rust-lang / rust-lang/rust

Tracking Issue for `const_default`

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C-tracking-issue S-tracking-unimplemented T-libs
Dominant language
Rust
Stars
119k
Forks
16.1k
PR merge metrics
PR metrics pending

Description

Feature gate: #![feature(const_default)]

This is a tracking issue for Default in const fn

Public API
// core::default

pub const trait Default: Sized {
    fn default() -> Self;
}

impl const Default types:

  • ()
  • bool
  • char
  • std::ascii::Char
  • usize
  • u8
  • u16
  • u32
  • u64
  • u128
  • i8
  • i16
  • i32
  • i64
  • i128
  • f16
  • f32
  • f64
  • f128
  • std::marker::PhantomData<T>
  • Option<T>
  • std::iter::Empty<T>
  • std::ptr::Alignment
  • &[T]
  • &mut [T]
  • &str
  • &mut str
  • String
  • Vec<T>
Steps / History

(Remember to update the S-tracking-* label when checking boxes.)

  • Implementation: #134628
  • Final comment period (FCP)^1
  • Stabilization PR
Unresolved Questions

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start with this tracking issue, the blocked issue #143874, and implementation PR #134628. Review the listed const Default API and implementation history; the tracking work is complete when the blocking questions are resolved, the final comment period finishes, and a stabilization PR can proceed.

Written by the indexing model from the issue text.

Assessment

Tech stack
rust
Domain
compilers
Issue type
Feature
Difficulty
5/5
Estimated time
Over a week
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
20/100

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