+AT_SETUP([Invalid $n and @n])
+
+AT_DATA([input.y],
+[[%%
+exp: { $$ = $1 ; };
+exp: { @$ = @1 ; };
+]])
+
+AT_BISON_CHECK([input.y], [1], [],
+[[input.y:2.13-14: integer out of range: `$1'
+input.y:3.13-14: integer out of range: `@1'
+]])
+
+AT_CLEANUP
+
+
+## -------------- ##
+## Type Clashes. ##
+## -------------- ##
+
+AT_SETUP([Type Clashes])
+
+AT_DATA([input.y],
+[[%union { int bar; }
+%token foo
+%type <bar> exp
+%%
+exp: foo { $$; } foo { $2; } foo
+ | foo
+ | /* Empty. */
+ ;
+]])
+
+AT_BISON_CHECK([input.y], [1], [],
+[[input.y:5.12-13: $$ for the midrule at $2 of `exp' has no declared type
+input.y:5.24-25: $2 of `exp' has no declared type
+input.y:5.6-32: warning: type clash on default action: <bar> != <>
+input.y:6.6-8: warning: type clash on default action: <bar> != <>
+input.y:7.5: warning: empty rule for typed nonterminal, and no action
+]])
+
+AT_CLEANUP
+
+
+# _AT_UNUSED_VALUES_DECLARATIONS()
+# --------------------------------
+# Generate the token, type, and destructor
+# declarations for the unused values tests.
+m4_define([_AT_UNUSED_VALUES_DECLARATIONS],
+[[[%token <integer> INT;
+%type <integer> a b c d e f g h i j k l;
+%destructor { destroy ($$); } INT a b c d e f g h i j k l;]]])
+
+
+# AT_CHECK_UNUSED_VALUES(DECLARATIONS_AFTER, CHECK_MIDRULE_VALUES)
+# ----------------------------------------------------------------
+# Generate a grammar to test unused values, compile it, run it. If
+# DECLARATIONS_AFTER is set, then the token, type, and destructor
+# declarations are generated after the rules rather than before. If
+# CHECK_MIDRULE_VALUES is set, then --warnings=midrule-values is set.
+m4_define([AT_CHECK_UNUSED_VALUES],
+[AT_DATA([input.y],
+m4_ifval($1, [
+
+
+], [_AT_UNUSED_VALUES_DECLARATIONS
+])[[%%
+start:
+ 'a' a { $]2[; } | 'b' b { $]2[; } | 'c' c { $]2[; } | 'd' d { $]2[; }
+| 'e' e { $]2[; } | 'f' f { $]2[; } | 'g' g { $]2[; } | 'h' h { $]2[; }
+| 'i' i { $]2[; } | 'j' j { $]2[; } | 'k' k { $]2[; } | 'l' l { $]2[; }
+;
+
+a: INT | INT { } INT { } INT { };
+b: INT | /* empty */;
+c: INT | INT { $]1[; } INT { $<integer>2; } INT { $<integer>4; };
+d: INT | INT { } INT { $]1[; } INT { $<integer>2; };
+e: INT | INT { } INT { } INT { $]1[; };
+f: INT | INT { } INT { } INT { $]$[ = $]1[ + $]3[ + $]5[; };
+g: INT | INT { $<integer>$; } INT { $<integer>$; } INT { };
+h: INT | INT { $<integer>$; } INT { $<integer>$ = $<integer>2; } INT { };
+i: INT | INT INT { } { $]$[ = $]1[ + $]2[; };
+j: INT | INT INT { $<integer>$ = 1; } { $]$[ = $]1[ + $]2[; };
+k: INT | INT INT { $<integer>$; } { $<integer>$ = $<integer>3; } { };
+l: INT | INT { $<integer>$ = $<integer>1; } INT { $<integer>$ = $<integer>2 + $<integer>3; } INT { $<integer>$ = $<integer>4 + $<integer>5; };]]m4_ifval($1, [
+_AT_UNUSED_VALUES_DECLARATIONS])
+)
+
+AT_BISON_CHECK(m4_ifval($2, [ --warnings=midrule-values ])[ input.y], [0], [],
+[[input.y:11.10-32: warning: unset value: $]$[
+input.y:11.10-32: warning: unused value: $]1[
+input.y:11.10-32: warning: unused value: $]3[
+input.y:11.10-32: warning: unused value: $]5[
+input.y:12.9: warning: empty rule for typed nonterminal, and no action
+]]m4_ifval($2, [[[input.y:13.14-20: warning: unset value: $$
+input.y:13.26-41: warning: unset value: $$
+]]])[[input.y:13.10-62: warning: unset value: $]$[
+input.y:13.10-62: warning: unused value: $]3[
+input.y:13.10-62: warning: unused value: $]5[
+]]m4_ifval($2, [[[input.y:14.14-16: warning: unset value: $$
+]]])[[input.y:14.10-49: warning: unset value: $]$[
+input.y:14.10-49: warning: unused value: $]3[
+input.y:14.10-49: warning: unused value: $]5[
+input.y:15.10-37: warning: unset value: $]$[
