+]AT_YYERROR_DEFINE[
+]AT_YYLEX_DEFINE([{ 1, 2, 3, 0 }])[
+
+int
+main (void)
+{
+ return yyparse ();
+}
+]])
+AT_BISON_OPTION_POPDEFS
+
+AT_BISON_CHECK([[-o input.c input.y]], [[0]],,
+[[input.y:23.5-19: warning: rule useless in parser due to conflicts: start: start
+input.y:27.5-19: warning: rule useless in parser due to conflicts: sr_conflict: TK2 "tok alias"
+]])
+AT_COMPILE([[input]])
+AT_PARSER_CHECK([[./input]])
+
+AT_CLEANUP
+
+
+
+## --------------------------- ##
+## parse-gram.y: LALR = IELR. ##
+## --------------------------- ##
+
+# If parse-gram.y's LALR and IELR parser tables ever begin to differ, we
+# need to fix parse-gram.y or start using IELR.
+
+AT_SETUP([[parse-gram.y: LALR = IELR]])
+
+# Avoid differences in synclines by telling bison that the output files
+# have the same name.
+[cp $abs_top_srcdir/src/parse-gram.y input.y]
+AT_BISON_CHECK([[-o input.c -Dlr.type=lalr input.y]])
+[mv input.c lalr.c]
+AT_CAPTURE_FILE([lalr.c])
+AT_BISON_CHECK([[-o input.c -Dlr.type=ielr input.y]])
+[mv input.c ielr.c]
+AT_CAPTURE_FILE([ielr.c])
+AT_CHECK([[diff lalr.c ielr.c]], [[0]])
+
+AT_CLEANUP
+
+
+
+## --------------------------------------- ##
+## %error-verbose and YYSTACK_USE_ALLOCA. ##
+## --------------------------------------- ##
+
+AT_SETUP([[%error-verbose and YYSTACK_USE_ALLOCA]])
+
+AT_BISON_OPTION_PUSHDEFS
+AT_DATA_GRAMMAR([input.y],
+[[%code {
+ #include <stdio.h>
+ ]AT_YYERROR_DECLARE[
+ ]AT_YYLEX_DECLARE[
+ #define YYSTACK_USE_ALLOCA 1
+}
+
+%error-verbose
+
+%%
+
+start: check syntax_error syntax_error ;
+
+check:
+{
+ if (128 < sizeof yymsgbuf)
+ {
+ fprintf (stderr,
+ "The initial size of yymsgbuf in yyparse has increased\n"
+ "since this test group was last updated. As a result,\n"
+ "this test group may no longer manage to induce a\n"
+ "reallocation of the syntax error message buffer.\n"
+ "This test group must be adjusted to produce a longer\n"
+ "error message.\n");
+ YYABORT;
+ }
+}
+;
+
+// Induce a syntax error message whose total length is more than
+// sizeof yymsgbuf in yyparse. Each token here is 64 bytes.
+syntax_error:
+ "123456789112345678921234567893123456789412345678951234567896123A"
+| "123456789112345678921234567893123456789412345678951234567896123B"
+| error 'a' 'b' 'c'
+;
+
+%%
+
+]AT_YYERROR_DEFINE[
+/* Induce two syntax error messages (which requires full error
+ recovery by shifting 3 tokens) in order to detect any loss of the
+ reallocated buffer. */
+]AT_YYLEX_DEFINE(["abc"])[
+int
+main (void)
+{
+ return yyparse ();
+}
+]])
+AT_BISON_OPTION_POPDEFS
+
+AT_BISON_CHECK([[-o input.c input.y]])
+AT_COMPILE([[input]])
+AT_PARSER_CHECK([[./input]], [[1]], [],
+[[syntax error, unexpected 'a', expecting 123456789112345678921234567893123456789412345678951234567896123A or 123456789112345678921234567893123456789412345678951234567896123B
+syntax error, unexpected $end, expecting 123456789112345678921234567893123456789412345678951234567896123A or 123456789112345678921234567893123456789412345678951234567896123B
+]])
+
+AT_CLEANUP
+
+
+
+## ------------------------- ##
+## %error-verbose overflow. ##
+## ------------------------- ##
+
+# Imagine the case where YYSTACK_ALLOC_MAXIMUM = YYSIZE_MAXIMUM and an
+# invocation of yysyntax_error has caused yymsg_alloc to grow to exactly
+# YYSTACK_ALLOC_MAXIMUM (perhaps because the normal doubling of size had
+# to be clipped to YYSTACK_ALLOC_MAXIMUM). In an old version of yacc.c,
+# a subsequent invocation of yysyntax_error that overflows during its
+# size calculation would return YYSIZE_MAXIMUM to yyparse. Then,
+# yyparse would invoke yyerror using the old contents of yymsg.
+
+AT_SETUP([[%error-verbose overflow]])
+AT_BISON_OPTION_PUSHDEFS
+AT_DATA_GRAMMAR([input.y],
+[[%code {
+ #include <stdio.h>
+ ]AT_YYERROR_DECLARE[
+ ]AT_YYLEX_DECLARE[
+
+ /* This prevents this test case from having to induce error messages
+ large enough to overflow size_t. */
+ #define YYSIZE_T unsigned char
+
+ /* Bring in malloc and set EXIT_SUCCESS so yacc.c doesn't try to
+ provide a malloc prototype using our YYSIZE_T. */
+ #include <stdlib.h>
+ #ifndef EXIT_SUCCESS
+ # define EXIT_SUCCESS 0
+ #endif
+
+ /* Max depth is usually much smaller than YYSTACK_ALLOC_MAXIMUM, and
+ we don't want gcc to warn everywhere this constant would be too big
+ to make sense for our YYSIZE_T. */
+ #define YYMAXDEPTH 100
+}
+
+%error-verbose
+
+%%
+
+start: syntax_error1 check syntax_error2 ;
+
+// Induce a syntax error message whose total length causes yymsg in
+// yyparse to be reallocated to size YYSTACK_ALLOC_MAXIMUM, which
+// should be 255. Each token here is 64 bytes.
+syntax_error1:
+ "123456789112345678921234567893123456789412345678951234567896123A"
+| "123456789112345678921234567893123456789412345678951234567896123B"
+| "123456789112345678921234567893123456789412345678951234567896123C"
+| error 'a' 'b' 'c'
+;
+
+check: