From 1377c332b9f3b76eecda04371889ce9fdfae9a00 Mon Sep 17 00:00:00 2001
From: Akim Demaille <address@hidden>
Date: Wed, 2 Mar 2011 17:06:58 +0100
Subject: [PATCH 2/2] named references: fix double free.

In `rhs[name]: "a" | "b"', do not free "name" twice.
Reported by Tys Lefering.
<http://lists.gnu.org/archive/html/bug-bison/2010-06/msg00002.html>

	* src/named-ref.h, src/named-ref.c (named_ref_copy): New.
	* src/parse-gram.y (current_lhs): Rename as...
	(current_lhs_symbol): this.
	(current_lhs): New function.  Use it to free the current lhs
	named reference.
	* src/reader.c: Bind lhs to a copy of the current named reference.
	* src/symlist.c: Rely on free (0) being valid.
	* tests/named-refs.at: Test this.
---
 ChangeLog           |   15 +
 src/named-ref.c     |    6 +
 src/named-ref.h     |    3 +
 src/parse-gram.c    | 1458 ++++++++++++++++++++++++++-------------------------
 src/parse-gram.h    |   25 +-
 src/parse-gram.y    |   26 +-
 src/reader.c        |    2 +-
 src/symlist.c       |    3 +-
 tests/named-refs.at |   13 +
 9 files changed, 827 insertions(+), 724 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 6c1b92a..dfa846b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,20 @@
 2011-03-02  Akim Demaille  <address@hidden>
 
+	named references: fix double free.
+	In `rhs[name]: "a" | "b"', do not free "name" twice.
+	Reported by Tys Lefering.
+	<http://lists.gnu.org/archive/html/bug-bison/2010-06/msg00002.html>
+	* src/named-ref.h, src/named-ref.c (named_ref_copy): New.
+	* src/parse-gram.y (current_lhs): Rename as...
+	(current_lhs_symbol): this.
+	(current_lhs): New function.  Use it to free the current lhs
+	named reference.
+	* src/reader.c: Bind lhs to a copy of the current named reference.
+	* src/symlist.c: Rely on free (0) being valid.
+	* tests/named-refs.at: Test this.
+
+2011-03-02  Akim Demaille  <address@hidden>
+
 	tests: style changes.
 	* tests/named-refs.at (Redundant words in LHS brackets)
 	(Unresolved references): here.
diff --git a/src/named-ref.c b/src/named-ref.c
index 4bf3da1..132c741 100644
--- a/src/named-ref.c
+++ b/src/named-ref.c
@@ -33,6 +33,12 @@ named_ref_new (uniqstr id, location loc)
   return res;
 }
 
+named_ref *
+named_ref_copy (const named_ref *r)
+{
+  return named_ref_new (r->id, r->loc);
+}
+
 void
 named_ref_free (named_ref *r)
 {
diff --git a/src/named-ref.h b/src/named-ref.h
index 0f96e46..46d9d8d 100644
--- a/src/named-ref.h
+++ b/src/named-ref.h
@@ -37,6 +37,9 @@ typedef struct named_ref
 /* Allocate a named reference object. */
 named_ref *named_ref_new (uniqstr id, location loc);
 
+/* Allocate and return a copy.  */
+named_ref *named_ref_copy (const named_ref *r);
+
 /* Free a named reference object. */
 void named_ref_free (named_ref *r);
 
diff --git a/src/parse-gram.c b/src/parse-gram.c
index ad5a6fc..376f2f0 100644
--- a/src/parse-gram.c
+++ b/src/parse-gram.c
@@ -1,19 +1,19 @@
-/* A Bison parser, made by GNU Bison 2.4.1.266-7e5e.  */
+/* A Bison parser, made by GNU Bison 2.4.570-7a582.  */
+
+/* Implementation for Bison's Yacc-like parsers in C
+
+   Copyright (C) 1984, 1989-1990, 2000-2011 Free Software Foundation, Inc.
 
-/* Bison implementation for Yacc-like parsers in C
-   
-      Copyright (C) 1984, 1989-1990, 2000-2011 Free Software Foundation, Inc.
-   
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.
-   
+
    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
-   
+
    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
@@ -26,7 +26,7 @@
    special exception, which will cause the skeleton and the resulting
    Bison output files to be licensed under the GNU General Public
    License without this special exception.
-   
+
    This special exception was added by the Free Software Foundation in
    version 2.2 of Bison.  */
 
@@ -44,7 +44,7 @@
 #define YYBISON 1
 
 /* Bison version.  */
-#define YYBISON_VERSION "2.4.1.266-7e5e"
+#define YYBISON_VERSION "2.4.570-7a582"
 
 /* Skeleton name.  */
 #define YYSKELETON_NAME "yacc.c"
@@ -72,8 +72,7 @@
 #define yylloc          gram_lloc
 
 /* Copy the first part of user declarations.  */
-
-/* Line 268 of yacc.c  */
+/* Line 269 of yacc.c  */
 #line 1 "parse-gram.y"
 /* Bison Grammar Parser                             -*- C -*-
 
@@ -138,19 +137,37 @@ static void add_param (char const *type, char *decl, location loc);
 
 static symbol_class current_class = unknown_sym;
 static uniqstr current_type = NULL;
-static symbol *current_lhs;
+static symbol *current_lhs_symbol;
 static location current_lhs_location;
 static named_ref *current_lhs_named_ref;
 static int current_prec = 0;
 
+/** Set the new current left-hand side symbol, possibly common
+ * to several right-hand side parts of rule. 
+ */
+static 
+void 
+current_lhs(symbol *sym, location loc, named_ref *ref)
+{
+  current_lhs_symbol = sym;
+  current_lhs_location = loc;
+  /* In order to simplify memory management, named references for lhs
+     are always assigned by deep copy into the current symbol_list
+     node.  This is because a single named-ref in the grammar may
+     result in several uses when the user factors lhs between several
+     rules using "|".  Therefore free the parser's original copy.  */
+  free (current_lhs_named_ref);
+  current_lhs_named_ref = ref;
+}
+
+
 #define YYTYPE_INT16 int_fast16_t
 #define YYTYPE_INT8 int_fast8_t
 #define YYTYPE_UINT16 uint_fast16_t
 #define YYTYPE_UINT8 uint_fast8_t
 
-
-/* Line 268 of yacc.c  */
-#line 154 "parse-gram.c"
+/* Line 269 of yacc.c  */
+#line 171 "../../../src/parse-gram.c"
 
 /* Enabling traces.  */
 #ifndef YYDEBUG
@@ -299,9 +316,8 @@ static int current_prec = 0;
 #if ! defined YYSTYPE && ! defined YYSTYPE_IS_DECLARED
 typedef union YYSTYPE
 {
-
-/* Line 293 of yacc.c  */
-#line 94 "parse-gram.y"
+/* Line 294 of yacc.c  */
+#line 113 "parse-gram.y"
 
   symbol *symbol;
   symbol_list *list;
@@ -314,9 +330,8 @@ typedef union YYSTYPE
   named_ref *named_ref;
 
 
-
-/* Line 293 of yacc.c  */
-#line 320 "parse-gram.c"
+/* Line 294 of yacc.c  */
+#line 335 "../../../src/parse-gram.c"
 } YYSTYPE;
 # define YYSTYPE_IS_TRIVIAL 1
 # define yystype YYSTYPE /* obsolescent; will be withdrawn */
@@ -339,9 +354,8 @@ typedef struct YYLTYPE
 
 /* Copy the second part of user declarations.  */
 
-
-/* Line 343 of yacc.c  */
-#line 345 "parse-gram.c"
+/* Line 344 of yacc.c  */
+#line 359 "../../../src/parse-gram.c"
 
 #ifdef short
 # undef short
@@ -547,17 +561,19 @@ union yyalloc
 #define YYNNTS  34
 /* YYNRULES -- Number of rules.  */
 #define YYNRULES  108
-/* YYNRULES -- Number of states.  */
+/* YYNSTATES -- Number of states.  */
 #define YYNSTATES  148
 
-/* YYTRANSLATE(YYLEX) -- Bison symbol number corresponding to YYLEX.  */
+/* YYTRANSLATE[YYX] -- Symbol number corresponding to YYX as returned
+   by yylex, with out-of-bounds checking.  */
 #define YYUNDEFTOK  2
 #define YYMAXUTOK   312
 
 #define YYTRANSLATE(YYX)						\
   ((unsigned int) (YYX) <= YYMAXUTOK ? yytranslate[YYX] : YYUNDEFTOK)
 
-/* YYTRANSLATE[YYLEX] -- Bison symbol number corresponding to YYLEX.  */
+/* YYTRANSLATE[TOKEN-NUM] -- Symbol number corresponding to TOKEN-NUM
+   as returned by yylex, without out-of-bounds checking.  */
 static const yytype_uint8 yytranslate[] =
 {
        0,     2,     2,     2,     2,     2,     2,     2,     2,     2,
@@ -595,70 +611,20 @@ static const yytype_uint8 yytranslate[] =
 };
 
 #if YYDEBUG
-/* YYPRHS[YYN] -- Index of the first RHS symbol of rule number YYN in
-   YYRHS.  */
-static const yytype_uint16 yyprhs[] =
-{
-       0,     0,     3,     8,     9,    12,    14,    16,    18,    22,
-      24,    27,    29,    32,    35,    38,    42,    44,    47,    50,
-      53,    55,    58,    62,    64,    66,    69,    73,    76,    78,
-      81,    84,    86,    88,    90,    92,    94,    96,    99,   103,
-     107,   109,   111,   114,   118,   119,   121,   125,   126,   130,
-     131,   135,   139,   143,   145,   147,   149,   150,   152,   154,
-     157,   159,   162,   164,   167,   169,   172,   174,   176,   178,
-     180,   182,   184,   187,   190,   194,   196,   199,   201,   204,
-     206,   209,   212,   213,   218,   220,   224,   227,   228,   232,
-     236,   240,   244,   248,   249,   251,   253,   255,   256,   258,
-     260,   262,   264,   266,   268,   270,   272,   274,   275
-};
-
-/* YYRHS -- A `-1'-separated list of the rules' RHS.  */
-static const yytype_int8 yyrhs[] =
-{
-      59,     0,    -1,    60,    50,    77,    91,    -1,    -1,    60,
-      61,    -1,    62,    -1,    52,    -1,    17,    -1,    19,    84,
-      85,    -1,    20,    -1,    20,     3,    -1,    21,    -1,    22,
-       4,    -1,    23,     4,    -1,    24,     3,    -1,    24,    47,
-       3,    -1,    25,    -1,    26,    43,    -1,    27,     3,    -1,
-      28,    43,    -1,    29,    -1,    30,     3,    -1,    30,    47,
-       3,    -1,    32,    -1,    33,    -1,    34,     3,    -1,    34,
-      47,     3,    -1,    35,    43,    -1,    36,    -1,    37,     3,
-      -1,    38,     3,    -1,    40,    -1,    41,    -1,    42,    -1,
-      53,    -1,    67,    -1,    64,    -1,    39,    89,    -1,     8,
-      43,    73,    -1,     9,    43,    73,    -1,    18,    -1,    31,
-      -1,    16,    86,    -1,    16,    48,    86,    -1,    -1,    48,
-      -1,    57,    63,    86,    -1,    -1,     6,    65,    76,    -1,
-      -1,     5,    66,    76,    -1,     7,    54,    72,    -1,    68,
-      69,    70,    -1,    10,    -1,    11,    -1,    12,    -1,    -1,
-      54,    -1,    71,    -1,    70,    71,    -1,    89,    -1,    89,
-       4,    -1,    89,    -1,    72,    89,    -1,    74,    -1,    73,
-      74,    -1,    89,    -1,    54,    -1,    55,    -1,    56,    -1,
-      54,    -1,    87,    -1,    87,     4,    -1,    87,    90,    -1,
-      87,     4,    90,    -1,    75,    -1,    76,    75,    -1,    78,
-      -1,    77,    78,    -1,    79,    -1,    62,    53,    -1,     1,
-      53,    -1,    -1,    88,    83,    80,    81,    -1,    82,    -1,
-      81,    51,    82,    -1,    81,    53,    -1,    -1,    82,    89,
-      83,    -1,    82,    43,    83,    -1,    82,    13,    89,    -1,
-      82,    14,     4,    -1,    82,    15,    54,    -1,    -1,    44,
-      -1,    48,    -1,     3,    -1,    -1,    48,    -1,     3,    -1,
-      43,    -1,    48,    -1,    45,    -1,    49,    -1,    87,    -1,
-      90,    -1,     3,    -1,    -1,    50,    46,    -1
-};
-
-/* YYRLINE[YYN] -- source line where rule number YYN was defined.  */
+  /* YYRLINEYYN -- Source line where rule number YYN was defined.    */
 static const yytype_uint16 yyrline[] =
 {
-       0,   209,   209,   217,   219,   223,   224,   234,   235,   240,
-     241,   246,   247,   248,   249,   250,   251,   256,   265,   266,
-     267,   268,   269,   270,   271,   272,   273,   274,   275,   290,
-     291,   315,   316,   317,   318,   322,   323,   324,   328,   335,
-     342,   346,   350,   357,   372,   373,   377,   389,   389,   394,
-     394,   399,   410,   425,   426,   427,   431,   432,   437,   439,
-     444,   445,   450,   452,   457,   458,   462,   463,   464,   465,
-     470,   475,   480,   486,   492,   503,   504,   513,   514,   520,
-     521,   522,   529,   529,   534,   535,   536,   541,   543,   545,
-     547,   549,   551,   556,   558,   569,   570,   575,   576,   577,
-     586,   606,   608,   617,   622,   623,   628,   635,   637
+       0,   228,   228,   236,   238,   242,   243,   253,   254,   259,
+     260,   265,   266,   267,   268,   269,   270,   275,   284,   285,
+     286,   287,   288,   289,   290,   291,   292,   293,   294,   309,
+     310,   334,   335,   336,   337,   341,   342,   343,   347,   354,
+     361,   365,   369,   376,   391,   392,   396,   408,   408,   413,
+     413,   418,   429,   444,   445,   446,   450,   451,   456,   458,
+     463,   464,   469,   471,   476,   477,   481,   482,   483,   484,
+     489,   494,   499,   505,   511,   522,   523,   532,   533,   539,
+     540,   541,   548,   548,   552,   553,   554,   559,   561,   563,
+     565,   567,   569,   574,   576,   587,   588,   593,   594,   595,
+     604,   624,   626,   635,   640,   641,   646,   653,   655
 };
 #endif
 
