X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/c70fdfcd207a394121c7dac271bbd04ce2a91c98..e4f0316ae096a728e62032fa33bc6c42cf4b6455:/tests/glr-regression.at?ds=inline

diff --git a/tests/glr-regression.at b/tests/glr-regression.at
index dfe4b73c..9e3cec79 100644
--- a/tests/glr-regression.at
+++ b/tests/glr-regression.at
@@ -1,5 +1,5 @@
 # Checking GLR Parsing: Regression Tests           -*- Autotest -*-
-# Copyright (C) 2002, 2003, 2005 Free Software Foundation, Inc.
+# Copyright (C) 2002, 2003, 2005, 2006 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
@@ -34,7 +34,7 @@ AT_DATA_GRAMMAR([glr-regr1.y],
 #define YYSTYPE int
 static YYSTYPE exprMerge (YYSTYPE x0, YYSTYPE x1);
 int yylex (void);
-int yyerror (char const *msg);
+void yyerror (char const *msg);
 %}
 
 
@@ -70,11 +70,10 @@ main (void)
   return yyparse ();
 }
 
-int
+void
 yyerror (char const *msg)
 {
   fprintf (stderr, "%s\n", msg);
-  exit (4);
 }
 
 
@@ -121,9 +120,7 @@ AT_DATA_GRAMMAR([glr-regr2a.y],
 /* Reported by S. Eken */
 
 %{
-  #define YYSTYPE char const *
-  #define yyfalse 0
-  #define yytrue 1
+  #define YYSTYPE char *
 
   #include <ctype.h>
   #include <stdio.h>
@@ -141,9 +138,11 @@ command:
     's' var 't'
        { printf ("Variable: '%s'\n", $2); }
     'v' 'x' 'q'
+       { free ($2); }
   | 's' var_list 't' 'e'
-       { printf ("Varlist: '%s'\n", $2); }
+       { printf ("Varlist: '%s'\n", $2); free ($2); }
   | 's' var 't' var_printer 'x'
+       { free ($2); }
   ;
 
 var:
@@ -156,10 +155,10 @@ var_list:
     { $$ = $1; }
   | var ',' var_list
     {
-      char *s = (char *) malloc (strlen ($1) + 1 + strlen ($3) + 1);
-      strcpy (s, $1);
+      char *s = (char *) realloc ($1, strlen ($1) + 1 + strlen ($3) + 1);
       strcat (s, ",");
       strcat (s, $3);
+      free ($3);
       $$ = s;
     }
   ;
@@ -169,14 +168,14 @@ var_printer: 'v'
 
 %%
 
-FILE *yyin = NULL;
+FILE *input = NULL;
 
 int
 yylex (void)
 {
   char buf[50];
   char *s;
-  switch (fscanf (yyin, " %1[a-z,]", buf)) {
+  switch (fscanf (input, " %1[a-z,]", buf)) {
   case 1:
     return buf[0];
   case EOF:
@@ -184,8 +183,8 @@ yylex (void)
   default:
     break;
   }
-  if (fscanf (yyin, "%49s", buf) != 1)
-    abort ();
+  if (fscanf (input, "%49s", buf) != 1)
+    return 0;
   if (sizeof buf - 1 <= strlen (buf))
     abort ();
   s = (char *) malloc (strlen (buf) + 1);
@@ -202,8 +201,8 @@ yyerror (char const *s)
 int
 main (int argc, char **argv)
 {
-  yyin = stdin;
-  if (argc == 2 && !(yyin = fopen (argv[1], "r"))) return 1;
+  input = stdin;
+  if (argc == 2 && !(input = fopen (argv[1], "r"))) return 3;
   return yyparse ();
 }
 ]])
@@ -241,7 +240,7 @@ AT_DATA_GRAMMAR([glr-regr3.y],
 #include <stdarg.h>
 
 static int MergeRule (int x0, int x1);
-static void yyerror(char const * s);
+static void yyerror (char const * s);
 int yylex (void);
 
 #define RULE(x) (1 << (x))
@@ -291,7 +290,7 @@ static void yyerror(char const * s) {
   fprintf(stderr,"error: %s\n",s);
 }
 
-FILE *yyin = NULL;
+FILE *input = NULL;
 
 int P[] = { P1, P2 };
 int O[] = { O1, O2 };
@@ -300,7 +299,7 @@ int T[] = { T1, T2, T3, T4 };
 int yylex (void)
 {
   char inp[3];
-  if (fscanf (yyin, "%2s", inp) == EOF)
+  if (fscanf (input, "%2s", inp) == EOF)
     return 0;
   switch (inp[0])
     {
@@ -312,8 +311,8 @@ int yylex (void)
 }
 
 int main(int argc, char* argv[]) {
-  yyin = stdin;
-  if (argc == 2 && !(yyin = fopen (argv[1], "r"))) return 1;
+  input = stdin;
+  if (argc == 2 && !(input = fopen (argv[1], "r"))) return 3;
   return yyparse ();
 }
 ]])
@@ -328,3 +327,1337 @@ AT_CHECK([[echo p1 t4 o2 p1 p1 t1 o1 t2 p2 o1 t3 p2 p2 | ./glr-regr3]], 0,
 ]], [])
 
