[v4] c++: DR2237, cdtor and template-id tweaks [PR107126]
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On Fri, Feb 09, 2024 at 10:20:04AM -0500, Jason Merrill wrote:
> On 2/8/24 16:26, Marek Polacek wrote:
> > This patch does *not* fix
> > <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97202#c8>
> > where the C++20 diagnostic is missing altogether.
>
> What would it take to fix that as well?
It's the "further DR2237 fix" below which is basically a one liner.
I'd thought it would be more involved than that.
> > * doc/invoke.texi: Document -Wdeprecated-template-id-cdtor.
>
> Was it ever deprecated? I'm not seeing that in
>
> https://timsong-cpp.github.io/cppwp/n4659/#depr (C++17)
Aha, [diff] != [depr]...
> Let's drop the word "deprecated" from the option name and documentation.
Done throughout.
> > @@ -32331,11 +32338,11 @@ cp_parser_constructor_declarator_p (cp_parser *parser, cp_parser_flags flags,
> > if (next_token->type != CPP_NAME
> > && next_token->type != CPP_SCOPE
> > && next_token->type != CPP_NESTED_NAME_SPECIFIER
> > - /* DR 2237 (C++20 only): A simple-template-id is no longer valid as the
> > - declarator-id of a constructor or destructor. */
> > - && (next_token->type != CPP_TEMPLATE_ID || cxx_dialect >= cxx20))
> > + && next_token->type != CPP_TEMPLATE_ID)
> > return false;
> > + const bool saw_template_id = (next_token->type == CPP_TEMPLATE_ID);
>
> Please incorporate your "further DR2237 fix" patch into this one.
Patches squashed.
> > @@ -32552,6 +32559,19 @@ cp_parser_constructor_declarator_p (cp_parser *parser, cp_parser_flags flags,
> > /* We did not really want to consume any tokens. */
> > cp_parser_abort_tentative_parse (parser);
> > + /* DR 2237 (C++20 only): A simple-template-id is no longer valid as the
> > + declarator-id of a constructor or destructor. */
> > + if (constructor_p && saw_template_id)
> > + {
> > + gcc_checking_assert
> > + (!cp_parser_uncommitted_to_tentative_parse_p (parser));
>
> Now I see the abort_ just above, so this seems unnecessary after all.
Done, thanks.
Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
-- >8 --
Since my r11-532 changes to implement DR2237, for this test:
template<typename T>
struct S {
S<T>();
};
in C++20 we emit the ugly:
q.C:3:8: error: expected unqualified-id before ')' token
3 | S<T>();
which doesn't explain what the problem is. This patch improves that
diagnostic, reduces the error to a pedwarn, and adds a -Wc++20-compat
diagnostic. We now say:
q.C:3:7: warning: template-id not allowed for constructor in C++20 [-Wtemplate-id-cdtor]
3 | S<T>();
q.C:3:7: note: remove the '< >'
This patch also fixes
<https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97202#c8>
where the C++20 diagnostic was missing altogether: The problem was that I checked
for CPP_TEMPLATE_ID too early, at a point at which cp_parser_template_id may not
have been called yet. So let's check for it at the end of the function, after
the tentative parse and rollback.
-Wc++20-compat triggered in libitm/; I sent a patch for that.
DR 2237
PR c++/107126
PR c++/97202
gcc/c-family/ChangeLog:
* c-opts.cc (c_common_post_options): In C++20 or with -Wc++20-compat,
turn on -Wtemplate-id-cdtor.
* c.opt (Wtemplate-id-cdtor): New.
gcc/cp/ChangeLog:
* parser.cc (cp_parser_unqualified_id): Downgrade the DR2237 error to
a pedwarn.
(cp_parser_constructor_declarator_p): Likewise.
gcc/ChangeLog:
* doc/invoke.texi: Document -Wtemplate-id-cdtor.
gcc/testsuite/ChangeLog:
* g++.dg/DRs/dr2237.C: Adjust dg-error.
* g++.dg/parse/constructor2.C: Likewise.
* g++.dg/template/error34.C: Likewise.
* g++.old-deja/g++.pt/ctor2.C: Likewise.
* g++.dg/DRs/dr2237-2.C: New test.
* g++.dg/DRs/dr2237-3.C: New test.
* g++.dg/DRs/dr2237-4.C: New test.
* g++.dg/DRs/dr2237-5.C: New test.
* g++.dg/warn/Wtemplate-id-cdtor-1.C: New test.
* g++.dg/warn/Wtemplate-id-cdtor-2.C: New test.
* g++.dg/warn/Wtemplate-id-cdtor-3.C: New test.
* g++.dg/warn/Wtemplate-id-cdtor-4.C: New test.
