+AT_CHECK_PRINTER_AND_DESTRUCTOR([%glr-parser], [ with union])
+
+
+
+## ----------------------------------------- ##
+## Default tagless %printer and %destructor. ##
+## ----------------------------------------- ##
+
+# Check that the right %printer and %destructor are called, that they're not
+# called for $end, and that $$ and @$ work correctly.
+
+AT_SETUP([Default tagless %printer and %destructor])
+AT_BISON_OPTION_PUSHDEFS([%locations %debug])
+AT_DATA_GRAMMAR([[input.y]],
+[[%define parse.error verbose
+%debug
+%locations
+
+%code {
+]AT_YYLEX_DECLARE[
+]AT_YYERROR_DECLARE[
+# define USE(SYM)
+}
+
+%printer {
+ fprintf (yyoutput, "<*> printer should not be called.\n");
+} <*>
+
+%printer {
+ fprintf (yyoutput, "<> printer for '%c' @ %d", $$, @$.first_column);
+} <>
+%destructor {
+ fprintf (stdout, "<> destructor for '%c' @ %d.\n", $$, @$.first_column);
+} <>
+
+%printer {
+ fprintf (yyoutput, "'b'/'c' printer for '%c' @ %d", $$, @$.first_column);
+} 'b' 'c'
+%destructor {
+ fprintf (stdout, "'b'/'c' destructor for '%c' @ %d.\n", $$, @$.first_column);
+} 'b' 'c'
+
+%destructor {
+ fprintf (yyoutput, "<*> destructor should not be called.\n");
+} <*>
+
+%%
+
+start: 'a' 'b' 'c' 'd' 'e' { $$ = 'S'; USE(($1, $2, $3, $4, $5)); } ;
+
+%%
+]AT_YYERROR_DEFINE[
+]AT_YYLEX_DEFINE(["abcd"], [[yylval = res]])[
+]AT_MAIN_DEFINE[
+]])
+
+AT_BISON_CHECK([-o input.c input.y], [], [],
+[[input.y:30.3-5: warning: useless %destructor for type <*> [-Wother]
+input.y:30.3-5: warning: useless %printer for type <*> [-Wother]
+]])
+AT_COMPILE([input])
+AT_PARSER_CHECK([./input --debug], 1,
+[[<> destructor for 'd' @ 4.
+'b'/'c' destructor for 'c' @ 3.
+'b'/'c' destructor for 'b' @ 2.
+<> destructor for 'a' @ 1.
+]],
+[[Starting parse
+Entering state 0
+Reading a token: Next token is token 'a' (1.1: <> printer for 'a' @ 1)
+Shifting token 'a' (1.1: <> printer for 'a' @ 1)
+Entering state 1
+Reading a token: Next token is token 'b' (1.2: 'b'/'c' printer for 'b' @ 2)
+Shifting token 'b' (1.2: 'b'/'c' printer for 'b' @ 2)
+Entering state 3
+Reading a token: Next token is token 'c' (1.3: 'b'/'c' printer for 'c' @ 3)
+Shifting token 'c' (1.3: 'b'/'c' printer for 'c' @ 3)
+Entering state 5
+Reading a token: Next token is token 'd' (1.4: <> printer for 'd' @ 4)
+Shifting token 'd' (1.4: <> printer for 'd' @ 4)
+Entering state 6
+Reading a token: Now at end of input.
