Add a test for type comments as well.

Author: PetterS

pyflakes/test/test_imports.py

@@ -1069,6 +1069,18 @@ def f() -> "b":
             pass
         ''')
 
+    def test_uses_typing_imports_for_annotations_in_comments(self):
+        """Uses imports within 'if TYPE_CHECKING' checking annotations."""
+        if self.withDoctest:
+            return
+        self.flakes('''
+        from typing import TYPE_CHECKING
+        if TYPE_CHECKING:
+            from a import b
+        def f():  # type: () -> b
+            pass
+        ''')
+
 
 class TestSpecialAll(TestCase):
     """