Hi!
The simple presence of ellipsis as next token after the parameter
declaration doesn't imply it is a parameter pack, it sometimes is, e.g.
if its type is a pack, but sometimes is not and in that case it acts
the same as if the next tokens were , ... instead of just ...
The xobj param cannot be a function parameter pack though treats both
the declarator->parameter_pack_p and token->type == CPP_ELLIPSIS as
sufficient conditions for the error. The conditions for CPP_ELLIPSIS
are done a little bit later in the same function and complex enough that
IMHO shouldn't be repeated, on the other side for the
declarator->parameter_pack_p case we clear that flag for xobj params
for error recovery reasons.
In order to avoid diagnosing this in two spots, one at the current spot
for declarator->parameter_pack_p and one for the ellipsis case after
we decide if it is parameter pack or varargs, the following patch instead
just sets a boolean flag whether we should emit this diagnostics, does it
early for declarator->parameter_pack_p case and clears the parameter_pack_p
flag in that case like the older patch did, and for the ellipsis case
sets the flag later, then emits the diagnostics.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2024-02-16 Jakub Jelinek <ja...@redhat.com>
PR c++/113802
* parser.cc (cp_parser_parameter_declaration): Don't emit
PR113307 diagnostics too early, instead for the
declarator->parameter_pack_p case just set a flag it should be emitted
later. Set that flag also when consuming following ellipsis as part
of a parameter pack and diagnose either afterwards. Formatting fix.
* g++.dg/cpp23/explicit-obj-diagnostics3.C (S0, S1, S2, S3, S4): Don't
expect any diagnostics on f and fd member function templates, add
similar templates with ...Selves instead of Selves as k and kd and
expect diagnostics for those.
--- gcc/cp/parser.cc.jj 2024-02-14 14:26:19.000000000 +0100
+++ gcc/cp/parser.cc 2024-02-15 11:58:27.033618967 +0100
@@ -25727,17 +25727,10 @@ cp_parser_parameter_declaration (cp_pars
bool const xobj_param_p
= decl_spec_seq_has_spec_p (&decl_specifiers, ds_this);
- if (xobj_param_p
- && ((declarator && declarator->parameter_pack_p)
- || cp_lexer_next_token_is (parser->lexer, CPP_ELLIPSIS)))
+ bool diag_xobj_parameter_pack = false;
+ if (xobj_param_p && (declarator && declarator->parameter_pack_p))
{
- location_t xobj_param
- = make_location (decl_specifiers.locations[ds_this],
- decl_spec_token_start->location,
- input_location);
- error_at (xobj_param,
- "an explicit object parameter cannot "
- "be a function parameter pack");
+ diag_xobj_parameter_pack = true;
/* Suppress errors that occur down the line. */
if (declarator)
declarator->parameter_pack_p = false;
@@ -25755,9 +25748,10 @@ cp_parser_parameter_declaration (cp_pars
(INNERMOST_TEMPLATE_PARMS (current_template_parms));
if (latest_template_parm_idx != template_parm_idx)
- decl_specifiers.type = convert_generic_types_to_packs
- (decl_specifiers.type,
- template_parm_idx, latest_template_parm_idx);
+ decl_specifiers.type
+ = convert_generic_types_to_packs (decl_specifiers.type,
+ template_parm_idx,
+ latest_template_parm_idx);
}
if (cp_lexer_next_token_is (parser->lexer, CPP_ELLIPSIS))
@@ -25773,6 +25767,8 @@ cp_parser_parameter_declaration (cp_pars
|| (!type && template_parm_p))
&& declarator_can_be_parameter_pack (declarator))
{
+ if (xobj_param_p)
+ diag_xobj_parameter_pack = true;
/* Consume the `...'. */
cp_lexer_consume_token (parser->lexer);
maybe_warn_variadic_templates ();
@@ -25787,6 +25783,17 @@ cp_parser_parameter_declaration (cp_pars
}
}
+ if (diag_xobj_parameter_pack)
+ {
+ location_t xobj_param
+ = make_location (decl_specifiers.locations[ds_this],
+ decl_spec_token_start->location,
+ input_location);
+ error_at (xobj_param,
+ "an explicit object parameter cannot "
