On 1/8/19 10:42 AM, Marek Polacek wrote:
On Mon, Jan 07, 2019 at 09:52:55PM -0500, Jason Merrill wrote:
On 1/7/19 6:56 PM, Marek Polacek wrote:
At the risk of seeming overly eager, I thought it would be reasonable to
go with the following: enabling braced-init-list as a template-argument.
As the discussion on the reflector clearly indicates, this was the intent
from the get-go.
I know, it's not a regression. But I restricted the change to C++20, and it
should strictly allow code that wasn't accepted before -- when a template
argument starts with {. Perhaps we could even drop the C++20 check.
What's your preference?
Let's keep the C++20 check for now at least. I'd suggest moving the change
further down, with this code:
Okay. I've experimented with checking expr_non_constant_p, but this version
gives better diagnostics.
Bootstrapped/regtested running on x86_64-linux, ok for trunk if it passes?
2019-01-08 Marek Polacek <pola...@redhat.com>
PR c++/88538 - braced-init-list in template-argument-list.
* parser.c (cp_parser_template_argument): Handle braced-init-list when
in C++20.
* g++.dg/cpp2a/nontype-class11.C: New test.
diff --git gcc/cp/parser.c gcc/cp/parser.c
index bca1739ace3..87f37d8ab2b 100644
--- gcc/cp/parser.c
+++ gcc/cp/parser.c
@@ -17020,6 +17020,18 @@ cp_parser_template_argument (cp_parser* parser)
argument = cp_parser_constant_expression (parser);
else
{
+ /* In C++20, we can encounter a braced-init-list. */
+ if (cxx_dialect >= cxx2a
+ && cp_lexer_next_token_is (parser->lexer, CPP_OPEN_BRACE))
+ {
+ cp_parser_parse_tentatively (parser);
Hmm, I wonder if we would get better diagnostics for an ill-formed
braced-init-list without tentative parsing here. OK either way.
Jason
