+AT_BISON_CHECK([-o input.c input.y])
+
+AT_CLEANUP
+
+
+## --------------------- ##
+## %prec takes a token. ##
+## --------------------- ##
+
+AT_SETUP([%prec takes a token])
+
+# Bison once allowed %prec sym where sym was a nonterminal.
+
+AT_DATA([input.y],
+[[%%
+start: PREC %prec PREC ;
+PREC: ;
+]])
+
+AT_BISON_CHECK([input.y], [1], [],
+[[input.y:3.1-4: rule given for PREC, which is a token
+]])
+
+AT_CLEANUP
+
+
+## ------------------------------- ##
+## %prec's token must be defined. ##
+## ------------------------------- ##
+
+AT_SETUP([[%prec's token must be defined]])
+
+# According to POSIX, a %prec token must be defined separately.
+
+AT_DATA([[input.y]],
+[[%%
+start: %prec PREC ;
+]])
+
+AT_BISON_CHECK([[input.y]], [[0]], [],
+[[input.y:2.8-17: warning: token for %prec is not defined: PREC
+]])
+
+AT_CLEANUP
+
+
+## -------------------------------- ##
+## Reject unused %code qualifiers. ##
+## -------------------------------- ##
+
+AT_SETUP([Reject unused %code qualifiers])
+
+AT_DATA([input-c.y],
+[[%code q {}
+%code bad {}
+%code bad {}
+%code format {}
+%%
+start: ;
+]])
+AT_BISON_CHECK([[input-c.y]], [[1]], [],
+[[input-c.y:1.7: %code qualifier 'q' is not used
+input-c.y:2.7-9: %code qualifier 'bad' is not used
+input-c.y:3.7-9: %code qualifier 'bad' is not used
+input-c.y:4.7-12: %code qualifier 'format' is not used
+]])
+
+AT_DATA([input-c-glr.y],
+[[%code q {}
+%code bad {}
+ %code bad {}
+%%
+start: ;
+]])
+AT_BISON_CHECK([[input-c-glr.y]], [[1]], [],
+[[input-c-glr.y:1.7: %code qualifier 'q' is not used
+input-c-glr.y:2.7-9: %code qualifier 'bad' is not used
+input-c-glr.y:3.8-10: %code qualifier 'bad' is not used
+]])
+
+AT_DATA([input-c++.y],
+[[%code q {}
+%code bad {}
+ %code q {}
+%%
+start: ;
+]])
+AT_BISON_CHECK([[input-c++.y]], [[1]], [],
+[[input-c++.y:1.7: %code qualifier 'q' is not used
+input-c++.y:2.7-9: %code qualifier 'bad' is not used
+input-c++.y:3.8: %code qualifier 'q' is not used
+]])
+
+AT_DATA([input-c++-glr.y],
+[[%code bad {}
+%code q {}
+%code q {}
+%%
+start: ;
+]])
+AT_BISON_CHECK([[input-c++-glr.y]], [[1]], [],
+[[input-c++-glr.y:1.7-9: %code qualifier 'bad' is not used
+input-c++-glr.y:2.7: %code qualifier 'q' is not used
+input-c++-glr.y:3.7: %code qualifier 'q' is not used
+]])
+
+AT_DATA([special-char-@@.y],
+[[%code bad {}
+%code q {}
+%code q {}
+%%
+start: ;
+]])
+AT_BISON_CHECK([[special-char-@@.y]], [[1]], [],
+[[special-char-@@.y:1.7-9: %code qualifier 'bad' is not used
+special-char-@@.y:2.7: %code qualifier 'q' is not used
+special-char-@@.y:3.7: %code qualifier 'q' is not used
+]])
+
+AT_DATA([special-char-@:>@.y],
+[[%code bad {}
+%code q {}
+%code q {}
+%%
+start: ;
+]])
+AT_BISON_CHECK([[special-char-@:>@.y]], [[1]], [],
+[[special-char-@:>@.y:1.7-9: %code qualifier 'bad' is not used