@@ -693,8 +659,8 @@ static const char *const yytname[] =
 #endif
 
 # ifdef YYPRINT
-/* YYTOKNUM[YYLEX-NUM] -- Internal token number corresponding to
-   token YYLEX-NUM.  */
+/* YYTOKNUM[NUM] -- (External) token number corresponding to the
+   (internal) symbol number NUM (which must be that of a token).  */
 static const yytype_uint16 yytoknum[] =
 {
        0,   256,   257,   258,   259,   260,   261,   262,   263,   264,
@@ -706,72 +672,18 @@ static const yytype_uint16 yytoknum[] =
 };
 # endif
 
-/* YYR1[YYN] -- Symbol number of symbol that rule YYN derives.  */
-static const yytype_uint8 yyr1[] =
-{
-       0,    58,    59,    60,    60,    61,    61,    61,    61,    61,
-      61,    61,    61,    61,    61,    61,    61,    61,    61,    61,
-      61,    61,    61,    61,    61,    61,    61,    61,    61,    61,
-      61,    61,    61,    61,    61,    62,    62,    62,    62,    62,
-      62,    62,    62,    62,    63,    63,    62,    65,    64,    66,
-      64,    64,    67,    68,    68,    68,    69,    69,    70,    70,
-      71,    71,    72,    72,    73,    73,    74,    74,    74,    74,
-      75,    75,    75,    75,    75,    76,    76,    77,    77,    78,
-      78,    78,    80,    79,    81,    81,    81,    82,    82,    82,
-      82,    82,    82,    83,    83,    84,    84,    85,    85,    85,
-      86,    87,    87,    88,    89,    89,    90,    91,    91
-};
+#define YYPACT_NINF -91
 
-/* YYR2[YYN] -- Number of symbols composing right hand side of rule YYN.  */
-static const yytype_uint8 yyr2[] =
-{
-       0,     2,     4,     0,     2,     1,     1,     1,     3,     1,
-       2,     1,     2,     2,     2,     3,     1,     2,     2,     2,
-       1,     2,     3,     1,     1,     2,     3,     2,     1,     2,
-       2,     1,     1,     1,     1,     1,     1,     2,     3,     3,
-       1,     1,     2,     3,     0,     1,     3,     0,     3,     0,
-       3,     3,     3,     1,     1,     1,     0,     1,     1,     2,
-       1,     2,     1,     2,     1,     2,     1,     1,     1,     1,
-       1,     1,     2,     2,     3,     1,     2,     1,     2,     1,
-       2,     2,     0,     4,     1,     3,     2,     0,     3,     3,
-       3,     3,     3,     0,     1,     1,     1,     0,     1,     1,
-       1,     1,     1,     1,     1,     1,     1,     0,     2
-};
+#define yypact_value_is_default(yystate) \
+  ((yystate) == (-91))
 
-/* YYDEFACT[STATE-NAME] -- Default reduction number in state STATE-NUM.
-   Performed when YYTABLE doesn't specify something else to do.  Zero
-   means the default is an error.  */
-static const yytype_uint8 yydefact[] =
-{
-       3,     0,     0,     1,    49,    47,     0,     0,     0,    53,
-      54,    55,     0,     7,    40,     0,     9,    11,     0,     0,
-       0,    16,     0,     0,     0,    20,     0,    41,    23,    24,
-       0,     0,    28,     0,     0,     0,    31,    32,    33,     0,
-       6,    34,    44,     4,     5,    36,    35,    56,     0,     0,
-       0,     0,     0,   100,     0,    42,    96,    95,    97,    10,
-      12,    13,    14,     0,    17,    18,    19,    21,     0,    25,
-       0,    27,    29,    30,   106,   102,   101,   104,    37,   105,
-       0,   103,     0,     0,    77,    79,    93,    45,     0,    57,
-       0,    70,    75,    50,    71,    48,    51,    62,    67,    68,
-      69,    38,    64,    66,    39,    43,    99,    98,     8,    15,
-      22,    26,    81,    80,     0,    78,     2,    94,    82,    46,
-      52,    58,    60,    76,    72,    73,    63,    65,   108,    87,
-      59,    61,    74,    83,    84,    87,    86,     0,     0,     0,
-      93,    93,    85,    90,    91,    92,    89,    88
-};
+#define YYTABLE_NINF -108
 
-/* YYDEFGOTO[NTERM-NUM].  */
-static const yytype_int16 yydefgoto[] =
-{
-      -1,     1,     2,    43,    82,    88,    45,    49,    48,    46,
-      47,    90,   120,   121,    96,   101,   102,    92,    93,    83,
-      84,    85,   129,   133,   134,   118,    58,   108,    55,    77,
-      86,   103,    79,   116
-};
+#define yytable_value_is_error(yytable_value) \
+  YYID (0)
 
-/* YYPACT[STATE-NUM] -- Index in YYTABLE of the portion describing
-   STATE-NUM.  */
-#define YYPACT_NINF -91
+  /* YYPACT[STATE-NUM] -- Index in YYTABLE of the portion describing
+     STATE-NUM.    */
 static const yytype_int16 yypact[] =
 {
      -91,     3,   103,   -91,   -91,   -91,   -36,     2,    10,   -91,
@@ -791,7 +703,29 @@ static const yytype_int16 yypact[] =
       62,    62,    34,   -91,   -91,   -91,   -91,   -91
 };
 
-/* YYPGOTO[NTERM-NUM].  */
+  /* YYDEFACT[S] -- default reduction number in state S.  Performed when
+     YYTABLE does not specify something else to do.  Zero means the default
+     is an error.    */
+static const yytype_uint8 yydefact[] =
+{
+       3,     0,     0,     1,    49,    47,     0,     0,     0,    53,
+      54,    55,     0,     7,    40,     0,     9,    11,     0,     0,
+       0,    16,     0,     0,     0,    20,     0,    41,    23,    24,
+       0,     0,    28,     0,     0,     0,    31,    32,    33,     0,
+       6,    34,    44,     4,     5,    36,    35,    56,     0,     0,
+       0,     0,     0,   100,     0,    42,    96,    95,    97,    10,
+      12,    13,    14,     0,    17,    18,    19,    21,     0,    25,
+       0,    27,    29,    30,   106,   102,   101,   104,    37,   105,
+       0,   103,     0,     0,    77,    79,    93,    45,     0,    57,
+       0,    70,    75,    50,    71,    48,    51,    62,    67,    68,
+      69,    38,    64,    66,    39,    43,    99,    98,     8,    15,
+      22,    26,    81,    80,     0,    78,     2,    94,    82,    46,
+      52,    58,    60,    76,    72,    73,    63,    65,   108,    87,
+      59,    61,    74,    83,    84,    87,    86,     0,     0,     0,
+      93,    93,    85,    90,    91,    92,    89,    88
+};
+
+  /* YYPGOTO[NTERM-NUM].    */
 static const yytype_int16 yypgoto[] =
 {
      -91,   -91,   -91,   -91,   147,   -91,   -91,   -91,   -91,   -91,
@@ -800,10 +734,18 @@ static const yytype_int16 yypgoto[] =
      -91,   -35,   -90,   -91
 };
 
-/* YYTABLE[YYPACT[STATE-NUM]].  What to do in state STATE-NUM.  If
-   positive, shift that token.  If negative, reduce the rule which
-   number is the opposite.  If YYTABLE_NINF, syntax error.  */
-#define YYTABLE_NINF -108
+  /* YYDEFGOTO[NTERM-NUM].    */
+static const yytype_int16 yydefgoto[] =
+{
+      -1,     1,     2,    43,    82,    88,    45,    49,    48,    46,
+      47,    90,   120,   121,    96,   101,   102,    92,    93,    83,
+      84,    85,   129,   133,   134,   118,    58,   108,    55,    77,
+      86,   103,    79,   116
+};
+
+  /* YYTABLE[YYPACT[STATE-NUM]].  What to do in state STATE-NUM.  If
+     positive, shift that token.  If negative, reduce the rule which
+     number is the opposite.  If YYTABLE_NINF, syntax error.    */
 static const yytype_int16 yytable[] =
 {
       78,  -107,    80,     3,   125,   105,     4,     5,     6,     7,
@@ -825,12 +767,6 @@ static const yytype_int16 yytable[] =
       42
 };
 
-#define yypact_value_is_default(yystate) \
-  ((yystate) == (-91))
-
-#define yytable_value_is_error(yytable_value) \
-  YYID (0)
-
 static const yytype_uint8 yycheck[] =
 {
       35,     0,     1,     0,    94,    54,     5,     6,     7,     8,
@@ -852,8 +788,8 @@ static const yytype_uint8 yycheck[] =
       57
 };
 
-/* YYSTOS[STATE-NUM] -- The (internal number of the) accessing
-   symbol of state STATE-NUM.  */
+  /* STOS_[STATE-NUM] -- The (internal number of the) accessing
+     symbol of state STATE-NUM.    */
 static const yytype_uint8 yystos[] =
 {
        0,    59,    60,     0,     5,     6,     7,     8,     9,    10,
@@ -873,6 +809,39 @@ static const yytype_uint8 yystos[] =
       43,    89,    82,    89,     4,    54,    83,    83
 };
 
