diff --git a/gcc/m2/gm2-gcc/m2builtins.cc b/gcc/m2/gm2-gcc/m2builtins.cc
index b9ac7fc5da4b340e318ff049c1a454676e4c0efc..8d104c41a1ee319ffe44468cf7170013f31f11ab 100644
--- a/gcc/m2/gm2-gcc/m2builtins.cc
+++ b/gcc/m2/gm2-gcc/m2builtins.cc
@@ -40,7 +40,7 @@ along with GNU Modula-2; see the file COPYING3.  If not see
     if (!(X))                                                                 \
       {                                                                       \
         debug_tree (Y);                                                       \
-        internal_error ("%s:%d:assertion of condition `%s' failed", __FILE__, __LINE__,  \
+        internal_error ("%s:%d:assertion of condition %qs failed", __FILE__, __LINE__,  \
                         #X);                                                  \
       }                                                                       \
   }