diff --git a/lib/python/pyflyby/_autoimp.py b/lib/python/pyflyby/_autoimp.py
index 4ab44033..73c5ffcf 100644
--- a/lib/python/pyflyby/_autoimp.py
+++ b/lib/python/pyflyby/_autoimp.py
@@ -575,6 +575,11 @@ def _NewScopeCtx(self, **kwargs):
         try:
             yield
         finally:
+            logger.debug("throwing last scope from scopestack: %r", new_scopestack[-1])
+            for name, use_checker in new_scopestack[-1].items():
+                if use_checker and use_checker.used == False:
+                    logger.debug("unused checker %r ", use_checker)
+                    self.unused_imports.append((use_checker.lineno, use_checker.source))
             assert self.scopestack is new_scopestack
             self.scopestack = prev_scopestack