+  /* YYR1[YYN] -- Symbol number of symbol that rule YYN derives.    */
+static const yytype_uint8 yyr1[] =
+{
+       0,    58,    59,    60,    60,    61,    61,    61,    61,    61,
+      61,    61,    61,    61,    61,    61,    61,    61,    61,    61,
+      61,    61,    61,    61,    61,    61,    61,    61,    61,    61,
+      61,    61,    61,    61,    61,    62,    62,    62,    62,    62,
+      62,    62,    62,    62,    63,    63,    62,    65,    64,    66,
+      64,    64,    67,    68,    68,    68,    69,    69,    70,    70,
+      71,    71,    72,    72,    73,    73,    74,    74,    74,    74,
+      75,    75,    75,    75,    75,    76,    76,    77,    77,    78,
+      78,    78,    80,    79,    81,    81,    81,    82,    82,    82,
+      82,    82,    82,    83,    83,    84,    84,    85,    85,    85,
+      86,    87,    87,    88,    89,    89,    90,    91,    91
+};
+
+  /* YYR2[YYN] -- Number of symbols composing right hand side of rule YYN.    */
+static const yytype_uint8 yyr2[] =
+{
+       0,     2,     4,     0,     2,     1,     1,     1,     3,     1,
+       2,     1,     2,     2,     2,     3,     1,     2,     2,     2,
+       1,     2,     3,     1,     1,     2,     3,     2,     1,     2,
+       2,     1,     1,     1,     1,     1,     1,     2,     3,     3,
+       1,     1,     2,     3,     0,     1,     3,     0,     3,     0,
+       3,     3,     3,     1,     1,     1,     0,     1,     1,     2,
+       1,     2,     1,     2,     1,     2,     1,     1,     1,     1,
+       1,     1,     2,     2,     3,     1,     2,     1,     2,     1,
+       2,     2,     0,     4,     1,     3,     2,     0,     3,     3,
+       3,     3,     3,     0,     1,     1,     1,     0,     1,     1,
+       1,     1,     1,     1,     1,     1,     1,     0,     2
+};
+
+
 #define yyerrok		(yyerrstatus = 0)
 #define yyclearin	(yychar = YYEMPTY)
 #define YYEMPTY		(-2)
@@ -1027,168 +996,168 @@ yy_symbol_value_print (yyoutput, yytype, yyvaluep, yylocationp)
 # endif
   switch (yytype)
     {
-      case 3: /* "\"string\"" */
-
-/* Line 819 of yacc.c  */
-#line 184 "parse-gram.y"
-	{ fputs (quotearg_style (c_quoting_style, (yyvaluep->chars)), stderr); };
-
-/* Line 819 of yacc.c  */
-#line 1038 "parse-gram.c"
-	break;
-      case 4: /* "\"integer\"" */
-
-/* Line 819 of yacc.c  */
-#line 196 "parse-gram.y"
-	{ fprintf (stderr, "%d", (yyvaluep->integer)); };
-
-/* Line 819 of yacc.c  */
-#line 1047 "parse-gram.c"
-	break;
-      case 43: /* "\"{...}\"" */
-
-/* Line 819 of yacc.c  */
-#line 186 "parse-gram.y"
-	{ fprintf (stderr, "{\n%s\n}", (yyvaluep->code)); };
-
-/* Line 819 of yacc.c  */
-#line 1056 "parse-gram.c"
-	break;
-      case 44: /* "\"[identifier]\"" */
-
-/* Line 819 of yacc.c  */
-#line 191 "parse-gram.y"
-	{ fprintf (stderr, "[%s]", (yyvaluep->uniqstr)); };
-
-/* Line 819 of yacc.c  */
-#line 1065 "parse-gram.c"
-	break;
-      case 45: /* "\"char\"" */
-
-/* Line 819 of yacc.c  */
-#line 178 "parse-gram.y"
-	{ fputs (char_name ((yyvaluep->character)), stderr); };
-
-/* Line 819 of yacc.c  */
-#line 1074 "parse-gram.c"
-	break;
-      case 46: /* "\"epilogue\"" */
-
-/* Line 819 of yacc.c  */
-#line 186 "parse-gram.y"
-	{ fprintf (stderr, "{\n%s\n}", (yyvaluep->chars)); };
-
-/* Line 819 of yacc.c  */
-#line 1083 "parse-gram.c"
-	break;
-      case 48: /* "\"identifier\"" */
-
-/* Line 819 of yacc.c  */
-#line 190 "parse-gram.y"
-	{ fputs ((yyvaluep->uniqstr), stderr); };
-
-/* Line 819 of yacc.c  */
-#line 1092 "parse-gram.c"
-	break;
-      case 49: /* "\"identifier:\"" */
-
-/* Line 819 of yacc.c  */
-#line 192 "parse-gram.y"
-	{ fprintf (stderr, "%s:", (yyvaluep->uniqstr)); };
-
-/* Line 819 of yacc.c  */
-#line 1101 "parse-gram.c"
-	break;
-      case 52: /* "\"%{...%}\"" */
-
-/* Line 819 of yacc.c  */
-#line 186 "parse-gram.y"
-	{ fprintf (stderr, "{\n%s\n}", (yyvaluep->chars)); };
-
-/* Line 819 of yacc.c  */
-#line 1110 "parse-gram.c"
-	break;
-      case 54: /* "\"type\"" */
-
-/* Line 819 of yacc.c  */
-#line 193 "parse-gram.y"
-	{ fprintf (stderr, "<%s>", (yyvaluep->uniqstr)); };
-
-/* Line 819 of yacc.c  */
-#line 1119 "parse-gram.c"
-	break;
-      case 71: /* "symbol.prec" */
-
-/* Line 819 of yacc.c  */
-#line 199 "parse-gram.y"
-	{ fprintf (stderr, "%s", (yyvaluep->symbol)->tag); };
-
-/* Line 819 of yacc.c  */
-#line 1128 "parse-gram.c"
-	break;
-      case 84: /* "variable" */
-
-/* Line 819 of yacc.c  */
-#line 190 "parse-gram.y"
-	{ fputs ((yyvaluep->uniqstr), stderr); };
-
-/* Line 819 of yacc.c  */
-#line 1137 "parse-gram.c"
-	break;
-      case 85: /* "content.opt" */
-
-/* Line 819 of yacc.c  */
-#line 186 "parse-gram.y"
-	{ fprintf (stderr, "{\n%s\n}", (yyvaluep->chars)); };
-
-/* Line 819 of yacc.c  */
-#line 1146 "parse-gram.c"
-	break;
-      case 86: /* "braceless" */
-
-/* Line 819 of yacc.c  */
-#line 186 "parse-gram.y"
-	{ fprintf (stderr, "{\n%s\n}", (yyvaluep->chars)); };
-
-/* Line 819 of yacc.c  */
-#line 1155 "parse-gram.c"
-	break;
-      case 87: /* "id" */
-
-/* Line 819 of yacc.c  */
-#line 199 "parse-gram.y"
-	{ fprintf (stderr, "%s", (yyvaluep->symbol)->tag); };
-
-/* Line 819 of yacc.c  */
-#line 1164 "parse-gram.c"
-	break;
-      case 88: /* "id_colon" */
-
-/* Line 819 of yacc.c  */
-#line 200 "parse-gram.y"
-	{ fprintf (stderr, "%s:", (yyvaluep->symbol)->tag); };
-
-/* Line 819 of yacc.c  */
-#line 1173 "parse-gram.c"
-	break;
-      case 89: /* "symbol" */
+            case 3: // "string"
+
+/* Line 751 of yacc.c  */
+#line 203 "parse-gram.y"
+        { fputs (quotearg_style (c_quoting_style, ((*yyvaluep).chars)), stderr); }
+/* Line 751 of yacc.c  */
+#line 1006 "../../../src/parse-gram.c"
+        break;
+
+            case 4: // "integer"
+
+/* Line 751 of yacc.c  */
+#line 215 "parse-gram.y"
+        { fprintf (stderr, "%d", ((*yyvaluep).integer)); }
+/* Line 751 of yacc.c  */
+#line 1015 "../../../src/parse-gram.c"
+        break;
+
+            case 43: // "{...}"
+
+/* Line 751 of yacc.c  */
+#line 205 "parse-gram.y"
+        { fprintf (stderr, "{\n%s\n}", ((*yyvaluep).code)); }
+/* Line 751 of yacc.c  */
+#line 1024 "../../../src/parse-gram.c"
+        break;
+
+            case 44: // "[identifier]"
+
+/* Line 751 of yacc.c  */
+#line 210 "parse-gram.y"
+        { fprintf (stderr, "[%s]", ((*yyvaluep).uniqstr)); }
+/* Line 751 of yacc.c  */
+#line 1033 "../../../src/parse-gram.c"
+        break;
+
+            case 45: // "char"
+
+/* Line 751 of yacc.c  */
+#line 197 "parse-gram.y"
+        { fputs (char_name (((*yyvaluep).character)), stderr); }
+/* Line 751 of yacc.c  */
+#line 1042 "../../../src/parse-gram.c"
+        break;
+
+            case 46: // "epilogue"
+
+/* Line 751 of yacc.c  */
+#line 205 "parse-gram.y"
+        { fprintf (stderr, "{\n%s\n}", ((*yyvaluep).chars)); }
+/* Line 751 of yacc.c  */
+#line 1051 "../../../src/parse-gram.c"
+        break;
+
+            case 48: // "identifier"
+
+/* Line 751 of yacc.c  */
+#line 209 "parse-gram.y"
+        { fputs (((*yyvaluep).uniqstr), stderr); }
+/* Line 751 of yacc.c  */
+#line 1060 "../../../src/parse-gram.c"
+        break;
+
+            case 49: // "identifier:"
+
+/* Line 751 of yacc.c  */
+#line 211 "parse-gram.y"
+        { fprintf (stderr, "%s:", ((*yyvaluep).uniqstr)); }
+/* Line 751 of yacc.c  */
+#line 1069 "../../../src/parse-gram.c"
+        break;
+
+            case 52: // "%{...%}"
+
+/* Line 751 of yacc.c  */
+#line 205 "parse-gram.y"
+        { fprintf (stderr, "{\n%s\n}", ((*yyvaluep).chars)); }
+/* Line 751 of yacc.c  */
+#line 1078 "../../../src/parse-gram.c"
+        break;
+
+            case 54: // "type"
+
+/* Line 751 of yacc.c  */
+#line 212 "parse-gram.y"
+        { fprintf (stderr, "<%s>", ((*yyvaluep).uniqstr)); }
+/* Line 751 of yacc.c  */
+#line 1087 "../../../src/parse-gram.c"
+        break;
+
+            case 71: // symbol.prec
+
+/* Line 751 of yacc.c  */
+#line 218 "parse-gram.y"
+        { fprintf (stderr, "%s", ((*yyvaluep).symbol)->tag); }
+/* Line 751 of yacc.c  */
+#line 1096 "../../../src/parse-gram.c"
+        break;
+
+            case 84: // variable
+
+/* Line 751 of yacc.c  */
+#line 209 "parse-gram.y"
+        { fputs (((*yyvaluep).uniqstr), stderr); }
+/* Line 751 of yacc.c  */
+#line 1105 "../../../src/parse-gram.c"
+        break;
+
+            case 85: // content.opt
+
+/* Line 751 of yacc.c  */
+#line 205 "parse-gram.y"
+        { fprintf (stderr, "{\n%s\n}", ((*yyvaluep).chars)); }
+/* Line 751 of yacc.c  */
+#line 1114 "../../../src/parse-gram.c"
+        break;
+
+            case 86: // braceless
+
+/* Line 751 of yacc.c  */
+#line 205 "parse-gram.y"
+        { fprintf (stderr, "{\n%s\n}", ((*yyvaluep).chars)); }
+/* Line 751 of yacc.c  */
+#line 1123 "../../../src/parse-gram.c"
+        break;
+
+            case 87: // id
+
+/* Line 751 of yacc.c  */
+#line 218 "parse-gram.y"
+        { fprintf (stderr, "%s", ((*yyvaluep).symbol)->tag); }
+/* Line 751 of yacc.c  */
+#line 1132 "../../../src/parse-gram.c"
+        break;
+
+            case 88: // id_colon
+
+/* Line 751 of yacc.c  */
+#line 219 "parse-gram.y"
+        { fprintf (stderr, "%s:", ((*yyvaluep).symbol)->tag); }
+/* Line 751 of yacc.c  */
+#line 1141 "../../../src/parse-gram.c"
+        break;
+
+            case 89: // symbol
+
+/* Line 751 of yacc.c  */
+#line 218 "parse-gram.y"
+        { fprintf (stderr, "%s", ((*yyvaluep).symbol)->tag); }
+/* Line 751 of yacc.c  */
+#line 1150 "../../../src/parse-gram.c"
+        break;
+
+            case 90: // string_as_id
+
+/* Line 751 of yacc.c  */
+#line 218 "parse-gram.y"
+        { fprintf (stderr, "%s", ((*yyvaluep).symbol)->tag); }
+/* Line 751 of yacc.c  */
+#line 1159 "../../../src/parse-gram.c"
+        break;
 
-/* Line 819 of yacc.c  */
-#line 199 "parse-gram.y"
-	{ fprintf (stderr, "%s", (yyvaluep->symbol)->tag); };
-
-/* Line 819 of yacc.c  */
-#line 1182 "parse-gram.c"
-	break;
-      case 90: /* "string_as_id" */
-
-/* Line 819 of yacc.c  */
-#line 199 "parse-gram.y"
-	{ fprintf (stderr, "%s", (yyvaluep->symbol)->tag); };
-
-/* Line 819 of yacc.c  */
-#line 1191 "parse-gram.c"
-	break;
       default:
 	break;
     }
@@ -1262,27 +1231,29 @@ do {								\
 #if (defined __STDC__ || defined __C99__FUNC__ \
      || defined __cplusplus || defined _MSC_VER)
 static void
-yy_reduce_print (YYSTYPE *yyvsp, YYLTYPE *yylsp, int yyrule)
+yy_reduce_print (yytype_int16 *yyssp, YYSTYPE *yyvsp, YYLTYPE *yylsp, int yyrule)
 #else
 static void
-yy_reduce_print (yyvsp, yylsp, yyrule)
+yy_reduce_print (yyssp, yyvsp, yylsp, yyrule)
+    yytype_int16 *yyssp;
     YYSTYPE *yyvsp;
     YYLTYPE *yylsp;
     int yyrule;
 #endif
 {
+  unsigned long int yylno = yyrline[yyrule];
   int yynrhs = yyr2[yyrule];
   int yyi;
-  unsigned long int yylno = yyrline[yyrule];
   YYFPRINTF (stderr, "Reducing stack by rule %d (line %lu):\n",
-	     yyrule - 1, yylno);
+             yyrule - 1, yylno);
   /* The symbols being reduced.  */
   for (yyi = 0; yyi < yynrhs; yyi++)
     {
       YYFPRINTF (stderr, "   $%d = ", yyi + 1);
-      yy_symbol_print (stderr, yyrhs[yyprhs[yyrule] + yyi],
-		       &(yyvsp[(yyi + 1) - (yynrhs)])
-		       , &(yylsp[(yyi + 1) - (yynrhs)])		       );
+      yy_symbol_print (stderr,
+                       yystos[yyssp[yyi + 1 - yynrhs]],
+                       &(yyvsp[(yyi + 1) - (yynrhs)])
+                       , &(yylsp[(yyi + 1) - (yynrhs)])                       );
       YYFPRINTF (stderr, "\n");
     }
 }
@@ -1290,7 +1261,7 @@ yy_reduce_print (yyvsp, yylsp, yyrule)
 # define YY_REDUCE_PRINT(Rule)		\
 do {					\
   if (yydebug)				\
-    yy_reduce_print (yyvsp, yylsp, Rule); \
+    yy_reduce_print (yyssp, yyvsp, yylsp, Rule); \
 } while (YYID (0))
 
 /* Nonzero means print parse trace.  It is left uninitialized so that
@@ -1824,7 +1795,6 @@ yydestruct (yymsg, yytype, yyvaluep, yylocationp)
 
   switch (yytype)
     {
-
       default:
 	break;
     }
@@ -1833,13 +1803,15 @@ yydestruct (yymsg, yytype, yyvaluep, yylocationp)
 
 /* Prevent warnings from -Wmissing-prototypes.  */
 #ifdef YYPARSE_PARAM
-#if defined __STDC__ || defined __cplusplus
+#if (defined __STDC__ || defined __C99__FUNC__ \
+     || defined __cplusplus || defined _MSC_VER)
 int yyparse (void *YYPARSE_PARAM);
 #else
 int yyparse ();
 #endif
 #else /* ! YYPARSE_PARAM */
-#if defined __STDC__ || defined __cplusplus
+#if (defined __STDC__ || defined __C99__FUNC__ \
+     || defined __cplusplus || defined _MSC_VER)
 int yyparse (void);
 #else
 int yyparse ();
@@ -1977,18 +1949,16 @@ YYLTYPE yylloc;
 #endif
 
 /* User initialization code.  */
-
-/* Line 1590 of yacc.c  */
-#line 86 "parse-gram.y"
+/* Line 1524 of yacc.c  */
+#line 105 "parse-gram.y"
 {
   /* Bison's grammar can initial empty locations, hence a default
      location is needed. */
   boundary_set (&yylloc.start, current_file, 1, 1);
   boundary_set (&yylloc.end, current_file, 1, 1);
 }
-
-/* Line 1590 of yacc.c  */
-#line 1992 "parse-gram.c"
+/* Line 1524 of yacc.c  */
+#line 1962 "../../../src/parse-gram.c"
   yylsp[0] = yylloc;
 
   goto yysetstate;
@@ -2181,216 +2151,239 @@ yyreduce:
     switch (yyn)
       {
           case 6:
-
-/* Line 1806 of yacc.c  */
-#line 225 "parse-gram.y"
+/* Line 1740 of yacc.c  */
+#line 244 "parse-gram.y"
     {
       code_props plain_code;
-      code_props_plain_init (&plain_code, (yyvsp[(1) - (1)].chars), (yylsp[(1) - (1)]));
+      code_props_plain_init (&plain_code, (yyvsp[0].chars), (yylsp[0]));
       code_props_translate_code (&plain_code);
       gram_scanner_last_string_free ();
       muscle_code_grow (union_seen ? "post_prologue" : "pre_prologue",
-                        plain_code.code, (yylsp[(1) - (1)]));
+                        plain_code.code, (yylsp[0]));
       code_scanner_last_string_free ();
     }
+/* Line 1740 of yacc.c  */
+#line 2167 "../../../src/parse-gram.c"
     break;
 
   case 7:
-
-/* Line 1806 of yacc.c  */
-#line 234 "parse-gram.y"
+/* Line 1740 of yacc.c  */
+#line 253 "parse-gram.y"
     { debug_flag = true; }
+/* Line 1740 of yacc.c  */
+#line 2175 "../../../src/parse-gram.c"
     break;
 
   case 8:
-
-/* Line 1806 of yacc.c  */
-#line 236 "parse-gram.y"
+/* Line 1740 of yacc.c  */
+#line 255 "parse-gram.y"
     {
-      muscle_percent_define_insert ((yyvsp[(2) - (3)].uniqstr), (yylsp[(2) - (3)]), (yyvsp[(3) - (3)].chars),
+      muscle_percent_define_insert ((yyvsp[-1].uniqstr), (yylsp[-1]), (yyvsp[0].chars),
                                     MUSCLE_PERCENT_DEFINE_GRAMMAR_FILE);
     }
+/* Line 1740 of yacc.c  */
+#line 2186 "../../../src/parse-gram.c"
     break;
 
   case 9:
-
-/* Line 1806 of yacc.c  */
-#line 240 "parse-gram.y"
+/* Line 1740 of yacc.c  */
+#line 259 "parse-gram.y"
     { defines_flag = true; }
+/* Line 1740 of yacc.c  */
+#line 2194 "../../../src/parse-gram.c"
     break;
 
   case 10:
-
-/* Line 1806 of yacc.c  */
-#line 242 "parse-gram.y"
+/* Line 1740 of yacc.c  */
+#line 261 "parse-gram.y"
     {
       defines_flag = true;
-      spec_defines_file = xstrdup ((yyvsp[(2) - (2)].chars));
+      spec_defines_file = xstrdup ((yyvsp[0].chars));
     }
+/* Line 1740 of yacc.c  */
+#line 2205 "../../../src/parse-gram.c"
     break;
 
   case 11:
-
-/* Line 1806 of yacc.c  */
-#line 246 "parse-gram.y"
+/* Line 1740 of yacc.c  */
+#line 265 "parse-gram.y"
     { error_verbose = true; }
+/* Line 1740 of yacc.c  */
+#line 2213 "../../../src/parse-gram.c"
     break;
 
   case 12:
-
-/* Line 1806 of yacc.c  */
-#line 247 "parse-gram.y"
-    { expected_sr_conflicts = (yyvsp[(2) - (2)].integer); }
+/* Line 1740 of yacc.c  */
+#line 266 "parse-gram.y"
+    { expected_sr_conflicts = (yyvsp[0].integer); }
+/* Line 1740 of yacc.c  */
+#line 2221 "../../../src/parse-gram.c"
     break;
 
   case 13:
-
-/* Line 1806 of yacc.c  */
-#line 248 "parse-gram.y"
-    { expected_rr_conflicts = (yyvsp[(2) - (2)].integer); }
+/* Line 1740 of yacc.c  */
+#line 267 "parse-gram.y"
+    { expected_rr_conflicts = (yyvsp[0].integer); }
+/* Line 1740 of yacc.c  */
+#line 2229 "../../../src/parse-gram.c"
     break;
 
   case 14:
-
-/* Line 1806 of yacc.c  */
-#line 249 "parse-gram.y"
-    { spec_file_prefix = (yyvsp[(2) - (2)].chars); }
+/* Line 1740 of yacc.c  */
+#line 268 "parse-gram.y"
+    { spec_file_prefix = (yyvsp[0].chars); }
+/* Line 1740 of yacc.c  */
+#line 2237 "../../../src/parse-gram.c"
     break;
 
   case 15:
-
-/* Line 1806 of yacc.c  */
-#line 250 "parse-gram.y"
-    { spec_file_prefix = (yyvsp[(3) - (3)].chars); }
+/* Line 1740 of yacc.c  */
+#line 269 "parse-gram.y"
+    { spec_file_prefix = (yyvsp[0].chars); }
+/* Line 1740 of yacc.c  */
+#line 2245 "../../../src/parse-gram.c"
     break;
 
   case 16:
-
-/* Line 1806 of yacc.c  */
-#line 252 "parse-gram.y"
+/* Line 1740 of yacc.c  */
+#line 271 "parse-gram.y"
     {
       nondeterministic_parser = true;
       glr_parser = true;
     }
+/* Line 1740 of yacc.c  */
+#line 2256 "../../../src/parse-gram.c"
     break;
 
   case 17:
-
-/* Line 1806 of yacc.c  */
-#line 257 "parse-gram.y"
+/* Line 1740 of yacc.c  */
+#line 276 "parse-gram.y"
     {
       code_props action;
-      code_props_symbol_action_init (&action, (yyvsp[(2) - (2)].code), (yylsp[(2) - (2)]));
+      code_props_symbol_action_init (&action, (yyvsp[0].code), (yylsp[0]));
       code_props_translate_code (&action);
       gram_scanner_last_string_free ();
-      muscle_code_grow ("initial_action", action.code, (yylsp[(2) - (2)]));
+      muscle_code_grow ("initial_action", action.code, (yylsp[0]));
       code_scanner_last_string_free ();
     }
+/* Line 1740 of yacc.c  */
+#line 2271 "../../../src/parse-gram.c"
     break;
 
   case 18:
-
-/* Line 1806 of yacc.c  */
-#line 265 "parse-gram.y"
-    { language_argmatch ((yyvsp[(2) - (2)].chars), grammar_prio, (yylsp[(1) - (2)])); }
+/* Line 1740 of yacc.c  */
+#line 284 "parse-gram.y"
+    { language_argmatch ((yyvsp[0].chars), grammar_prio, (yylsp[-1])); }
+/* Line 1740 of yacc.c  */
+#line 2279 "../../../src/parse-gram.c"
     break;
 
