gcc - GNU Compiler Collection (original) (raw)

author	Marek Polacek polacek@redhat.com	2026-03-20 12:34:31 -0400
committer	Marek Polacek polacek@redhat.com	2026-04-09 14:22:13 -0400
commit	c684613dea0b00d222ebbae8439ea8fd8c1f1865 (patch)
tree	da7d4c8f95e4072d59c40dbd7e93cd2971c775b5
parent	fortran: Diagnose invalid array initializer after parameter substitution [PR1... (diff)

c++/reflection: reject invalid template splice [PR123998]HEAD trunk master

When we have "template [:R:]" without template arguments, the splice has to designate a function template. E.g., void foo (int); template [: ^^foo :] (0); // invalid We check this in cp_parser_splice_expression. But when the splice is dependent, we don't check it when instantiating, thus missing the error in template [: N == 0 ? ^^foo : ^^:: :] (0); This patch introduces SPLICE_EXPR_TEMPLATE_P and SPLICE_EXPR_TARGS_P, and moves the checking into check_splice_expr. It also adds a missing check for DECL_TYPE_TEMPLATE_P in case we have a splice-expression of the form template splice-specialization-specifier. PR c++/123998 gcc/cp/ChangeLog: * cp-tree.h (SPLICE_EXPR_TEMPLATE_P): Define. (SET_SPLICE_EXPR_TEMPLATE_P): Define. (SPLICE_EXPR_TARGS_P): Define. (SET_SPLICE_EXPR_TARGS_P): Define. (check_splice_expr): Adjust. * parser.cc (cp_parser_splice_expression): Do SET_SPLICE_EXPR_TEMPLATE_P and SET_SPLICE_EXPR_TARGS_P. Adjust the call to check_splice_expr. Move the template_p checking into check_splice_expr. * pt.cc (tsubst_splice_expr): Do SET_SPLICE_EXPR_TEMPLATE_P and SET_SPLICE_EXPR_TARGS_P. Adjust the call to check_splice_expr. * reflect.cc (eval_constant_of): Adjust the call to check_splice_expr. (check_splice_expr): Two new bool parameters. Add the template_p checking from cp_parser_splice_expression. Allow variable_template_p in the assert. Add a check for DECL_TYPE_TEMPLATE_P. gcc/testsuite/ChangeLog: * g++.dg/reflect/crash11.C: Adjust dg-error. * g++.dg/reflect/splice5.C: Likewise. Reviewed-by: Jason Merrill jason@redhat.com

-rw-r--r--	gcc/cp/cp-tree.h	24
-rw-r--r--	gcc/cp/parser.cc	41
-rw-r--r--	gcc/cp/pt.cc	6
-rw-r--r--	gcc/cp/reflect.cc	53
-rw-r--r--	gcc/testsuite/g++.dg/reflect/crash11.C	4
-rw-r--r--	gcc/testsuite/g++.dg/reflect/splice5.C	7

6 files changed, 93 insertions, 42 deletions

diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.hindex 1ea3319c37b8..1080203ac8a4 100644--- a/gcc/cp/cp-tree.h+++ b/gcc/cp/cp-tree.h
@@ -522,6 +522,7 @@ extern GTY(()) tree cp_global_trees[CPTI_MAX];
522	TARGET_EXPR_ELIDING_P (in TARGET_EXPR)	522	TARGET_EXPR_ELIDING_P (in TARGET_EXPR)
523	IF_STMT_VACUOUS_INIT_P (IF_STMT)	523	IF_STMT_VACUOUS_INIT_P (IF_STMT)
524	TYPENAME_IS_RESOLVING_P (in TYPENAME_TYPE)	524	TYPENAME_IS_RESOLVING_P (in TYPENAME_TYPE)
525	SPLICE_EXPR_TEMPLATE_P (in SPLICE_EXPR)
525	4: IDENTIFIER_MARKED (IDENTIFIER_NODEs)	526	4: IDENTIFIER_MARKED (IDENTIFIER_NODEs)
526	TREE_HAS_CONSTRUCTOR (in INDIRECT_REF, SAVE_EXPR, CONSTRUCTOR,	527	TREE_HAS_CONSTRUCTOR (in INDIRECT_REF, SAVE_EXPR, CONSTRUCTOR,
