On 9/27/24 5:30 PM, Marek Polacek wrote:
On Fri, Sep 27, 2024 at 04:57:58PM -0400, Jason Merrill wrote:
On 9/18/24 5:06 PM, Marek Polacek wrote:
Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
-- >8 --
1) We're hitting the assert in cp_parser_placeholder_type_specifier.
It says that if it turns out to be false, we should do error() instead.
Do so, then.
2) lambda-targ8.C should compile fine, though. The problem was that
local_variables_forbidden_p wasn't cleared when we're about to parse
the optional template-parameter-list for a lambda in a default argument.
PR c++/109859
gcc/cp/ChangeLog:
* parser.cc (cp_parser_lambda_declarator_opt): Temporarily clear
local_variables_forbidden_p.
(cp_parser_placeholder_type_specifier): Turn an assert into an error.
gcc/testsuite/ChangeLog:
* g++.dg/cpp2a/concepts-defarg3.C: New test.
* g++.dg/cpp2a/lambda-targ8.C: New test.
---
gcc/cp/parser.cc | 9 +++++++--
gcc/testsuite/g++.dg/cpp2a/concepts-defarg3.C | 8 ++++++++
gcc/testsuite/g++.dg/cpp2a/lambda-targ8.C | 10 ++++++++++
3 files changed, 25 insertions(+), 2 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/cpp2a/concepts-defarg3.C
create mode 100644 gcc/testsuite/g++.dg/cpp2a/lambda-targ8.C
diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc
index 4dd9474cf60..bdc4fef243a 100644
--- a/gcc/cp/parser.cc
+++ b/gcc/cp/parser.cc
@@ -11891,6 +11891,11 @@ cp_parser_lambda_declarator_opt (cp_parser* parser,
tree lambda_expr)
"lambda templates are only available with "
"%<-std=c++20%> or %<-std=gnu++20%>");
+ /* Even though the whole lambda may be a default argument, its
+ template-parameter-list is a context where it's OK to create
+ new parameters. */
+ auto lvf = make_temp_override (parser->local_variables_forbidden_p, 0u);
+
cp_lexer_consume_token (parser->lexer);
template_param_list = cp_parser_template_parameter_list (parser);
@@ -20978,8 +20983,8 @@ cp_parser_placeholder_type_specifier (cp_parser
*parser, location_t loc,
/* In a default argument we may not be creating new parameters. */
if (parser->local_variables_forbidden_p & LOCAL_VARS_FORBIDDEN)
{
- /* If this assert turns out to be false, do error() instead. */
- gcc_assert (tentative);
+ if (!tentative)
+ error_at (loc, "local variables may not appear in this context");
There's no local variable in the new testcase, the error should talk about a
concept-name.
Ah sure. So like this?
Tested dg.exp.
-- >8 --
1) We're hitting the assert in cp_parser_placeholder_type_specifier.
It says that if it turns out to be false, we should do error() instead.
Do so, then.
2) lambda-targ8.C should compile fine, though. The problem was that
local_variables_forbidden_p wasn't cleared when we're about to parse
the optional template-parameter-list for a lambda in a default argument.
PR c++/109859
gcc/cp/ChangeLog:
* parser.cc (cp_parser_lambda_declarator_opt): Temporarily clear
local_variables_forbidden_p.
(cp_parser_placeholder_type_specifier): Turn an assert into an error.
gcc/testsuite/ChangeLog:
* g++.dg/cpp2a/concepts-defarg3.C: New test.
* g++.dg/cpp2a/lambda-targ8.C: New test.
---
gcc/cp/parser.cc | 9 +++++++--
gcc/testsuite/g++.dg/cpp2a/concepts-defarg3.C | 8 ++++++++
gcc/testsuite/g++.dg/cpp2a/lambda-targ8.C | 10 ++++++++++
3 files changed, 25 insertions(+), 2 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/cpp2a/concepts-defarg3.C
create mode 100644 gcc/testsuite/g++.dg/cpp2a/lambda-targ8.C
diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc
index f50534f5f39..a92e6a29ba6 100644
--- a/gcc/cp/parser.cc
+++ b/gcc/cp/parser.cc
@@ -11891,6 +11891,11 @@ cp_parser_lambda_declarator_opt (cp_parser* parser,
tree lambda_expr)
"lambda templates are only available with "
"%<-std=c++20%> or %<-std=gnu++20%>");
+ /* Even though the whole lambda may be a default argument, its
+ template-parameter-list is a context where it's OK to create
+ new parameters. */
+ auto lvf = make_temp_override (parser->local_variables_forbidden_p, 0u);
+
cp_lexer_consume_token (parser->lexer);
template_param_list = cp_parser_template_parameter_list (parser);
@@ -20989,8 +20994,8 @@ cp_parser_placeholder_type_specifier (cp_parser
*parser, location_t loc,
/* In a default argument we may not be creating new parameters. */
if (parser->local_variables_forbidden_p & LOCAL_VARS_FORBIDDEN)
{
- /* If this assert turns out to be false, do error() instead. */
- gcc_assert (tentative);
+ if (!tentative)
+ error_at (loc, "concept-name may not appear in this context");
Hmm, actually I expect it can appear in a concept-id. What if we fall
through to the next case instead of erroring/returning at this point?
Jason