+1.5: syntax error, unexpected $end, expecting 'e'
+Error: popping token 'd' (1.4: <> printer for 'd' @ 4)
+Stack now 0 1 3 5
+Error: popping token 'c' (1.3: 'b'/'c' printer for 'c' @ 3)
+Stack now 0 1 3
+Error: popping token 'b' (1.2: 'b'/'c' printer for 'b' @ 2)
+Stack now 0 1
+Error: popping token 'a' (1.1: <> printer for 'a' @ 1)
+Stack now 0
+Cleanup: discarding lookahead token $end (1.5: )
+Stack now 0
+]])
+
+AT_BISON_OPTION_POPDEFS
+AT_CLEANUP
+
+
+
+## ------------------------------------------------------ ##
+## Default tagged and per-type %printer and %destructor. ##
+## ------------------------------------------------------ ##
+
+AT_SETUP([Default tagged and per-type %printer and %destructor])
+AT_BISON_OPTION_PUSHDEFS([%debug])
+AT_DATA_GRAMMAR([[input.y]],
+[[%define parse.error verbose
+%debug
+
+%{
+]AT_YYERROR_DECLARE[
+]AT_YYLEX_DECLARE[
+# define USE(SYM)
+%}
+
+%printer {
+ fprintf (yyoutput, "<> printer should not be called.\n");
+} <>
+
+%union { int field0; int field1; int field2; }
+%type <field0> start 'a' 'g'
+%type <field1> 'e'
+%type <field2> 'f'
+%printer {
+ fprintf (yyoutput, "<*>/<field2>/e printer");
+} <*> 'e' <field2>
+%destructor {
+ fprintf (stdout, "<*>/<field2>/e destructor.\n");
+} <*> 'e' <field2>
+
+%type <field1> 'b'
+%printer { fprintf (yyoutput, "<field1> printer"); } <field1>
+%destructor { fprintf (stdout, "<field1> destructor.\n"); } <field1>
+
+%type <field0> 'c'
+%printer { fprintf (yyoutput, "'c' printer"); } 'c'
+%destructor { fprintf (stdout, "'c' destructor.\n"); } 'c'
+
+%type <field1> 'd'
+%printer { fprintf (yyoutput, "'d' printer"); } 'd'
+%destructor { fprintf (stdout, "'d' destructor.\n"); } 'd'
+
+%destructor {
+ fprintf (yyoutput, "<> destructor should not be called.\n");
+} <>
+
+%%
+
+start:
+ 'a' 'b' 'c' 'd' 'e' 'f' 'g'
+ {
+ USE(($1, $2, $3, $4, $5, $6, $7));
+ $$ = 'S';
+ }
+ ;
+
+%%
+]AT_YYERROR_DEFINE[
+]AT_YYLEX_DEFINE(["abcdef"])[
+]AT_MAIN_DEFINE[
+]])
+
+AT_BISON_CHECK([-o input.c input.y], [], [],
+[[input.y:22.3-4: warning: useless %destructor for type <> [-Wother]
+input.y:22.3-4: warning: useless %printer for type <> [-Wother]
+]])
+AT_COMPILE([input])
+AT_PARSER_CHECK([./input --debug], 1,
+[[<*>/<field2>/e destructor.
+<*>/<field2>/e destructor.
+'d' destructor.
+'c' destructor.
+<field1> destructor.
+<*>/<field2>/e destructor.
+]],
+[[Starting parse
+Entering state 0
+Reading a token: Next token is token 'a' (<*>/<field2>/e printer)
+Shifting token 'a' (<*>/<field2>/e printer)
+Entering state 1
+Reading a token: Next token is token 'b' (<field1> printer)
+Shifting token 'b' (<field1> printer)
+Entering state 3
+Reading a token: Next token is token 'c' ('c' printer)
+Shifting token 'c' ('c' printer)
+Entering state 5
+Reading a token: Next token is token 'd' ('d' printer)
+Shifting token 'd' ('d' printer)
+Entering state 6
+Reading a token: Next token is token 'e' (<*>/<field2>/e printer)
+Shifting token 'e' (<*>/<field2>/e printer)
+Entering state 7
+Reading a token: Next token is token 'f' (<*>/<field2>/e printer)
+Shifting token 'f' (<*>/<field2>/e printer)
+Entering state 8
+Reading a token: Now at end of input.