+special-char-@:>@.y:2.7: %code qualifier 'q' is not used
+special-char-@:>@.y:3.7: %code qualifier 'q' is not used
+]])
+
+AT_CLEANUP
+
+
+## ---------------- ##
+## %define errors. ##
+## ---------------- ##
+
+AT_SETUP([%define errors])
+
+AT_DATA([input-redefined.y],
+[[%define var "value1"
+%define var "value1"
+ %define var "value2"
+%define special1 "@:>@"
+%define special2 "@<:@"
+%%
+start: ;
+]])
+
+AT_BISON_CHECK([[input-redefined.y]], [[1]], [],
+[[input-redefined.y:2.9-11: %define variable 'var' redefined
+input-redefined.y:1.9-11: previous definition
+input-redefined.y:3.10-12: %define variable 'var' redefined
+input-redefined.y:2.9-11: previous definition
+]])
+
+AT_DATA([input-unused.y],
+[[%define var "value"
+%%
+start: ;
+]])
+
+AT_BISON_CHECK([[input-unused.y]], [[1]], [],
+[[input-unused.y:1.9-11: %define variable 'var' is not used
+]])
+
+AT_CLEANUP
+
+
+## ----------------------------------- ##
+## %define, --define, --force-define. ##
+## ----------------------------------- ##
+
+AT_SETUP([[%define, --define, --force-define]])
+
+AT_DATA([[skel.c]],
+[[m4@&t@_divert_push(0)@
+@output(b4_parser_file_name@)@
+[var-dd: ]b4_percent_define_get([[var-dd]])[
+var-ff: ]b4_percent_define_get([[var-ff]])[
+var-dfg: ]b4_percent_define_get([[var-dfg]])[
+var-fd: ]b4_percent_define_get([[var-fd]])
+m4@&t@_divert_pop(0)
+]])
+AT_DATA([[input.y]],
+[[%define var-dfg "gram"
+%%
+start: ;
+]])
+AT_BISON_CHECK([[-Dvar-dd=cmd-d1 -Dvar-dd=cmd-d2 \
+ -Fvar-ff=cmd-f1 -Fvar-ff=cmd-f2 \
+ -Dvar-dfg=cmd-d -Fvar-dfg=cmd-f \
+ -Fvar-fd=cmd-f -Dvar-fd=cmd-d \
+ --skeleton ./skel.c input.y]])
+AT_CHECK([[cat input.tab.c]], [[0]],
+[[var-dd: cmd-d2
+var-ff: cmd-f2
+var-dfg: cmd-f
+var-fd: cmd-d
+]])
+
+AT_DATA([[input-dg.y]],
+[[%define var "gram"
+%%
+start: ;
+]])
+AT_BISON_CHECK([[-Dvar=cmd-d input-dg.y]], [[1]], [],
+[[input-dg.y:1.9-11: %define variable 'var' redefined
+<command line>:2: previous definition
+]])
+
+AT_DATA([[input-unused.y]],
+[[%%
+start: ;
+]])
+AT_BISON_CHECK([[-Dunused-d -Funused-f input-unused.y]], [[1]], [],
+[[<command line>:2: %define variable 'unused-d' is not used
+<command line>:3: %define variable 'unused-f' is not used
+]])
+
+AT_CLEANUP
+
+## --------------------------- ##
+## %define Boolean variables. ##
+## --------------------------- ##
+
+AT_SETUP([[%define Boolean variables]])
+
+AT_DATA([Input.y],
+[[%language "Java"
+%define public "maybe"
+%define parser_class_name "Input"
+%%
+start: ;
+]])
+
+AT_BISON_CHECK([[Input.y]], [1], [],
+[[Input.y:2.9-14: invalid value for %define Boolean variable 'public'
+]])
+
+AT_CLEANUP
+
+## ------------------------ ##
+## %define enum variables. ##
+## ------------------------ ##
+
+AT_SETUP([[%define enum variables]])
+
+# Front-end.
