From: Jason Merrill <jason@redhat.com>
To: Marek Polacek <polacek@redhat.com>,
GCC Patches <gcc-patches@gcc.gnu.org>
Subject: Re: [PATCH] c++: warn about using keywords as identifiers [PR106111]
Date: Fri, 1 Jul 2022 11:05:42 -0400 [thread overview]
Message-ID: <88d81423-f0c0-a0da-f08f-94dad002d78b@redhat.com> (raw)
In-Reply-To: <20220629161142.29196-1-polacek@redhat.com>
On 6/29/22 12:11, Marek Polacek wrote:
> In C++03, -Wc++11-compat should warn about
>
> int constexpr;
>
> since 'constexpr' is a keyword in C++11. Jonathan reports that
> we don't emit a similar warning for 'alignas' or 'alignof', and,
> as I found out, 'thread_local'.
>
> Similarly, we don't warn for most C++20 keywords. That happens
> because RID_LAST_CXX20 hasn't been updated in a while.
>
> Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
OK.
> PR c++/106111
>
> gcc/c-family/ChangeLog:
>
> * c-common.h (enum rid): Update RID_LAST_CXX20.
>
> gcc/cp/ChangeLog:
>
> * parser.cc (cp_lexer_get_preprocessor_token): Also warn about
> RID_ALIGNOF, RID_ALIGNAS, RID_THREAD.
>
> gcc/testsuite/ChangeLog:
>
> * g++.dg/cpp0x/keywords1.C: New test.
> * g++.dg/cpp2a/keywords1.C: New test.
> ---
> gcc/c-family/c-common.h | 2 +-
> gcc/cp/parser.cc | 10 +++++++---
> gcc/testsuite/g++.dg/cpp0x/keywords1.C | 15 +++++++++++++++
> gcc/testsuite/g++.dg/cpp2a/keywords1.C | 12 ++++++++++++
> 4 files changed, 35 insertions(+), 4 deletions(-)
> create mode 100644 gcc/testsuite/g++.dg/cpp0x/keywords1.C
> create mode 100644 gcc/testsuite/g++.dg/cpp2a/keywords1.C
>
> diff --git a/gcc/c-family/c-common.h b/gcc/c-family/c-common.h
> index 47442c95a53..a1e6a55158d 100644
> --- a/gcc/c-family/c-common.h
> +++ b/gcc/c-family/c-common.h
> @@ -271,7 +271,7 @@ enum rid
> RID_FIRST_CXX11 = RID_CONSTEXPR,
> RID_LAST_CXX11 = RID_STATIC_ASSERT,
> RID_FIRST_CXX20 = RID_CONSTINIT,
> - RID_LAST_CXX20 = RID_CONSTINIT,
> + RID_LAST_CXX20 = RID_CO_RETURN,
> RID_FIRST_AT = RID_AT_ENCODE,
> RID_LAST_AT = RID_AT_IMPLEMENTATION,
> RID_FIRST_PQ = RID_IN,
> diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc
> index da2f370cdca..cc6525e0509 100644
> --- a/gcc/cp/parser.cc
> +++ b/gcc/cp/parser.cc
> @@ -890,10 +890,14 @@ cp_lexer_get_preprocessor_token (unsigned flags, cp_token *token)
> else
> {
> if (warn_cxx11_compat
> - && C_RID_CODE (token->u.value) >= RID_FIRST_CXX11
> - && C_RID_CODE (token->u.value) <= RID_LAST_CXX11)
> + && ((C_RID_CODE (token->u.value) >= RID_FIRST_CXX11
> + && C_RID_CODE (token->u.value) <= RID_LAST_CXX11)
> + /* These are outside the CXX11 range. */
> + || C_RID_CODE (token->u.value) == RID_ALIGNOF
> + || C_RID_CODE (token->u.value) == RID_ALIGNAS
> + || C_RID_CODE (token->u.value)== RID_THREAD))
> {
> - /* Warn about the C++0x keyword (but still treat it as
> + /* Warn about the C++11 keyword (but still treat it as
> an identifier). */
> warning_at (token->location, OPT_Wc__11_compat,
> "identifier %qE is a keyword in C++11",
> diff --git a/gcc/testsuite/g++.dg/cpp0x/keywords1.C b/gcc/testsuite/g++.dg/cpp0x/keywords1.C
> new file mode 100644
> index 00000000000..2b2ab6404ea
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp0x/keywords1.C
> @@ -0,0 +1,15 @@
> +// PR c++/106111
> +// { dg-do compile { target c++98_only } }
> +// { dg-options "-Wc++11-compat" }
> +
> +int alignof; // { dg-warning "is a keyword in C\\\+\\\+11" }
> +int alignas; // { dg-warning "is a keyword in C\\\+\\\+11" }
> +int constexpr; // { dg-warning "is a keyword in C\\\+\\\+11" }
> +int decltype; // { dg-warning "is a keyword in C\\\+\\\+11" }
> +int noexcept; // { dg-warning "is a keyword in C\\\+\\\+11" }
> +int nullptr; // { dg-warning "is a keyword in C\\\+\\\+11" }
> +int static_assert; // { dg-warning "is a keyword in C\\\+\\\+11" }
> +int thread_local; // { dg-warning "is a keyword in C\\\+\\\+11" }
> +int _Alignas;
> +int _Alignof;
> +int _Thread_local;
> diff --git a/gcc/testsuite/g++.dg/cpp2a/keywords1.C b/gcc/testsuite/g++.dg/cpp2a/keywords1.C
> new file mode 100644
> index 00000000000..7f4dba2d3b7
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp2a/keywords1.C
> @@ -0,0 +1,12 @@
> +// PR c++/106111
> +// { dg-do compile { target c++17_down } }
> +// { dg-options "-Wc++20-compat -Wc++11-compat -Wc++14-compat -Wc++17-compat" }
> +
> +int constinit; // { dg-warning "is a keyword in C\\\+\\\+20" }
> +int consteval; // { dg-warning "is a keyword in C\\\+\\\+20" }
> +int requires; // { dg-warning "is a keyword in C\\\+\\\+20" }
> +int concept; // { dg-warning "is a keyword in C\\\+\\\+20" }
> +int co_await; // { dg-warning "is a keyword in C\\\+\\\+20" }
> +int co_yield; // { dg-warning "is a keyword in C\\\+\\\+20" }
> +int co_return; // { dg-warning "is a keyword in C\\\+\\\+20" }
> +int char8_t; // { dg-warning "is a keyword in C\\\+\\\+20" }
>
> base-commit: b01c075e7e6d84da846c2ff9087433a30ebeb0d2
prev parent reply other threads:[~2022-07-01 15:05 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-29 16:11 Marek Polacek
2022-07-01 15:05 ` Jason Merrill [this message]
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