+syntax error, unexpected $end, expecting 'g'
+Error: popping token 'f' (<*>/<field2>/e printer)
+Stack now 0 1 3 5 6 7
+Error: popping token 'e' (<*>/<field2>/e printer)
+Stack now 0 1 3 5 6
+Error: popping token 'd' ('d' printer)
+Stack now 0 1 3 5
+Error: popping token 'c' ('c' printer)
+Stack now 0 1 3
+Error: popping token 'b' (<field1> printer)
+Stack now 0 1
+Error: popping token 'a' (<*>/<field2>/e printer)
+Stack now 0
+Cleanup: discarding lookahead token $end ()
+Stack now 0
+]])
+
+AT_BISON_OPTION_POPDEFS
+AT_CLEANUP
+
+
+
+## ------------------------------------------------------------- ##
+## Default %printer and %destructor for user-defined end token. ##
+## ------------------------------------------------------------- ##
+
+AT_SETUP([Default %printer and %destructor for user-defined end token])
+
+# AT_TEST(TYPED)
+# --------------
+m4_pushdef([AT_TEST],
+[m4_if($1, 0,
+ [m4_pushdef([kind], []) m4_pushdef([not_kind], [*])],
+ [m4_pushdef([kind], [*]) m4_pushdef([not_kind], [])])
+
+AT_BISON_OPTION_PUSHDEFS([%locations %debug])
+AT_DATA_GRAMMAR([[input]]$1[[.y]],
+[[%define parse.error verbose
+%debug
+%locations
+
+%code {
+]AT_YYERROR_DECLARE[
+]AT_YYLEX_DECLARE[
+# define USE(SYM)
+}
+
+%destructor {
+ fprintf (yyoutput, "<]]not_kind[[> destructor should not be called.\n");
+} <]]not_kind[[>
+
+%token END 0
+%printer {
+ fprintf (yyoutput, "<]]kind[[> for '%c' @ %d", $$, @$.first_column);
+} <]]kind[[>
+%destructor {
+ fprintf (stdout, "<]]kind[[> for '%c' @ %d.\n", $$, @$.first_column);
+} <]]kind[[>
+
+%printer {
+ fprintf (yyoutput, "<]]not_kind[[> printer should not be called.\n");
+} <]]not_kind[[>
+
+]]m4_if($1, 0, [[[
+]]],
+[[[%union { char tag; }
+%type <tag> start END]]])[[
+
+%%
+
+start: { $$ = 'S'; } ;
+
+%%
+#include <stdlib.h> /* abort */
+static int
+yylex (void)
+{
+ static int called;
+ if (called++)
+ abort ();
+ yylval]]m4_if($1, 0,, [[[.tag]]])[[ = 'E';
+ yylloc.first_line = yylloc.last_line = 1;
+ yylloc.first_column = yylloc.last_column = 1;
+ return 0;
+}
+]AT_YYERROR_DEFINE[
+]AT_MAIN_DEFINE[
+]])
+AT_BISON_OPTION_POPDEFS
+
+AT_BISON_CHECK([-o input$1.c input$1.y], [], [],
+[m4_if([$1], [0],
+[[input0.y:30.3-5: warning: useless %destructor for type <*> [-Wother]
+input0.y:30.3-5: warning: useless %printer for type <*> [-Wother]
+]],
+[[input1.y:30.3-4: warning: useless %destructor for type <> [-Wother]
+input1.y:30.3-4: warning: useless %printer for type <> [-Wother]
+]])])
+
+AT_COMPILE([input$1])
+
+AT_PARSER_CHECK([./input$1 --debug], 0,
+[[<]]kind[[> for 'E' @ 1.
+<]]kind[[> for 'S' @ 1.
+]],
+[[Starting parse
+Entering state 0
+Reducing stack by rule 1 (line 49):
+-> $$ = nterm start (1.1: <]]kind[[> for 'S' @ 1)
+Stack now 0
+Entering state 1
+Reading a token: Now at end of input.
+Shifting token END (1.1: <]]kind[[> for 'E' @ 1)
+Entering state 2
+Stack now 0 1 2
+Cleanup: popping token END (1.1: <]]kind[[> for 'E' @ 1)
+Cleanup: popping nterm start (1.1: <]]kind[[> for 'S' @ 1)
+]])
+
+m4_popdef([kind])
+m4_popdef([not_kind])
+])
+
+AT_TEST(0)
+AT_TEST(1)
+
+m4_popdef([AT_TEST])
+
+AT_CLEANUP
+
+
+
+## ------------------------------------------------------------------ ##
+## Default %printer and %destructor are not for error or $undefined. ##
+## ------------------------------------------------------------------ ##
+
+AT_SETUP([Default %printer and %destructor are not for error or $undefined])
+
+# If Bison were to apply the default %printer and %destructor to the error
+# token or to $undefined:
+# - For the error token:
+# - It would generate warnings for unused $n.
+# - It would invoke the %printer and %destructor on the error token's
+# semantic value, which would be initialized from the lookahead, which
+# would be destroyed separately.
+# - For $undefined, who knows what the semantic value would be.
