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From: "netcan1996 at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/102229] [11/12 Regression] 'decltype(auto)' cannot be cv-qualified
Date: Thu, 09 Sep 2021 13:56:33 +0000	[thread overview]
Message-ID: <bug-102229-4-h2HtaG3HyS@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-102229-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102229

--- Comment #7 from Net Can <netcan1996 at gmail dot com> ---
here is my use case:
https://github.com/netcan/config-loader/blob/master/include/config-loader/serialize/TypeSerializer.h

the key is
```c++
#define TYPE_SERIALIZER(_type, _typeName)                 \
    struct TypeSerializer<PARE _type>                     \
    { static constexpr decltype(auto) name = _typeName; }

template<> TYPE_SERIALIZER((int8_t), "int8_t"); // (1)

template<typename T>
TYPE_SERIALIZER((std::vector<T>),
                    concat("vector<", TypeSerializer<T>::name, ">")); // (2)
```

in case (1), the `name` type is `const char(&)[N]`, but in case(2), the `name`
type is `array[N]`, so I use `decltype(auto)` rather `auto`, becase latter
loses char length info.

I tried `static decltype(auto)` not work because it is defined in class, and
requires `constexpr`.

  parent reply	other threads:[~2021-09-09 13:56 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-07 13:33 [Bug c++/102229] New: " netcan1996 at gmail dot com
2021-09-07 14:36 ` [Bug c++/102229] " marxin at gcc dot gnu.org
2021-09-07 14:37 ` [Bug c++/102229] [11/12 Regression] " rguenth at gcc dot gnu.org
2021-09-07 14:43 ` mpolacek at gcc dot gnu.org
2021-09-07 15:17 ` mpolacek at gcc dot gnu.org
2021-09-07 19:43 ` jason at gcc dot gnu.org
2021-09-07 20:06 ` mpolacek at gcc dot gnu.org
2021-09-09 13:56 ` netcan1996 at gmail dot com [this message]
2021-09-09 15:08 ` jason at gcc dot gnu.org
2021-12-09 13:58 ` mpolacek at gcc dot gnu.org
2021-12-09 18:34 ` mpolacek at gcc dot gnu.org
2021-12-15 22:48 ` cvs-commit at gcc dot gnu.org
2021-12-15 22:52 ` [Bug c++/102229] [11 " mpolacek at gcc dot gnu.org
2022-01-03 23:45 ` cvs-commit at gcc dot gnu.org
2022-01-03 23:45 ` mpolacek at gcc dot gnu.org

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