On Fri, Feb 16, 2024 at 10:47:47PM +0100, Jakub Jelinek wrote:
> The following patch works.
Or yet another option would be instead of (sometimes) clearing
declarator->parameter_pack_p when we diagnose this bug for error
recovery ignore the this specifier.
With the following patch (testsuite patch remains the same),
I get excess errors though:
/usr/src/gcc/gcc/testsuite/g++.dg/cpp23/explicit-obj-diagnostics3.C:30:25:
error: expansion pattern 'Selves' contains no parameter packs
/usr/src/gcc/gcc/testsuite/g++.dg/cpp23/explicit-obj-diagnostics3.C:42:26:
error: expansion pattern 'Selves' contains no parameter packs
/usr/src/gcc/gcc/testsuite/g++.dg/cpp23/explicit-obj-diagnostics3.C:56:26:
error: expansion pattern 'Selves&' contains no parameter packs
/usr/src/gcc/gcc/testsuite/g++.dg/cpp23/explicit-obj-diagnostics3.C:68:27:
error: expansion pattern 'Selves&' contains no parameter packs
/usr/src/gcc/gcc/testsuite/g++.dg/cpp23/explicit-obj-diagnostics3.C:82:27:
error: expansion pattern 'Selves&&' contains no parameter packs
/usr/src/gcc/gcc/testsuite/g++.dg/cpp23/explicit-obj-diagnostics3.C:94:28:
error: expansion pattern 'Selves&&' contains no parameter packs
/usr/src/gcc/gcc/testsuite/g++.dg/cpp23/explicit-obj-diagnostics3.C:108:32:
error: expansion pattern 'const Selves&' contains no parameter packs
/usr/src/gcc/gcc/testsuite/g++.dg/cpp23/explicit-obj-diagnostics3.C:120:33:
error: expansion pattern 'const Selves&' contains no parameter packs
/usr/src/gcc/gcc/testsuite/g++.dg/cpp23/explicit-obj-diagnostics3.C:134:33:
error: expansion pattern 'const Selves&&' contains no parameter packs
/usr/src/gcc/gcc/testsuite/g++.dg/cpp23/explicit-obj-diagnostics3.C:146:34:
error: expansion pattern 'const Selves&&' contains no parameter packs
though, that is e.g. on
struct S0 {
template<typename Selves>
void g(this Selves... selves) {} // { dg-error "an explicit object parameter
cannot be a function parameter pack" }
}
where such an extra error would have been emitted if the this keyword was
omitted.
--- gcc/cp/parser.cc.jj 2024-02-16 17:38:27.802845433 +0100
+++ gcc/cp/parser.cc 2024-02-16 23:08:40.835437740 +0100
@@ -25734,22 +25734,6 @@ cp_parser_parameter_declaration (cp_pars
decl_specifiers.locations[ds_this] = 0;
}
- if (xobj_param_p
- && ((declarator && declarator->parameter_pack_p)
- || cp_lexer_next_token_is (parser->lexer, CPP_ELLIPSIS)))
- {
- 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");
- /* Suppress errors that occur down the line. */
- if (declarator)
- declarator->parameter_pack_p = false;
- }
-
/* If a function parameter pack was specified and an implicit template
parameter was introduced during cp_parser_parameter_declaration,
change any implicit parameters introduced into packs. */
@@ -25762,9 +25746,10 @@ 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))
@@ -25794,6 +25779,21 @@ cp_parser_parameter_declaration (cp_pars
}
}
+ if (xobj_param_p
+ && (declarator ? declarator->parameter_pack_p
+ : PACK_EXPANSION_P (decl_specifiers.type)))
+ {
+ 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");
+ xobj_param_p = false;
+ decl_specifiers.locations[ds_this] = 0;
+ }
+
/* 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;
Jakub