+AT_BISON_OPTION_PUSHDEFS([%debug])
+AT_DATA_GRAMMAR([[input.y]],
+[[%debug
+
+%{
+# include <stdio.h>
+# include <stdlib.h>
+]AT_YYERROR_DECLARE[
+]AT_YYLEX_DECLARE[
+# define USE(SYM)
+%}
+
+%printer {
+ fprintf (yyoutput, "'%c'", $$);
+} <> <*>
+%destructor {
+ fprintf (stderr, "DESTROY '%c'\n", $$);
+} <> <*>
+
+%%
+
+start:
+ { $$ = 'S'; }
+ /* In order to reveal the problems that this bug caused during parsing, add
+ * $2 to USE. */
+ | 'a' error 'b' 'c' { USE(($1, $3, $4)); $$ = 'S'; }
+ ;
+
+%%
+]AT_YYERROR_DEFINE[
+]AT_YYLEX_DEFINE(["abd"], [yylval = res])[
+]AT_MAIN_DEFINE[
+]])
+AT_BISON_OPTION_POPDEFS
+
+AT_BISON_CHECK([-o input.c input.y], [], [],
+[[input.y:23.6-8: warning: useless %destructor for type <*> [-Wother]
+input.y:23.6-8: warning: useless %printer for type <*> [-Wother]
+]])
+AT_COMPILE([input])
+AT_PARSER_CHECK([./input --debug], [1], [],
+[[Starting parse
+Entering state 0
+Reading a token: Next token is token 'a' ('a')
+Shifting token 'a' ('a')
+Entering state 1
+Reading a token: Next token is token 'b' ('b')
+syntax error
+Shifting token error ()
+Entering state 3
+Next token is token 'b' ('b')
+Shifting token 'b' ('b')
+Entering state 5
+Reading a token: Next token is token $undefined ()
+Error: popping token 'b' ('b')
+DESTROY 'b'
+Stack now 0 1 3
+Error: popping token error ()
+Stack now 0 1
+Shifting token error ()
+Entering state 3
+Next token is token $undefined ()
+Error: discarding token $undefined ()
+Error: popping token error ()
+Stack now 0 1
+Shifting token error ()
+Entering state 3
+Reading a token: Now at end of input.
+Cleanup: discarding lookahead token $end ()
+Stack now 0 1 3
+Cleanup: popping token error ()
+Cleanup: popping token 'a' ('a')
+DESTROY 'a'
+]])
+
+AT_CLEANUP
+
+
+
+## ------------------------------------------------------ ##
+## Default %printer and %destructor are not for $accept. ##
+## ------------------------------------------------------ ##
+
+AT_SETUP([Default %printer and %destructor are not for $accept])
+
+# If YYSTYPE is a union and Bison were to apply the default %printer and
+# %destructor to $accept:
+# - The %printer and %destructor code generated for $accept would always be
+# dead code because $accept is currently never shifted onto the stack.
+# - $$ for $accept would always be of type YYSTYPE because it's not possible
+# to declare '%type <field> $accept'. (Also true for $undefined.)
+# - Thus, the compiler might complain that the user code assumes the wrong
+# type for $$ since the code might assume the type associated with a
+# specific union field, which is especially reasonable in C++ since that
+# type may be a base type. This test case checks for this problem. (Also
+# true for $undefined and the error token, so there are three warnings for
+# %printer and three for %destructor.)
