Index: tool/lemon.c
==================================================================
--- tool/lemon.c
+++ tool/lemon.c
@@ -4151,10 +4151,11 @@
   struct state *stp;
   struct action *ap;
   struct rule *rp;
   struct acttab *pActtab;
   int i, j, n, sz;
+  int nLookAhead;
   int szActionType;     /* sizeof(YYACTIONTYPE) */
   int szCodeType;       /* sizeof(YYCODETYPE)   */
   const char *name;
   int mnTknOfst, mxTknOfst;
   int mnNtOfst, mxNtOfst;
@@ -4401,17 +4402,33 @@
   for(i=j=0; i<n; i++){
     int la = acttab_yylookahead(pActtab, i);
     if( la<0 ) la = lemp->nsymbol;
     if( j==0 ) fprintf(out," /* %5d */ ", i);
     fprintf(out, " %4d,", la);
-    if( j==9 || i==n-1 ){
+    if( j==9 ){
+      fprintf(out, "\n"); lineno++;
+      j = 0;
+    }else{
+      j++;
+    }
+  }
+  /* Add extra entries to the end of the yy_lookahead[] table so that
+  ** yy_shift_ofst[]+iToken will always be a valid index into the array,
+  ** even for the largest possible value of yy_shift_ofst[] and iToken. */
+  nLookAhead = lemp->nterminal + lemp->nactiontab;
+  while( i<nLookAhead ){
+    if( j==0 ) fprintf(out," /* %5d */ ", i);
+    fprintf(out, " %4d,", lemp->nterminal);
+    if( j==9 ){
       fprintf(out, "\n"); lineno++;
       j = 0;
     }else{
       j++;
     }
+    i++;
   }
+  if( j>0 ) fprintf(out, "\n"); lineno++;
   fprintf(out, "};\n"); lineno++;
 
   /* Output the yy_shift_ofst[] table */
   n = lemp->nxstate;
   while( n>0 && lemp->sorted[n-1]->iTknOfst==NO_OFFSET ) n--;
@@ -4487,11 +4504,13 @@
 
   /* Generate the table of fallback tokens.
   */
   if( lemp->has_fallback ){
     int mx = lemp->nterminal - 1;
-    while( mx>0 && lemp->symbols[mx]->fallback==0 ){ mx--; }
+    /* 2019-08-28:  Generate fallback entries for every token to avoid
+    ** having to do a range check on the index */
+    /* while( mx>0 && lemp->symbols[mx]->fallback==0 ){ mx--; } */
     lemp->tablesize += (mx+1)*szCodeType;
     for(i=0; i<=mx; i++){
       struct symbol *p = lemp->symbols[i];
       if( p->fallback==0 ){
         fprintf(out, "    0,  /* %10s => nothing */\n", p->name);

Index: tool/lempar.c
==================================================================
--- tool/lempar.c
+++ tool/lempar.c
@@ -519,19 +519,22 @@
   yycoverage[stateno][iLookAhead] = 1;
 #endif
   do{
     i = yy_shift_ofst[stateno];
     assert( i>=0 );
-    /* assert( i+YYNTOKEN<=(int)YY_NLOOKAHEAD ); */
+    assert( i<=YY_ACTTAB_COUNT );
+    assert( i+YYNTOKEN<=(int)YY_NLOOKAHEAD );
     assert( iLookAhead!=YYNOCODE );
     assert( iLookAhead < YYNTOKEN );
     i += iLookAhead;
-    if( i>=YY_NLOOKAHEAD || yy_lookahead[i]!=iLookAhead ){
+    assert( i<(int)YY_NLOOKAHEAD );
+    if( yy_lookahead[i]!=iLookAhead ){
 #ifdef YYFALLBACK
       YYCODETYPE iFallback;            /* Fallback token */
-      if( iLookAhead<sizeof(yyFallback)/sizeof(yyFallback[0])
-             && (iFallback = yyFallback[iLookAhead])!=0 ){
+      assert( iLookAhead<sizeof(yyFallback)/sizeof(yyFallback[0]) );
+      iFallback = yyFallback[iLookAhead];
+      if( iFallback!=0 ){
 #ifndef NDEBUG
         if( yyTraceFILE ){
           fprintf(yyTraceFILE, "%sFALLBACK %s => %s\n",
              yyTracePrompt, yyTokenName[iLookAhead], yyTokenName[iFallback]);
         }
@@ -542,20 +545,12 @@
       }
 #endif
 #ifdef YYWILDCARD
       {
         int j = i - iLookAhead + YYWILDCARD;
-        if( 
-#if YY_SHIFT_MIN+YYWILDCARD<0
-          j>=0 &&
-#endif
-#if YY_SHIFT_MAX+YYWILDCARD>=YY_ACTTAB_COUNT
-          j<YY_ACTTAB_COUNT &&
-#endif
-          j<(int)(sizeof(yy_lookahead)/sizeof(yy_lookahead[0])) &&
-          yy_lookahead[j]==YYWILDCARD && iLookAhead>0
-        ){
+        assert( j<(int)(sizeof(yy_lookahead)/sizeof(yy_lookahead[0])) );
+        if( yy_lookahead[j]==YYWILDCARD && iLookAhead>0 ){
 #ifndef NDEBUG
           if( yyTraceFILE ){
             fprintf(yyTraceFILE, "%sWILDCARD %s => %s\n",
                yyTracePrompt, yyTokenName[iLookAhead],
                yyTokenName[YYWILDCARD]);
@@ -1067,13 +1062,12 @@
 ** Return the fallback token corresponding to canonical token iToken, or
 ** 0 if iToken has no fallback.
 */
 int ParseFallback(int iToken){
 #ifdef YYFALLBACK
-  if( iToken<(int)(sizeof(yyFallback)/sizeof(yyFallback[0])) ){
-    return yyFallback[iToken];
-  }
+  assert( iToken<(int)(sizeof(yyFallback)/sizeof(yyFallback[0])) );
+  return yyFallback[iToken];
 #else
   (void)iToken;
 #endif
   return 0;
 }