On Fri, 25 Aug 2023, Marek Polacek via Gcc-patches wrote:
> Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
LGTM
>
> -- >8 --
>
> This CWG clarifies that designated initializer support direct-initialization.
> Just be careful what Note 2 in [dcl.init.aggr]/4.2 says: "If the
> initialization is by designated-initializer-clause, its form determines
> whether copy-initialization or direct-initialization is performed." Hence
> this patch sets CONSTRUCTOR_IS_DIRECT_INIT only when we are dealing with
> ".x{}", but not ".x = {}".
>
> PR c++/91319
>
> gcc/cp/ChangeLog:
>
> * parser.cc (cp_parser_initializer_list): Set CONSTRUCTOR_IS_DIRECT_INIT
> when the designated initializer is of the .x{} form.
>
> gcc/testsuite/ChangeLog:
>
> * g++.dg/cpp2a/desig30.C: New test.
> ---
> gcc/cp/parser.cc | 6 ++++++
> gcc/testsuite/g++.dg/cpp2a/desig30.C | 22 ++++++++++++++++++++++
> 2 files changed, 28 insertions(+)
> create mode 100644 gcc/testsuite/g++.dg/cpp2a/desig30.C
>
> diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc
> index eeb22e44fb4..b3d5c65b469 100644
> --- a/gcc/cp/parser.cc
> +++ b/gcc/cp/parser.cc
> @@ -25718,6 +25718,7 @@ cp_parser_initializer_list (cp_parser* parser, bool*
> non_constant_p,
> tree designator;
> tree initializer;
> bool clause_non_constant_p;
> + bool direct_p = false;
> location_t loc = cp_lexer_peek_token (parser->lexer)->location;
>
> /* Handle the C++20 syntax, '. id ='. */
> @@ -25740,6 +25741,8 @@ cp_parser_initializer_list (cp_parser* parser, bool*
> non_constant_p,
> if (cp_lexer_next_token_is (parser->lexer, CPP_EQ))
> /* Consume the `='. */
> cp_lexer_consume_token (parser->lexer);
> + else
> + direct_p = true;
> }
> /* Also, if the next token is an identifier and the following one is a
> colon, we are looking at the GNU designated-initializer
> @@ -25817,6 +25820,9 @@ cp_parser_initializer_list (cp_parser* parser, bool*
> non_constant_p,
> if (clause_non_constant_p && non_constant_p)
> *non_constant_p = true;
>
> + if (TREE_CODE (initializer) == CONSTRUCTOR)
> + CONSTRUCTOR_IS_DIRECT_INIT (initializer) |= direct_p;
> +
> /* If we have an ellipsis, this is an initializer pack
> expansion. */
> if (cp_lexer_next_token_is (parser->lexer, CPP_ELLIPSIS))
> diff --git a/gcc/testsuite/g++.dg/cpp2a/desig30.C
> b/gcc/testsuite/g++.dg/cpp2a/desig30.C
> new file mode 100644
> index 00000000000..d9292df9de2
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp2a/desig30.C
> @@ -0,0 +1,22 @@
> +// PR c++/91319
> +// { dg-do compile { target c++20 } }
> +
> +struct X {
> + explicit X() { }
> +};
> +
> +struct Aggr {
> + X x;
> +};
> +
> +Aggr
> +f ()
> +{
> + return Aggr{.x{}};
> +}
> +
> +Aggr
> +f2 ()
> +{
> + return Aggr{.x = {}}; // { dg-error "explicit constructor" }
> +}
>
> base-commit: 54cc21eaf5f3eb7f7a508919a086f6c8bf5c4c17
> --
> 2.41.0
>
>
