completion-ref-matching

[Shourya742]

closes #17310

[ChayimFriedman2]

Please add a test.

[Shourya742]

Hello @ChayimFriedman2, this only addresses part of the issue and does not cover the aspect related to unsized types. The approach I took was as follows: In the case of a redundant borrowing suggestion, the issue was that the completion type was (&'{error} AdtId(StructId(StructId(1191))), whereas the expected type was (&'static AdtId(StructId(StructId(1191)))<[]>). I believe the lifetime error indicates undetermined lifetimes in this context. My approach was to strip the reference from the expected_type, append the undetermined lifetime annotation, and check if it matches the completion_type. If they match, the suggestion should not be made. However, I might be wrong—please let me know if you see any issues with this approach.

[ChayimFriedman2]

A better approach will be to fold both types and convert all lifetimes to error lifetimes. You can see examples of type folders in this file: https://github.com/rust-lang/rust-analyzer/blob/master/crates/hir-ty/src/lib.rs.

[Shourya742]

A better approach will be to fold both types and convert all lifetimes to error lifetimes. You can see examples of type folders in this file: https://github.com/rust-lang/rust-analyzer/blob/master/crates/hir-ty/src/lib.rs.

@ChayimFriedman2 , Ah! I updated the check to use the could_unify_with method, which, in turn, folds both types to verify compatibility.

[ChayimFriedman2]

Thanks!