 AT_CLEANUP
+
+
+## ------------------------------------------------------------------------- ##
+## Duplicate representation of merged trees.  See			     ##
+## <http://lists.gnu.org/archive/html/help-bison/2005-07/msg00013.html>.     ##
+## ------------------------------------------------------------------------- ##
+
+AT_SETUP([Duplicate representation of merged trees])
+
+AT_DATA_GRAMMAR([glr-regr4.y],
+[[
+%union { char *ptr; }
+%type <ptr> S A A1 A2 B
+%glr-parser
+
+%{
+  #include <stdio.h>
+  #include <stdlib.h>
+  #include <string.h>
+  static char *merge (YYSTYPE, YYSTYPE);
+  static char *make_value (char const *, char const *);
+  static void yyerror (char const *);
+  static int yylex (void);
+%}
+
+%%
+
+tree: S { printf ("%s\n", $1); } ;
+
+S:
+  A   %merge<merge> { $$ = make_value ("S", $1); }
+  | B %merge<merge> { $$ = make_value ("S", $1); }
+  ;
+
+A:
+  A1   %merge<merge> { $$ = make_value ("A", $1); }
+  | A2 %merge<merge> { $$ = make_value ("A", $1); }
+  ;
+
+A1: 'a' { $$ = make_value ("A1", "'a'"); } ;
+A2: 'a' { $$ = make_value ("A2", "'a'"); } ;
+B:  'a' { $$ = make_value ("B", "'a'");  } ;
+
+%%
+
+static int
+yylex (void)
+{
+  static char const *input = "a";
+  return *input++;
+}
+
+int
+main (void)
+{
+  return yyparse ();
+}
+
+static char *
+make_value (char const *parent, char const *child)
+{
+  char const format[] = "%s <- %s";
+  char *value =
+    (char *) malloc (strlen (parent) + strlen (child) + sizeof format);
+  sprintf (value, format, parent, child);
+  return value;
+}
+
+static char *
+merge (YYSTYPE s1, YYSTYPE s2)
+{
+  char const format[] = "merge{ %s and %s }";
+  char *value =
+    (char *) malloc (strlen (s1.ptr) + strlen (s2.ptr) + sizeof format);
+  sprintf (value, format, s1.ptr, s2.ptr);
+  return value;
+}
+
+static void
+yyerror (char const *msg)
+{
+  fprintf (stderr, "%s\n", msg);
+}
+]])
+
+AT_CHECK([[bison -o glr-regr4.c glr-regr4.y]], 0, [],
+[glr-regr4.y: conflicts: 1 reduce/reduce
+])
+AT_COMPILE([glr-regr4])
+
+AT_CHECK([[./glr-regr4]], 0,
+[[merge{ S <- merge{ A <- A1 <- 'a' and A <- A2 <- 'a' } and S <- B <- 'a' }
+]], [])
+
+AT_CLEANUP
+
+
+## -------------------------------------------------------------------------- ##
+## User destructor for unresolved GLR semantic value.  See		      ##
+## <http://lists.gnu.org/archive/html/bison-patches/2005-08/msg00016.html>.   ##
+## -------------------------------------------------------------------------- ##
+
+AT_SETUP([User destructor for unresolved GLR semantic value])
+
+AT_DATA_GRAMMAR([glr-regr5.y],
+[[
+%{
+  #include <stdio.h>
+  #include <stdlib.h>
+  static void yyerror (char const *);
+  static int yylex (void);
+  enum { MAGIC_VALUE = -1057808125 }; /* originally chosen at random */
+%}
+
+%glr-parser
+%union { int value; }
+%type <value> start
+
+%destructor {
+  if ($$ != MAGIC_VALUE)
+    {
+      fprintf (stderr, "Bad destructor call.\n");
+      exit (EXIT_FAILURE);
+    }
+} start
+
+%%
+
+start:
+   'a' { $$ = MAGIC_VALUE; }
+   | 'a' { $$ = MAGIC_VALUE; }
+   ;
+
+%%
+
+static int
+yylex (void)
+{
+  static char const *input = "a";
+  return *input++;
+}
+
+static void
+yyerror (char const *msg)
+{
+  fprintf (stderr, "%s\n", msg);
+}
+
+int
+main (void)
+{
+  return yyparse () != 1;
+}
+]])
+
+AT_CHECK([[bison -o glr-regr5.c glr-regr5.y]], 0, [],
+[glr-regr5.y: conflicts: 1 reduce/reduce
+])
+AT_COMPILE([glr-regr5])
+
+AT_CHECK([[./glr-regr5]], 0, [],
+[syntax is ambiguous
+])
+
+AT_CLEANUP
+
+
+## -------------------------------------------------------------------------- ##
+## User destructor after an error during a split parse.  See		      ##
+## <http://lists.gnu.org/archive/html/bison-patches/2005-08/msg00029.html>.   ##
+## -------------------------------------------------------------------------- ##
+
+AT_SETUP([User destructor after an error during a split parse])
+
+AT_DATA_GRAMMAR([glr-regr6.y],
+[[
+%{
+  #include <stdio.h>
+  #include <stdlib.h>
+  static void yyerror (char const *);
+  static int yylex (void);
+%}
+
+%glr-parser