527	CALL_EXPR, or FIELD_DECL).	528	CALL_EXPR, or FIELD_DECL).
@@ -533,6 +534,7 @@ extern GTY(()) tree cp_global_trees[CPTI_MAX];
533	TARGET_EXPR_INTERNAL_P (in TARGET_EXPR)	534	TARGET_EXPR_INTERNAL_P (in TARGET_EXPR)
534	CONTRACT_CONST (in ASSERTION_, PRECONDITION_, POSTCONDITION_STMT)	535	CONTRACT_CONST (in ASSERTION_, PRECONDITION_, POSTCONDITION_STMT)
535	DECL_HAS_DEFAULT_ARGUMENT_P (in PARM_DECL)	536	DECL_HAS_DEFAULT_ARGUMENT_P (in PARM_DECL)
537	SPLICE_EXPR_TARGS_P (in SPLICE_EXPR)
536	5: IDENTIFIER_VIRTUAL_P (in IDENTIFIER_NODE)	538	5: IDENTIFIER_VIRTUAL_P (in IDENTIFIER_NODE)
537	FUNCTION_RVALUE_QUALIFIED (in FUNCTION_TYPE, METHOD_TYPE)	539	FUNCTION_RVALUE_QUALIFIED (in FUNCTION_TYPE, METHOD_TYPE)
538	CALL_EXPR_REVERSE_ARGS (in CALL_EXPR, AGGR_INIT_EXPR)	540	CALL_EXPR_REVERSE_ARGS (in CALL_EXPR, AGGR_INIT_EXPR)
@@ -1979,6 +1981,24 @@ enum reflect_kind : addr_space_t {
1979	(SPLICE_EXPR_ADDRESS_P (TREE_CODE (NODE) == SPLICE_EXPR \	1981	(SPLICE_EXPR_ADDRESS_P (TREE_CODE (NODE) == SPLICE_EXPR \
1980	? NODE : TREE_OPERAND (NODE, 0)) = (VAL))	1982	? NODE : TREE_OPERAND (NODE, 0)) = (VAL))
1981	1983
1984	/* True if this SPLICE_EXPR was decorated with 'template'. */
1985	#define SPLICE_EXPR_TEMPLATE_P(NODE) \
1986	TREE_LANG_FLAG_3 (SPLICE_EXPR_CHECK (NODE))
1987
1988	/* Helper macro to set SPLICE_EXPR_TEMPLATE_P. */
1989	#define SET_SPLICE_EXPR_TEMPLATE_P(NODE, VAL) \
1990	(SPLICE_EXPR_TEMPLATE_P (TREE_CODE (NODE) == SPLICE_EXPR \
1991	? NODE : TREE_OPERAND (NODE, 0)) = (VAL))
1992
1993	/* True if this SPLICE_EXPR has template arguments. */
1994	#define SPLICE_EXPR_TARGS_P(NODE) \
1995	TREE_LANG_FLAG_4 (SPLICE_EXPR_CHECK (NODE))
1996
1997	/* Helper macro to set SPLICE_EXPR_TARGS_P. */
1998	#define SET_SPLICE_EXPR_TARGS_P(NODE, VAL) \
1999	(SPLICE_EXPR_TARGS_P (TREE_CODE (NODE) == SPLICE_EXPR \
2000	? NODE : TREE_OPERAND (NODE, 0)) = (VAL))
2001
1982	/* The expression in question for a SPLICE_SCOPE. */	2002	/* The expression in question for a SPLICE_SCOPE. */
1983	#define SPLICE_SCOPE_EXPR(NODE) \	2003	#define SPLICE_SCOPE_EXPR(NODE) \
1984	(TYPE_VALUES_RAW (SPLICE_SCOPE_CHECK (NODE)))	2004	(TYPE_VALUES_RAW (SPLICE_SCOPE_CHECK (NODE)))
@@ -9416,8 +9436,8 @@ extern bool consteval_only_p (tree) ATTRIBUTE_PURE;
9416	extern bool compare_reflections (tree, tree) ATTRIBUTE_PURE;	9436	extern bool compare_reflections (tree, tree) ATTRIBUTE_PURE;
9417	extern bool valid_splice_type_p (const_tree) ATTRIBUTE_PURE;	9437	extern bool valid_splice_type_p (const_tree) ATTRIBUTE_PURE;
9418	extern bool valid_splice_scope_p (const_tree) ATTRIBUTE_PURE;	9438	extern bool valid_splice_scope_p (const_tree) ATTRIBUTE_PURE;
9419	extern bool check_splice_expr (location_t, location_t, tree, bool, bool, bool)	9439	extern bool check_splice_expr (location_t, location_t, tree, bool, bool, bool,
9420	ATTRIBUTE_PURE;	9440	bool, bool) ATTRIBUTE_PURE;
9421	extern tree make_splice_scope (tree, bool);	9441	extern tree make_splice_scope (tree, bool);
9422	extern bool dependent_splice_p (const_tree) ATTRIBUTE_PURE;	9442	extern bool dependent_splice_p (const_tree) ATTRIBUTE_PURE;
9423	extern tree reflection_mangle_prefix (tree, char [3]);	9443	extern tree reflection_mangle_prefix (tree, char [3]);
diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.ccindex bbebc1257656..fe27a15a2835 100644--- a/gcc/cp/parser.cc+++ b/gcc/cp/parser.cc
@@ -6318,6 +6318,8 @@ cp_parser_splice_expression (cp_parser *parser, bool template_p,
6318	SET_SPLICE_EXPR_EXPRESSION_P (t);	6318	SET_SPLICE_EXPR_EXPRESSION_P (t);
6319	SET_SPLICE_EXPR_MEMBER_ACCESS_P (t, member_access_p);	6319	SET_SPLICE_EXPR_MEMBER_ACCESS_P (t, member_access_p);
6320	SET_SPLICE_EXPR_ADDRESS_P (t, address_p);	6320	SET_SPLICE_EXPR_ADDRESS_P (t, address_p);
6321	SET_SPLICE_EXPR_TEMPLATE_P (t, template_p);
6322	SET_SPLICE_EXPR_TARGS_P (t, targs_p);
6321	return t;	6323	return t;
6322	}	6324	}
6323	6325
@@ -6330,38 +6332,17 @@ cp_parser_splice_expression (cp_parser *parser, bool template_p,
6330	6332
6331	/* Make sure this splice-expression produces an expression. */	6333	/* Make sure this splice-expression produces an expression. */
6332	if (!check_splice_expr (loc, expr.get_start (), t, address_p,	6334	if (!check_splice_expr (loc, expr.get_start (), t, address_p,
6333	member_access_p, /complain=/true))	6335	member_access_p, template_p, targs_p,
6336	/complain=/true))
6334	return error_mark_node;	6337	return error_mark_node;
6335	6338
6336	if (template_p)	6339	if (!template_p
6337	{	6340	/* No 'template' but there were template arguments? */
6338	/* [expr.prim.splice] For a splice-expression of the form template	6341	&& (targs_p
6339	splice-specifier, the splice-specifier shall designate a function	6342	/* No 'template' but the splice-specifier designates a function
6340	template. */	6343	template? */
6341	if (!targs_p	6344	\|
6342	&& !really_overloaded_fn (t)	6345	&& warning_enabled_at (loc, OPT_Wmissing_template_keyword))
6343	&& !dependent_splice_p (t))
6344	{
6345	auto_diagnostic_group d;
6346	error_at (loc, "expected a reflection of a function template");
6347	inform_tree_category (t);
6348	return error_mark_node;
6349	}
6350	/* [expr.prim.splice] For a splice-expression of the form
6351	template splice-specialization-specifier, the splice-specifier of the
6352	splice-specialization-specifier shall designate a template. Since
6353	we would have already complained, just check that we have a template. */
6354	gcc_checking_assert (really_overloaded_fn (t)
6355	\|	get_template_info (t)
6356	\|	TREE_CODE (t) == TEMPLATE_ID_EXPR
6357	\|	dependent_splice_p (t));
6358	}
6359	else if (/* No 'template' but there were template arguments? */
6360	(targs_p
6361	/* No 'template' but the splice-specifier designates a function
6362	template? */
6363	\|	really_overloaded_fn (t))
6364	&& warning_enabled_at (loc, OPT_Wmissing_template_keyword))
6365	/* Were 'template' present, this would be valid code, so keep going. */	6346	/* Were 'template' present, this would be valid code, so keep going. */
6366	missing_template_diag (loc, diagnostics::kind::pedwarn);	6347	missing_template_diag (loc, diagnostics::kind::pedwarn);
6367	6348
diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.ccindex c10ca09cdb16..18aec7ebb561 100644--- a/gcc/cp/pt.cc+++ b/gcc/cp/pt.cc
@@ -16833,12 +16833,18 @@ tsubst_splice_expr (tree t, tree args, tsubst_flags_t complain, tree in_decl)
16833	SET_SPLICE_EXPR_MEMBER_ACCESS_P (op, true);	16833	SET_SPLICE_EXPR_MEMBER_ACCESS_P (op, true);
16834	if (SPLICE_EXPR_ADDRESS_P (t))	16834	if (SPLICE_EXPR_ADDRESS_P (t))
16835	SET_SPLICE_EXPR_ADDRESS_P (op, true);	16835	SET_SPLICE_EXPR_ADDRESS_P (op, true);
16836	if (SPLICE_EXPR_TEMPLATE_P (t))
16837	SET_SPLICE_EXPR_TEMPLATE_P (op, true);
16838	if (SPLICE_EXPR_TARGS_P (t))
16839	SET_SPLICE_EXPR_TARGS_P (op, true);
16836	return op;	16840	return op;
16837	}	16841	}
16838	if (SPLICE_EXPR_EXPRESSION_P (t)	16842	if (SPLICE_EXPR_EXPRESSION_P (t)
16839	&& !check_splice_expr (input_location, UNKNOWN_LOCATION, op,	16843	&& !check_splice_expr (input_location, UNKNOWN_LOCATION, op,
16840	SPLICE_EXPR_ADDRESS_P (t),	16844	SPLICE_EXPR_ADDRESS_P (t),
16841	SPLICE_EXPR_MEMBER_ACCESS_P (t),	16845	SPLICE_EXPR_MEMBER_ACCESS_P (t),
16846	SPLICE_EXPR_TEMPLATE_P (t),
16847	SPLICE_EXPR_TARGS_P (t),
16842	(complain & tf_error)))	16848	(complain & tf_error)))
16843	return error_mark_node;	16849	return error_mark_node;
16844	16850
diff --git a/gcc/cp/reflect.cc b/gcc/cp/reflect.ccindex 78d48db29ba2..8925bf49465d 100644--- a/gcc/cp/reflect.cc+++ b/gcc/cp/reflect.cc
@@ -2752,6 +2752,8 @@ eval_constant_of (location_t loc, const constexpr_ctx *ctx, tree r,
2752	else if (!check_splice_expr (loc, UNKNOWN_LOCATION, r,	2752	else if (!check_splice_expr (loc, UNKNOWN_LOCATION, r,
2753	/address_p=/false,	2753	/address_p=/false,
2754	/member_access_p=/false,	2754	/member_access_p=/false,
2755	/template_p=/false,
2756	/targs_p=/false,
2755	/complain_p=/false)	2757	/complain_p=/false)
2756	/* One cannot query the value of a function template.	2758	/* One cannot query the value of a function template.
2757	??? But if [:^^X:] where X is a template is OK, should we	2759	??? But if [:^^X:] where X is a template is OK, should we
@@ -8812,13 +8814,15 @@ check_consteval_only_fn (tree decl)
8812	8814
8813	/* Check if T is a valid result of splice-expression. ADDRESS_P is true if	8815	/* Check if T is a valid result of splice-expression. ADDRESS_P is true if
8814	we are taking the address of the splice. MEMBER_ACCESS_P is true if this	8816	we are taking the address of the splice. MEMBER_ACCESS_P is true if this
8815	splice is used in foo.[: bar :] or foo->[: bar :] context. COMPLAIN_P is	8817	splice is used in foo.[: bar :] or foo->[: bar :] context. TEMPLATE_P is
8816	true if any errors should be emitted. Returns true is no problems are	8818	true if the splice-expression was preceded by 'template'. TARGS_P is true
8817	found, false otherwise. */	8819	if there were template arguments. COMPLAIN_P is true if any errors should
8820	be emitted. Returns true is no problems are found, false otherwise. */
8818	8821
8819	bool	8822	bool
8820	check_splice_expr (location_t loc, location_t start_loc, tree t,	8823	check_splice_expr (location_t loc, location_t start_loc, tree t,
8821	bool address_p, bool member_access_p, bool complain_p)	8824	bool address_p, bool member_access_p, bool template_p,
8825	bool targs_p, bool complain_p)
8822	{	8826	{
8823	/* We may not have gotten an expression. */	8827	/* We may not have gotten an expression. */
8824	if (TREE_CODE (t) == TYPE_DECL	8828	if (TREE_CODE (t) == TYPE_DECL
