1800293 - mfbt: Don't use deprecated std::is_literal_type when compiling as C++20

Status: RESOLVED FIXED

(Core :: MFBT, task, P3)

Description

[Chris Peterson [:cpeterson]]

std::is_literal_type was deprecated in C++17 and removed in C++20. Continue using it when compiling as C++17 to retain what benefits it does provide for generic code.

The is_literal type trait offers negligible value to generic code, as what is really needed is the ability to know that a specific construction would produce constant initialization. The core term of a literal type having at least one constexpr constructor is too weak to be used meaningfully.

https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0174r2.html

https://en.cppreference.com/w/cpp/types/is_literal_type

Comment 1

[Chris Peterson [:cpeterson]]

Attachment: Bug 1800293 - mfbt: Don't use std::is_literal_type when compiling as C++20. r?glandium

std::is_literal_type was deprecated in C++17 and removed in C++20. Continue using it when compiling as C++17 to retain what benefits it does provide for generic code.

The is_literal type trait offers negligible value to generic code, as what is really needed is the ability to know that a specific construction would produce constant initialization. The core term of a literal type having at least one constexpr constructor is too weak to be used meaningfully.

https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0174r2.html

https://en.cppreference.com/w/cpp/types/is_literal_type

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/c7998ea7ac24
mfbt: Don't use std::is_literal_type when compiling as C++20. r=glandium

Comment 3

[Norisz Fay [:noriszfay]]

https://hg.mozilla.org/mozilla-central/rev/c7998ea7ac24

Comment 4

[Norisz Fay [:noriszfay]]

https://hg.mozilla.org/mozilla-central/rev/c7998ea7ac24