---
gcc/c-family/c-opts.cc | 5 +++
gcc/c-family/c.opt | 4 +++
gcc/cp/parser.cc | 33 ++++++++++++++-----
gcc/doc/invoke.texi | 19 ++++++++++-
gcc/testsuite/g++.dg/DRs/dr2237-2.C | 9 +++++
gcc/testsuite/g++.dg/DRs/dr2237-3.C | 16 +++++++++
gcc/testsuite/g++.dg/DRs/dr2237-4.C | 11 +++++++
gcc/testsuite/g++.dg/DRs/dr2237-5.C | 7 ++++
gcc/testsuite/g++.dg/DRs/dr2237.C | 2 +-
gcc/testsuite/g++.dg/parse/constructor2.C | 16 ++++-----
gcc/testsuite/g++.dg/template/error34.C | 10 +++---
.../g++.dg/warn/Wtemplate-id-cdtor-1.C | 9 +++++
.../g++.dg/warn/Wtemplate-id-cdtor-2.C | 9 +++++
.../g++.dg/warn/Wtemplate-id-cdtor-3.C | 9 +++++
.../g++.dg/warn/Wtemplate-id-cdtor-4.C | 9 +++++
gcc/testsuite/g++.old-deja/g++.pt/ctor2.C | 2 +-
16 files changed, 146 insertions(+), 24 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/DRs/dr2237-2.C
create mode 100644 gcc/testsuite/g++.dg/DRs/dr2237-3.C
create mode 100644 gcc/testsuite/g++.dg/DRs/dr2237-4.C
create mode 100644 gcc/testsuite/g++.dg/DRs/dr2237-5.C
create mode 100644 gcc/testsuite/g++.dg/warn/Wtemplate-id-cdtor-1.C
create mode 100644 gcc/testsuite/g++.dg/warn/Wtemplate-id-cdtor-2.C
create mode 100644 gcc/testsuite/g++.dg/warn/Wtemplate-id-cdtor-3.C
create mode 100644 gcc/testsuite/g++.dg/warn/Wtemplate-id-cdtor-4.C
base-commit: f29f7f86935e29786bf9f976ec99d7639b381b14
Comments
On 2/9/24 18:46, Marek Polacek wrote:
> On Fri, Feb 09, 2024 at 10:20:04AM -0500, Jason Merrill wrote:
>> On 2/8/24 16:26, Marek Polacek wrote:
>>> This patch does *not* fix
>>> <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97202#c8>
>>> where the C++20 diagnostic is missing altogether.
>>
>> What would it take to fix that as well?
>
> It's the "further DR2237 fix" below which is basically a one liner.
> I'd thought it would be more involved than that.
>
>>> * doc/invoke.texi: Document -Wdeprecated-template-id-cdtor.
>>
>> Was it ever deprecated? I'm not seeing that in
>>
>> https://timsong-cpp.github.io/cppwp/n4659/#depr (C++17)
>
> Aha, [diff] != [depr]...
>
>> Let's drop the word "deprecated" from the option name and documentation.
>
> Done throughout.
>
>>> @@ -32331,11 +32338,11 @@ cp_parser_constructor_declarator_p (cp_parser *parser, cp_parser_flags flags,
>>> if (next_token->type != CPP_NAME
>>> && next_token->type != CPP_SCOPE
>>> && next_token->type != CPP_NESTED_NAME_SPECIFIER
>>> - /* DR 2237 (C++20 only): A simple-template-id is no longer valid as the
>>> - declarator-id of a constructor or destructor. */
>>> - && (next_token->type != CPP_TEMPLATE_ID || cxx_dialect >= cxx20))
>>> + && next_token->type != CPP_TEMPLATE_ID)
>>> return false;
>>> + const bool saw_template_id = (next_token->type == CPP_TEMPLATE_ID);
>>
>> Please incorporate your "further DR2237 fix" patch into this one.
>
> Patches squashed.
>
>>> @@ -32552,6 +32559,19 @@ cp_parser_constructor_declarator_p (cp_parser *parser, cp_parser_flags flags,
>>> /* We did not really want to consume any tokens. */
>>> cp_parser_abort_tentative_parse (parser);
>>> + /* DR 2237 (C++20 only): A simple-template-id is no longer valid as the
>>> + declarator-id of a constructor or destructor. */
>>> + if (constructor_p && saw_template_id)
>>> + {
>>> + gcc_checking_assert
>>> + (!cp_parser_uncommitted_to_tentative_parse_p (parser));
>>
>> Now I see the abort_ just above, so this seems unnecessary after all.
>
> Done, thanks.
>
> Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
OK, thanks.
> -- >8 --
> Since my r11-532 changes to implement DR2237, for this test:
>
> template<typename T>
> struct S {
> S<T>();
> };
>
> in C++20 we emit the ugly:
>
> q.C:3:8: error: expected unqualified-id before ')' token
> 3 | S<T>();
>
> which doesn't explain what the problem is. This patch improves that
> diagnostic, reduces the error to a pedwarn, and adds a -Wc++20-compat
> diagnostic. We now say:
>
> q.C:3:7: warning: template-id not allowed for constructor in C++20 [-Wtemplate-id-cdtor]
> 3 | S<T>();
> q.C:3:7: note: remove the '< >'
>
> This patch also fixes
> <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97202#c8>
> where the C++20 diagnostic was missing altogether: The problem was that I checked
> for CPP_TEMPLATE_ID too early, at a point at which cp_parser_template_id may not
> have been called yet. So let's check for it at the end of the function, after
> the tentative parse and rollback.
>
> -Wc++20-compat triggered in libitm/; I sent a patch for that.
>
> DR 2237
> PR c++/107126
> PR c++/97202
>
> gcc/c-family/ChangeLog:
>
> * c-opts.cc (c_common_post_options): In C++20 or with -Wc++20-compat,
> turn on -Wtemplate-id-cdtor.