+AT_DATA([[input.y]],
+[[%define lr.default-reductions bogus
+%%
+start: ;
+]])
+AT_BISON_CHECK([[input.y]], [[1]], [[]],
+[[input.y:1.9-29: invalid value for %define variable 'lr.default-reductions': 'bogus'
+input.y:1.9-29: accepted value: 'most'
+input.y:1.9-29: accepted value: 'consistent'
+input.y:1.9-29: accepted value: 'accepting'
+]])
+
+# Back-end.
+AT_DATA([[input.y]],
+[[%define api.push-pull neither
+%%
+start: ;
+]])
+AT_BISON_CHECK([[input.y]], [1], [],
+[[input.y:1.9-21: invalid value for %define variable 'api.push-pull': 'neither'
+input.y:1.9-21: accepted value: 'pull'
+input.y:1.9-21: accepted value: 'push'
+input.y:1.9-21: accepted value: 'both'
+]])
+
+AT_CLEANUP
+
+## -------------------------------- ##
+## %define backward compatibility. ##
+## -------------------------------- ##
+
+AT_SETUP([[%define backward compatibility]])
+
+# The error messages tell us whether underscores in these variables are
+# being converted to dashes.
+
+AT_DATA([[input.y]],
+[[%define api.push_pull "neither"
+%%
+start: ;
+]])
+AT_BISON_CHECK([[input.y]], [1], [],
+[[input.y:1.9-21: invalid value for %define variable 'api.push-pull': 'neither'
+input.y:1.9-21: accepted value: 'pull'
+input.y:1.9-21: accepted value: 'push'
+input.y:1.9-21: accepted value: 'both'
+]])
+
+AT_DATA([[input.y]],
+[[%define lr.keep_unreachable_states maybe
+%%
+start: ;
+]])
+AT_BISON_CHECK([[input.y]], [1], [],
+[[input.y:1.9-34: invalid value for %define Boolean variable 'lr.keep-unreachable-states'
+]])
+
+AT_DATA([[input.y]],
+[[%define foo_bar "baz"
+%%
+start: ;
+]])
+AT_BISON_CHECK([[input.y]], [[1]], [],
+[[input.y:1.9-15: %define variable 'foo_bar' is not used
+]])
+
+AT_CLEANUP
+
+## ------------------------- ##
+## Unused %define api.pure. ##
+## ------------------------- ##
+
+AT_SETUP([[Unused %define api.pure]])
+
+# AT_CHECK_API_PURE(DECLS, VALUE)
+# -------------------------------
+# Make sure Bison reports that `%define api.pure VALUE' is unused when DECLS
+# are specified.
+m4_define([AT_CHECK_API_PURE],
+[
+AT_DATA([[input.y]],
+[[%define api.pure ]$2[
+]$1[
+%%
+start: ;
+]])
+
+AT_BISON_CHECK([[input.y]], [[1]], [],
+[[input.y:1.9-16: %define variable 'api.pure' is not used
+]])
+])
+
+AT_CHECK_API_PURE([[%language "c++" %defines]], [[]])
+AT_CHECK_API_PURE([[%language "c++" %defines]], [[false]])
+AT_CHECK_API_PURE([[%language "c++" %defines %glr-parser]], [[""]])
+AT_CHECK_API_PURE([[%language "c++" %defines %glr-parser]], [[false]])
+AT_CHECK_API_PURE([[%language "java"]], [[true]])
+AT_CHECK_API_PURE([[%language "java"]], [[false]])
+
+AT_CLEANUP
+
+## -------------------------------- ##
+## C++ namespace reference errors. ##
+## -------------------------------- ##
+
+AT_SETUP([[C++ namespace reference errors]])
+
+# AT_CHECK_NAMESPACE_ERROR(NAMESPACE-DECL, ERROR, [ERROR], ...)
+# -------------------------------------------------------------
+# Make sure Bison reports all ERROR's for %define namespace "NAMESPACE-DECL".
