Incorrect statement about unsized coercion in method lookup
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Assessment
- Difficulty
- 3/5
- Estimated time
- 1-2 days
- Newbie friendliness
- 48/100
- Issue type
- Documentation
- Clarity
- Mostly clear
- Activity status
- Stale
- Tech stack
- rust
- Domain
- documentation
Research direction
Start with the method-call expression section linked in the issue and reproduce the Rust Playground example to verify how method lookup handles trait-object and slice coercions. Update the explanation to match the observed behavior and clarify whether slices are a special case; done means the reference no longer claims unsupported general unsized coercion.
Written by the indexing model from the issue text.
Description
When explaining method lookup, the reference says:
The first step is to build a list of candidate receiver types. Obtain these by repeatedly dereferencing the receiver expression's type, adding each type encountered to the list, then finally attempting an unsized coercion at the end, and adding the result type if that is successful.
However, general unsized coercions are not allowed for method call. In particular, this example shows unsized coercion to a trait object is not performed during method lookup. It seems it was mentioned when this paragraph of the reference was written that the unsized coercion is only performed for slices, but it does not seem to have been changed accordingly. It would be good if it could be fixed to reflect what actually happens during method lookup, and if we could clarify whether slices are truly a special case.
- Dominant language
- Rust
- Stars
- 1.6k
- Forks
- 607
- Avg merge
- 1d 1h
- Merged PRs (30d)
- 12
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