> * c.opt (Wtemplate-id-cdtor): New.
>
> gcc/cp/ChangeLog:
>
> * parser.cc (cp_parser_unqualified_id): Downgrade the DR2237 error to
> a pedwarn.
> (cp_parser_constructor_declarator_p): Likewise.
>
> gcc/ChangeLog:
>
> * doc/invoke.texi: Document -Wtemplate-id-cdtor.
>
> gcc/testsuite/ChangeLog:
>
> * g++.dg/DRs/dr2237.C: Adjust dg-error.
> * g++.dg/parse/constructor2.C: Likewise.
> * g++.dg/template/error34.C: Likewise.
> * g++.old-deja/g++.pt/ctor2.C: Likewise.
> * g++.dg/DRs/dr2237-2.C: New test.
> * g++.dg/DRs/dr2237-3.C: New test.
> * g++.dg/DRs/dr2237-4.C: New test.
> * g++.dg/DRs/dr2237-5.C: New test.
> * g++.dg/warn/Wtemplate-id-cdtor-1.C: New test.
> * g++.dg/warn/Wtemplate-id-cdtor-2.C: New test.
> * g++.dg/warn/Wtemplate-id-cdtor-3.C: New test.
> * g++.dg/warn/Wtemplate-id-cdtor-4.C: New test.
> ---
> gcc/c-family/c-opts.cc | 5 +++
> gcc/c-family/c.opt | 4 +++
> gcc/cp/parser.cc | 33 ++++++++++++++-----
> gcc/doc/invoke.texi | 19 ++++++++++-
> gcc/testsuite/g++.dg/DRs/dr2237-2.C | 9 +++++
> gcc/testsuite/g++.dg/DRs/dr2237-3.C | 16 +++++++++
> gcc/testsuite/g++.dg/DRs/dr2237-4.C | 11 +++++++
> gcc/testsuite/g++.dg/DRs/dr2237-5.C | 7 ++++
> gcc/testsuite/g++.dg/DRs/dr2237.C | 2 +-
> gcc/testsuite/g++.dg/parse/constructor2.C | 16 ++++-----
> gcc/testsuite/g++.dg/template/error34.C | 10 +++---
> .../g++.dg/warn/Wtemplate-id-cdtor-1.C | 9 +++++
> .../g++.dg/warn/Wtemplate-id-cdtor-2.C | 9 +++++
> .../g++.dg/warn/Wtemplate-id-cdtor-3.C | 9 +++++
> .../g++.dg/warn/Wtemplate-id-cdtor-4.C | 9 +++++
> gcc/testsuite/g++.old-deja/g++.pt/ctor2.C | 2 +-
> 16 files changed, 146 insertions(+), 24 deletions(-)
> create mode 100644 gcc/testsuite/g++.dg/DRs/dr2237-2.C
> create mode 100644 gcc/testsuite/g++.dg/DRs/dr2237-3.C
> create mode 100644 gcc/testsuite/g++.dg/DRs/dr2237-4.C
> create mode 100644 gcc/testsuite/g++.dg/DRs/dr2237-5.C
> create mode 100644 gcc/testsuite/g++.dg/warn/Wtemplate-id-cdtor-1.C
> create mode 100644 gcc/testsuite/g++.dg/warn/Wtemplate-id-cdtor-2.C
> create mode 100644 gcc/testsuite/g++.dg/warn/Wtemplate-id-cdtor-3.C
> create mode 100644 gcc/testsuite/g++.dg/warn/Wtemplate-id-cdtor-4.C
>
> diff --git a/gcc/c-family/c-opts.cc b/gcc/c-family/c-opts.cc
> index b845aff2226..be3058dca63 100644
> --- a/gcc/c-family/c-opts.cc
> +++ b/gcc/c-family/c-opts.cc
> @@ -998,6 +998,11 @@ c_common_post_options (const char **pfilename)
> warn_deprecated_enum_float_conv,
> cxx_dialect >= cxx20 && warn_deprecated);
>
> + /* -Wtemplate-id-cdtor is enabled by default in C++20. */
> + SET_OPTION_IF_UNSET (&global_options, &global_options_set,
> + warn_template_id_cdtor,
> + cxx_dialect >= cxx20 || warn_cxx20_compat);
> +
> /* Declone C++ 'structors if -Os. */
> if (flag_declone_ctor_dtor == -1)
> flag_declone_ctor_dtor = optimize_size;
> diff --git a/gcc/c-family/c.opt b/gcc/c-family/c.opt
> index 9c0a28092fc..b7a4a1a68e3 100644
> --- a/gcc/c-family/c.opt
> +++ b/gcc/c-family/c.opt
> @@ -1408,6 +1408,10 @@ Wtautological-compare
> C ObjC C++ ObjC++ Var(warn_tautological_compare) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
> Warn if a comparison always evaluates to true or false.
>
> +Wtemplate-id-cdtor
> +C++ ObjC++ Var(warn_template_id_cdtor) Warning
> +Warn about simple-template-id in a constructor or destructor.
> +
> Wterminate
> C++ ObjC++ Warning Var(warn_terminate) Init(1)
> Warn if a throw expression will always result in a call to terminate().
> diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc
> index 09ecfa23b5d..8bba2fdef96 100644
> --- a/gcc/cp/parser.cc
> +++ b/gcc/cp/parser.cc
> @@ -6719,12 +6719,19 @@ cp_parser_unqualified_id (cp_parser* parser,
>
> /* 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 && declarator_p
> - && cxx_dialect >= cxx20)
> + if (token->type == CPP_TEMPLATE_ID && declarator_p)
> {
> - if (!cp_parser_simulate_error (parser))
> - error_at (tilde_loc, "template-id not allowed for destructor");
> - return error_mark_node;
> + auto_diagnostic_group d;
> + bool w = false;
> + if (cxx_dialect >= cxx20 && !cp_parser_simulate_error (parser))
> + w = pedwarn (tilde_loc, OPT_Wtemplate_id_cdtor,
> + "template-id not allowed for destructor in C++20");
> + else if (cxx_dialect < cxx20
> + && !cp_parser_uncommitted_to_tentative_parse_p (parser))
> + w = warning_at (tilde_loc, OPT_Wtemplate_id_cdtor,
> + "template-id not allowed for destructor in C++20");
> + if (w)
> + inform (tilde_loc, "remove the %qs", "< >");
> }
>
> /* If there was an explicit qualification (S::~T), first look
> @@ -32331,9 +32338,7 @@ cp_parser_constructor_declarator_p (cp_parser *parser, cp_parser_flags flags,
> if (next_token->type != CPP_NAME
> && next_token->type != CPP_SCOPE
> && next_token->type != CPP_NESTED_NAME_SPECIFIER
> - /* DR 2237 (C++20 only): A simple-template-id is no longer valid as the
> - declarator-id of a constructor or destructor. */
> - && (next_token->type != CPP_TEMPLATE_ID || cxx_dialect >= cxx20))
> + && next_token->type != CPP_TEMPLATE_ID)
> return false;
>
> /* Parse tentatively; we are going to roll back all of the tokens
> @@ -32552,6 +32557,18 @@ cp_parser_constructor_declarator_p (cp_parser *parser, cp_parser_flags flags,
> /* We did not really want to consume any tokens. */
> cp_parser_abort_tentative_parse (parser);
>
> + /* DR 2237 (C++20 only): A simple-template-id is no longer valid as the
> + declarator-id of a constructor or destructor. */
> + if (constructor_p
> + && cp_lexer_peek_token (parser->lexer)->type == CPP_TEMPLATE_ID)
> + {
> + auto_diagnostic_group d;
> + if (emit_diagnostic (cxx_dialect >= cxx20 ? DK_PEDWARN : DK_WARNING,
> + input_location, OPT_Wtemplate_id_cdtor,
> + "template-id not allowed for constructor in C++20"))
> + inform (input_location, "remove the %qs", "< >");
> + }
> +
> return constructor_p;
> }
>
> diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
> index 71339b8b30f..0de184f6241 100644
> --- a/gcc/doc/invoke.texi
> +++ b/gcc/doc/invoke.texi
> @@ -270,7 +270,7 @@ in the following sections.
> -Wno-non-template-friend -Wold-style-cast
> -Woverloaded-virtual -Wno-pmf-conversions -Wself-move -Wsign-promo
> -Wsized-deallocation -Wsuggest-final-methods
> --Wsuggest-final-types -Wsuggest-override
> +-Wsuggest-final-types -Wsuggest-override -Wno-template-id-cdtor
> -Wno-terminate -Wno-vexing-parse -Wvirtual-inheritance
> -Wno-virtual-move-assign -Wvolatile -Wzero-as-null-pointer-constant}
>
> @@ -4604,6 +4604,23 @@ namespaces, and this may be used to enforce that rule. The warning is
> inactive inside a system header file, such as the STL, so one can still
> use the STL. One may also use using directives and qualified names.
>
> +@opindex Wtemplate-id-cdtor
> +@opindex Wno-template-id-cdtor
> +@item -Wno-template-id-cdtor @r{(C++ and Objective-C++ only)}
> +Disable the warning about the use of simple-template-id as the declarator-id
> +of a constructor or destructor, which became invalid in C++20 via DR 2237.
> +For example:
> +
> +@smallexample
> +template<typename T> struct S @{
> + S<T>(); // should be S();
> + ~S<T>(); // should be ~S();
> +@};
> +@end smallexample
> +
> +@option{-Wtemplate-id-cdtor} is enabled by default with
> +@option{-std=c++20}; it is also enabled by @option{-Wc++20-compat}.
> +
> @opindex Wterminate
> @opindex Wno-terminate
> @item -Wno-terminate @r{(C++ and Objective-C++ only)}
> diff --git a/gcc/testsuite/g++.dg/DRs/dr2237-2.C b/gcc/testsuite/g++.dg/DRs/dr2237-2.C
> new file mode 100644
> index 00000000000..1d99347229c
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/DRs/dr2237-2.C
> @@ -0,0 +1,9 @@
> +// DR 2237 - Can a template-id name a constructor?
> +// { dg-options "" }
> +
> +template<class T>
> +struct X {
> + X<T>(); // { dg-warning "template-id not allowed for constructor" "" { target c++20 } }
> + X(int); // OK, injected-class-name used
> + ~X<T>(); // { dg-warning "template-id not allowed for destructor" "" { target c++20 } }
> +};
> diff --git a/gcc/testsuite/g++.dg/DRs/dr2237-3.C b/gcc/testsuite/g++.dg/DRs/dr2237-3.C
> new file mode 100644
> index 00000000000..c8ad6852389
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/DRs/dr2237-3.C
> @@ -0,0 +1,16 @@
> +// PR c++/107126
> +// { dg-options "" }
> +
> +template<typename T>
> +struct C
> +{
> + ~C();
> +};
> +template<typename T>
> +C<T>::~C<T>() // { dg-warning "template-id not allowed for destructor" "" { target c++20 } }
> +{
> +}
> +int main()
> +{
> + C<int> c;;
> +}
> diff --git a/gcc/testsuite/g++.dg/DRs/dr2237-4.C b/gcc/testsuite/g++.dg/DRs/dr2237-4.C
> new file mode 100644
> index 00000000000..a358dd521b5
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/DRs/dr2237-4.C
> @@ -0,0 +1,11 @@
> +// PR c++/97202
> +// { dg-options "" }
> +
> +template<typename T>
> +struct F
> +{
> + F<T>(); // { dg-warning "template-id not allowed for constructor" "" { target c++20 } }
> +};
> +
> +template<typename T>
> +inline F<T>::F() { }
> diff --git a/gcc/testsuite/g++.dg/DRs/dr2237-5.C b/gcc/testsuite/g++.dg/DRs/dr2237-5.C
> new file mode 100644
> index 00000000000..fd51968f7e1
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/DRs/dr2237-5.C
> @@ -0,0 +1,7 @@
> +// PR c++/97202
> +// { dg-options "" }
> +
> +template<typename Base> struct S : Base {
> + inline S<Base>() {} // { dg-warning "template-id not allowed for constructor" "" { target c++20 } }
> + inline ~S<Base>() {} // { dg-warning "template-id not allowed for destructor" "" { target c++20 } }
> +};
> diff --git a/gcc/testsuite/g++.dg/DRs/dr2237.C b/gcc/testsuite/g++.dg/DRs/dr2237.C
> index f3d6d11e61e..830c8f5a2a6 100644
> --- a/gcc/testsuite/g++.dg/DRs/dr2237.C
> +++ b/gcc/testsuite/g++.dg/DRs/dr2237.C
> @@ -2,7 +2,7 @@
>
> template<class T>
> struct X {
> - X<T>(); // { dg-error "expected" "" { target c++20 } }
> + X<T>(); // { dg-error "template-id not allowed for constructor" "" { target c++20 } }
> X(int); // OK, injected-class-name used
> ~X<T>(); // { dg-error "template-id not allowed for destructor" "" { target c++20 } }
> };
> diff --git a/gcc/testsuite/g++.dg/parse/constructor2.C b/gcc/testsuite/g++.dg/parse/constructor2.C
> index d620f41e027..e4b2ad3f2fe 100644
> --- a/gcc/testsuite/g++.dg/parse/constructor2.C
> +++ b/gcc/testsuite/g++.dg/parse/constructor2.C
> @@ -1,11 +1,11 @@
> // PR c++/14260
>
> -template <class TClass>
> -class T
> -{
> -public:
> - T(short,short f=0) {}
> - T<TClass>(int f) {} // { dg-error "expected" "" { target c++20 } }
> - T<TClass>(int f=0,const char* b=0) {} // { dg-error "expected" "" { target c++20 } }
> -};
> +template <class TClass>
> +class T
> +{
> +public:
> + T(short,short f=0) {}
> + T<TClass>(int f) {} // { dg-error "template-id not allowed for constructor" "" { target c++20 } }
> + T<TClass>(int f=0,const char* b=0) {} // { dg-error "template-id not allowed for constructor" "" { target c++20 } }
> +};
>
> diff --git a/gcc/testsuite/g++.dg/template/error34.C b/gcc/testsuite/g++.dg/template/error34.C
> index ab688d9ba8c..921cb8fb729 100644
> --- a/gcc/testsuite/g++.dg/template/error34.C
> +++ b/gcc/testsuite/g++.dg/template/error34.C
> @@ -3,27 +3,27 @@
>
> template<typename T> struct A
> {
> - A<__builtin_offsetof(T, x)>(); // { dg-error "type/value mismatch|offsetof\\(T, x\\)|expected" }
> + A<__builtin_offsetof(T, x)>(); // { dg-error "type/value mismatch|offsetof\\(T, x\\)|template-id" }
> };
>
> template<typename T> struct B
> {
> - B<__builtin_offsetof(T, x.y)>(); // { dg-error "type/value mismatch|offsetof\\(T, x.y\\)|expected" }
> + B<__builtin_offsetof(T, x.y)>(); // { dg-error "type/value mismatch|offsetof\\(T, x.y\\)|template-id" }
> };
>
> template<typename T> struct C
> {
> - C<__builtin_offsetof(T, x[6])>(); // { dg-error "type/value mismatch|offsetof\\(T, x\\\[6\\\]\\)|expected" }