   case 19:
-
-/* Line 1806 of yacc.c  */
-#line 266 "parse-gram.y"
-    { add_param ("lex_param", (yyvsp[(2) - (2)].code), (yylsp[(2) - (2)])); }
+/* Line 1740 of yacc.c  */
+#line 285 "parse-gram.y"
+    { add_param ("lex_param", (yyvsp[0].code), (yylsp[0])); }
+/* Line 1740 of yacc.c  */
+#line 2287 "../../../src/parse-gram.c"
     break;
 
   case 20:
-
-/* Line 1806 of yacc.c  */
-#line 267 "parse-gram.y"
+/* Line 1740 of yacc.c  */
+#line 286 "parse-gram.y"
     { locations_flag = true; }
+/* Line 1740 of yacc.c  */
+#line 2295 "../../../src/parse-gram.c"
     break;
 
   case 21:
-
-/* Line 1806 of yacc.c  */
-#line 268 "parse-gram.y"
-    { spec_name_prefix = (yyvsp[(2) - (2)].chars); }
+/* Line 1740 of yacc.c  */
+#line 287 "parse-gram.y"
+    { spec_name_prefix = (yyvsp[0].chars); }
+/* Line 1740 of yacc.c  */
+#line 2303 "../../../src/parse-gram.c"
     break;
 
   case 22:
-
-/* Line 1806 of yacc.c  */
-#line 269 "parse-gram.y"
-    { spec_name_prefix = (yyvsp[(3) - (3)].chars); }
+/* Line 1740 of yacc.c  */
+#line 288 "parse-gram.y"
+    { spec_name_prefix = (yyvsp[0].chars); }
+/* Line 1740 of yacc.c  */
+#line 2311 "../../../src/parse-gram.c"
     break;
 
   case 23:
-
-/* Line 1806 of yacc.c  */
-#line 270 "parse-gram.y"
+/* Line 1740 of yacc.c  */
+#line 289 "parse-gram.y"
     { no_lines_flag = true; }
+/* Line 1740 of yacc.c  */
+#line 2319 "../../../src/parse-gram.c"
     break;
 
   case 24:
-
-/* Line 1806 of yacc.c  */
-#line 271 "parse-gram.y"
+/* Line 1740 of yacc.c  */
+#line 290 "parse-gram.y"
     { nondeterministic_parser = true; }
+/* Line 1740 of yacc.c  */
+#line 2327 "../../../src/parse-gram.c"
     break;
 
   case 25:
-
-/* Line 1806 of yacc.c  */
-#line 272 "parse-gram.y"
-    { spec_outfile = (yyvsp[(2) - (2)].chars); }
+/* Line 1740 of yacc.c  */
+#line 291 "parse-gram.y"
+    { spec_outfile = (yyvsp[0].chars); }
+/* Line 1740 of yacc.c  */
+#line 2335 "../../../src/parse-gram.c"
     break;
 
   case 26:
-
-/* Line 1806 of yacc.c  */
-#line 273 "parse-gram.y"
-    { spec_outfile = (yyvsp[(3) - (3)].chars); }
+/* Line 1740 of yacc.c  */
+#line 292 "parse-gram.y"
+    { spec_outfile = (yyvsp[0].chars); }
+/* Line 1740 of yacc.c  */
+#line 2343 "../../../src/parse-gram.c"
     break;
 
   case 27:
-
-/* Line 1806 of yacc.c  */
-#line 274 "parse-gram.y"
-    { add_param ("parse_param", (yyvsp[(2) - (2)].code), (yylsp[(2) - (2)])); }
+/* Line 1740 of yacc.c  */
+#line 293 "parse-gram.y"
+    { add_param ("parse_param", (yyvsp[0].code), (yylsp[0])); }
+/* Line 1740 of yacc.c  */
+#line 2351 "../../../src/parse-gram.c"
     break;
 
   case 28:
-
-/* Line 1806 of yacc.c  */
-#line 276 "parse-gram.y"
+/* Line 1740 of yacc.c  */
+#line 295 "parse-gram.y"
     {
       /* %pure-parser is deprecated in favor of `%define api.pure', so use
          `%define api.pure' in a backward-compatible manner here.  First, don't
          complain if %pure-parser is specified multiple times.  */
       if (!muscle_find_const ("percent_define(api.pure)"))
-        muscle_percent_define_insert ("api.pure", (yylsp[(1) - (1)]), "",
+        muscle_percent_define_insert ("api.pure", (yylsp[0]), "",
                                       MUSCLE_PERCENT_DEFINE_GRAMMAR_FILE);
       /* In all cases, use api.pure now so that the backend doesn't complain if
          the skeleton ignores api.pure, but do warn now if there's a previous
          conflicting definition from an actual %define.  */
       if (!muscle_percent_define_flag_if ("api.pure"))
-        muscle_percent_define_insert ("api.pure", (yylsp[(1) - (1)]), "",
+        muscle_percent_define_insert ("api.pure", (yylsp[0]), "",
                                       MUSCLE_PERCENT_DEFINE_GRAMMAR_FILE);
     }
+/* Line 1740 of yacc.c  */
+#line 2372 "../../../src/parse-gram.c"
     break;
 
   case 29:
-
-/* Line 1806 of yacc.c  */
-#line 290 "parse-gram.y"
-    { version_check (&(yylsp[(2) - (2)]), (yyvsp[(2) - (2)].chars)); }
+/* Line 1740 of yacc.c  */
+#line 309 "parse-gram.y"
+    { version_check (&(yylsp[0]), (yyvsp[0].chars)); }
+/* Line 1740 of yacc.c  */
+#line 2380 "../../../src/parse-gram.c"
     break;
 
   case 30:
-
-/* Line 1806 of yacc.c  */
-#line 292 "parse-gram.y"
+/* Line 1740 of yacc.c  */
+#line 311 "parse-gram.y"
     {
-      char const *skeleton_user = (yyvsp[(2) - (2)].chars);
+      char const *skeleton_user = (yyvsp[0].chars);
       if (strchr (skeleton_user, '/'))
         {
           size_t dir_length = strlen (current_file);
@@ -2410,542 +2403,604 @@ yyreduce:
           skeleton_user = uniqstr_new (skeleton_build);
           free (skeleton_build);
         }
-      skeleton_arg (skeleton_user, grammar_prio, (yylsp[(1) - (2)]));
+      skeleton_arg (skeleton_user, grammar_prio, (yylsp[-1]));
     }
+/* Line 1740 of yacc.c  */
+#line 2410 "../../../src/parse-gram.c"
     break;
 
   case 31:
-
-/* Line 1806 of yacc.c  */
-#line 315 "parse-gram.y"
+/* Line 1740 of yacc.c  */
+#line 334 "parse-gram.y"
     { token_table_flag = true; }
+/* Line 1740 of yacc.c  */
+#line 2418 "../../../src/parse-gram.c"
     break;
 
   case 32:
-
-/* Line 1806 of yacc.c  */
-#line 316 "parse-gram.y"
+/* Line 1740 of yacc.c  */
+#line 335 "parse-gram.y"
     { report_flag |= report_states; }
+/* Line 1740 of yacc.c  */
+#line 2426 "../../../src/parse-gram.c"
     break;
 
   case 33:
-
-/* Line 1806 of yacc.c  */
-#line 317 "parse-gram.y"
+/* Line 1740 of yacc.c  */
+#line 336 "parse-gram.y"
     { yacc_flag = true; }
+/* Line 1740 of yacc.c  */
+#line 2434 "../../../src/parse-gram.c"
     break;
 
   case 37:
-
-/* Line 1806 of yacc.c  */
-#line 325 "parse-gram.y"
+/* Line 1740 of yacc.c  */
+#line 344 "parse-gram.y"
     {
-      grammar_start_symbol_set ((yyvsp[(2) - (2)].symbol), (yylsp[(2) - (2)]));
+      grammar_start_symbol_set ((yyvsp[0].symbol), (yylsp[0]));
     }
+/* Line 1740 of yacc.c  */
+#line 2444 "../../../src/parse-gram.c"
     break;
 
   case 38:
-
-/* Line 1806 of yacc.c  */
-#line 329 "parse-gram.y"
+/* Line 1740 of yacc.c  */
+#line 348 "parse-gram.y"
     {
       symbol_list *list;
-      for (list = (yyvsp[(3) - (3)].list); list; list = list->next)
-	symbol_list_destructor_set (list, (yyvsp[(2) - (3)].code), (yylsp[(2) - (3)]));
-      symbol_list_free ((yyvsp[(3) - (3)].list));
+      for (list = (yyvsp[0].list); list; list = list->next)
+	symbol_list_destructor_set (list, (yyvsp[-1].code), (yylsp[-1]));
+      symbol_list_free ((yyvsp[0].list));
     }
+/* Line 1740 of yacc.c  */
+#line 2457 "../../../src/parse-gram.c"
     break;
 
   case 39:
-
-/* Line 1806 of yacc.c  */
-#line 336 "parse-gram.y"
+/* Line 1740 of yacc.c  */
+#line 355 "parse-gram.y"
     {
       symbol_list *list;
-      for (list = (yyvsp[(3) - (3)].list); list; list = list->next)
-	symbol_list_printer_set (list, (yyvsp[(2) - (3)].code), (yylsp[(2) - (3)]));
-      symbol_list_free ((yyvsp[(3) - (3)].list));
+      for (list = (yyvsp[0].list); list; list = list->next)
+	symbol_list_printer_set (list, (yyvsp[-1].code), (yylsp[-1]));
+      symbol_list_free ((yyvsp[0].list));
     }
+/* Line 1740 of yacc.c  */
+#line 2470 "../../../src/parse-gram.c"
     break;
 
   case 40:
-
-/* Line 1806 of yacc.c  */
-#line 343 "parse-gram.y"
+/* Line 1740 of yacc.c  */
+#line 362 "parse-gram.y"
     {
       default_prec = true;
     }
+/* Line 1740 of yacc.c  */
+#line 2480 "../../../src/parse-gram.c"
     break;
 
   case 41:
-
-/* Line 1806 of yacc.c  */
-#line 347 "parse-gram.y"
+/* Line 1740 of yacc.c  */
+#line 366 "parse-gram.y"
     {
       default_prec = false;
     }
+/* Line 1740 of yacc.c  */
+#line 2490 "../../../src/parse-gram.c"
     break;
 
   case 42:
-
-/* Line 1806 of yacc.c  */
-#line 351 "parse-gram.y"
+/* Line 1740 of yacc.c  */
+#line 370 "parse-gram.y"
     {
       /* Do not invoke muscle_percent_code_grow here since it invokes
          muscle_user_name_list_grow.  */
-      muscle_code_grow ("percent_code()", (yyvsp[(2) - (2)].chars), (yylsp[(2) - (2)]));
+      muscle_code_grow ("percent_code()", (yyvsp[0].chars), (yylsp[0]));
       code_scanner_last_string_free ();
     }
+/* Line 1740 of yacc.c  */
+#line 2503 "../../../src/parse-gram.c"
     break;
 
   case 43:
-
-/* Line 1806 of yacc.c  */
-#line 358 "parse-gram.y"
+/* Line 1740 of yacc.c  */
+#line 377 "parse-gram.y"
     {
-      muscle_percent_code_grow ((yyvsp[(2) - (3)].uniqstr), (yylsp[(2) - (3)]), (yyvsp[(3) - (3)].chars), (yylsp[(3) - (3)]));
+      muscle_percent_code_grow ((yyvsp[-1].uniqstr), (yylsp[-1]), (yyvsp[0].chars), (yylsp[0]));
       code_scanner_last_string_free ();
     }
+/* Line 1740 of yacc.c  */
+#line 2514 "../../../src/parse-gram.c"
     break;
 
   case 44:
-
-/* Line 1806 of yacc.c  */
-#line 372 "parse-gram.y"
+/* Line 1740 of yacc.c  */
+#line 391 "parse-gram.y"
     {}
+/* Line 1740 of yacc.c  */
+#line 2522 "../../../src/parse-gram.c"
     break;
 
