Arbitrary self types v2: Weak & NonNull diagnostics #134264
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The recently landed PR to adjust arbitrary self types was a bit overenthusiastic, advising folks to use the new Receiver trait even before it's been stabilized. Revert to the older wording of the lint in such cases.
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| @@ -1749,7 +1750,20 @@ fn check_method_receiver<'tcx>( | |||
| { | |||
| match receiver_validity_err { | |||
| ReceiverValidityError::DoesNotDeref if arbitrary_self_types_level.is_some() => { | |||
| tcx.dcx().emit_err(errors::InvalidReceiverTy { span, receiver_ty }) | |||
| let hint = match receiver_ty | |||
| .ty_def_id() | |||
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don't use this, it's an internal detail of the query system. use Ty::ty_adt_def to check that it's an adt.
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r? compiler-errors |
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maybe worth providing some background in the note to explain why
would be "ok, why don't I just suggest adding an impl to libstd?" |
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Various types can be used as method receivers, such as Rc<>, Box<> and Arc<>. The arbitrary self types v2 work allows further types to be made method receivers by implementing the Receiver trait. With that in mind, it may come as a surprise to people when certain common types do not implement Receiver and thus cannot be used as a method receiver. The RFC for arbitrary self types v2 therefore proposes emitting specific lint hints for these cases: * NonNull * Weak * Raw pointers The code already emits a hint for this third case, in that it advises folks that the `arbitrary_self_types_pointers` feature may meet their need. This PR adds diagnostic hints for the Weak and NonNull cases.
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This builds on top of #134262 which is more urgent to review and merge first. I'll likely rebase this PR once that lands.
This is the first part of the diagnostic enhancements planned for Arbitrary Self Types v2.
Various types can be used as method receivers, such as
Rc<>,Box<>andArc<>. The arbitrary self types v2 work allows further types to be made method receivers by implementing the Receiver trait.With that in mind, it may come as a surprise to people when certain common types do not implement Receiver and thus cannot be used as a method receiver.
The RFC for arbitrary self types v2 therefore proposes emitting specific
lint hints for these cases:
NonNullWeakThe code already emits a hint for this third case, in that it advises folks that the
arbitrary_self_types_pointersfeature may meet their need. This PR adds diagnostic hints for theWeakandNonNullcases.Tracking issue #44874
r? @wesleywiser