+ "be a function parameter pack");
+ }
+
/* The restriction on defining new types applies only to the type
of the parameter, not to the default argument. */
parser->type_definition_forbidden_message = saved_message;
--- gcc/testsuite/g++.dg/cpp23/explicit-obj-diagnostics3.C.jj 2024-01-17
10:34:49.812597960 +0100
+++ gcc/testsuite/g++.dg/cpp23/explicit-obj-diagnostics3.C 2024-02-15
12:14:29.994356800 +0100
@@ -24,7 +24,7 @@ void S::f12(this S s = {}) {} // { dg-er
struct S0 {
template<typename Selves>
- void f(this Selves...) {} // { dg-error "an explicit object parameter cannot be a
function parameter pack" }
+ void f(this Selves...) {}
template<typename Selves>
void g(this Selves... selves) {} // { dg-error "an explicit object parameter
cannot be a function parameter pack" }
@@ -32,19 +32,25 @@ struct S0 {
void h(this auto...) {} // { dg-error "an explicit object parameter cannot be a
function parameter pack" }
void j(this auto... selves) {} // { dg-error "an explicit object parameter
cannot be a function parameter pack" }
+ template<typename ...Selves>
+ void k(this Selves...) {} // { dg-error "an explicit object parameter cannot be
a function parameter pack" }
+
template<typename Selves>
- void fd(this Selves...); // { dg-error "an explicit object parameter cannot be a
function parameter pack" }
+ void fd(this Selves...);
template<typename Selves>
void gd(this Selves... selves); // { dg-error "an explicit object parameter
cannot be a function parameter pack" }
void hd(this auto...); // { dg-error "an explicit object parameter cannot be a function parameter pack" }
void jd(this auto... selves); // { dg-error "an explicit object parameter
cannot be a function parameter pack" }
+
+ template<typename ...Selves>
+ void kd(this Selves...); // { dg-error "an explicit object parameter cannot be a
function parameter pack" }
};
struct S1 {
template<typename Selves>
- void f(this Selves&...) {} // { dg-error "an explicit object parameter cannot be
a function parameter pack" }
+ void f(this Selves&...) {}
template<typename Selves>
void g(this Selves&... selves) {} // { dg-error "an explicit object parameter
cannot be a function parameter pack" }
@@ -52,19 +58,25 @@ struct S1 {
void h(this auto&...) {} // { dg-error "an explicit object parameter cannot be
a function parameter pack" }
void j(this auto&... selves) {} // { dg-error "an explicit object parameter
cannot be a function parameter pack" }
+ template<typename ...Selves>
+ void k(this Selves&...) {} // { dg-error "an explicit object parameter cannot be
a function parameter pack" }
+
template<typename Selves>
- void fd(this Selves&...); // { dg-error "an explicit object parameter cannot be
a function parameter pack" }
+ void fd(this Selves&...);
template<typename Selves>
void gd(this Selves&... selves); // { dg-error "an explicit object parameter
cannot be a function parameter pack" }
void hd(this auto&...); // { dg-error "an explicit object parameter cannot be a function parameter pack" }
void jd(this auto&... selves); // { dg-error "an explicit object parameter
cannot be a function parameter pack" }
+
+ template<typename ...Selves>
+ void kd(this Selves&...); // { dg-error "an explicit object parameter cannot be
a function parameter pack" }
};
struct S2 {
template<typename Selves>
- void f(this Selves&&...) {} // { dg-error "an explicit object parameter cannot
be a function parameter pack" }
+ void f(this Selves&&...) {}
template<typename Selves>
void g(this Selves&&... selves) {} // { dg-error "an explicit object parameter
cannot be a function parameter pack" }
@@ -72,19 +84,25 @@ struct S2 {
void h(this auto&&...) {} // { dg-error "an explicit object parameter cannot be
a function parameter pack" }
void j(this auto&&... selves) {} // { dg-error "an explicit object parameter