+input.y:15.10-37: warning: unused value: $]3[
+input.y:15.10-37: warning: unused value: $]5[
+input.y:17.10-58: warning: unset value: $]$[
+input.y:17.10-58: warning: unused value: $]1[
+]]m4_ifval($2, [[[input.y:17.10-58: warning: unused value: $]2[
+]]])[[input.y:17.10-58: warning: unused value: $]3[
+]]m4_ifval($2, [[[input.y:17.10-58: warning: unused value: $]4[
+]]])[[input.y:17.10-58: warning: unused value: $]5[
+input.y:18.10-72: warning: unset value: $]$[
+input.y:18.10-72: warning: unused value: $]1[
+input.y:18.10-72: warning: unused value: $]3[
+]]m4_ifval($2, [[[input.y:18.10-72: warning: unused value: $]4[
+]]])[[input.y:18.10-72: warning: unused value: $]5[
+]]m4_ifval($2, [[[input.y:20.10-55: warning: unused value: $]3[
+]]])[[input.y:21.10-68: warning: unset value: $]$[
+input.y:21.10-68: warning: unused value: $]1[
+input.y:21.10-68: warning: unused value: $]2[
+]]m4_ifval($2, [[[input.y:21.10-68: warning: unused value: $]4[
+]]]))])
+
+
+## --------------- ##
+## Unused values. ##
+## --------------- ##
+
+AT_SETUP([Unused values])
+AT_CHECK_UNUSED_VALUES
+AT_CHECK_UNUSED_VALUES(, [1])
+AT_CLEANUP
+
+
+## ------------------------------------------ ##
+## Unused values before symbol declarations. ##
+## ------------------------------------------ ##
+
+AT_SETUP([Unused values before symbol declarations])
+AT_CHECK_UNUSED_VALUES([1])
+AT_CHECK_UNUSED_VALUES([1], [1])
+AT_CLEANUP
+
+
+## --------------------------------------------- ##
+## Default %printer and %destructor redeclared. ##
+## --------------------------------------------- ##
+
+AT_SETUP([Default %printer and %destructor redeclared])
+
+AT_DATA([[input.y]],
+[[%destructor { destroy ($$); } <*> <*>
+%printer { destroy ($$); } <*> <*>
+
+%destructor { destroy ($$); } <*>
+%printer { destroy ($$); } <*>
+
+%destructor { destroy ($$); } <> <>
+%printer { destroy ($$); } <> <>
+
+%destructor { destroy ($$); } <>
+%printer { destroy ($$); } <>
+
+%%
+
+start: ;
+
+%destructor { destroy ($$); } <*>;
+%printer { destroy ($$); } <*>;
+
+%destructor { destroy ($$); } <>;
+%printer { destroy ($$); } <>;
+]])
+
+AT_BISON_CHECK([input.y], [1], [],
+[[input.y:1.13-29: redeclaration for default tagged %destructor
+input.y:1.13-29: previous declaration
+input.y:2.10-26: redeclaration for default tagged %printer
+input.y:2.10-26: previous declaration
+input.y:4.13-29: redeclaration for default tagged %destructor
+input.y:1.13-29: previous declaration
+input.y:5.10-26: redeclaration for default tagged %printer
+input.y:2.10-26: previous declaration
+input.y:7.13-29: redeclaration for default tagless %destructor
+input.y:7.13-29: previous declaration
+input.y:8.10-26: redeclaration for default tagless %printer
+input.y:8.10-26: previous declaration
+input.y:10.13-29: redeclaration for default tagless %destructor
+input.y:7.13-29: previous declaration
+input.y:11.10-26: redeclaration for default tagless %printer
+input.y:8.10-26: previous declaration
+input.y:17.13-29: redeclaration for default tagged %destructor
+input.y:4.13-29: previous declaration
+input.y:18.10-26: redeclaration for default tagged %printer
+input.y:5.10-26: previous declaration
+input.y:20.13-29: redeclaration for default tagless %destructor
+input.y:10.13-29: previous declaration
+input.y:21.10-26: redeclaration for default tagless %printer
+input.y:11.10-26: previous declaration
+]])
+
+AT_CLEANUP
+
+
+## ---------------------------------------------- ##
+## Per-type %printer and %destructor redeclared. ##
+## ---------------------------------------------- ##
+
+AT_SETUP([Per-type %printer and %destructor redeclared])
+
