Tracking Issue for comparing `TypeId` in const items

[raldone01]

Feature gate: #![feature(const_cmp_type_id)]

This is a tracking issue for comparing TypeId in const items.

Public API

impl const PartialEq for TypeId {}
impl const PartialOrd for TypeId {}
impl const Ord for TypeId {}

Steps / History

• Implementation: Constify TypeId ordering impls #101698
• Final comment period (FCP)¹
• Stabilization PR

Unresolved Questions

• Making these const precludes some possible implementations, such as the one where TypeId includes a pointer to a static as proposed in TypeId: use a (v0) mangled type to remain sound in the face of hash collisions. #95845. This const-ness should not be stabilized without an explicit decision that we never want such an implementation.

  raldone01: I don't think adding a 'static pointer would be a problem as the contents of the pointer would be compared and not the pointer addresses.

Footnotes

1. https://std-dev-guide.rust-lang.org/feature-lifecycle/stabilization.html ↩