+m4_define([AT_CHECK_NAMESPACE_ERROR],
+[
+AT_DATA([[input.y]],
+[[%language "C++"
+%defines
+%define namespace "]$1["
+%%
+start: ;
+]])
+
+AT_BISON_CHECK([[input.y]], [1], [],
+[m4_foreach([b4_arg], m4_dquote(m4_shift($@)),
+[[input.y:3.9-17: ]b4_arg[
+]])])
+])
+
+AT_CHECK_NAMESPACE_ERROR([[]],
+ [[namespace reference is empty]])
+AT_CHECK_NAMESPACE_ERROR([[ ]],
+ [[namespace reference is empty]])
+AT_CHECK_NAMESPACE_ERROR([[foo::::bar]],
+ [[namespace reference has consecutive "::"]])
+AT_CHECK_NAMESPACE_ERROR([[foo:: ::bar]],
+ [[namespace reference has consecutive "::"]])
+AT_CHECK_NAMESPACE_ERROR([[::::bar]],
+ [[namespace reference has consecutive "::"]])
+AT_CHECK_NAMESPACE_ERROR([[:: ::bar]],
+ [[namespace reference has consecutive "::"]])
+AT_CHECK_NAMESPACE_ERROR([[foo::bar:: ::]],
+ [[namespace reference has consecutive "::"]],
+ [[namespace reference has a trailing "::"]])
+AT_CHECK_NAMESPACE_ERROR([[foo::bar::]],
+ [[namespace reference has a trailing "::"]])
+AT_CHECK_NAMESPACE_ERROR([[foo::bar:: ]],
+ [[namespace reference has a trailing "::"]])
+AT_CHECK_NAMESPACE_ERROR([[::]],
+ [[namespace reference has a trailing "::"]])
+
+AT_CLEANUP
+
+## ------------------------ ##
+## Bad character literals. ##
+## ------------------------ ##
+
+# Bison used to accept character literals that were empty or contained
+# too many characters.
+
+# FIXME: AT_DATA or some variant of AT_DATA may eventually permit
+# the final newline to be omitted. See the threads starting at
+# <http://lists.gnu.org/archive/html/bison-patches/2009-07/msg00019.html>.
+
+AT_SETUP([[Bad character literals]])
+
+AT_DATA([empty.y],
+[[%%
+start: '';
+start: '
+]])
+AT_CHECK([[perl -e "print 'start: \'';" >> empty.y || exit 77]])
+
+AT_BISON_CHECK([empty.y], [1], [],
+[[empty.y:2.8-9: warning: empty character literal
+empty.y:3.8-4.0: warning: empty character literal
+empty.y:3.8-4.0: missing "'" at end of line
+empty.y:4.8: warning: empty character literal
+empty.y:4.8: missing "'" at end of file
+]])
+
+AT_DATA([two.y],
+[[%%
+start: 'ab';
+start: 'ab
+]])
+AT_CHECK([[perl -e "print 'start: \'ab';" >> two.y || exit 77]])
+
+AT_BISON_CHECK([two.y], [1], [],
+[[two.y:2.8-11: warning: extra characters in character literal
+two.y:3.8-4.0: warning: extra characters in character literal
+two.y:3.8-4.0: missing "'" at end of line
+two.y:4.8-10: warning: extra characters in character literal
+two.y:4.8-10: missing "'" at end of file
+]])
+
+AT_DATA([three.y],
+[[%%
+start: 'abc';
+start: 'abc
+]])
+AT_CHECK([[perl -e "print 'start: \'abc';" >> three.y || exit 77]])
+
+AT_BISON_CHECK([three.y], [1], [],
+[[three.y:2.8-12: warning: extra characters in character literal
+three.y:3.8-4.0: warning: extra characters in character literal
+three.y:3.8-4.0: missing "'" at end of line
+three.y:4.8-11: warning: extra characters in character literal
+three.y:4.8-11: missing "'" at end of file
+]])
+
+AT_CLEANUP
+
+## ------------------------- ##
+## Bad escapes in literals. ##
+## ------------------------- ##
+
+AT_SETUP([[Bad escapes in literals]])
+
+AT_DATA([input.y],
+[[%%
+start: '\777' '\0' '\xfff' '\x0'
+ '\uffff' '\u0000' '\Uffffffff' '\U00000000'
+ '\ ' '\A';
+]])
+
+# It is not easy to create special characters, we cannot even trust tr.
