From 0a1ed1b9701552b09379f142e60e1364390f4b69 Mon Sep 17 00:00:00 2001
From: "Ryan C. Gordon" <icculus@icculus.org>
Date: Wed, 17 Feb 2010 15:35:15 -0500
Subject: [PATCH] Lemon fix: don't let grammar define the same nonterminal
 %type more than once.

---
 misc/lemon.c | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/misc/lemon.c b/misc/lemon.c
index a5fa3388..31efa0ea 100644
--- a/misc/lemon.c
+++ b/misc/lemon.c
@@ -2357,10 +2357,20 @@ to follow the previous rule.");
         psp->errorcnt++;
         psp->state = RESYNC_AFTER_DECL_ERROR;
       }else{
-        struct symbol *sp = Symbol_new(x);
-        psp->declargslot = &sp->datatype;
-        psp->insertLineMacro = 0;
-        psp->state = WAITING_FOR_DECL_ARG;
+        struct symbol *sp = Symbol_find(x);
+        if((sp) && (sp->datatype)){
+          ErrorMsg(psp->filename,psp->tokenlineno,
+            "Symbol %%type \"%s\" already defined", x);
+          psp->errorcnt++;
+          psp->state = RESYNC_AFTER_DECL_ERROR;
+        }else{
+          if (!sp){
+            sp = Symbol_new(x);
+          }
+          psp->declargslot = &sp->datatype;
+          psp->insertLineMacro = 0;
+          psp->state = WAITING_FOR_DECL_ARG;
+        }
       }
       break;
     case WAITING_FOR_PRECEDENCE_SYMBOL: