Tracking Issue for partial_init_locals #153699
Description
This is a tracking issue for the RFC "XXX" (rust-lang/rfcs#NNN).
The feature gate for the issue is #![feature(partial_init_locals)].
This is a small subgoal for the experiment rust-lang/lang-team#336.
This feature is to partially undo #54986 on a sane set-up. Types with no Drop can be sanely initialised gradually one field at a time.
struct A {
a: u8,
b: (u64, u64),
}
let data: A;
data.b.0 = 0;
//~ `data` not initialised
data.b.1 = 1;
//~ `data` still not initialised, but `data.b` is
data.a = 0;
// `data` is fully initialised.
data.a = 1;
//~ ERROR `data` is not mutable.Steps
- Implement the feature, see Allow phased initializing structs #152774
- Adjust documentation (see instructions on rustc-dev-guide)
- Style updates for any new syntax (nightly-style-procedure)
- Style team decision on new formatting
- Formatting for new syntax has been added to the Style Guide
- (non-blocking) Formatting has been implemented in
rustfmt
- Stabilization PR (see instructions on rustc-dev-guide)
Unresolved Questions
Implementation history
- Initial implementation in Allow phased initializing structs #152774