> + C<__builtin_offsetof(T, x[6])>(); // { dg-error "type/value mismatch|offsetof\\(T, x\\\[6\\\]\\)|template-id" }
> };
>
> template<typename T> struct D
> {
> - D<__builtin_offsetof(T, x.y[6].z)>(); // { dg-error "type/value mismatch|offsetof\\(T, x.y\\\[6\\\].z\\)|expected" }
> + D<__builtin_offsetof(T, x.y[6].z)>(); // { dg-error "type/value mismatch|offsetof\\(T, x.y\\\[6\\\].z\\)|template-id" }
> };
>
> struct E { int x; };
>
> template<typename T> struct F
> {
> - F<__builtin_offsetof(E, x)>(); // { dg-error "type/value mismatch|offsetof\\(E, x\\)|expected" }
> + F<__builtin_offsetof(E, x)>(); // { dg-error "type/value mismatch|offsetof\\(E, x\\)|template-id" }
> };
> diff --git a/gcc/testsuite/g++.dg/warn/Wtemplate-id-cdtor-1.C b/gcc/testsuite/g++.dg/warn/Wtemplate-id-cdtor-1.C
> new file mode 100644
> index 00000000000..429490708bc
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/warn/Wtemplate-id-cdtor-1.C
> @@ -0,0 +1,9 @@
> +// PR c++/107126
> +// { dg-do compile }
> +// { dg-options "-Wc++20-compat" }
> +
> +template<class T>
> +struct X {
> + X<T>(); // { dg-warning "template-id not allowed for constructor" }
> + ~X<T>(); // { dg-warning "template-id not allowed for destructor" }
> +};
> diff --git a/gcc/testsuite/g++.dg/warn/Wtemplate-id-cdtor-2.C b/gcc/testsuite/g++.dg/warn/Wtemplate-id-cdtor-2.C
> new file mode 100644
> index 00000000000..2b1c4ea8222
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/warn/Wtemplate-id-cdtor-2.C
> @@ -0,0 +1,9 @@
> +// PR c++/107126
> +// { dg-do compile }
> +// { dg-options "-Wtemplate-id-cdtor" }
> +
> +template<class T>
> +struct X {
> + X<T>(); // { dg-warning "template-id not allowed for constructor" }
> + ~X<T>(); // { dg-warning "template-id not allowed for destructor" }
> +};
> diff --git a/gcc/testsuite/g++.dg/warn/Wtemplate-id-cdtor-3.C b/gcc/testsuite/g++.dg/warn/Wtemplate-id-cdtor-3.C
> new file mode 100644
> index 00000000000..bed96e84bd2
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/warn/Wtemplate-id-cdtor-3.C
> @@ -0,0 +1,9 @@
> +// PR c++/107126
> +// { dg-do compile }
> +// { dg-options "-Wc++20-compat -Wno-template-id-cdtor" }
> +
> +template<class T>
> +struct X {
> + X<T>(); // { dg-bogus "template-id not allowed for constructor" }
> + ~X<T>(); // { dg-bogus "template-id not allowed for destructor" }
> +};
> diff --git a/gcc/testsuite/g++.dg/warn/Wtemplate-id-cdtor-4.C b/gcc/testsuite/g++.dg/warn/Wtemplate-id-cdtor-4.C
> new file mode 100644
> index 00000000000..706e5746e60
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/warn/Wtemplate-id-cdtor-4.C
> @@ -0,0 +1,9 @@
> +// PR c++/107126
> +// { dg-do compile }
> +// { dg-options "-Wtemplate-id-cdtor -Wno-c++20-compat" }
> +
> +template<class T>
> +struct X {
> + X<T>(); // { dg-warning "template-id not allowed for constructor" }
> + ~X<T>(); // { dg-warning "template-id not allowed for destructor" }
> +};
> diff --git a/gcc/testsuite/g++.old-deja/g++.pt/ctor2.C b/gcc/testsuite/g++.old-deja/g++.pt/ctor2.C
> index bf418ba48c7..56b4232d04b 100644
> --- a/gcc/testsuite/g++.old-deja/g++.pt/ctor2.C
> +++ b/gcc/testsuite/g++.old-deja/g++.pt/ctor2.C
> @@ -4,7 +4,7 @@
>
> template <class T>
> struct A {
> - A<T>(); // { dg-error "expected" "" { target c++20 } }
> + A<T>(); // { dg-error "template-id" "" { target c++20 } }
> };
>
> template <class T>
>
> base-commit: f29f7f86935e29786bf9f976ec99d7639b381b14
@@ -998,6 +998,11 @@ c_common_post_options (const char **pfilename)
warn_deprecated_enum_float_conv,
cxx_dialect >= cxx20 && warn_deprecated);
+ /* -Wtemplate-id-cdtor is enabled by default in C++20. */
+ SET_OPTION_IF_UNSET (&global_options, &global_options_set,
+ warn_template_id_cdtor,
+ cxx_dialect >= cxx20 || warn_cxx20_compat);
+
/* Declone C++ 'structors if -Os. */
if (flag_declone_ctor_dtor == -1)
flag_declone_ctor_dtor = optimize_size;
@@ -1408,6 +1408,10 @@ Wtautological-compare
C ObjC C++ ObjC++ Var(warn_tautological_compare) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
Warn if a comparison always evaluates to true or false.
+Wtemplate-id-cdtor
+C++ ObjC++ Var(warn_template_id_cdtor) Warning
+Warn about simple-template-id in a constructor or destructor.
