Tracking Issue for APC #316: In-place case change methods for String

Feature gate: #![feature(string_make_uplowercase)]

This is a tracking issue for APC #316

This APC proposes that a new API is added to String to change cases and do so efficiently by consuming self and reusing the buffer, not allocating in most cases.

The exact implementation remains to be discussed, but the idea would be that in cases where it is possible, the case change is done in place. Once that isn't possible, a auxiliary DE-queue can be used to store bytes temporarily.

Public API

This would add the following methods (names to be determined)

impl String {
	fn into_uppercase(&mut self);
	fn into_lowercase(&mut self);
}

Steps / History

• Implementation: #135888
• Final comment period (FCP)^1
• Stabilization PR

Unresolved Questions

• None yet.