+AT_DATA([[input.y]],
+[[%destructor { destroy ($$); } <field1> <field2>
+%printer { destroy ($$); } <field1> <field2>
+
+%destructor { destroy ($$); } <field1> <field1>
+%printer { destroy ($$); } <field2> <field2>
+
+%%
+
+start: ;
+
+%destructor { destroy ($$); } <field2> <field1>;
+%printer { destroy ($$); } <field2> <field1>;
+]])
+
+AT_BISON_CHECK([input.y], [1], [],
+[[input.y:4.13-29: %destructor redeclaration for <field1>
+input.y:1.13-29: previous declaration
+input.y:4.13-29: %destructor redeclaration for <field1>
+input.y:4.13-29: previous declaration
+input.y:5.10-26: %printer redeclaration for <field2>
+input.y:2.10-26: previous declaration
+input.y:5.10-26: %printer redeclaration for <field2>
+input.y:5.10-26: previous declaration
+input.y:11.13-29: %destructor redeclaration for <field1>
+input.y:4.13-29: previous declaration
+input.y:11.13-29: %destructor redeclaration for <field2>
+input.y:1.13-29: previous declaration
+input.y:12.10-26: %printer redeclaration for <field1>
+input.y:2.10-26: previous declaration
+input.y:12.10-26: %printer redeclaration for <field2>
+input.y:5.10-26: previous declaration
+]])
+
+AT_CLEANUP
+
+
+## ---------------------------------------- ##
+## Unused values with default %destructor. ##
+## ---------------------------------------- ##
+
+AT_SETUP([Unused values with default %destructor])
+
+AT_DATA([[input.y]],
+[[%destructor { destroy ($$); } <>
+%type <tag> tagged
+
+%%
+
+start: end end tagged tagged { $<tag>1; $3; } ;
+end: { } ;
+tagged: { } ;
+]])
+
+AT_BISON_CHECK([input.y], [0], [],
+[[input.y:6.8-45: warning: unset value: $$
+input.y:6.8-45: warning: unused value: $2
+input.y:7.6-8: warning: unset value: $$
+]])
+
+AT_DATA([[input.y]],
+[[%destructor { destroy ($$); } <*>
+%type <tag> tagged
+
+%%
+
+start: end end tagged tagged { $<tag>1; $3; } ;
+end: { } ;
+tagged: { } ;
+]])
+
+AT_BISON_CHECK([input.y], [0], [],
+[[input.y:6.8-45: warning: unused value: $4
+input.y:8.9-11: warning: unset value: $$
+]])
+
+AT_CLEANUP
+
+
+## ----------------------------------------- ##
+## Unused values with per-type %destructor. ##
+## ----------------------------------------- ##
+
+AT_SETUP([Unused values with per-type %destructor])
+
+AT_DATA([[input.y]],
+[[%destructor { destroy ($$); } <field1>
+%type <field1> start end
+
+%%
+
+start: end end { $1; } ;
+end: { } ;
+]])
+
+AT_BISON_CHECK([input.y], [0], [],
+[[input.y:6.8-22: warning: unset value: $$
+input.y:6.8-22: warning: unused value: $2
+input.y:7.6-8: warning: unset value: $$
+]])
+
+AT_CLEANUP
+
+
+## ---------------------- ##
+## Incompatible Aliases. ##
+## ---------------------- ##
+
+AT_SETUP([Incompatible Aliases])
+
+AT_DATA([input.y],
+[[%token foo "foo"
+
+%type <bar> foo
+%printer {bar} foo
+%destructor {bar} foo
+%left foo
+
+%type <baz> "foo"
+%printer {baz} "foo"
+%destructor {baz} "foo"
+%left "foo"
+
+%%
+exp: foo;
+]])
+
+AT_BISON_CHECK([input.y], [1], [],
+[[input.y:8.7-11: %type redeclaration for foo
+input.y:3.7-11: previous declaration
+input.y:10.13-17: %destructor redeclaration for foo
+input.y:5.13-17: previous declaration
+input.y:9.10-14: %printer redeclaration for foo
+input.y:4.10-14: previous declaration
+input.y:11.1-5: %left redeclaration for foo
+input.y:6.1-5: previous declaration
+]])
+
+AT_CLEANUP
+
+
+
+## ----------------------- ##
+## Torturing the Scanner. ##
+## ----------------------- ##
+
+# Be sure to compile and run, so that the C compiler checks what
+# we do.
+
+AT_SETUP([Torturing the Scanner])
+
+
+AT_DATA([input.y], [])
+AT_BISON_CHECK([input.y], [1], [],
+[[input.y:1.1: syntax error, unexpected end of file
+]])