+%union { int value; }
+%type <value> 'a'
+
+%destructor {
+  printf ("Destructor called.\n");
+} 'a'
+
+%%
+
+start: 'a' | 'a' ;
+
+%%
+
+static int
+yylex (void)
+{
+  static char const *input = "a";
+  return *input++;
+}
+
+static void
+yyerror (char const *msg)
+{
+  fprintf (stderr, "%s\n", msg);
+}
+
+int
+main (void)
+{
+  return yyparse () != 1;
+}
+]])
+
+AT_CHECK([[bison -o glr-regr6.c glr-regr6.y]], 0, [],
+[glr-regr6.y: conflicts: 1 reduce/reduce
+])
+AT_COMPILE([glr-regr6])
+
+AT_CHECK([[./glr-regr6]], 0,
+[Destructor called.
+],
+[syntax is ambiguous
+])
+
+AT_CLEANUP
+
+
+## ------------------------------------------------------------------------- ##
+## Duplicated user destructor for lookahead.  See			     ##
+## <http://lists.gnu.org/archive/html/bison-patches/2005-08/msg00035.html>.  ##
+## ------------------------------------------------------------------------- ##
+
+AT_SETUP([Duplicated user destructor for lookahead])
+
+AT_DATA_GRAMMAR([glr-regr7.y],
+[[
+%{
+  #include <stdio.h>
+  #include <stdlib.h>
+  static void yyerror (char const *);
+  static int yylex (void);
+  #define YYSTACKEXPANDABLE 0
+%}
+
+%glr-parser
+%union { int *count; }
+%type <count> 'a'
+
+%destructor {
+  if ((*$$)++)
+    fprintf (stderr, "Destructor called on same value twice.\n");
+} 'a'
+
+%%
+
+start:
+    stack1 start
+  | stack2 start
+  | /* empty */
+  ;
+stack1: 'a' ;
+stack2: 'a' ;
+
+%%
+
+static int
+yylex (void)
+{
+  yylval.count = (int *) malloc (sizeof (int));
+  if (!yylval.count)
+    {
+      fprintf (stderr, "Test inconclusive.\n");
+      exit (EXIT_FAILURE);
+    }
+  *yylval.count = 0;
+  return 'a';
+}
+
+static void
+yyerror (char const *msg)
+{
+  fprintf (stderr, "%s\n", msg);
+}
+
+int
+main (void)
+{
+  return yyparse ();
+}
+]])
+
+AT_CHECK([[bison -o glr-regr7.c glr-regr7.y]], 0, [],
+[glr-regr7.y: conflicts: 2 reduce/reduce
+])
+AT_COMPILE([glr-regr7])
+
+AT_CHECK([[./glr-regr7]], 2, [],
+[memory exhausted
+])
+
+AT_CLEANUP
+
+
+## ------------------------------------------------------------------------- ##
+## Incorrect default location for empty right-hand sides.  Adapted from bug  ##
+## report by Claudia Hermann.						     ##
+## See http://lists.gnu.org/archive/html/bug-bison/2005-10/msg00069.html and ##
+## http://lists.gnu.org/archive/html/bug-bison/2005-10/msg00072.html         ##
+## ------------------------------------------------------------------------- ##
+
+AT_SETUP([Incorrectly initialized location for empty right-hand side in GLR])
+
+AT_DATA_GRAMMAR([glr-regr8.y],
+[[
+%{
+  #include <stdio.h>
+  #include <stdlib.h>
+  static void yyerror (char const *);
+  static int yylex (void);
+  static void yyerror (char const *msg);
+%}
+
+%token T_CONSTANT
+%token T_PORT
+%token T_SIGNAL
+
+%glr-parser
+
+%%
+
+
+PortClause	: T_PORT InterfaceDeclaration T_PORT
+		{ printf("%d/%d - %d/%d - %d/%d\n",
+			 @1.first_column, @1.last_column,
+			 @2.first_column, @2.last_column,
+			 @3.first_column, @3.last_column); }
+	;
+
+InterfaceDeclaration	: OptConstantWord	%dprec 1
+	| OptSignalWord	%dprec 2
+	;
+
+OptConstantWord	: /* empty */
+	| T_CONSTANT
+	;
+
+OptSignalWord	: /* empty */
+		{ printf("empty: %d/%d\n", @$.first_column, @$.last_column); }
+	| T_SIGNAL
+	;
+
+%%
+
+void
+yyerror (char const *msg)
+{
+  fprintf (stderr, "%s\n", msg);
+}
+
+static int lexIndex;
+
+int yylex (void)
+{
+  lexIndex += 1;
+  switch (lexIndex)
+    {
+    case 1:
+      yylloc.first_column = 1;
+      yylloc.last_column = 9;
+      return T_PORT;
+    case 2:
+      yylloc.first_column = 13;
+      yylloc.last_column = 17;
+      return T_PORT;
+    default:
+      return 0;
+    }
+}
+
+int
+main (void)
+{
+  yyparse();
+  return 0;
+}
+]])
+
+AT_CHECK([[bison -o glr-regr8.c glr-regr8.y]], 0, [],
+[glr-regr8.y: conflicts: 1 reduce/reduce
+])
+AT_COMPILE([glr-regr8])
+
+AT_CHECK([[./glr-regr8]], 0,
+[empty: 9/9
+1/9 - 9/9 - 13/17
+],
+[])
+
+AT_CLEANUP
+
+
+## ------------------------------------------------------------------------- ##
