diff --git a/data/skeletons/lalr1.cc b/data/skeletons/lalr1.cc
index 9036575b..1507122b 100644
--- a/data/skeletons/lalr1.cc
+++ b/data/skeletons/lalr1.cc
@@ -640,7 +640,7 @@ m4_if(b4_prefix, [yy], [],
     if (state == empty_state)
       return empty_symbol;
     else
-      return yystos_[state];
+      return yystos_[+state];
   }
 
   ]b4_parser_class[::stack_symbol_type::stack_symbol_type ()
@@ -866,7 +866,7 @@ b4_dollar_popdef])[]dnl
   `-----------*/
   yybackup:
     // Try to take a decision without lookahead.
-    yyn = yypact_[yystack_[0].state];
+    yyn = yypact_[+yystack_[0].state];
     if (yy_pact_value_is_default_ (yyn))
       goto yydefault;
 
@@ -930,7 +930,7 @@ b4_dollar_popdef])[]dnl
   | yydefault -- do the default action for the current state.  |
   `-----------------------------------------------------------*/
   yydefault:
-    yyn = yydefact_[yystack_[0].state];
+    yyn = yydefact_[+yystack_[0].state];
     if (yyn == 0)
       goto yyerrlab;
     goto yyreduce;
@@ -1057,7 +1057,7 @@ b4_dollar_popdef])[]dnl
       stack_symbol_type error_token;
       for (;;)
         {
-          yyn = yypact_[yystack_[0].state];
+          yyn = yypact_[+yystack_[0].state];
           if (!yy_pact_value_is_default_ (yyn))
             {
               yyn += yy_error_token_;
@@ -1166,13 +1166,13 @@ b4_dollar_popdef])[]dnl
         state_type top_state = (yylac_stack_.empty ()
                                 ? yystack_[lac_top].state
                                 : yylac_stack_.back ());
-        int yyrule = yypact_[top_state];
+        int yyrule = yypact_[+top_state];
         if (yy_pact_value_is_default_ (yyrule)
             || (yyrule += yytoken) < 0 || yylast_ < yyrule
             || yycheck_[yyrule] != yytoken)
           {
             // Use the default action.
-            yyrule = yydefact_[top_state];
+            yyrule = yydefact_[+top_state];
             if (yyrule == 0)
               {
                 YYCDEBUG << " Err\n";
@@ -1345,7 +1345,7 @@ b4_error_verbose_if([state_type yystate, const symbol_type& yyla],
           yy_lac_check_ (yytoken);
 #endif]])[
 
-        int yyn = yypact_[yystate];
+        int yyn = yypact_[+yystate];
         if (!yy_pact_value_is_default_ (yyn))
           {]b4_lac_if([[
             for (int yyx = 0; yyx < yyntokens_; ++yyx)