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Also warn about non-used mid-rule values.
* src/symlist.h, src/symlist.c (symbol_list): Add a mid_rule member. (symbol_list_new): Adjust. * src/reader.c (symbol_typed_p): New. (grammar_rule_check): Use it. (grammar_midrule_action): Bind a mid-rule LHS to its rule. Check its rule. * tests/input.at (AT_CHECK_UNUSED_VALUES): New. Use it. * tests/actions.at (Exotic Dollars): Adjust.
This commit is contained in:
Akim Demaille
14
ChangeLog
14
ChangeLog
@@ -1,3 +1,17 @@
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2006-01-04 Akim Demaille <akim@epita.fr>
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Also warn about non-used mid-rule values.
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* src/symlist.h, src/symlist.c (symbol_list): Add a mid_rule
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member.
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(symbol_list_new): Adjust.
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* src/reader.c (symbol_typed_p): New.
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(grammar_rule_check): Use it.
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(grammar_midrule_action): Bind a mid-rule LHS to its rule.
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Check its rule.
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* tests/input.at (AT_CHECK_UNUSED_VALUES): New.
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Use it.
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* tests/actions.at (Exotic Dollars): Adjust.
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2006-01-04 Akim Demaille <akim@epita.fr>
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* src/reader.c (grammar_midrule_action): If $$ is set in a
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11
NEWS
11
NEWS
@@ -26,6 +26,17 @@ Changes in version 2.1a:
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| exp "+" exp { $$ = $1; (void) $3; }
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;
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If there are mid-rule actions, the warning is issued if no action
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uses it. The following triggers no warning: $1 and $3 are used.
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exp: exp { push ($1); } '+' exp { push ($3); sum (); };
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Mid-rule actions that use $$ cause the corresponding value to be
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set, therefore the following action must use it. The following rule
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triggers a warning about $2.
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exp: '1' { $$ = 1; } '+' exp { $$ = $1 + $4; };
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The warning is intended to help catching lost values and memory leaks.
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If a value is ignored, its associated memory typically is not reclaimed.
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26
src/reader.c
26
src/reader.c
@@ -210,6 +210,20 @@ grammar_current_rule_begin (symbol *lhs, location loc)
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}
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/*-----------------------------------------------------------------.
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| A symbol is typed if it has a declared %type, or if it is a |
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| mid-rule symbol (i.e., the generated LHS replacing a mid-rule |
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| action) that was assigned to, as in `exp: { $$ = 1; } { $$ = $1; |
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| }'. |
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`-----------------------------------------------------------------*/
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static bool
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symbol_typed_p (const symbol_list *s)
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{
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return (s->sym->type_name
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|| s->mid_rule && s->mid_rule->used);
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}
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/*----------------------------------------------------------------.
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| Check that the rule R is properly defined. For instance, there |
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| should be no type clash on the default action. |
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@@ -251,7 +265,7 @@ grammar_rule_check (const symbol_list *r)
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int n = 0;
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for (; l && l->sym; l = l->next, ++n)
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if (! (l->used
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|| !l->sym->type_name
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|| !symbol_typed_p (l)
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/* The default action, $$ = $1, `uses' both. */
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|| (!r->action && (n == 0 || n == 1))))
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{
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@@ -318,14 +332,16 @@ grammar_midrule_action (void)
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grammar = midrule;
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/* End the dummy's rule. */
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previous_rule_end = symbol_list_new (NULL, dummy_location);
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previous_rule_end->next = current_rule;
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midrule->next = symbol_list_new (NULL, dummy_location);
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grammar_rule_check (midrule);
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midrule->next->next = current_rule;
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midrule->next = previous_rule_end;
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previous_rule_end = midrule->next;
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/* Insert the dummy nonterminal replacing the midrule action into
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the current rule. */
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the current rule. Bind it to its dedicated rule. */
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grammar_current_rule_symbol_append (dummy, dummy_location);
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grammar_end->mid_rule = midrule;
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}
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/* Set the precedence symbol of the current rule to PRECSYM. */
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@@ -1,6 +1,6 @@
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/* Lists of symbols for Bison
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Copyright (C) 2002, 2005 Free Software Foundation, Inc.
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Copyright (C) 2002, 2005, 2006 Free Software Foundation, Inc.
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This file is part of Bison, the GNU Compiler Compiler.