+## No users destructors if stack 0 deleted.  See			     ##
+## <http://lists.gnu.org/archive/html/bison-patches/2005-09/msg00109.html>.  ##
+## ------------------------------------------------------------------------- ##
+
+AT_SETUP([No users destructors if stack 0 deleted])
+
+AT_DATA_GRAMMAR([glr-regr9.y],
+[[
+%{
+# include <stdio.h>
+# include <stdlib.h>
+  static void yyerror (char const *);
+  static int yylex (void);
+# define YYSTACKEXPANDABLE 0
+  static int tokens = 0;
+  static int destructors = 0;
+# define USE(Var)
+%}
+
+%glr-parser
+%union { int dummy; }
+%type <dummy> 'a'
+
+%destructor {
+  destructors += 1;
+} 'a'
+
+%%
+
+start:
+    ambig0 'a'   { destructors += 2; USE ($2); }
+  | ambig1 start { destructors += 1; }
+  | ambig2 start { destructors += 1; }
+  ;
+
+ambig0: 'a' ;
+ambig1: 'a' ;
+ambig2: 'a' ;
+
+%%
+
+static int
+yylex (void)
+{
+  tokens += 1;
+  return 'a';
+}
+
+static void
+yyerror (char const *msg)
+{
+  fprintf (stderr, "%s\n", msg);
+}
+
+int
+main (void)
+{
+  int exit_status;
+  exit_status = yyparse ();
+  if (tokens != destructors)
+    {
+      fprintf (stderr, "Tokens = %d, Destructors = %d\n", tokens, destructors);
+      return 1;
+    }
+  return !exit_status;
+}
+]])
+
+AT_CHECK([[bison -o glr-regr9.c glr-regr9.y]], 0, [],
+[glr-regr9.y: conflicts: 1 reduce/reduce
+])
+AT_COMPILE([glr-regr9])
+
+AT_CHECK([[./glr-regr9]], 0, [],
+[memory exhausted
+])
+
+AT_CLEANUP
+
+
+## ------------------------------------------------------------------------- ##
+## Corrupted semantic options if user action cuts parse.	             ##
+## ------------------------------------------------------------------------- ##
+
+AT_SETUP([Corrupted semantic options if user action cuts parse])
+
+AT_DATA_GRAMMAR([glr-regr10.y],
+[[
+%{
+# include <stdio.h>
+  static void yyerror (char const *);
+  static int yylex (void);
+  #define GARBAGE_SIZE 50
+  static char garbage[GARBAGE_SIZE];
+%}
+
+%glr-parser
+%union { char *ptr; }
+%type <ptr> start
+
+%%
+
+start:
+    %dprec 2 { $$ = garbage; YYACCEPT; }
+  | %dprec 1 { $$ = garbage; YYACCEPT; }
+  ;
+
+%%
+
+static void
+yyerror (char const *msg)
+{
+  fprintf (stderr, "%s\n", msg);
+}
+
+static int
+yylex (void)
+{
+  return 0;
+}
+
+int
+main (void)
+{
+  int i;
+  for (i = 0; i < GARBAGE_SIZE; i+=1)
+    garbage[i] = 108;
+  return yyparse ();
+}
+]])
+
+AT_CHECK([[bison -o glr-regr10.c glr-regr10.y]], 0, [],
+[glr-regr10.y: conflicts: 1 reduce/reduce
+])
+AT_COMPILE([glr-regr10])
+
+AT_CHECK([[./glr-regr10]], 0, [], [])
+
+AT_CLEANUP
+
+
+## ------------------------------------------------------------------------- ##
+## Undesirable destructors if user action cuts parse.			     ##
+## ------------------------------------------------------------------------- ##
+
+AT_SETUP([Undesirable destructors if user action cuts parse])
+
+AT_DATA_GRAMMAR([glr-regr11.y],
+[[
+%{
+# include <stdlib.h>
+  static void yyerror (char const *);
+  static int yylex (void);
+  static int destructors = 0;
+# define USE(val)
+%}
+
+%glr-parser
+%union { int dummy; }
+%type <int> 'a'
+%destructor { destructors += 1; } 'a'
+
+%%
+
+start:
+    'a' %dprec 2 { USE ($1); destructors += 1; YYACCEPT; }
+  | 'a' %dprec 1 { USE ($1); destructors += 1; YYACCEPT; }
+  ;
+
+%%
+
+static void
+yyerror (char const *msg)
+{
+  fprintf (stderr, "%s\n", msg);
+}
+
+static int
+yylex (void)
+{
+  static char const *input = "a";
+  return *input++;
+}
+
+int
+main (void)
+{
+  int exit_status = yyparse ();
+  if (destructors != 1)
+    {
+      fprintf (stderr, "Destructor calls: %d\n", destructors);
+      return 1;
+    }
+  return exit_status;
+}
+]])
+
+AT_CHECK([[bison -o glr-regr11.c glr-regr11.y]], 0, [],
+[glr-regr11.y: conflicts: 1 reduce/reduce
+])
+AT_COMPILE([glr-regr11])
+
+AT_CHECK([[./glr-regr11]], 0, [], [])
+
+AT_CLEANUP
+
+
+## ------------------------------------------------------------------------- ##
+## Leaked semantic values if user action cuts parse.			     ##
+## ------------------------------------------------------------------------- ##
+
