Index: languages/tcl/src/pmc/tclstring.pmc
===================================================================
--- languages/tcl/src/pmc/tclstring.pmc	(revision 15075)
+++ languages/tcl/src/pmc/tclstring.pmc	(working copy)
@@ -60,7 +60,7 @@
           return 1;
         }
 
-        return 0; /* XXX Throw exception about invalid boolean type. */
+        return 0; /* XXX (#40637): Throw exception about invalid boolean type. */
     }
 }