+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_CHECK([bison 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_CHECK([bison 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 ($$); } <>
+%type <tag> tagged
+
+%%
+
+start: end end tagged tagged { $<tag>1; $3; } ;
+end: { } ;
+tagged: { } ;
+]])
+
+AT_CHECK([bison input.y], [0], [],
+[[input.y:6.8-45: warning: unset value: $$
+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_CHECK([bison 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_CHECK([bison input.y], [0], [],
+[[input.y:6.8-22: warning: unset value: $$
+input.y:6.8-22: warning: unused value: $2
+input.y:7.6-8: warning: unset value: $$
+]])
+