+# Beside we cannot even expect "echo '\0'" to output two characters
+# (well three with \n): at least Bash 3.2 converts the two-character
+# sequence "\0" into a single NUL character.
+AT_CHECK([[perl -e 'print "start: \"\\\t\\\f\\\0\\\1\" ;";' >> input.y \
+ || exit 77]])
+
+AT_BISON_CHECK([input.y], [1], [],
+[[input.y:2.9-12: invalid number after \-escape: 777
+input.y:2.8-13: warning: empty character literal
+input.y:2.16-17: invalid number after \-escape: 0
+input.y:2.15-18: warning: empty character literal
+input.y:2.21-25: invalid number after \-escape: xfff
+input.y:2.20-26: warning: empty character literal
+input.y:2.29-31: invalid number after \-escape: x0
+input.y:2.28-32: warning: empty character literal
+input.y:3.9-14: invalid number after \-escape: uffff
+input.y:3.8-15: warning: empty character literal
+input.y:3.18-23: invalid number after \-escape: u0000
+input.y:3.17-24: warning: empty character literal
+input.y:3.27-36: invalid number after \-escape: Uffffffff
+input.y:3.26-37: warning: empty character literal
+input.y:3.40-49: invalid number after \-escape: U00000000
+input.y:3.39-50: warning: empty character literal
+input.y:4.9-10: invalid character after \-escape: ' '
+input.y:4.8-11: warning: empty character literal
+input.y:4.14-15: invalid character after \-escape: A
+input.y:4.13-16: warning: empty character literal
+input.y:5.9-16: invalid character after \-escape: \t
+input.y:5.17: invalid character after \-escape: \f
+input.y:5.18: invalid character after \-escape: \0
+input.y:5.19: invalid character after \-escape: \001
+]])
+
+AT_CLEANUP
+
+## ------------------------- ##
+## LAC: Errors for %define. ##
+## ------------------------- ##
+
+AT_SETUP([[LAC: Errors for %define]])
+
+AT_DATA([[input.y]],
+[[%%
+start: ;
+]])
+
+# parse.lac.* options are useless if LAC isn't actually activated.
+AT_BISON_CHECK([[-Dparse.lac.es-capacity-initial=1 input.y]],
+ [[1]], [],
+[[<command line>:2: %define variable 'parse.lac.es-capacity-initial' is not used
+]])
+AT_BISON_CHECK([[-Dparse.lac.memory-trace=full input.y]],
+ [[1]], [],
+[[<command line>:2: %define variable 'parse.lac.memory-trace' is not used
+]])
+
+AT_CLEANUP
+
+## --------------------------------------------- ##
+## -Werror is not affected by -Wnone and -Wall. ##
+## --------------------------------------------- ##
+
+AT_SETUP([[-Werror is not affected by -Wnone and -Wall]])
+
+AT_DATA([[input.y]],
+[[%%
+foo-bar: ;
+]])
+
+# -Werror is not enabled by -Wall or equivalent.
+AT_BISON_CHECK([[-Wall input.y]], [[0]], [[]],
+[[input.y:2.1-7: warning: POSIX Yacc forbids dashes in symbol names: foo-bar
+]])
+AT_BISON_CHECK([[-W input.y]], [[0]], [[]],
+[[input.y:2.1-7: warning: POSIX Yacc forbids dashes in symbol names: foo-bar
+]])
+AT_BISON_CHECK([[-Wno-none input.y]], [[0]], [[]],
+[[input.y:2.1-7: warning: POSIX Yacc forbids dashes in symbol names: foo-bar
+]])
+
+# -Werror is not disabled by -Wnone or equivalent.
+AT_BISON_CHECK([[-Werror,none,yacc input.y]], [[1]], [[]], [[stderr]])
+AT_CHECK([[sed 's/^.*bison:/bison:/' stderr]], [[0]],
+[[bison: warnings being treated as errors
+input.y:2.1-7: warning: POSIX Yacc forbids dashes in symbol names: foo-bar
+]])
+[mv stderr experr]
+AT_BISON_CHECK([[-Werror,no-all,yacc input.y]], [[1]], [[]], [[experr]])