+
+AT_BISON_OPTION_PUSHDEFS([%debug])
+AT_DATA_GRAMMAR([[input.y]],
+[[%debug /* So that %printer is actually compiled. */
+
+%{
+# include <stdio.h>
+# include <stdlib.h>
+]AT_YYERROR_DECLARE[
+]AT_YYLEX_DECLARE[
+# define USE(SYM)
+%}
+
+%printer {
+ char chr = $$;
+ fprintf (yyoutput, "'%c'", chr);
+} <> <*>
+%destructor {
+ char chr = $$;
+ fprintf (stderr, "DESTROY '%c'\n", chr);
+} <> <*>
+
+%union { char chr; }
+%type <chr> start
+
+%%
+
+start: { USE($$); } ;
+
+%%
+]AT_YYERROR_DEFINE[
+]AT_YYLEX_DEFINE[
+]AT_MAIN_DEFINE[
+]])
+AT_BISON_OPTION_POPDEFS
+
+AT_BISON_CHECK([-o input.c input.y], [], [],
+[[input.y:24.3-4: warning: useless %destructor for type <> [-Wother]
+input.y:24.3-4: warning: useless %printer for type <> [-Wother]
+]])
+AT_COMPILE([input])
+
+AT_CLEANUP
+
+
+
+## ------------------------------------------------------ ##
+## Default %printer and %destructor for mid-rule values. ##
+## ------------------------------------------------------ ##
+
+AT_SETUP([Default %printer and %destructor for mid-rule values])
+
+AT_BISON_OPTION_PUSHDEFS([%debug])
+AT_DATA_GRAMMAR([[input.y]],
+[[%debug /* So that %printer is actually compiled. */
+
+%{
+]AT_YYERROR_DECLARE[
+]AT_YYLEX_DECLARE[
+# define USE(SYM)
+# define YYLTYPE int
+# define YYLLOC_DEFAULT(Current, Rhs, N) (void)(Rhs)
+# define LOCATION_PRINT(File, Loc)
+%}
+
+%printer { fprintf (yyoutput, "%d", @$); } <>
+%destructor { fprintf (stderr, "DESTROY %d\n", @$); } <>
+%printer { fprintf (yyoutput, "<*> printer should not be called"); } <*>
+%destructor { fprintf (yyoutput, "<*> destructor should not be called"); } <*>
+
+%%
+
+start:
+ { @$ = 1; } // Not set or used.
+ { USE ($$); @$ = 2; } // Both set and used.
+ { USE ($$); @$ = 3; } // Only set.
+ { @$ = 4; } // Only used.
+ 'c'
+ { USE (($$, $2, $4, $5)); @$ = 0; }
+ ;
+
+%%
+]AT_YYERROR_DEFINE[
+]AT_YYLEX_DEFINE[
+]AT_MAIN_DEFINE[
+]])
+AT_BISON_OPTION_POPDEFS
+
+AT_BISON_CHECK([-o input.c input.y], 0,,
+[[input.y:24.70-72: warning: useless %destructor for type <*> [-Wother]
+input.y:24.70-72: warning: useless %printer for type <*> [-Wother]
+input.y:33.3-23: warning: unset value: $$ [-Wother]
+input.y:32.3-23: warning: unused value: $3 [-Wother]
+]])
+
+AT_BISON_CHECK([-fcaret -o input.c input.y], 0,,
+[[input.y:24.70-72: warning: useless %destructor for type <*> [-Wother]
+ %printer { fprintf (yyoutput, "<*> printer should not be called"); } <*>
+ ^^^
+input.y:24.70-72: warning: useless %printer for type <*> [-Wother]
+ %printer { fprintf (yyoutput, "<*> printer should not be called"); } <*>
+ ^^^
+input.y:33.3-23: warning: unset value: $$ [-Wother]
+ { @$ = 4; } // Only used.
+ ^^^^^^^^^^^^^^^^^^^^^
+input.y:32.3-23: warning: unused value: $3 [-Wother]
+ { USE ($$); @$ = 3; } // Only set.
+ ^^^^^^^^^^^^^^^^^^^^^
+]])
+
+AT_COMPILE([input])
+AT_PARSER_CHECK([./input --debug], 1,,
+[[Starting parse
+Entering state 0
+Reducing stack by rule 1 (line 30):
+-> $$ = nterm $@1 (: )
+Stack now 0
+Entering state 2
+Reducing stack by rule 2 (line 31):
+-> $$ = nterm @2 (: 2)
+Stack now 0 2
+Entering state 4
+Reducing stack by rule 3 (line 32):
+-> $$ = nterm @3 (: 3)
+Stack now 0 2 4
+Entering state 5
+Reducing stack by rule 4 (line 33):
+-> $$ = nterm @4 (: 4)
+Stack now 0 2 4 5
+Entering state 6
+Reading a token: Now at end of input.
+syntax error
+Error: popping nterm @4 (: 4)
+DESTROY 4
+Stack now 0 2 4 5
+Error: popping nterm @3 (: 3)
+DESTROY 3
+Stack now 0 2 4
+Error: popping nterm @2 (: 2)
+DESTROY 2
+Stack now 0 2
+Error: popping nterm $@1 (: )
+Stack now 0
+Cleanup: discarding lookahead token $end (: )
+Stack now 0
+]])
+
+AT_CLEANUP
+
+
+## ----------------------- ##
+## @$ implies %locations. ##
+## ----------------------- ##
+
+# Bison once forgot to check for @$ in actions other than semantic actions.