   case 45:
-
-/* Line 1806 of yacc.c  */
-#line 373 "parse-gram.y"
-    { muscle_code_grow ("union_name", (yyvsp[(1) - (1)].uniqstr), (yylsp[(1) - (1)])); }
+/* Line 1740 of yacc.c  */
+#line 392 "parse-gram.y"
+    { muscle_code_grow ("union_name", (yyvsp[0].uniqstr), (yylsp[0])); }
+/* Line 1740 of yacc.c  */
+#line 2530 "../../../src/parse-gram.c"
     break;
 
   case 46:
-
-/* Line 1806 of yacc.c  */
-#line 378 "parse-gram.y"
+/* Line 1740 of yacc.c  */
+#line 397 "parse-gram.y"
     {
       union_seen = true;
-      muscle_code_grow ("stype", (yyvsp[(3) - (3)].chars), (yylsp[(3) - (3)]));
+      muscle_code_grow ("stype", (yyvsp[0].chars), (yylsp[0]));
       code_scanner_last_string_free ();
     }
+/* Line 1740 of yacc.c  */
+#line 2542 "../../../src/parse-gram.c"
     break;
 
   case 47:
-
-/* Line 1806 of yacc.c  */
-#line 389 "parse-gram.y"
+/* Line 1740 of yacc.c  */
+#line 408 "parse-gram.y"
     { current_class = nterm_sym; }
+/* Line 1740 of yacc.c  */
+#line 2550 "../../../src/parse-gram.c"
     break;
 
   case 48:
-
-/* Line 1806 of yacc.c  */
-#line 390 "parse-gram.y"
+/* Line 1740 of yacc.c  */
+#line 409 "parse-gram.y"
     {
       current_class = unknown_sym;
       current_type = NULL;
     }
+/* Line 1740 of yacc.c  */
+#line 2561 "../../../src/parse-gram.c"
     break;
 
   case 49:
-
-/* Line 1806 of yacc.c  */
-#line 394 "parse-gram.y"
+/* Line 1740 of yacc.c  */
+#line 413 "parse-gram.y"
     { current_class = token_sym; }
+/* Line 1740 of yacc.c  */
+#line 2569 "../../../src/parse-gram.c"
     break;
 
   case 50:
-
-/* Line 1806 of yacc.c  */
-#line 395 "parse-gram.y"
+/* Line 1740 of yacc.c  */
+#line 414 "parse-gram.y"
     {
       current_class = unknown_sym;
       current_type = NULL;
     }
+/* Line 1740 of yacc.c  */
+#line 2580 "../../../src/parse-gram.c"
     break;
 
   case 51:
-
-/* Line 1806 of yacc.c  */
-#line 400 "parse-gram.y"
+/* Line 1740 of yacc.c  */
+#line 419 "parse-gram.y"
     {
       symbol_list *list;
       tag_seen = true;
-      for (list = (yyvsp[(3) - (3)].list); list; list = list->next)
-	symbol_type_set (list->content.sym, (yyvsp[(2) - (3)].uniqstr), (yylsp[(2) - (3)]));
-      symbol_list_free ((yyvsp[(3) - (3)].list));
+      for (list = (yyvsp[0].list); list; list = list->next)
+	symbol_type_set (list->content.sym, (yyvsp[-1].uniqstr), (yylsp[-1]));
+      symbol_list_free ((yyvsp[0].list));
     }
+/* Line 1740 of yacc.c  */
+#line 2594 "../../../src/parse-gram.c"
     break;
 
   case 52:
-
-/* Line 1806 of yacc.c  */
-#line 411 "parse-gram.y"
+/* Line 1740 of yacc.c  */
+#line 430 "parse-gram.y"
     {
       symbol_list *list;
       ++current_prec;
-      for (list = (yyvsp[(3) - (3)].list); list; list = list->next)
+      for (list = (yyvsp[0].list); list; list = list->next)
 	{
-	  symbol_type_set (list->content.sym, current_type, (yylsp[(2) - (3)]));
-	  symbol_precedence_set (list->content.sym, current_prec, (yyvsp[(1) - (3)].assoc), (yylsp[(1) - (3)]));
+	  symbol_type_set (list->content.sym, current_type, (yylsp[-1]));
+	  symbol_precedence_set (list->content.sym, current_prec, (yyvsp[-2].assoc), (yylsp[-2]));
 	}
-      symbol_list_free ((yyvsp[(3) - (3)].list));
+      symbol_list_free ((yyvsp[0].list));
       current_type = NULL;
     }
+/* Line 1740 of yacc.c  */
+#line 2612 "../../../src/parse-gram.c"
     break;
 
   case 53:
-
-/* Line 1806 of yacc.c  */
-#line 425 "parse-gram.y"
+/* Line 1740 of yacc.c  */
+#line 444 "parse-gram.y"
     { (yyval.assoc) = left_assoc; }
+/* Line 1740 of yacc.c  */
+#line 2620 "../../../src/parse-gram.c"
     break;
 
   case 54:
-
-/* Line 1806 of yacc.c  */
-#line 426 "parse-gram.y"
+/* Line 1740 of yacc.c  */
+#line 445 "parse-gram.y"
     { (yyval.assoc) = right_assoc; }
+/* Line 1740 of yacc.c  */
+#line 2628 "../../../src/parse-gram.c"
     break;
 
   case 55:
-
-/* Line 1806 of yacc.c  */
-#line 427 "parse-gram.y"
+/* Line 1740 of yacc.c  */
+#line 446 "parse-gram.y"
     { (yyval.assoc) = non_assoc; }
+/* Line 1740 of yacc.c  */
+#line 2636 "../../../src/parse-gram.c"
     break;
 
   case 56:
-
-/* Line 1806 of yacc.c  */
-#line 431 "parse-gram.y"
+/* Line 1740 of yacc.c  */
+#line 450 "parse-gram.y"
     { current_type = NULL; }
+/* Line 1740 of yacc.c  */
+#line 2644 "../../../src/parse-gram.c"
     break;
 
   case 57:
-
-/* Line 1806 of yacc.c  */
-#line 432 "parse-gram.y"
-    { current_type = (yyvsp[(1) - (1)].uniqstr); tag_seen = true; }
+/* Line 1740 of yacc.c  */
+#line 451 "parse-gram.y"
+    { current_type = (yyvsp[0].uniqstr); tag_seen = true; }
+/* Line 1740 of yacc.c  */
+#line 2652 "../../../src/parse-gram.c"
     break;
 
   case 58:
-
-/* Line 1806 of yacc.c  */
-#line 438 "parse-gram.y"
-    { (yyval.list) = symbol_list_sym_new ((yyvsp[(1) - (1)].symbol), (yylsp[(1) - (1)])); }
+/* Line 1740 of yacc.c  */
+#line 457 "parse-gram.y"
+    { (yyval.list) = symbol_list_sym_new ((yyvsp[0].symbol), (yylsp[0])); }
+/* Line 1740 of yacc.c  */
+#line 2660 "../../../src/parse-gram.c"
     break;
 
   case 59:
-
-/* Line 1806 of yacc.c  */
-#line 440 "parse-gram.y"
-    { (yyval.list) = symbol_list_prepend ((yyvsp[(1) - (2)].list), symbol_list_sym_new ((yyvsp[(2) - (2)].symbol), (yylsp[(2) - (2)]))); }
+/* Line 1740 of yacc.c  */
+#line 459 "parse-gram.y"
+    { (yyval.list) = symbol_list_prepend ((yyvsp[-1].list), symbol_list_sym_new ((yyvsp[0].symbol), (yylsp[0]))); }
+/* Line 1740 of yacc.c  */
+#line 2668 "../../../src/parse-gram.c"
     break;
 
   case 60:
-
-/* Line 1806 of yacc.c  */
-#line 444 "parse-gram.y"
-    { (yyval.symbol) = (yyvsp[(1) - (1)].symbol); }
+/* Line 1740 of yacc.c  */
+#line 463 "parse-gram.y"
+    { (yyval.symbol) = (yyvsp[0].symbol); }
+/* Line 1740 of yacc.c  */
+#line 2676 "../../../src/parse-gram.c"
     break;
 
   case 61:
-
-/* Line 1806 of yacc.c  */
-#line 445 "parse-gram.y"
-    { (yyval.symbol) = (yyvsp[(1) - (2)].symbol); symbol_user_token_number_set ((yyvsp[(1) - (2)].symbol), (yyvsp[(2) - (2)].integer), (yylsp[(2) - (2)])); }
+/* Line 1740 of yacc.c  */
+#line 464 "parse-gram.y"
+    { (yyval.symbol) = (yyvsp[-1].symbol); symbol_user_token_number_set ((yyvsp[-1].symbol), (yyvsp[0].integer), (yylsp[0])); }
+/* Line 1740 of yacc.c  */
+#line 2684 "../../../src/parse-gram.c"
     break;
 
   case 62:
-
-/* Line 1806 of yacc.c  */
-#line 451 "parse-gram.y"
-    { (yyval.list) = symbol_list_sym_new ((yyvsp[(1) - (1)].symbol), (yylsp[(1) - (1)])); }
+/* Line 1740 of yacc.c  */
+#line 470 "parse-gram.y"
+    { (yyval.list) = symbol_list_sym_new ((yyvsp[0].symbol), (yylsp[0])); }
+/* Line 1740 of yacc.c  */
+#line 2692 "../../../src/parse-gram.c"
     break;
 
   case 63:
-
-/* Line 1806 of yacc.c  */
-#line 453 "parse-gram.y"
-    { (yyval.list) = symbol_list_prepend ((yyvsp[(1) - (2)].list), symbol_list_sym_new ((yyvsp[(2) - (2)].symbol), (yylsp[(2) - (2)]))); }
+/* Line 1740 of yacc.c  */
+#line 472 "parse-gram.y"
+    { (yyval.list) = symbol_list_prepend ((yyvsp[-1].list), symbol_list_sym_new ((yyvsp[0].symbol), (yylsp[0]))); }
+/* Line 1740 of yacc.c  */
+#line 2700 "../../../src/parse-gram.c"
     break;
 
   case 64:
-
-/* Line 1806 of yacc.c  */
-#line 457 "parse-gram.y"
-    { (yyval.list) = (yyvsp[(1) - (1)].list); }
+/* Line 1740 of yacc.c  */
+#line 476 "parse-gram.y"
+    { (yyval.list) = (yyvsp[0].list); }
+/* Line 1740 of yacc.c  */
+#line 2708 "../../../src/parse-gram.c"
     break;
 
   case 65:
-
-/* Line 1806 of yacc.c  */
-#line 458 "parse-gram.y"
-    { (yyval.list) = symbol_list_prepend ((yyvsp[(1) - (2)].list), (yyvsp[(2) - (2)].list)); }
+/* Line 1740 of yacc.c  */
+#line 477 "parse-gram.y"
+    { (yyval.list) = symbol_list_prepend ((yyvsp[-1].list), (yyvsp[0].list)); }
+/* Line 1740 of yacc.c  */
+#line 2716 "../../../src/parse-gram.c"
     break;
 
   case 66:
-
-/* Line 1806 of yacc.c  */
-#line 462 "parse-gram.y"
-    { (yyval.list) = symbol_list_sym_new ((yyvsp[(1) - (1)].symbol), (yylsp[(1) - (1)])); }
+/* Line 1740 of yacc.c  */
+#line 481 "parse-gram.y"
+    { (yyval.list) = symbol_list_sym_new ((yyvsp[0].symbol), (yylsp[0])); }
+/* Line 1740 of yacc.c  */
+#line 2724 "../../../src/parse-gram.c"
     break;
 
   case 67:
-
-/* Line 1806 of yacc.c  */
-#line 463 "parse-gram.y"
-    { (yyval.list) = symbol_list_type_new ((yyvsp[(1) - (1)].uniqstr), (yylsp[(1) - (1)])); }
+/* Line 1740 of yacc.c  */
+#line 482 "parse-gram.y"
+    { (yyval.list) = symbol_list_type_new ((yyvsp[0].uniqstr), (yylsp[0])); }
+/* Line 1740 of yacc.c  */
+#line 2732 "../../../src/parse-gram.c"
     break;
 