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@@ -38,6 +38,8 @@ symbol_list_new (symbol *sym, location loc)
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res->sym = sym;
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res->location = loc;
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res->mid_rule = NULL;
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res->action = NULL;
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res->used = false;
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@@ -32,6 +32,10 @@ typedef struct symbol_list
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symbol *sym;
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location location;
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/* If this symbol is the generated lhs for a mid-rule, a pointer to
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that mid-rule. */
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struct symbol_list *mid_rule;
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/* The action is attached to the LHS of a rule. */
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const char *action;
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location action_location;
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@@ -113,6 +113,7 @@ AT_DATA_GRAMMAR([[input.y]],
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exp: a_1 a_2 { $<val>$ = 3; } { $<val>$ = $<val>3 + 1; } a_5
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sum_of_the_five_previous_values
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{
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USE (($1, $2, $<foo>3, $<foo>4, $5));
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printf ("%d\n", $6);
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}
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;
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@@ -146,11 +147,7 @@ main (void)
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}
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]])
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AT_CHECK([bison -d -v -o input.c input.y], 0, [],
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[input.y:30.6-34.5: warning: unused value: $1
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input.y:30.6-34.5: warning: unused value: $2
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input.y:30.6-34.5: warning: unused value: $5
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])
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AT_CHECK([bison -d -v -o input.c input.y], 0)
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AT_COMPILE([input])
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AT_PARSER_CHECK([./input], 0,
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[[15
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@@ -86,51 +86,80 @@ AT_CLEANUP
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## Unused values. ##
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## --------------- ##
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AT_SETUP([Unused values])
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m4_define([AT_CHECK_UNUSED_VALUES],
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[AT_SETUP([Unused values])
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AT_DATA([input.y],
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[[%token <integer> INT
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%type <integer> exp
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%%
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exp:
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INT { } INT { } INT { }
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/* Ideally we would like to complain also about $2 and $4 here, but
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it's hard to implement. */
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| INT { $$ } INT { $$ } INT { }
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| INT { $1 } INT { } INT { }
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| INT { } INT { $1 } INT { }
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| INT { } INT { } INT { $1 }
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| INT { } INT { } INT { $$ = $1 + $3 + $5; }
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$1
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| INT
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;
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]])
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AT_CHECK([bison input.y], [], [],
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[[input.y:5.3-25: warning: unset value: $$
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[[$2]])
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AT_CLEANUP
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])
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AT_CHECK_UNUSED_VALUES([INT { } INT { } INT { }],
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[input.y:5.3-25: warning: unset value: $$
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input.y:5.3-25: warning: unused value: $1
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input.y:5.3-25: warning: unused value: $3
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input.y:5.3-25: warning: unused value: $5
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input.y:8.3-31: warning: unset value: $$
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input.y:8.3-31: warning: unused value: $1
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input.y:8.3-31: warning: unused value: $3
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input.y:8.3-31: warning: unused value: $5
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input.y:9.3-28: warning: unset value: $$
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input.y:9.3-28: warning: unused value: $3
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input.y:9.3-28: warning: unused value: $5
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input.y:10.3-28: warning: unset value: $$
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input.y:10.3-28: warning: unused value: $3
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input.y:10.3-28: warning: unused value: $5
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input.y:11.3-29: warning: unset value: $$
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input.y:11.3-29: warning: unused value: $3
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input.y:11.3-29: warning: unused value: $5
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input.y: conflicts: 1 reduce/reduce
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input.y:8.7-12: warning: rule never reduced because of conflicts: @3: /* empty */
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input.y:9.7-12: warning: rule never reduced because of conflicts: @5: /* empty */
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input.y:10.7-9: warning: rule never reduced because of conflicts: @7: /* empty */
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input.y:11.7-9: warning: rule never reduced because of conflicts: @9: /* empty */
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input.y:12.7-9: warning: rule never reduced because of conflicts: @11: /* empty */
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]])
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])
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AT_CHECK_UNUSED_VALUES([INT { $1 } INT { } INT { }],
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[input.y:5.3-28: warning: unset value: $$
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input.y:5.3-28: warning: unused value: $3
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input.y:5.3-28: warning: unused value: $5
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])
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AT_CHECK_UNUSED_VALUES([INT { } INT { $1 } INT { }],
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[input.y:5.3-28: warning: unset value: $$
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input.y:5.3-28: warning: unused value: $3
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input.y:5.3-28: warning: unused value: $5
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])
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AT_CHECK_UNUSED_VALUES([INT { } INT { } INT { $1 }],
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[input.y:5.3-29: warning: unset value: $$
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input.y:5.3-29: warning: unused value: $3
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input.y:5.3-29: warning: unused value: $5
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])
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AT_CHECK_UNUSED_VALUES([INT { } INT { } INT { $$ = $1 + $3 + $5; }])
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# Checking mid-rule values.
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AT_CHECK_UNUSED_VALUES([INT { $$ } INT { $$ } INT { }],
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[input.y:5.3-31: warning: unset value: $$
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input.y:5.3-31: warning: unused value: $1
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input.y:5.3-31: warning: unused value: $2
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input.y:5.3-31: warning: unused value: $3
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input.y:5.3-31: warning: unused value: $4
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input.y:5.3-31: warning: unused value: $5
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])
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AT_CHECK_UNUSED_VALUES([INT { $$ } INT { $$ = $2 } INT { }],
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[input.y:5.3-36: warning: unset value: $$
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input.y:5.3-36: warning: unused value: $1
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input.y:5.3-36: warning: unused value: $3
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input.y:5.3-36: warning: unused value: $4
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input.y:5.3-36: warning: unused value: $5
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])
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# AT_CHECK_UNUSED_VALUES([INT { $$ } { $$ = $2 } { }],
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# [input.y:5.3-36: warning: unset value: $$
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# input.y:5.3-36: warning: unused value: $1
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# input.y:5.3-36: warning: unused value: $3
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# input.y:5.3-36: warning: unused value: $4
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# input.y:5.3-36: warning: unused value: $5
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# ])
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AT_CHECK_UNUSED_VALUES([INT { $$ = $1 } INT { $$ = $2 + $3 } INT { $$ = $4 + $5 }])
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AT_CLEANUP
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## ---------------------- ##
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