+
+# AT_CHECK_ACTION_LOCATIONS(ACTION-DIRECTIVE)
+# -------------------------------------------
+m4_define([AT_CHECK_ACTION_LOCATIONS],
+[AT_SETUP([[@$ in ]$1[ implies %locations]])
+AT_BISON_OPTION_PUSHDEFS([%debug])
+AT_DATA_GRAMMAR([[input.y]],
+[[%code {
+ #include <stdio.h>
+]AT_YYERROR_DECLARE[
+]AT_YYLEX_DECLARE[
+}
+
+%debug
+
+]$1[ {
+ fprintf (stderr, "%d\n", @$.first_line);
+} ]m4_if($1, [%initial-action], [], [[start]])[
+
+%%
+
+start: ;
+
+%%
+
+static int
+yylex (void)
+{
+ return 0;
+}
+
+]AT_YYERROR_DEFINE[
+]AT_MAIN_DEFINE[
+]])
+
+AT_BISON_CHECK([[-o input.c input.y]])
+AT_COMPILE([[input]])
+AT_BISON_OPTION_POPDEFS
+AT_CLEANUP])
+
+AT_CHECK_ACTION_LOCATIONS([[%initial-action]])
+AT_CHECK_ACTION_LOCATIONS([[%destructor]])
+AT_CHECK_ACTION_LOCATIONS([[%printer]])
+
+
+## ------------------------- ##
+## Qualified $$ in actions. ##
+## ------------------------- ##
+
+# Check that we can use qualified $$ (v.g., $<type>$) not only in rule
+# actions, but also where $$ is valid: %destructor/%printer and
+# %initial-action.
+#
+# FIXME: Not actually checking %destructor, but it's the same code as
+# %printer...
+#
+# To do that, use a semantic value that has two fields (sem_type),
+# declare symbols to have only one of these types (INT, float), and
+# use $<type>$ to get the other one. Including for symbols that are
+# not typed (UNTYPED).
+
+m4_pushdef([AT_TEST],
+[AT_SETUP([[Qualified $$ in actions: $1]])
+
+AT_BISON_OPTION_PUSHDEFS([%skeleton "$1" %debug])
+
+AT_DATA_GRAMMAR([[input.y]],
+[[%skeleton "$1"
+%debug
+%code requires
+{
+ typedef struct sem_type
+ {
+ int ival;
+ float fval;
+ } sem_type;
+
+# define YYSTYPE sem_type
+
+]AT_SKEL_CC_IF([[
+# include <iostream>
+ static void
+ report (std::ostream& yyo, int ival, float fval)
+ {
+ yyo << "ival: " << ival << ", fval: " << fval;
+ }
+]], [[
+# include <stdio.h>
+ static void
+ report (FILE* yyo, int ival, float fval)
+ {
+ fprintf (yyo, "ival: %d, fval: %1.1f", ival, fval);
+ }
+]])[
+}
+
+%code
+{
+ ]AT_YYERROR_DECLARE[
+ ]AT_YYLEX_DECLARE[
+}
+
+%token UNTYPED
+%token <ival> INT
+%type <fval> float
+%printer { report (yyo, $$, $<fval>$); } <ival>;
+%printer { report (yyo, $<ival>$, $$ ); } <fval>;
+%printer { report (yyo, $<ival>$, $<fval>$); } <>;
+
+%initial-action
+{
+ $<ival>$ = 42;
+ $<fval>$ = 4.2;
+}
+
+%%
+float: UNTYPED INT
+{
+ $$ = $<fval>1 + $<fval>2;
+ $<ival>$ = $<ival>1 + $][2;
+};
+%%
+]AT_YYERROR_DEFINE[
+]AT_YYLEX_DEFINE(AT_SKEL_CC_IF([[{yy::parser::token::UNTYPED,
+ yy::parser::token::INT,
+ EOF}]],
+ [[{UNTYPED, INT, EOF}]]),
+ [AT_VAL.ival = toknum * 10; AT_VAL.fval = toknum / 10.0;])[
+]AT_MAIN_DEFINE[
+]])
+
+AT_FULL_COMPILE([[input]])
+AT_PARSER_CHECK([./input --debug], 0, [], [stderr])
+# Don't be too picky on the traces, GLR is not exactly the same. Keep
+# only the lines from the printer.
