+
+
+## --------- ##
+## Require. ##
+## --------- ##
+
+m4_define([AT_CHECK_REQUIRE],
+[AT_SETUP([Require $1])
+AT_DATA_GRAMMAR([input.y],
+[[%require "$1";
+%%
+empty_file:;
+]])
+AT_CHECK([bison -o input.c input.y], $2, [], ignore)
+AT_CLEANUP
+])
+
+AT_CHECK_REQUIRE(1.0, 0)
+AT_CHECK_REQUIRE(AT_PACKAGE_VERSION, 0)
+## FIXME: Some day augment this version number.
+AT_CHECK_REQUIRE(100.0, 63)
+
+
+## ------------------------------------- ##
+## String aliases for character tokens. ##
+## ------------------------------------- ##
+
+AT_SETUP([String aliases for character tokens])
+
+# Bison once thought a character token and its alias were different symbols
+# with the same user token number.
+
+AT_DATA_GRAMMAR([input.y],
+[[%token 'a' "a"
+%%
+start: 'a';
+%%
+]])
+
+AT_CHECK([bison -o input.c input.y])
+
+AT_CLEANUP
+
+
+## --------------------- ##
+## Unclosed constructs. ##
+## --------------------- ##
+
+AT_SETUP([Unclosed constructs])
+
+# Bison's scan-gram.l once forgot to STRING_FINISH some unclosed constructs, so
+# they were prepended to whatever it STRING_GROW'ed next. It also threw them
+# away rather than returning them to the parser. The effect was confusing
+# subsequent error messages.
+
+AT_DATA([input.y],
+[[%token A "a
+%token B "b"
+%token AB "ab" // Used to complain that "ab" was already used.
+%token C '1
+%token TWO "2"
+%token TICK_TWELVE "'12" // Used to complain that "'12" was already used.
+
+%%
+
+start: ;
+
+// Used to report a syntax error because it didn't see any kind of symbol
+// identifier.
+%type <f> 'a
+;
+%type <f> "a
+;
+// Used to report a syntax error because it didn't see braced code.
+%destructor { free ($$)
+]])
+
+AT_CHECK([bison -o input.c input.y], 1, [],
+[[input.y:1.10-2.0: missing `"' at end of line
+input.y:4.10-5.0: missing `'' at end of line
+input.y:14.11-15.0: missing `'' at end of line
+input.y:16.11-17.0: missing `"' at end of line
+input.y:19.13-20.0: missing `}' at end of file
+input.y:20.1: syntax error, unexpected end of file
+]])
+
+AT_CLEANUP
+
+
+## ------------------------- ##
+## %start after first rule. ##
+## ------------------------- ##
+
+AT_SETUP([%start after first rule])
+
+# Bison once complained that a %start after the first rule was a redeclaration
+# of the start symbol.
+
+AT_DATA([input.y],
+[[%%
+false_start: ;
+start: false_start ;
+%start start;
+]])
+
+AT_CHECK([bison -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_CHECK([bison input.y], [1], [],
+[[input.y:3.1-4: rule given for PREC, which is a token
+]])
+
+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_CHECK([[bison input-c.y]], [0], [],
+[[input-c.y:1.7: warning: %code qualifier `q' is not used
+input-c.y:2.7-9: warning: %code qualifier `bad' is not used
+input-c.y:3.7-9: warning: %code qualifier `bad' is not used
+input-c.y:4.7-12: warning: %code qualifier `format' is not used
+]])
+
+AT_DATA([input-c-glr.y],
+[[%code q {}
+%code bad {}
+ %code bad {}
+%%
+start: ;
+]])
+AT_CHECK([[bison input-c-glr.y]], [0], [],
+[[input-c-glr.y:1.7: warning: %code qualifier `q' is not used
+input-c-glr.y:2.7-9: warning: %code qualifier `bad' is not used
+input-c-glr.y:3.8-10: warning: %code qualifier `bad' is not used
+]])
+
+AT_DATA([input-c++.y],
+[[%code q {}
+%code bad {}
+ %code q {}
+%%
+start: ;
+]])
+AT_CHECK([[bison input-c++.y]], [0], [],
+[[input-c++.y:1.7: warning: %code qualifier `q' is not used
+input-c++.y:2.7-9: warning: %code qualifier `bad' is not used
+input-c++.y:3.8: warning: %code qualifier `q' is not used
+]])
+
+AT_DATA([input-c++-glr.y],
+[[%code bad {}
+%code q {}
+%code q {}
+%%
+start: ;
+]])
+AT_CHECK([[bison input-c++-glr.y]], [0], [],
+[[input-c++-glr.y:1.7-9: warning: %code qualifier `bad' is not used
+input-c++-glr.y:2.7: warning: %code qualifier `q' is not used
+input-c++-glr.y:3.7: warning: %code qualifier `q' is not used
+]])
+
+AT_DATA([special-char-@@.y],
+[[%code bad {}
+%code q {}
+%code q {}
+%%
+start: ;
+]])
+AT_CHECK([[bison special-char-@@.y]], [0], [],
+[[special-char-@@.y:1.7-9: warning: %code qualifier `bad' is not used
+special-char-@@.y:2.7: warning: %code qualifier `q' is not used
+special-char-@@.y:3.7: warning: %code qualifier `q' is not used
+]])
+
+AT_DATA([special-char-@:>@.y],
+[[%code bad {}
+%code q {}
+%code q {}
+%%
+start: ;
+]])
+AT_CHECK([[bison special-char-@:>@.y]], [0], [],
+[[special-char-@:>@.y:1.7-9: warning: %code qualifier `bad' is not used
+special-char-@:>@.y:2.7: warning: %code qualifier `q' is not used
+special-char-@:>@.y:3.7: warning: %code qualifier `q' is not used
+]])
+
+AT_CLEANUP
+
+
+## ---------------- ##
+## %define errors. ##
+## ---------------- ##
+
+AT_SETUP([%define errors])
+
+AT_DATA([input.y],
+[[%define var "value1"
+%define var "value1"
+ %define var "value2"
+%define special1 "@:>@"
+%define special2 "@<:@"
+%%
+start: ;
+]])
+
+AT_CHECK([[bison input.y]], [0], [],
+[[input.y:2.9-11: warning: %define variable `var' redefined
+input.y:1.9-11: warning: previous definition
+input.y:3.10-12: warning: %define variable `var' redefined
+input.y:2.9-11: warning: previous definition
+input.y:1.9-11: warning: %define variable `var' is not used
+input.y:2.9-11: warning: %define variable `var' is not used
+input.y:3.10-12: warning: %define variable `var' is not used
+input.y:4.9-16: warning: %define variable `special1' is not used
+input.y:5.9-16: warning: %define variable `special2' is not used
+]])
+
+AT_CLEANUP
+
+## --------------------------- ##
+## Boolean %define variables. ##
+## --------------------------- ##
+
+AT_SETUP([Boolean %define variables])
+
+AT_DATA([Input.y],
+[[%language "Java"
+%define public "maybe"
+%define parser_class_name "Input"
+%%
+start: ;
+]])
+
+AT_CHECK([[bison Input.y]], [1], [],
+[[Input.y:2.9-14: invalid value for %define boolean variable `public'
+]])
+
+AT_CLEANUP