+
Wterminate
C++ ObjC++ Warning Var(warn_terminate) Init(1)
Warn if a throw expression will always result in a call to terminate().
@@ -6719,12 +6719,19 @@ cp_parser_unqualified_id (cp_parser* parser,
/* 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 && declarator_p
- && cxx_dialect >= cxx20)
+ if (token->type == CPP_TEMPLATE_ID && declarator_p)
{
- if (!cp_parser_simulate_error (parser))
- error_at (tilde_loc, "template-id not allowed for destructor");
- return error_mark_node;
+ auto_diagnostic_group d;
+ bool w = false;
+ if (cxx_dialect >= cxx20 && !cp_parser_simulate_error (parser))
+ w = pedwarn (tilde_loc, OPT_Wtemplate_id_cdtor,
+ "template-id not allowed for destructor in C++20");
+ else if (cxx_dialect < cxx20
+ && !cp_parser_uncommitted_to_tentative_parse_p (parser))
+ w = warning_at (tilde_loc, OPT_Wtemplate_id_cdtor,
+ "template-id not allowed for destructor in C++20");
+ if (w)
+ inform (tilde_loc, "remove the %qs", "< >");
}
/* If there was an explicit qualification (S::~T), first look
@@ -32331,9 +32338,7 @@ cp_parser_constructor_declarator_p (cp_parser *parser, cp_parser_flags flags,
if (next_token->type != CPP_NAME
&& next_token->type != CPP_SCOPE
&& next_token->type != CPP_NESTED_NAME_SPECIFIER
- /* DR 2237 (C++20 only): A simple-template-id is no longer valid as the
- declarator-id of a constructor or destructor. */
- && (next_token->type != CPP_TEMPLATE_ID || cxx_dialect >= cxx20))
+ && next_token->type != CPP_TEMPLATE_ID)
return false;
/* Parse tentatively; we are going to roll back all of the tokens
@@ -32552,6 +32557,18 @@ cp_parser_constructor_declarator_p (cp_parser *parser, cp_parser_flags flags,
/* We did not really want to consume any tokens. */
cp_parser_abort_tentative_parse (parser);
+ /* DR 2237 (C++20 only): A simple-template-id is no longer valid as the
+ declarator-id of a constructor or destructor. */
+ if (constructor_p
+ && cp_lexer_peek_token (parser->lexer)->type == CPP_TEMPLATE_ID)
+ {
+ auto_diagnostic_group d;
+ if (emit_diagnostic (cxx_dialect >= cxx20 ? DK_PEDWARN : DK_WARNING,
+ input_location, OPT_Wtemplate_id_cdtor,
+ "template-id not allowed for constructor in C++20"))
+ inform (input_location, "remove the %qs", "< >");
+ }
+
return constructor_p;
}
@@ -270,7 +270,7 @@ in the following sections.
-Wno-non-template-friend -Wold-style-cast
-Woverloaded-virtual -Wno-pmf-conversions -Wself-move -Wsign-promo
-Wsized-deallocation -Wsuggest-final-methods
--Wsuggest-final-types -Wsuggest-override
+-Wsuggest-final-types -Wsuggest-override -Wno-template-id-cdtor
-Wno-terminate -Wno-vexing-parse -Wvirtual-inheritance
-Wno-virtual-move-assign -Wvolatile -Wzero-as-null-pointer-constant}
@@ -4604,6 +4604,23 @@ namespaces, and this may be used to enforce that rule. The warning is
inactive inside a system header file, such as the STL, so one can still
use the STL. One may also use using directives and qualified names.
+@opindex Wtemplate-id-cdtor
+@opindex Wno-template-id-cdtor
+@item -Wno-template-id-cdtor @r{(C++ and Objective-C++ only)}
+Disable the warning about the use of simple-template-id as the declarator-id
+of a constructor or destructor, which became invalid in C++20 via DR 2237.
+For example:
+
+@smallexample
+template<typename T> struct S @{
+ S<T>(); // should be S();
+ ~S<T>(); // should be ~S();
+@};
+@end smallexample
+
+@option{-Wtemplate-id-cdtor} is enabled by default with
+@option{-std=c++20}; it is also enabled by @option{-Wc++20-compat}.
+
@opindex Wterminate
@opindex Wno-terminate
@item -Wno-terminate @r{(C++ and Objective-C++ only)}
new file mode 100644
@@ -0,0 +1,9 @@
+// DR 2237 - Can a template-id name a constructor?