+AT_SETUP([Leaked semantic values if user action cuts parse])
+
+AT_DATA_GRAMMAR([glr-regr12.y],
+[[
+%glr-parser
+%union { int dummy; }
+%token PARENT_RHS_AFTER
+%type <dummy> parent_rhs_before merged PARENT_RHS_AFTER
+%destructor { parent_rhs_before_value = 0; } parent_rhs_before
+%destructor { merged_value = 0; } merged
+%destructor { parent_rhs_after_value = 0; } PARENT_RHS_AFTER
+
+%{
+# include <stdlib.h>
+  static int merge (YYSTYPE, YYSTYPE);
+  static void yyerror (char const *);
+  static int yylex (void);
+  static int parent_rhs_before_value = 0;
+  static int merged_value = 0;
+  static int parent_rhs_after_value = 0;
+# define USE(val)
+%}
+
+%%
+
+start:
+  alt1 %dprec 1
+  | alt2 %dprec 2
+  ;
+
+alt1:
+  PARENT_RHS_AFTER {
+    USE ($1);
+    parent_rhs_after_value = 0;
+  }
+  ;
+
+alt2:
+  parent_rhs_before merged PARENT_RHS_AFTER {
+    USE (($1, $2, $3));
+    parent_rhs_before_value = 0;
+    merged_value = 0;
+    parent_rhs_after_value = 0;
+  }
+  ;
+
+parent_rhs_before:
+  {
+    USE ($$);
+    parent_rhs_before_value = 1;
+  }
+  ;
+
+merged:
+  %merge<merge> {
+    USE ($$);
+    merged_value = 1;
+  }
+  | cut %merge<merge> {
+    USE ($$);
+    merged_value = 1;
+  }
+  ;
+
+cut: { YYACCEPT; } ;
+
+%%
+
+static int
+merge (YYSTYPE s1, YYSTYPE s2)
+{
+  /* Not invoked. */
+  char dummy = s1.dummy + s2.dummy;
+  return dummy;
+}
+
+static void
+yyerror (char const *msg)
+{
+  fprintf (stderr, "%s\n", msg);
+}
+
+static int
+yylex (void)
+{
+  static int const input[] = { PARENT_RHS_AFTER, 0 };
+  static const int *inputp = input;
+  if (*inputp == PARENT_RHS_AFTER)
+    parent_rhs_after_value = 1;
+  return *inputp++;
+}
+
+int
+main (void)
+{
+  int exit_status = yyparse ();
+  if (parent_rhs_before_value)
+    {
+      fprintf (stderr, "`parent_rhs_before' destructor not called.\n");
+      exit_status = 1;
+    }
+  if (merged_value)
+    {
+      fprintf (stderr, "`merged' destructor not called.\n");
+      exit_status = 1;
+    }
+  if (parent_rhs_after_value)
+    {
+      fprintf (stderr, "`PARENT_RHS_AFTER' destructor not called.\n");
+      exit_status = 1;
+    }
+  return exit_status;
+}
+]])
+
+AT_CHECK([[bison -o glr-regr12.c glr-regr12.y]], 0, [],
+[glr-regr12.y: conflicts: 1 shift/reduce, 1 reduce/reduce
+])
+AT_COMPILE([glr-regr12])
+
+AT_CHECK([[./glr-regr12]], 0, [], [])
+
+AT_CLEANUP
+
+
+## ------------------------------------------------------------------------- ##
+## Incorrect lookahead during deterministic GLR.  See			     ##
+## <http://lists.gnu.org/archive/html/help-bison/2005-07/msg00017.html> and  ##
+## <http://lists.gnu.org/archive/html/bison-patches/2006-01/msg00060.html>.  ##
+## ------------------------------------------------------------------------- ##
+
+AT_SETUP([Incorrect lookahead during deterministic GLR])
+
+AT_DATA_GRAMMAR([glr-regr13.y],
+[[
+/* Tests:
+     - Defaulted state with initial yychar: yychar == YYEMPTY.
+     - Nondefaulted state: yychar != YYEMPTY.
+     - Defaulted state after lookahead: yychar != YYEMPTY.
+     - Defaulted state after shift: yychar == YYEMPTY.
+     - User action changing the lookahead.  */
+
+%{
+  #include <stdio.h>
+  static void yyerror (char const *);
+  static int yylex (void);
+  static void print_look_ahead (char const *);
+  #define USE(value)
+%}
+
+%union { char value; }
+%type <value> 'a' 'b'
+%glr-parser
+%locations
+
+%%
+
+start:
+  defstate_init defstate_shift 'b' change_lookahead 'a' {
+    USE ($3);
+    print_look_ahead ("start <- defstate_init defstate_shift 'b'");
+  }
+  ;
+defstate_init:
+  {
+    print_look_ahead ("defstate_init <- empty string");
+  }
+  ;
+defstate_shift:
+  nondefstate defstate_look 'a' {
+    USE ($3);
+    print_look_ahead ("defstate_shift <- nondefstate defstate_look 'a'");
+  }
+  ;
+defstate_look:
+  {
+    print_look_ahead ("defstate_look <- empty string");
+  }
+  ;
+nondefstate:
+  {
+    print_look_ahead ("nondefstate <- empty string");
+  }
+  | 'b' {
+    USE ($1);
+    print_look_ahead ("nondefstate <- 'b'");
+  }
+  ;
