+
+
+## ------------------------------------------------------------------------- ##
+## Leaked semantic values when reporting ambiguity. ##
+## ------------------------------------------------------------------------- ##
+
+AT_SETUP([Leaked semantic values when reporting ambiguity])
+
+AT_DATA_GRAMMAR([glr-regr15.y],
+[[
+%glr-parser
+%union { int dummy; }
+%type <dummy> parent_rhs_before
+%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