Index: tool/lemon.c
==================================================================
--- tool/lemon.c
+++ tool/lemon.c
@@ -3456,11 +3456,11 @@
       if( strcmp(types[hash],stddt)==0 ){
         sp->dtnum = hash + 1;
         break;
       }
       hash++;
-      if( hash>=arraysize ) hash = 0;
+      if( hash>=(unsigned)arraysize ) hash = 0;
     }
     if( types[hash]==0 ){
       sp->dtnum = hash + 1;
       types[hash] = (char*)malloc( lemonStrlen(stddt)+1 );
       if( types[hash]==0 ){