   case 68:
-
-/* Line 1806 of yacc.c  */
-#line 464 "parse-gram.y"
-    { (yyval.list) = symbol_list_default_tagged_new ((yylsp[(1) - (1)])); }
+/* Line 1740 of yacc.c  */
+#line 483 "parse-gram.y"
+    { (yyval.list) = symbol_list_default_tagged_new ((yylsp[0])); }
+/* Line 1740 of yacc.c  */
+#line 2740 "../../../src/parse-gram.c"
     break;
 
   case 69:
-
-/* Line 1806 of yacc.c  */
-#line 465 "parse-gram.y"
-    { (yyval.list) = symbol_list_default_tagless_new ((yylsp[(1) - (1)])); }
+/* Line 1740 of yacc.c  */
+#line 484 "parse-gram.y"
+    { (yyval.list) = symbol_list_default_tagless_new ((yylsp[0])); }
+/* Line 1740 of yacc.c  */
+#line 2748 "../../../src/parse-gram.c"
     break;
 
   case 70:
-
-/* Line 1806 of yacc.c  */
-#line 471 "parse-gram.y"
+/* Line 1740 of yacc.c  */
+#line 490 "parse-gram.y"
     {
-       current_type = (yyvsp[(1) - (1)].uniqstr);
+       current_type = (yyvsp[0].uniqstr);
        tag_seen = true;
      }
+/* Line 1740 of yacc.c  */
+#line 2759 "../../../src/parse-gram.c"
     break;
 
   case 71:
-
-/* Line 1806 of yacc.c  */
-#line 476 "parse-gram.y"
+/* Line 1740 of yacc.c  */
+#line 495 "parse-gram.y"
     {
-       symbol_class_set ((yyvsp[(1) - (1)].symbol), current_class, (yylsp[(1) - (1)]), true);
-       symbol_type_set ((yyvsp[(1) - (1)].symbol), current_type, (yylsp[(1) - (1)]));
+       symbol_class_set ((yyvsp[0].symbol), current_class, (yylsp[0]), true);
+       symbol_type_set ((yyvsp[0].symbol), current_type, (yylsp[0]));
      }
+/* Line 1740 of yacc.c  */
+#line 2770 "../../../src/parse-gram.c"
     break;
 
   case 72:
-
-/* Line 1806 of yacc.c  */
-#line 481 "parse-gram.y"
+/* Line 1740 of yacc.c  */
+#line 500 "parse-gram.y"
     {
-      symbol_class_set ((yyvsp[(1) - (2)].symbol), current_class, (yylsp[(1) - (2)]), true);
-      symbol_type_set ((yyvsp[(1) - (2)].symbol), current_type, (yylsp[(1) - (2)]));
-      symbol_user_token_number_set ((yyvsp[(1) - (2)].symbol), (yyvsp[(2) - (2)].integer), (yylsp[(2) - (2)]));
+      symbol_class_set ((yyvsp[-1].symbol), current_class, (yylsp[-1]), true);
+      symbol_type_set ((yyvsp[-1].symbol), current_type, (yylsp[-1]));
+      symbol_user_token_number_set ((yyvsp[-1].symbol), (yyvsp[0].integer), (yylsp[0]));
     }
+/* Line 1740 of yacc.c  */
+#line 2782 "../../../src/parse-gram.c"
     break;
 
   case 73:
-
-/* Line 1806 of yacc.c  */
-#line 487 "parse-gram.y"
+/* Line 1740 of yacc.c  */
+#line 506 "parse-gram.y"
     {
-      symbol_class_set ((yyvsp[(1) - (2)].symbol), current_class, (yylsp[(1) - (2)]), true);
-      symbol_type_set ((yyvsp[(1) - (2)].symbol), current_type, (yylsp[(1) - (2)]));
-      symbol_make_alias ((yyvsp[(1) - (2)].symbol), (yyvsp[(2) - (2)].symbol), (yyloc));
+      symbol_class_set ((yyvsp[-1].symbol), current_class, (yylsp[-1]), true);
+      symbol_type_set ((yyvsp[-1].symbol), current_type, (yylsp[-1]));
+      symbol_make_alias ((yyvsp[-1].symbol), (yyvsp[0].symbol), (yyloc));
     }
+/* Line 1740 of yacc.c  */
+#line 2794 "../../../src/parse-gram.c"
     break;
 
   case 74:
-
-/* Line 1806 of yacc.c  */
-#line 493 "parse-gram.y"
+/* Line 1740 of yacc.c  */
+#line 512 "parse-gram.y"
     {
-      symbol_class_set ((yyvsp[(1) - (3)].symbol), current_class, (yylsp[(1) - (3)]), true);
-      symbol_type_set ((yyvsp[(1) - (3)].symbol), current_type, (yylsp[(1) - (3)]));
-      symbol_user_token_number_set ((yyvsp[(1) - (3)].symbol), (yyvsp[(2) - (3)].integer), (yylsp[(2) - (3)]));
-      symbol_make_alias ((yyvsp[(1) - (3)].symbol), (yyvsp[(3) - (3)].symbol), (yyloc));
+      symbol_class_set ((yyvsp[-2].symbol), current_class, (yylsp[-2]), true);
+      symbol_type_set ((yyvsp[-2].symbol), current_type, (yylsp[-2]));
+      symbol_user_token_number_set ((yyvsp[-2].symbol), (yyvsp[-1].integer), (yylsp[-1]));
+      symbol_make_alias ((yyvsp[-2].symbol), (yyvsp[0].symbol), (yyloc));
     }
+/* Line 1740 of yacc.c  */
+#line 2807 "../../../src/parse-gram.c"
     break;
 
   case 81:
-
-/* Line 1806 of yacc.c  */
-#line 523 "parse-gram.y"
+/* Line 1740 of yacc.c  */
+#line 542 "parse-gram.y"
     {
       yyerrok;
     }
+/* Line 1740 of yacc.c  */
+#line 2817 "../../../src/parse-gram.c"
     break;
 
   case 82:
-
-/* Line 1806 of yacc.c  */
-#line 529 "parse-gram.y"
-    { current_lhs = (yyvsp[(1) - (2)].symbol); current_lhs_location = (yylsp[(1) - (2)]);
-    current_lhs_named_ref = (yyvsp[(2) - (2)].named_ref); }
+/* Line 1740 of yacc.c  */
+#line 548 "parse-gram.y"
+    { current_lhs ((yyvsp[-1].symbol), (yylsp[-1]), (yyvsp[0].named_ref)); }
+/* Line 1740 of yacc.c  */
+#line 2825 "../../../src/parse-gram.c"
     break;
 
   case 84:
-
-/* Line 1806 of yacc.c  */
-#line 534 "parse-gram.y"
-    { grammar_current_rule_end ((yylsp[(1) - (1)])); }
+/* Line 1740 of yacc.c  */
+#line 552 "parse-gram.y"
+    { grammar_current_rule_end ((yylsp[0])); }
+/* Line 1740 of yacc.c  */
+#line 2833 "../../../src/parse-gram.c"
     break;
 
   case 85:
-
-/* Line 1806 of yacc.c  */
-#line 535 "parse-gram.y"
-    { grammar_current_rule_end ((yylsp[(3) - (3)])); }
+/* Line 1740 of yacc.c  */
+#line 553 "parse-gram.y"
+    { grammar_current_rule_end ((yylsp[0])); }
+/* Line 1740 of yacc.c  */
+#line 2841 "../../../src/parse-gram.c"
     break;
 
   case 87:
-
-/* Line 1806 of yacc.c  */
-#line 541 "parse-gram.y"
-    { grammar_current_rule_begin (current_lhs, current_lhs_location,
+/* Line 1740 of yacc.c  */
+#line 559 "parse-gram.y"
+    { grammar_current_rule_begin (current_lhs_symbol, current_lhs_location,
 				  current_lhs_named_ref); }
+/* Line 1740 of yacc.c  */
+#line 2850 "../../../src/parse-gram.c"
     break;
 
   case 88:
-
-/* Line 1806 of yacc.c  */
-#line 544 "parse-gram.y"
-    { grammar_current_rule_symbol_append ((yyvsp[(2) - (3)].symbol), (yylsp[(2) - (3)]), (yyvsp[(3) - (3)].named_ref)); }
+/* Line 1740 of yacc.c  */
+#line 562 "parse-gram.y"
+    { grammar_current_rule_symbol_append ((yyvsp[-1].symbol), (yylsp[-1]), (yyvsp[0].named_ref)); }
+/* Line 1740 of yacc.c  */
+#line 2858 "../../../src/parse-gram.c"
     break;
 
   case 89:
-
-/* Line 1806 of yacc.c  */
-#line 546 "parse-gram.y"
-    { grammar_current_rule_action_append ((yyvsp[(2) - (3)].code), (yylsp[(2) - (3)]), (yyvsp[(3) - (3)].named_ref)); }
+/* Line 1740 of yacc.c  */
+#line 564 "parse-gram.y"
+    { grammar_current_rule_action_append ((yyvsp[-1].code), (yylsp[-1]), (yyvsp[0].named_ref)); }
+/* Line 1740 of yacc.c  */
+#line 2866 "../../../src/parse-gram.c"
     break;
 
   case 90:
-
-/* Line 1806 of yacc.c  */
-#line 548 "parse-gram.y"
-    { grammar_current_rule_prec_set ((yyvsp[(3) - (3)].symbol), (yylsp[(3) - (3)])); }
+/* Line 1740 of yacc.c  */
+#line 566 "parse-gram.y"
+    { grammar_current_rule_prec_set ((yyvsp[0].symbol), (yylsp[0])); }
+/* Line 1740 of yacc.c  */
+#line 2874 "../../../src/parse-gram.c"
     break;
 
   case 91:
-
-/* Line 1806 of yacc.c  */
-#line 550 "parse-gram.y"
-    { grammar_current_rule_dprec_set ((yyvsp[(3) - (3)].integer), (yylsp[(3) - (3)])); }
+/* Line 1740 of yacc.c  */
+#line 568 "parse-gram.y"
+    { grammar_current_rule_dprec_set ((yyvsp[0].integer), (yylsp[0])); }
+/* Line 1740 of yacc.c  */
+#line 2882 "../../../src/parse-gram.c"
     break;
 
   case 92:
-
-/* Line 1806 of yacc.c  */
-#line 552 "parse-gram.y"
-    { grammar_current_rule_merge_set ((yyvsp[(3) - (3)].uniqstr), (yylsp[(3) - (3)])); }
+/* Line 1740 of yacc.c  */
+#line 570 "parse-gram.y"
+    { grammar_current_rule_merge_set ((yyvsp[0].uniqstr), (yylsp[0])); }
+/* Line 1740 of yacc.c  */
+#line 2890 "../../../src/parse-gram.c"
     break;
 
   case 93:
-
-/* Line 1806 of yacc.c  */
-#line 556 "parse-gram.y"
+/* Line 1740 of yacc.c  */
+#line 574 "parse-gram.y"
     { (yyval.named_ref) = 0; }
+/* Line 1740 of yacc.c  */
+#line 2898 "../../../src/parse-gram.c"
     break;
 
   case 94:
-
-/* Line 1806 of yacc.c  */
-#line 558 "parse-gram.y"
-    { (yyval.named_ref) = named_ref_new((yyvsp[(1) - (1)].uniqstr), (yylsp[(1) - (1)])); }
+/* Line 1740 of yacc.c  */
+#line 576 "parse-gram.y"
+    { (yyval.named_ref) = named_ref_new((yyvsp[0].uniqstr), (yylsp[0])); }
+/* Line 1740 of yacc.c  */
+#line 2906 "../../../src/parse-gram.c"
     break;
 
   case 96:
-
-/* Line 1806 of yacc.c  */
-#line 570 "parse-gram.y"
-    { (yyval.uniqstr) = uniqstr_new ((yyvsp[(1) - (1)].chars)); }
+/* Line 1740 of yacc.c  */
+#line 588 "parse-gram.y"
+    { (yyval.uniqstr) = uniqstr_new ((yyvsp[0].chars)); }
+/* Line 1740 of yacc.c  */
+#line 2914 "../../../src/parse-gram.c"
     break;
 
