+
+
+## ------------------------------------------------------------------------- ##
+## 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";
+ static size_t toknum;
+ if (! (toknum < sizeof input))
+ abort ();
+ if (input[toknum] == 'b')
+ lookahead_value = 1;
+ return input[toknum++];
+}
+
+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_BISON_CHECK([[-o glr-regr16.c glr-regr16.y]], 0, [],
+[glr-regr16.y: conflicts: 1 reduce/reduce
+])
+AT_COMPILE([glr-regr16])
+
+AT_PARSER_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
+%define api.pure
+%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, "%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 size_t toknum;
+ if (! (toknum < sizeof input))
+ abort ();
+ lvalp->dummy = 0;
+ llocp->first_line = llocp->last_line = 2;
+ llocp->first_column = toknum + 1;
+ llocp->last_column = llocp->first_column + 1;
+ return input[toknum++];
+}
+
+int
+main (void)
+{
+ return yyparse () != 1;
+}
+]])
+
+AT_BISON_CHECK([[-o glr-regr17.c glr-regr17.y]], 0, [],
+[glr-regr17.y: conflicts: 3 reduce/reduce
+])
+AT_COMPILE([glr-regr17])
+
+AT_PARSER_CHECK([[./glr-regr17]], 0, [],
+[1.1-2.3: syntax is ambiguous.
+])
+
+AT_CLEANUP
+
+
+## -------------------------------------------------------------##
+## Missed %merge type warnings when LHS type is declared later. ##
+## -------------------------------------------------------------##
+
+AT_SETUP([Missed %merge type warnings when LHS type is declared later])
+AT_DATA_GRAMMAR([glr-regr18.y],
+[[%glr-parser
+
+%{
+ #include <stdlib.h>
+ static void yyerror (char const *);
+ static int yylex ();
+%}
+
+%union {
+ int type1;
+ int type2;
+ int type3;
+}
+
+%%
+
+sym1: sym2 %merge<merge> { $$ = $1; } ;
+sym2: sym3 %merge<merge> { $$ = $1; } ;
+sym3: %merge<merge> { $$ = 0; } ;
+
+%type <type1> sym1;
+%type <type2> sym2;
+%type <type3> sym3;
+
+%%
+
+static void
+yyerror (char const *msg)
+{
+ fprintf (stderr, "%s\n", msg);
+}
+
+static int
+yylex ()
+{
+ static int called;
+ if (called++)
+ abort ();
+ return 0;
+}
+
+int
+main (void)
+{
+ return yyparse ();
+}
+]])
+
+AT_BISON_CHECK([[-o glr-regr18.c glr-regr18.y]], 1, [],
+[glr-regr18.y:26.18-24: result type clash on merge function 'merge': <type2> != <type1>
+glr-regr18.y:25.18-24: previous declaration
+glr-regr18.y:27.13-19: result type clash on merge function 'merge': <type3> != <type2>
+glr-regr18.y:26.18-24: previous declaration
+])
+
+AT_CLEANUP
+
+
+## ------------------- ##
+## Ambiguity reports. ##
+## ------------------- ##
+
+AT_SETUP([Ambiguity reports])
+
+AT_DATA_GRAMMAR([input.y],
+[[
+%{
+ #include <stdio.h>
+ #include <stdlib.h>
+ static void yyerror (char const *);
+ static int yylex (void);
+%}
+
+%debug
+%glr-parser
+
+%%
+start:
+ 'a' b 'c' d
+| 'a' b 'c' d
+;
+b: 'b';
+d: /* nada. */;
+%%
+
+static int
+yylex (void)
+{
+ static char const input[] = "abc";
+ static size_t toknum;
+ if (! (toknum < sizeof input))
+ abort ();
+ return input[toknum++];
+}
+
+static void
+yyerror (char const *msg)
+{
+ fprintf (stderr, "%s\n", msg);
+}
+
+int
+main (void)
+{
+ yydebug = 1;
+ return !!yyparse ();
+}
+]])
+
+AT_BISON_CHECK([[-o input.c input.y]], 0, [],
+[input.y: conflicts: 1 reduce/reduce
+])
+AT_COMPILE([input])
+
+AT_PARSER_CHECK([[./input]], 1, [],
+[Starting parse
+Entering state 0
+Reading a token: Next token is token 'a' ()
+Shifting token 'a' ()
+Entering state 1
+Reading a token: Next token is token 'b' ()
+Shifting token 'b' ()
+Entering state 3
+Reducing stack 0 by rule 3 (line 25):
+ $1 = token 'b' ()
+-> $$ = nterm b ()
+Entering state 4
+Reading a token: Next token is token 'c' ()
+Shifting token 'c' ()
+Entering state 6
+Reducing stack 0 by rule 4 (line 26):
+-> $$ = nterm d ()
+Entering state 7
+Reading a token: Now at end of input.
+Stack 0 Entering state 7
+Now at end of input.
+Splitting off stack 1 from 0.
+Reduced stack 1 by rule #2; action deferred. Now in state 2.
+Stack 1 Entering state 2
+Now at end of input.
+Reduced stack 0 by rule #1; action deferred. Now in state 2.
+Merging stack 0 into stack 1.
+Stack 1 Entering state 2
+Now at end of input.
+Removing dead stacks.
+Rename stack 1 -> 0.
+On stack 0, shifting token $end ()
+Stack 0 now in state #5
+Ambiguity detected.
+Option 1,
+ start -> <Rule 1, tokens 1 .. 3>
+ 'a' <tokens 1 .. 1>
+ b <tokens 2 .. 2>
+ 'c' <tokens 3 .. 3>
+ d <empty>
+
+Option 2,
+ start -> <Rule 2, tokens 1 .. 3>
+ 'a' <tokens 1 .. 1>
+ b <tokens 2 .. 2>
+ 'c' <tokens 3 .. 3>
+ d <empty>
+
+syntax is ambiguous
+Cleanup: popping token $end ()
+Cleanup: popping unresolved nterm start ()
+Cleanup: popping nterm d ()
+Cleanup: popping token 'c' ()
+Cleanup: popping nterm b ()
+Cleanup: popping token 'a' ()
+])
+
+AT_CLEANUP