+// { dg-options "" }
+
+template<class T>
+struct X {
+ X<T>(); // { dg-warning "template-id not allowed for constructor" "" { target c++20 } }
+ X(int); // OK, injected-class-name used
+ ~X<T>(); // { dg-warning "template-id not allowed for destructor" "" { target c++20 } }
+};
new file mode 100644
@@ -0,0 +1,16 @@
+// PR c++/107126
+// { dg-options "" }
+
+template<typename T>
+struct C
+{
+ ~C();
+};
+template<typename T>
+C<T>::~C<T>() // { dg-warning "template-id not allowed for destructor" "" { target c++20 } }
+{
+}
+int main()
+{
+ C<int> c;;
+}
new file mode 100644
@@ -0,0 +1,11 @@
+// PR c++/97202
+// { dg-options "" }
+
+template<typename T>
+struct F
+{
+ F<T>(); // { dg-warning "template-id not allowed for constructor" "" { target c++20 } }
+};
+
+template<typename T>
+inline F<T>::F() { }
new file mode 100644
@@ -0,0 +1,7 @@
+// PR c++/97202
+// { dg-options "" }
+
+template<typename Base> struct S : Base {
+ inline S<Base>() {} // { dg-warning "template-id not allowed for constructor" "" { target c++20 } }
+ inline ~S<Base>() {} // { dg-warning "template-id not allowed for destructor" "" { target c++20 } }
+};
@@ -2,7 +2,7 @@
template<class T>
struct X {
- X<T>(); // { dg-error "expected" "" { target c++20 } }
+ X<T>(); // { dg-error "template-id not allowed for constructor" "" { target c++20 } }
X(int); // OK, injected-class-name used
~X<T>(); // { dg-error "template-id not allowed for destructor" "" { target c++20 } }
};
@@ -1,11 +1,11 @@
// PR c++/14260
-template <class TClass>
-class T
-{
-public:
- T(short,short f=0) {}
- T<TClass>(int f) {} // { dg-error "expected" "" { target c++20 } }
- T<TClass>(int f=0,const char* b=0) {} // { dg-error "expected" "" { target c++20 } }
-};
+template <class TClass>
+class T
+{
+public:
+ T(short,short f=0) {}
+ T<TClass>(int f) {} // { dg-error "template-id not allowed for constructor" "" { target c++20 } }
+ T<TClass>(int f=0,const char* b=0) {} // { dg-error "template-id not allowed for constructor" "" { target c++20 } }
+};
@@ -3,27 +3,27 @@
template<typename T> struct A
{
- A<__builtin_offsetof(T, x)>(); // { dg-error "type/value mismatch|offsetof\\(T, x\\)|expected" }
+ A<__builtin_offsetof(T, x)>(); // { dg-error "type/value mismatch|offsetof\\(T, x\\)|template-id" }
};
template<typename T> struct B
{
- B<__builtin_offsetof(T, x.y)>(); // { dg-error "type/value mismatch|offsetof\\(T, x.y\\)|expected" }
+ B<__builtin_offsetof(T, x.y)>(); // { dg-error "type/value mismatch|offsetof\\(T, x.y\\)|template-id" }
};
template<typename T> struct C
{
- C<__builtin_offsetof(T, x[6])>(); // { dg-error "type/value mismatch|offsetof\\(T, x\\\[6\\\]\\)|expected" }
+ C<__builtin_offsetof(T, x[6])>(); // { dg-error "type/value mismatch|offsetof\\(T, x\\\[6\\\]\\)|template-id" }
};
template<typename T> struct D
{
- D<__builtin_offsetof(T, x.y[6].z)>(); // { dg-error "type/value mismatch|offsetof\\(T, x.y\\\[6\\\].z\\)|expected" }
+ D<__builtin_offsetof(T, x.y[6].z)>(); // { dg-error "type/value mismatch|offsetof\\(T, x.y\\\[6\\\].z\\)|template-id" }
};
struct E { int x; };
template<typename T> struct F
{
- F<__builtin_offsetof(E, x)>(); // { dg-error "type/value mismatch|offsetof\\(E, x\\)|expected" }
+ F<__builtin_offsetof(E, x)>(); // { dg-error "type/value mismatch|offsetof\\(E, x\\)|template-id" }
};
new file mode 100644
@@ -0,0 +1,9 @@
+// PR c++/107126
+// { dg-do compile }
+// { dg-options "-Wc++20-compat" }
+
+template<class T>
+struct X {
+ X<T>(); // { dg-warning "template-id not allowed for constructor" }
+ ~X<T>(); // { dg-warning "template-id not allowed for destructor" }
+};
new file mode 100644
@@ -0,0 +1,9 @@
+// PR c++/107126
+// { dg-do compile }
+// { dg-options "-Wtemplate-id-cdtor" }
+
+template<class T>
+struct X {
+ X<T>(); // { dg-warning "template-id not allowed for constructor" }
+ ~X<T>(); // { dg-warning "template-id not allowed for destructor" }
+};
new file mode 100644
@@ -0,0 +1,9 @@
+// PR c++/107126
+// { dg-do compile }
+// { dg-options "-Wc++20-compat -Wno-template-id-cdtor" }
+
+template<class T>
+struct X {
+ X<T>(); // { dg-bogus "template-id not allowed for constructor" }
+ ~X<T>(); // { dg-bogus "template-id not allowed for destructor" }
+};
new file mode 100644
@@ -0,0 +1,9 @@
+// PR c++/107126
+// { dg-do compile }
+// { dg-options "-Wtemplate-id-cdtor -Wno-c++20-compat" }
+
+template<class T>
+struct X {
+ X<T>(); // { dg-warning "template-id not allowed for constructor" }
+ ~X<T>(); // { dg-warning "template-id not allowed for destructor" }
+};
@@ -4,7 +4,7 @@
template <class T>
struct A {
- A<T>(); // { dg-error "expected" "" { target c++20 } }
+ A<T>(); // { dg-error "template-id" "" { target c++20 } }
};
template <class T>