+change_lookahead:
+  {
+    yychar = 'a';
+  }
+  ;
+
+%%
+
+static void
+yyerror (char const *msg)
+{
+  fprintf (stderr, "%s\n", msg);
+}
+
+static int
+yylex (void)
+{
+  static char const *input = "ab";
+  static int i = 0;
+  yylloc.first_line = yylloc.last_line = 1;
+  yylloc.first_column = yylloc.last_column = i + 1;
+  yylval.value = input[i] + 'A' - 'a';
+  return input[i++];
+}
+
+static void
+print_look_ahead (char const *reduction)
+{
+  printf ("%s:\n  yychar=", reduction);
+  if (yychar == YYEMPTY)
+    printf ("YYEMPTY");
+  else if (yychar == YYEOF)
+    printf ("YYEOF");
+  else
+    {
+      printf ("'%c', yylval='", yychar);
+      if (yylval.value > ' ')
+	printf ("%c", yylval.value);
+      printf ("', yylloc=(%d,%d),(%d,%d)",
+	      yylloc.first_line, yylloc.first_column,
+	      yylloc.last_line, yylloc.last_column);
+    }
+  printf ("\n");
+}
+
+int
+main (void)
+{
+  yychar = '#'; /* Not a token in the grammar.  */
+  yylval.value = '!';
+  return yyparse ();
+}
+]])
+
+AT_CHECK([[bison -o glr-regr13.c glr-regr13.y]], 0, [], [])
+AT_COMPILE([glr-regr13])
+
+AT_CHECK([[./glr-regr13]], 0,
+[defstate_init <- empty string:
+  yychar=YYEMPTY
+nondefstate <- empty string:
+  yychar='a', yylval='A', yylloc=(1,1),(1,1)
+defstate_look <- empty string:
+  yychar='a', yylval='A', yylloc=(1,1),(1,1)
+defstate_shift <- nondefstate defstate_look 'a':
+  yychar=YYEMPTY
+start <- defstate_init defstate_shift 'b':
+  yychar=YYEMPTY
+], [])
+
+AT_CLEANUP
+
+
+## ------------------------------------------------------------------------- ##
+## Incorrect lookahead during nondeterministic GLR.			     ##
+## ------------------------------------------------------------------------- ##
+
+AT_SETUP([Incorrect lookahead during nondeterministic GLR])
+
+AT_DATA_GRAMMAR([glr-regr14.y],
+[[
+/* Tests:
+     - Conflicting actions (split-off parse, which copies lookahead need,
+       which is necessarily yytrue) and nonconflicting actions (non-split-off
+       parse) for nondefaulted state: yychar != YYEMPTY.
+     - Merged deferred actions (lookahead need and RHS from different stack
+       than the target state) and nonmerged deferred actions (same stack).
+     - Defaulted state after lookahead: yychar != YYEMPTY.
+     - Defaulted state after shift: yychar == YYEMPTY.
+     - yychar != YYEMPTY but lookahead need is yyfalse (a previous stack has
+       seen the lookahead but current stack has not).
+     - Exceeding stack capacity (stack explosion), and thus reallocating
+       lookahead need array.
+   Note that it does not seem possible to see the initial yychar value during
+   nondeterministic operation since:
+     - In order to preserve the initial yychar, only defaulted states may be
+       entered.
+     - If only defaulted states are entered, there are no conflicts, so
+       nondeterministic operation does not start.  */
+
+%union { char value; }
+
+%{
+  #include <stdio.h>
+  static void yyerror (char const *);
+  static int yylex (void);
+  static void print_look_ahead (char const *);
+  static char merge (union YYSTYPE, union YYSTYPE);
+  #define USE(value)
+%}
+
+%type <value> 'a' 'b' 'c' 'd' stack_explosion
+%glr-parser
+%locations
+
+%%
+
+start:
+  merge 'c' stack_explosion {
+    USE ($2); USE ($3);
+    print_look_ahead ("start <- merge 'c' stack_explosion");
+  }
+  ;
+
+/* When merging the 2 deferred actions, the lookahead needs are different.  */
+merge:
+  nonconflict1 'a' 'b' nonconflict2 %dprec 1 {
+    USE ($2); USE ($3);
+    print_look_ahead ("merge <- nonconflict1 'a' 'b' nonconflict2");
+  }
+  | conflict defstate_look 'a' nonconflict2 'b' defstate_shift %dprec 2 {
+    USE ($3); USE ($5);
+    print_look_ahead ("merge <- conflict defstate_look 'a' nonconflict2 'b'"
+		      " defstate_shift");
+  }
+  ;
+
+nonconflict1:
+  {
+    print_look_ahead ("nonconflict1 <- empty string");
+  }
+  ;
+nonconflict2:
+  {
+    print_look_ahead ("nonconflict2 <- empty string");
+  }
+  | 'a' {
+    USE ($1);
+    print_look_ahead ("nonconflict2 <- 'a'");