@@ -8949,6 +8953,47 @@ check_splice_expr (location_t loc, location_t start_loc, tree t,
8949	return false;	8953	return false;
8950	}	8954	}
8951	8955
8956	if (template_p)
8957	{
8958	/* [expr.prim.splice] For a splice-expression of the form template
8959	splice-specifier, the splice-specifier shall designate a function
8960	template. */
8961	if (!targs_p)
8962	{
8963	if (!really_overloaded_fn (t) && !dependent_splice_p (t))
8964	{
8965	if (complain_p)
8966	{
8967	auto_diagnostic_group d;
8968	error_at (loc, "expected a reflection of a function "
8969	"template");
8970	inform_tree_category (t);
8971	}
8972	return false;
8973	}
8974	}
8975	/* [expr.prim.splice] For a splice-expression of the form
8976	template splice-specialization-specifier, the splice-specifier of the
8977	splice-specialization-specifier shall designate a template. The
8978	template should be a function template or a variable template. */
8979	else if (DECL_TYPE_TEMPLATE_P (t))
8980	{
8981	if (complain_p)
8982	{
8983	auto_diagnostic_group d;
8984	error_at (loc, "expected a reflection of a function or variable "
8985	"template");
8986	inform_tree_category (t);
8987	}
8988	return false;
8989	}
8990	gcc_checking_assert (really_overloaded_fn (t)
8991	\|	get_template_info (t)
8992	\|	TREE_CODE (t) == TEMPLATE_ID_EXPR
8993	\|	variable_template_p (t)
8994	\|	dependent_splice_p (t));
8995	}
8996
8952	return true;	8997	return true;
8953	}	8998	}
8954	8999
diff --git a/gcc/testsuite/g++.dg/reflect/crash11.C b/gcc/testsuite/g++.dg/reflect/crash11.Cindex 3aef5d0b2fe5..1d8e78994c24 100644--- a/gcc/testsuite/g++.dg/reflect/crash11.C+++ b/gcc/testsuite/g++.dg/reflect/crash11.C
@@ -12,8 +12,8 @@ template<typename T, auto R>
12	void	12	void
13	g ()	13	g ()
14	{	14	{
15	template [: R :] c0; // { dg-error "not a function template\|expected" }	15	template [: R :] c0; // { dg-error "function or variable template\|expected" }
16	template [: T::r :] c1; // { dg-error "not a function template\|expected" }	16	template [: T::r :] c1; // { dg-error "function or variable template\|expected" }
17	}	17	}
18	18
19	void	19	void
diff --git a/gcc/testsuite/g++.dg/reflect/splice5.C b/gcc/testsuite/g++.dg/reflect/splice5.Cindex 4f0d2fe61341..96d3192eb55f 100644--- a/gcc/testsuite/g++.dg/reflect/splice5.C+++ b/gcc/testsuite/g++.dg/reflect/splice5.C
@@ -25,10 +25,9 @@ template
25	void	25	void
26	qux (S &s)	26	qux (S &s)
27	{	27	{
28	// TODO: We don't reject this one.	28	template [: N == 0 ? ^^foo : ^^:: :] (0); // { dg-error "expected a reflection of a function template" }
29	template [: N == 0 ? ^^foo : ^^:: :] (0); // { dg-error "reflection 'foo' not usable in a template splice" "" { xfail --* } }	29	template [: N == 0 ? ^^bar : ^^:: :] (0);
30	template [: N == 0 ? ^^bar : ^^:: :] (0); // { dg-message "only function templates are allowed here" "" { xfail --* } .-1 }	30	s.template [: N == 0 ? ^^S::foo : ^^:: :] (0); // { dg-error "expected a reflection of a function template" }
31	s.template [: N == 0 ? ^^S::foo : ^^:: :] (0); // { dg-error "reflection 'foo' not usable in a template splice" "" { xfail --* } }
32	s.template [: N == 0 ? ^^S::bar : ^^:: :] (0);	31	s.template [: N == 0 ? ^^S::bar : ^^:: :] (0);
33	}	32	}
34	33