+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