+  }
+  ;
+conflict:
+  {
+    print_look_ahead ("conflict <- empty string");
+  }
+  ;
+defstate_look:
+  {
+    print_look_ahead ("defstate_look <- empty string");
+  }
+  ;
+
+/* yychar != YYEMPTY but lookahead need is yyfalse.  */
+defstate_shift:
+  {
+    print_look_ahead ("defstate_shift <- empty string");
+  }
+  ;
+
+stack_explosion:
+  { $$ = '\0'; }
+  | alt1 stack_explosion %merge<merge> { $$ = $2; }
+  | alt2 stack_explosion %merge<merge> { $$ = $2; }
+  | alt3 stack_explosion %merge<merge> { $$ = $2; }
+  ;
+alt1:
+  'd' no_look {
+    USE ($1);
+    if (yychar != 'd' && yychar != YYEOF)
+      {
+	fprintf (stderr, "Incorrect lookahead during stack explosion.\n");
+      }
+  }
+  ;
+alt2:
+  'd' no_look {
+    USE ($1);
+    if (yychar != 'd' && yychar != YYEOF)
+      {
+	fprintf (stderr, "Incorrect lookahead during stack explosion.\n");
+      }
+  }
+  ;
+alt3:
+  'd' no_look {
+    USE ($1);
+    if (yychar != 'd' && yychar != YYEOF)
+      {
+	fprintf (stderr, "Incorrect lookahead during stack explosion.\n");
+      }
+  }
+  ;
+no_look:
+  {
+    if (yychar != YYEMPTY)
+      {
+	fprintf (stderr,
+		 "Found lookahead where shouldn't during stack explosion.\n");
+      }
+  }
+  ;
+
+%%
+
+static void
+yyerror (char const *msg)
+{
+  fprintf (stderr, "%s\n", msg);
+}
+
+static int
+yylex (void)
+{
+  static char const *input = "abcdddd";
+  static int i = 0;
+  yylloc.first_line = yylloc.last_line = 1;
+  yylloc.first_column = yylloc.last_column = i + 1;
+  yylval.value = input[i] + 'A' - 'a';
+  return input[i++];
+}
+
+static void
+print_look_ahead (char const *reduction)
+{
+  printf ("%s:\n  yychar=", reduction);
+  if (yychar == YYEMPTY)
+    printf ("YYEMPTY");
+  else if (yychar == YYEOF)
+    printf ("YYEOF");
+  else
+    {
+      printf ("'%c', yylval='", yychar);
+      if (yylval.value > ' ')
+	printf ("%c", yylval.value);
+      printf ("', yylloc=(%d,%d),(%d,%d)",
+	      yylloc.first_line, yylloc.first_column,
+	      yylloc.last_line, yylloc.last_column);
+    }
+  printf ("\n");
+}
+
+static char
+merge (union YYSTYPE s1, union YYSTYPE s2)
+{
+  char dummy = s1.value + s2.value;
+  return dummy;
+}
+
+int
+main (void)
+{
+  yychar = '#'; /* Not a token in the grammar.  */
+  yylval.value = '!';
+  return yyparse ();
+}
+]])
+
+AT_CHECK([[bison -o glr-regr14.c glr-regr14.y]], 0, [],
+[glr-regr14.y: conflicts: 3 reduce/reduce
+])
+AT_COMPILE([glr-regr14])
+
+AT_CHECK([[./glr-regr14]], 0,
+[conflict <- empty string:
+  yychar='a', yylval='A', yylloc=(1,1),(1,1)
+defstate_look <- empty string:
+  yychar='a', yylval='A', yylloc=(1,1),(1,1)
+nonconflict2 <- empty string:
+  yychar='b', yylval='B', yylloc=(1,2),(1,2)
+defstate_shift <- empty string:
+  yychar=YYEMPTY
+merge <- conflict defstate_look 'a' nonconflict2 'b' defstate_shift:
+  yychar=YYEMPTY
+start <- merge 'c' stack_explosion:
+  yychar=YYEOF
+], [])
+
+AT_CLEANUP
+
+
+## ------------------------------------------------------------------------- ##
+## Leaked semantic values when reporting ambiguity.			     ##
+## ------------------------------------------------------------------------- ##
+
+AT_SETUP([Leaked semantic values when reporting ambiguity])
+
+AT_DATA_GRAMMAR([glr-regr15.y],
+[[
+%glr-parser
+%destructor { parent_rhs_before_value = 0; } parent_rhs_before
+
+%{
+# include <stdlib.h>
+  static void yyerror (char const *);
+  static int yylex (void);
+  static int parent_rhs_before_value = 0;
+# define USE(val)
+%}
+
+%%
+
+start:
+  alt1 %dprec 1
+  | alt2 %dprec 2
+  ;
+
+/* This stack must be merged into the other stacks *last* (added at the
+   beginning of the semantic options list) so that yyparse will choose to clean
+   it up rather than the tree for which some semantic actions have been
+   performed.  Thus, if yyreportAmbiguity longjmp's to yyparse, the values from
+   those other trees are not cleaned up.  */
+alt1: ;
+
+alt2:
+  parent_rhs_before ambiguity {
+    USE ($1);
+    parent_rhs_before_value = 0;
+  }
+  ;
+
+parent_rhs_before:
+  {
+    USE ($$);