cannot be a function parameter pack" }
+ template<typename ...Selves>
+ void k(this Selves&&...) {} // { dg-error "an explicit object parameter cannot
be a function parameter pack" }
+
template<typename Selves>
- void fd(this Selves&&...); // { dg-error "an explicit object parameter cannot be
a function parameter pack" }
+ void fd(this Selves&&...);
template<typename Selves>
void gd(this Selves&&... selves); // { dg-error "an explicit object parameter
cannot be a function parameter pack" }
void hd(this auto&&...); // { dg-error "an explicit object parameter cannot be a function parameter pack" }
void jd(this auto&&... selves); // { dg-error "an explicit object parameter
cannot be a function parameter pack" }
+
+ template<typename ...Selves>
+ void kd(this Selves&&...); // { dg-error "an explicit object parameter cannot be
a function parameter pack" }
};
struct S3 {
template<typename Selves>
- void f(this Selves const&...) {} // { dg-error "an explicit object parameter
cannot be a function parameter pack" }
+ void f(this Selves const&...) {}
template<typename Selves>
void g(this Selves const&... selves) {} // { dg-error "an explicit object
parameter cannot be a function parameter pack" }
@@ -92,19 +110,25 @@ struct S3 {
void h(this auto const&...) {} // { dg-error "an explicit object parameter
cannot be a function parameter pack" }
void j(this auto const&... selves) {} // { dg-error "an explicit object
parameter cannot be a function parameter pack" }
+ template<typename ...Selves>
+ void k(this Selves const&...) {} // { dg-error "an explicit object parameter
cannot be a function parameter pack" }
+
template<typename Selves>
- void fd(this Selves const&...); // { dg-error "an explicit object parameter
cannot be a function parameter pack" }
+ void fd(this Selves const&...);
template<typename Selves>
void gd(this Selves const&... selves); // { dg-error "an explicit object
parameter cannot be a function parameter pack" }
void hd(this auto const&...); // { dg-error "an explicit object parameter cannot be a function parameter pack" }
void jd(this auto const&... selves); // { dg-error "an explicit object
parameter cannot be a function parameter pack" }
+
+ template<typename ...Selves>
+ void kd(this Selves const&...); // { dg-error "an explicit object parameter
cannot be a function parameter pack" }
};
struct S4 {
template<typename Selves>
- void f(this Selves const&&...) {} // { dg-error "an explicit object parameter
cannot be a function parameter pack" }
+ void f(this Selves const&&...) {}
template<typename Selves>
void g(this Selves const&&... selves) {} // { dg-error "an explicit object
parameter cannot be a function parameter pack" }
@@ -112,13 +136,18 @@ struct S4 {
void h(this auto const&&...) {} // { dg-error "an explicit object parameter
cannot be a function parameter pack" }
void j(this auto const&&... selves) {} // { dg-error "an explicit object
parameter cannot be a function parameter pack" }
+ template<typename ...Selves>
+ void k(this Selves const&&...) {} // { dg-error "an explicit object parameter
cannot be a function parameter pack" }
+
template<typename Selves>
- void fd(this Selves const&&...); // { dg-error "an explicit object parameter
cannot be a function parameter pack" }
+ void fd(this Selves const&&...);
template<typename Selves>
void gd(this Selves const&&... selves); // { dg-error "an explicit object
parameter cannot be a function parameter pack" }
void hd(this auto const&&...); // { dg-error "an explicit object parameter cannot be a function parameter pack" }
void jd(this auto const&&... selves); // { dg-error "an explicit object
parameter cannot be a function parameter pack" }
-};
+ template<typename ...Selves>
+ void kd(this Selves const&&...); // { dg-error "an explicit object parameter
cannot be a function parameter pack" }
+};
Jakub
