer.py

@@ -3,6 +3,7 @@
 import ast
 import builtins
 import sys
+import typing
 from ast import (
     AST,
     Add,
@@ -395,14 +396,23 @@ def visit_Subscript(self, node: Subscript) -> Any:
                 if self._memo.name_matches(node.value, *annotated_names):
                     # Only treat the first argument to typing.Annotated as a potential
                     # forward reference
-                    items = [self.visit(slice_value.elts[0])] + slice_value.elts[1:]
+                    items = cast(
+                        typing.List[expr],
+                        [self.generic_visit(slice_value.elts[0])]
+                        + slice_value.elts[1:],
+                    )
                 else:
-                    items = [self.visit(item) for item in slice_value.elts]
+                    items = cast(
+                        typing.List[expr],
+                        [self.generic_visit(item) for item in slice_value.elts],
+                    )
 
-                # If this is a Union and any of the items is None, erase the entire
+                # If this is a Union and any of the items is Any, erase the entire
                 # annotation
                 if self._memo.name_matches(node.value, "typing.Union") and any(
-                    item is None for item in items
+                    isinstance(item, expr)
+                    and self._memo.name_matches(item, *anytype_names)
+                    for item in items
                 ):
                     return None
 

tests/test_typechecked.py

@@ -9,6 +9,7 @@
     AsyncGenerator,
     AsyncIterable,
     AsyncIterator,
+    Dict,
     Generator,
     Iterable,
     Iterator,
@@ -622,3 +623,13 @@ def foo(x: int) -> None:
             b'typeguard.TypeCheckError: argument "x" (str) is not an instance of '
             b"int\n"
         )
+
+
+def test_reference_imported_name_from_method() -> None:
+    # Regression test for #362
+    @typechecked
+    class A:
+        def foo(self) -> Dict[str, Any]:
+            return {}
+
+    A().foo()