Allocators 1.0

[nxsaken]

Metadata
Contact	@nia-e
Team(s)	compiler, lang (@joshtriplett), libs (@nia-e), types
Goal document	2026/allocators-1.0
Funding contact	Hexcat

Summary

Work on expanding the standard library to natively integrate with custom allocators, while facilitating key ecosystem usecases for implementors and consumers.

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This issue is intended for status updates only.

For general questions or comments, please contact the owner(s) directly.

[nxsaken]

This issue is intended for status updates only.

For general questions or comments, please contact the owner(s) directly.

[nia-e]

Current status is that the main Allocator trait stabilisation PR is virtually ready, awaiting FCP (rust-lang/rust#156882). Proposals for a split Deallocator trait are likely also going to be unblocked very soon thanks to supertrait item shadowing getting stabilised, and once that's merged a prototype implementation should be trivial.

[nia-e]

The Allocator trait and a couple of closely-related things (namely, the A parameters on Box and Vec) are now stable on nightly and should be available stably in 1.100!