Tracking issue for RFC 3621: `derive(CoercePointee)`

[traviscross]

This is a tracking issue for #[derive(CoercePointee)].

The feature gate for the issue is #![feature(derive_coerce_pointee)].

It was formerly known as:

• #[derive(UnsizeInner)]
• #[derive(SmartPtr)]
• #[feature(derive_smart_pointer)]

About tracking issues

Tracking issues are used to record the overall progress of implementation. They are also used as hubs connecting to other relevant issues, e.g., bugs or open design questions. A tracking issue is however not meant for large scale discussion, questions, or bug reports about a feature. Instead, open a dedicated issue for the specific matter and add the relevant feature gate label.

Steps

• Implement the language experiment.
  • SmartPointer derive-macro #125575
  • PinCoerceUnsized trait into core #125048
  • WIP: PoC for derive(SmartPointer) #123472
• Accept an RFC.
  • RFC: #[derive(SmartPointer)] rfcs#3621
• Decide on a final name.
  • Decide on name for derive(SmartPtr) #129104
• Adjust documentation (see instructions on rustc-dev-guide).
• Stabilization PR.
  • Stabilize derive(CoercePointee) #133820

Unresolved Questions

• is the derive name good? Should it be more general than "smart pointer"? (Do not discuss on this issue, open a zulip thread or separate GitHub issue)
  • Decide on name for derive(SmartPtr) #129104

Related

• RFC: #[derive(SmartPointer)] rfcs#3621
• SmartPointer derive-macro #125575
• PinCoerceUnsized trait into core #125048
• WIP: PoC for derive(SmartPointer) #123472
• Reject SmartPointer constructions not serving the purpose #127283
• arbitrary_self_types + derive_coerce_pointee allows calling methods whose where clauses are violated #136702
  • fix: Forbid freely casting lifetime bounds of dyn-types #136776
• Move CoercePointee to core::ops #147068
• Tracking issue for future-incompatibility lint ptr_cast_add_auto_to_object #127323