Index: fixes/basefix.py
===================================================================
--- fixes/basefix.py	(revision 57363)
+++ fixes/basefix.py	(working copy)
@@ -16,6 +16,7 @@
 # Local imports
 from patcomp import PatternCompiler
 import pygram
+from util import insert_comment
 
 class BaseFix(object):
 
@@ -130,8 +131,7 @@
         First argument is the top-level node for the code in question.
         Optional second argument is why it can't be converted.
         """
-        lineno = node.get_lineno()
-        self.logger.warning("At line %d: %s" % (lineno, reason))
+        insert_comment(node, 'py2to3: %s' % reason)
 
     def start_tree(self, tree, filename):
         """Some fixers need to maintain tree-wide state.