+    parent_rhs_before_value = 1;
+  }
+  ;
+
+ambiguity: ambiguity1 | ambiguity2 ;
+ambiguity1: ;
+ambiguity2: ;
+
+%%
+
+static void
+yyerror (char const *msg)
+{
+  fprintf (stderr, "%s\n", msg);
+}
+
+static int
+yylex (void)
+{
+  return 0;
+}
+
+int
+main (void)
+{
+  int exit_status = yyparse () != 1;
+  if (parent_rhs_before_value)
+    {
+      fprintf (stderr, "`parent_rhs_before' destructor not called.\n");
+      exit_status = 1;
+    }
+  return exit_status;
+}
+]])
+
+AT_CHECK([[bison -o glr-regr15.c glr-regr15.y]], 0, [],
+[glr-regr15.y: conflicts: 2 reduce/reduce
+])
+AT_COMPILE([glr-regr15])
+
+AT_CHECK([[./glr-regr15]], 0, [],
+[syntax is ambiguous
+])
+
+AT_CLEANUP
+
+
+## ------------------------------------------------------------------------- ##
+## Leaked lookahead after nondeterministic parse syntax error.		     ##
+## ------------------------------------------------------------------------- ##
+
+AT_SETUP([Leaked lookahead after nondeterministic parse syntax error])
+AT_DATA_GRAMMAR([glr-regr16.y],
+[[
+%glr-parser
+%destructor { lookahead_value = 0; } 'b'
+
+%{
+# include <stdlib.h>
+  static void yyerror (char const *);
+  static int yylex (void);
+  static int lookahead_value = 0;
+# define USE(val)
+%}
+
+%%
+
+start: alt1 'a' | alt2 'a' ;
+alt1: ;
+alt2: ;
+
+%%
+
+static void
+yyerror (char const *msg)
+{
+  fprintf (stderr, "%s\n", msg);
+}
+
+static int
+yylex (void)
+{
+  static char const *input = "ab";
+  if (*input == 'b')
+    lookahead_value = 1;
+  return *input++;
+}
+
+int
+main (void)
+{
+  int exit_status = yyparse () != 1;
+  if (lookahead_value)
+    {
+      fprintf (stderr, "Lookahead destructor not called.\n");
+      exit_status = 1;
+    }
+  return exit_status;
+}
+]])
+
+AT_CHECK([[bison -o glr-regr16.c glr-regr16.y]], 0, [],
+[glr-regr16.y: conflicts: 1 reduce/reduce
+])
+AT_COMPILE([glr-regr16])
+
+AT_CHECK([[./glr-regr16]], 0, [],
+[syntax error
+])
+
+AT_CLEANUP
+
+
+## ------------------------------------------------------------------------- ##
+## Uninitialized location when reporting ambiguity.			     ##
+## ------------------------------------------------------------------------- ##
+
+AT_SETUP([Uninitialized location when reporting ambiguity])
+AT_DATA_GRAMMAR([glr-regr17.y],
+[[
+%glr-parser
+%locations
+%pure-parser
+%error-verbose
+
+%union { int dummy; }
+
+%{
+  static void yyerror (YYLTYPE *, char const *);
+  static int yylex (YYSTYPE *, YYLTYPE *);
+%}
+
+%initial-action {
+  @$.first_line = 1;
+  @$.first_column = 1;
+  @$.last_line = 1;
+  @$.last_column = 1;
+}
+
+%%
+
+/* Tests the case of an empty RHS that has inherited the location of the
+   previous nonterminal, which is unresolved.  That location is reported as the
+   last position of the ambiguity.  */
+start: ambig1 empty1 | ambig2 empty2 ;
+
+/* Tests multiple levels of yyresolveLocations recursion.  */
+ambig1: sub_ambig1 | sub_ambig2 ;
+ambig2: sub_ambig1 | sub_ambig2 ;
+
+/* Tests the case of a non-empty RHS as well as the case of an empty RHS that
+   has inherited the initial location.  The empty RHS's location is reported as
+   the first position in the ambiguity.  */
+sub_ambig1: empty1 'a' 'b' ;
+sub_ambig2: empty2 'a' 'b' ;
+empty1: ;
+empty2: ;
+
+%%
+
+static void
+yyerror (YYLTYPE *locp, char const *msg)
+{
+  fprintf (stderr, "Error at %d.%d-%d.%d: %s.\n", locp->first_line,
+	   locp->first_column, locp->last_line, locp->last_column, msg);
+}
+
+static int
+yylex (YYSTYPE *lvalp, YYLTYPE *llocp)
+{
+  static char const input[] = "ab";
+  static char const *inputp = input;
+  lvalp->dummy = 0;
+  llocp->first_line = llocp->last_line = 2;
+  llocp->first_column = inputp - input + 1;
+  llocp->last_column = llocp->first_column + 1;
+  return *inputp++;
+}
+
+int
+main (void)
+{
+  return yyparse () != 1;
+}
+]])
+
+AT_CHECK([[bison -o glr-regr17.c glr-regr17.y]], 0, [],
+[glr-regr17.y: conflicts: 3 reduce/reduce
+])
+AT_COMPILE([glr-regr17])
+
+AT_CHECK([[./glr-regr17]], 0, [],
+[Error at 1.1-2.3: syntax is ambiguous.
+])
+
+AT_CLEANUP