On 4/4/20 7:30 PM, Marek Polacek wrote:
This patch implements DR 2237 which says that a simple-template-id is
no longer valid as the declarator-id of a constructor or destructor;
see <https://eel.is/c++draft/diff.cpp17.class#2>. It is not explicitly
stated but out-of-line destructors with a simple-template-id are also
meant to be ill-formed now. (Out-of-line constructors like that are
invalid since DR1435 I think.) This change only applies to C++20; it
is not a DR against C++17.
I'm not crazy about the diagnostic in constructors but ISTM that
cp_parser_constructor_declarator_p shouldn't print errors.
Does it seem reasonable to apply this now or should I defer to GCC 11?
A new error should wait for GCC 11.
Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
2020-04-04 Marek Polacek <pola...@redhat.com>
DR 2237
* parser.c (cp_parser_unqualified_id): Reject simple-template-id as
the declarator-id of a destructor.
(cp_parser_constructor_declarator_p): Reject simple-template-id as
the declarator-id of a constructor.
* g++.dg/DRs/dr2237.C: New test.
* g++.dg/parse/constructor2.C: Add dg-error for C++20.
* g++.dg/parse/dtor12.C: Likewise.
* g++.dg/parse/dtor4.C: Likewise.
* g++.dg/template/dtor4.C: Adjust dg-error.
* g++.dg/template/error34.C: Likewise.
* g++.old-deja/g++.other/inline15.C: Only run for C++17 and lesses.
* g++.old-deja/g++.pt/ctor2.C: Add dg-error for C++20.
---
gcc/cp/parser.c | 16 ++++++++++++++++
gcc/testsuite/g++.dg/DRs/dr2237.C | 18 ++++++++++++++++++
gcc/testsuite/g++.dg/parse/constructor2.C | 4 ++--
gcc/testsuite/g++.dg/parse/dtor12.C | 2 +-
gcc/testsuite/g++.dg/parse/dtor4.C | 2 +-
gcc/testsuite/g++.dg/template/dtor4.C | 2 +-
gcc/testsuite/g++.dg/template/error34.C | 10 +++++-----
.../g++.old-deja/g++.other/inline15.C | 2 +-
gcc/testsuite/g++.old-deja/g++.pt/ctor2.C | 2 +-
9 files changed, 46 insertions(+), 12 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/DRs/dr2237.C
diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index 7e5921e039f..810edfa87a9 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -6114,6 +6114,16 @@ cp_parser_unqualified_id (cp_parser* parser,
return build_min_nt_loc (loc, BIT_NOT_EXPR, make_auto ());
}
+ /* DR 2237 (C++20 only): A simple-template-id is no longer valid as the
+ declarator-id of a constructor or destructor. */
+ if (token->type == CPP_TEMPLATE_ID && cxx_dialect >= cxx2a)
+ {
+ if (!cp_parser_uncommitted_to_tentative_parse_p (parser))
+ error_at (tilde_loc, "template-id not allowed for destructor");
+ cp_parser_simulate_error (parser);
The usual pattern is
if (!cp_parser_simulate_error (parser))
error...
+ return error_mark_node;
+ }
+
/* If there was an explicit qualification (S::~T), first look
in the scope given by the qualification (i.e., S).
@@ -28675,6 +28685,12 @@ cp_parser_constructor_declarator_p (cp_parser *parser, cp_parser_flags flags,
if (!constructor_name_p (id, nested_name_specifier))
constructor_p = false;
}
+ /* DR 2237 (C++20 only): A simple-template-id is no longer valid as the
+ declarator-id of a constructor or destructor. */
+ else if (constructor_p
+ && cxx_dialect >= cxx2a
+ && cp_lexer_next_token_is (parser->lexer, CPP_TEMPLATE_ID))
+ constructor_p = false;
/* If we still think that this might be a constructor-declarator,
look for a class-name. */
else if (constructor_p)
Do you also want to exclude CPP_TEMPLATE_ID from the test at the top of
the function for C++20?
if (next_token->type != CPP_NAME
&& next_token->type != CPP_SCOPE
&& next_token->type != CPP_NESTED_NAME_SPECIFIER
&& next_token->type != CPP_TEMPLATE_ID)
return false;
Jason