+AT_CHECK([[sed -ne '/ival:/p' stderr]], 0,
+[[Reading a token: Next token is token UNTYPED (ival: 10, fval: 0.1)
+Shifting token UNTYPED (ival: 10, fval: 0.1)
+Reading a token: Next token is token INT (ival: 20, fval: 0.2)
+Shifting token INT (ival: 20, fval: 0.2)
+ $][1 = token UNTYPED (ival: 10, fval: 0.1)
+ $][2 = token INT (ival: 20, fval: 0.2)
+-> $$ = nterm float (ival: 30, fval: 0.3)
+Cleanup: popping nterm float (ival: 30, fval: 0.3)
+]])
+
+AT_BISON_OPTION_POPDEFS
+
+AT_CLEANUP
+])
+
+AT_TEST([yacc.c])
+AT_TEST([glr.c])
+AT_TEST([lalr1.cc])
+AT_TEST([glr.cc])
+
+m4_popdef([AT_TEST])
+
+## -------------------------------------------------- ##
+## Destroying lookahead assigned by semantic action. ##
+## -------------------------------------------------- ##
+
+AT_SETUP([[Destroying lookahead assigned by semantic action]])
+
+AT_BISON_OPTION_PUSHDEFS
+AT_DATA_GRAMMAR([input.y],
+[[
+%code {
+ #include <assert.h>
+ #include <stdio.h>
+]AT_YYERROR_DECLARE[
+]AT_YYLEX_DECLARE[
+ #define USE(Var)
+}
+
+%destructor { fprintf (stderr, "'a' destructor\n"); } 'a'
+%destructor { fprintf (stderr, "'b' destructor\n"); } 'b'
+
+%%
+
+// In a previous version of Bison, yychar assigned by the semantic
+// action below was not translated into yytoken before the lookahead was
+// discarded and thus before its destructor (selected according to
+// yytoken) was called in order to return from yyparse. This would
+// happen even if YYACCEPT was performed in a later semantic action as
+// long as only consistent states with default reductions were visited
+// in between. However, we leave YYACCEPT in the same semantic action
+// for this test in order to show that skeletons cannot simply translate
+// immediately after every semantic action because a semantic action
+// that has set yychar might not always return normally. Instead,
+// skeletons must translate before every use of yytoken.
+start: 'a' accept { USE($1); } ;
+accept: %empty {
+ assert (yychar == YYEMPTY);
+ yychar = 'b';
+ YYACCEPT;
+} ;
+
+%%
+]AT_YYERROR_DEFINE[
+]AT_YYLEX_DEFINE(["a"])[
+]AT_MAIN_DEFINE[
+]])
+AT_BISON_OPTION_POPDEFS
+AT_BISON_CHECK([[-o input.c input.y]])
+AT_COMPILE([[input]])
+AT_PARSER_CHECK([[./input]], [[0]], [],
+[['b' destructor
+'a' destructor
+]])
+
+AT_CLEANUP
+
+## ---------- ##
+## YYBACKUP. ##
+## ---------- ##
+
+AT_SETUP([[YYBACKUP]])
+
+AT_BISON_OPTION_PUSHDEFS([%pure-parser %debug])
+
+AT_DATA_GRAMMAR([input.y],
+[[
+%error-verbose
+%debug
+%pure-parser
+%code {
+# include <stdio.h>
+# include <stdlib.h>
+# include <assert.h>
+
+ ]AT_YYERROR_DECLARE[
+ ]AT_YYLEX_DECLARE[
+}
+%%
+input:
+ exp exp {}
+;
+
+exp:
+ 'a' { printf ("a: %d\n", $1); }
+| 'b' { YYBACKUP('a', 123); }
+| 'c' 'd' { YYBACKUP('a', 456); }
+;
+
+%%
+]AT_YYERROR_DEFINE[
+]AT_YYLEX_DEFINE(["bcd"], [*lvalp = (toknum + 1) * 10])[
+]AT_MAIN_DEFINE[
+]])
+AT_BISON_OPTION_POPDEFS
+
+AT_BISON_CHECK([[-o input.c input.y]])
+AT_COMPILE([[input]])
+AT_PARSER_CHECK([[./input]], [[0]],
+[[a: 123
+a: 456
+]])
+
+AT_CLEANUP