   case 97:
-
-/* Line 1806 of yacc.c  */
-#line 575 "parse-gram.y"
+/* Line 1740 of yacc.c  */
+#line 593 "parse-gram.y"
     { (yyval.chars) = ""; }
+/* Line 1740 of yacc.c  */
+#line 2922 "../../../src/parse-gram.c"
     break;
 
   case 98:
-
-/* Line 1806 of yacc.c  */
-#line 576 "parse-gram.y"
-    { (yyval.chars) = (yyvsp[(1) - (1)].uniqstr); }
+/* Line 1740 of yacc.c  */
+#line 594 "parse-gram.y"
+    { (yyval.chars) = (yyvsp[0].uniqstr); }
+/* Line 1740 of yacc.c  */
+#line 2930 "../../../src/parse-gram.c"
     break;
 
   case 100:
-
-/* Line 1806 of yacc.c  */
-#line 587 "parse-gram.y"
+/* Line 1740 of yacc.c  */
+#line 605 "parse-gram.y"
     {
       code_props plain_code;
-      (yyvsp[(1) - (1)].code)[strlen ((yyvsp[(1) - (1)].code)) - 1] = '\n';
-      code_props_plain_init (&plain_code, (yyvsp[(1) - (1)].code)+1, (yylsp[(1) - (1)]));
+      (yyvsp[0].code)[strlen ((yyvsp[0].code)) - 1] = '\n';
+      code_props_plain_init (&plain_code, (yyvsp[0].code)+1, (yylsp[0]));
       code_props_translate_code (&plain_code);
       gram_scanner_last_string_free ();
       (yyval.chars) = plain_code.code;
     }
+/* Line 1740 of yacc.c  */
+#line 2945 "../../../src/parse-gram.c"
     break;
 
   case 101:
-
-/* Line 1806 of yacc.c  */
-#line 607 "parse-gram.y"
-    { (yyval.symbol) = symbol_from_uniqstr ((yyvsp[(1) - (1)].uniqstr), (yylsp[(1) - (1)])); }
+/* Line 1740 of yacc.c  */
+#line 625 "parse-gram.y"
+    { (yyval.symbol) = symbol_from_uniqstr ((yyvsp[0].uniqstr), (yylsp[0])); }
+/* Line 1740 of yacc.c  */
+#line 2953 "../../../src/parse-gram.c"
     break;
 
   case 102:
-
-/* Line 1806 of yacc.c  */
-#line 609 "parse-gram.y"
+/* Line 1740 of yacc.c  */
+#line 627 "parse-gram.y"
     {
-      (yyval.symbol) = symbol_get (char_name ((yyvsp[(1) - (1)].character)), (yylsp[(1) - (1)]));
-      symbol_class_set ((yyval.symbol), token_sym, (yylsp[(1) - (1)]), false);
-      symbol_user_token_number_set ((yyval.symbol), (yyvsp[(1) - (1)].character), (yylsp[(1) - (1)]));
+      (yyval.symbol) = symbol_get (char_name ((yyvsp[0].character)), (yylsp[0]));
+      symbol_class_set ((yyval.symbol), token_sym, (yylsp[0]), false);
+      symbol_user_token_number_set ((yyval.symbol), (yyvsp[0].character), (yylsp[0]));
     }
+/* Line 1740 of yacc.c  */
+#line 2965 "../../../src/parse-gram.c"
     break;
 
   case 103:
-
-/* Line 1806 of yacc.c  */
-#line 617 "parse-gram.y"
-    { (yyval.symbol) = symbol_from_uniqstr ((yyvsp[(1) - (1)].uniqstr), (yylsp[(1) - (1)])); }
+/* Line 1740 of yacc.c  */
+#line 635 "parse-gram.y"
+    { (yyval.symbol) = symbol_from_uniqstr ((yyvsp[0].uniqstr), (yylsp[0])); }
+/* Line 1740 of yacc.c  */
+#line 2973 "../../../src/parse-gram.c"
     break;
 
   case 106:
-
-/* Line 1806 of yacc.c  */
-#line 629 "parse-gram.y"
+/* Line 1740 of yacc.c  */
+#line 647 "parse-gram.y"
     {
-      (yyval.symbol) = symbol_get (quotearg_style (c_quoting_style, (yyvsp[(1) - (1)].chars)), (yylsp[(1) - (1)]));
-      symbol_class_set ((yyval.symbol), token_sym, (yylsp[(1) - (1)]), false);
+      (yyval.symbol) = symbol_get (quotearg_style (c_quoting_style, (yyvsp[0].chars)), (yylsp[0]));
+      symbol_class_set ((yyval.symbol), token_sym, (yylsp[0]), false);
     }
+/* Line 1740 of yacc.c  */
+#line 2984 "../../../src/parse-gram.c"
     break;
 
   case 108:
-
-/* Line 1806 of yacc.c  */
-#line 638 "parse-gram.y"
+/* Line 1740 of yacc.c  */
+#line 656 "parse-gram.y"
     {
       code_props plain_code;
-      code_props_plain_init (&plain_code, (yyvsp[(2) - (2)].chars), (yylsp[(2) - (2)]));
+      code_props_plain_init (&plain_code, (yyvsp[0].chars), (yylsp[0]));
       code_props_translate_code (&plain_code);
       gram_scanner_last_string_free ();
-      muscle_code_grow ("epilogue", plain_code.code, (yylsp[(2) - (2)]));
+      muscle_code_grow ("epilogue", plain_code.code, (yylsp[0]));
       code_scanner_last_string_free ();
     }
+/* Line 1740 of yacc.c  */
+#line 2999 "../../../src/parse-gram.c"
     break;
 
 
-
-/* Line 1806 of yacc.c  */
-#line 2949 "parse-gram.c"
+/* Line 1740 of yacc.c  */
+#line 3004 "../../../src/parse-gram.c"
         default: break;
       }
     if (yychar_backup != yychar)
@@ -3192,10 +3247,8 @@ yyreturn:
   return YYID (yyresult);
 }
 
-
-
-/* Line 2067 of yacc.c  */
-#line 648 "parse-gram.y"
+/* Line 2000 of yacc.c  */
+#line 666 "parse-gram.y"
 
 
 
@@ -3316,4 +3369,3 @@ char_name (char c)
       return quotearg_style (escape_quoting_style, buf);
     }
 }
-
diff --git a/src/parse-gram.h b/src/parse-gram.h
index a30d5f8..83dee10 100644
--- a/src/parse-gram.h
+++ b/src/parse-gram.h
@@ -1,19 +1,19 @@
-/* A Bison parser, made by GNU Bison 2.4.1.266-7e5e.  */
+/* A Bison parser, made by GNU Bison 2.4.570-7a582.  */
 
 /* Bison interface for Yacc-like parsers in C
-   
-      Copyright (C) 1984, 1989-1990, 2000-2011 Free Software Foundation, Inc.
-   
+
+   Copyright (C) 1984, 1989-1990, 2000-2011 Free Software Foundation, Inc.
+
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.
-   
+
    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
-   
+
    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
@@ -26,11 +26,10 @@
    special exception, which will cause the skeleton and the resulting
    Bison output files to be licensed under the GNU General Public
    License without this special exception.
-   
+
    This special exception was added by the Free Software Foundation in
    version 2.2 of Bison.  */
 
-
 /* Tokens.  */
 #ifndef YYTOKENTYPE
 # define YYTOKENTYPE
@@ -159,9 +158,8 @@
 #if ! defined YYSTYPE && ! defined YYSTYPE_IS_DECLARED
 typedef union YYSTYPE
 {
-
-/* Line 2068 of yacc.c  */
-#line 94 "parse-gram.y"
+/* Line 2001 of yacc.c  */
+#line 113 "parse-gram.y"
 
   symbol *symbol;
   symbol_list *list;
@@ -174,9 +172,8 @@ typedef union YYSTYPE
   named_ref *named_ref;
 
 
-
-/* Line 2068 of yacc.c  */
-#line 180 "parse-gram.h"
+/* Line 2001 of yacc.c  */
+#line 177 "../../../src/parse-gram.h"
 } YYSTYPE;
 # define YYSTYPE_IS_TRIVIAL 1
 # define yystype YYSTYPE /* obsolescent; will be withdrawn */
diff --git a/src/parse-gram.y b/src/parse-gram.y
index 8871f67..156b65b 100644
--- a/src/parse-gram.y
+++ b/src/parse-gram.y
@@ -61,11 +61,30 @@ static void add_param (char const *type, char *decl, location loc);
 
 static symbol_class current_class = unknown_sym;
 static uniqstr current_type = NULL;
-static symbol *current_lhs;
+static symbol *current_lhs_symbol;
 static location current_lhs_location;
 static named_ref *current_lhs_named_ref;
 static int current_prec = 0;
 
+/** Set the new current left-hand side symbol, possibly common
+ * to several right-hand side parts of rule. 
+ */
+static 
+void 
+current_lhs(symbol *sym, location loc, named_ref *ref)
+{
+  current_lhs_symbol = sym;
+  current_lhs_location = loc;
+  /* In order to simplify memory management, named references for lhs
+     are always assigned by deep copy into the current symbol_list
+     node.  This is because a single named-ref in the grammar may
+     result in several uses when the user factors lhs between several
+     rules using "|".  Therefore free the parser's original copy.  */
+  free (current_lhs_named_ref);
+  current_lhs_named_ref = ref;
+}
+
+
 #define YYTYPE_INT16 int_fast16_t
 #define YYTYPE_INT8 int_fast8_t
 #define YYTYPE_UINT16 uint_fast16_t
@@ -526,8 +545,7 @@ rules_or_grammar_declaration:
 ;
 
 rules:
-  id_colon named_ref.opt { current_lhs = $1; current_lhs_location = @1;
-    current_lhs_named_ref = $2; } rhses.1
+  id_colon named_ref.opt { current_lhs ($1, @1, $2); } rhses.1
 ;
 
 rhses.1:
@@ -538,7 +556,7 @@ rhses.1:
 
 rhs:
   /* Nothing.  */
-    { grammar_current_rule_begin (current_lhs, current_lhs_location,
+    { grammar_current_rule_begin (current_lhs_symbol, current_lhs_location,
 				  current_lhs_named_ref); }
 | rhs symbol named_ref.opt
     { grammar_current_rule_symbol_append ($2, @2, $3); }
diff --git a/src/reader.c b/src/reader.c
index 852d3e1..88daa50 100644
--- a/src/reader.c
+++ b/src/reader.c
@@ -231,7 +231,7 @@ grammar_current_rule_begin (symbol *lhs, location loc,
 
   p = grammar_symbol_append (lhs, loc);
   if (lhs_name)
-    assign_named_ref(p, lhs_name);
+    assign_named_ref (p, named_ref_copy (lhs_name));
 
   current_rule = grammar_end;
 
diff --git a/src/symlist.c b/src/symlist.c
index e717c3e..190d007 100644
--- a/src/symlist.c
+++ b/src/symlist.c
@@ -151,8 +151,7 @@ symbol_list_free (symbol_list *list)
   for (node = list; node; node = next)
     {
       next = node->next;
-      if (node->named_ref)
-        named_ref_free (node->named_ref);
+      named_ref_free (node->named_ref);
       free (node);
     }
 }
diff --git a/tests/named-refs.at b/tests/named-refs.at
index 98f45a5..ff414a9 100644
--- a/tests/named-refs.at
+++ b/tests/named-refs.at
@@ -472,6 +472,19 @@ AT_CLEANUP
 
 #######################################################################
 
+# Bison used to free twice the named ref for "a", since a single copy
+# was used in two rules.
+AT_SETUP([Factored LHS])
+AT_DATA_GRAMMAR([test.y],
+[[
+%%
+start[a]: "foo" | "bar";
+]])
+AT_BISON_CHECK([-o test.c test.y])
+AT_CLEANUP
+
+#######################################################################
+
 AT_SETUP([Unresolved references])
 AT_DATA_GRAMMAR([test.y],
 [[
-- 
1.7.4.1