diff --git a/Lib/inspect.py b/Lib/inspect.py
index 2374e59..531b891 100644
--- a/Lib/inspect.py
+++ b/Lib/inspect.py
@@ -1357,6 +1357,8 @@ def getargvalues(frame):
 def formatannotation(annotation, base_module=None):
     if getattr(annotation, '__module__', None) == 'typing':
         return repr(annotation).replace('typing.', '')
+    if isinstance(annotation, types.GenericAlias):
+        return str(annotation)
     if isinstance(annotation, type):
         if annotation.__module__ in ('builtins', base_module):
             return annotation.__qualname__