hir_typeck: be more conservative in making "note caller chooses ty param" note by jieyouxu · Pull Request #126558 · rust-lang/rust

jieyouxu · 2024-06-16T18:03:06Z

In #122195 I added a "caller chooses ty for type param" note for when the return expression type a.k.a. found type does not match the expected return type.

#126547 found that this note was confusing when the found return type contains the expected type, e.g.

fnf<T>(t:&T) -> T{
t
}

because the found return type &T will always be different from the expected return type T, so the note was needlessly redundant and confusing.

This PR addresses that by not making the note if the found return type contains the expected return type.

r? @fmease (since you reviewed the original PR)

Fixes#126547

fmease

Thanks!

fmease · 2024-06-18T16:19:31Z

+ debug!("return type (hir::Ty) {:?}", hir_ty);
 let ty = self.lowerer().lower_ty(hir_ty);
- debug!("return type {:?}", ty);
+ debug!("return type (ty) {:?}", ty);
 debug!("expected type {:?}", expected);


Btw, tracing has a nice shorthand for this but it doesn't matter. For future reference:
debug!(?hir_ty,"return type");let ty = self.lowerer().lower_ty(hir_ty);debug!(?ty,"return type");debug!(ty = ?expected,"expected type");
which will print:
return type hir_ty=... return type ty=... expected type ty=...

(I actually did know that shorthand, I just copied over what existed lol)

... but now that you mentioned it, it's indeed nicer so I changed it ^^

fmease · 2024-06-18T16:26:57Z

@bors r+ rollup

bors · 2024-06-18T16:26:59Z

📌 Commit a5eff62 has been approved by fmease

It is now in the queue for this repository.

hir_typeck: be more conservative in making "note caller chooses ty param" note In rust-lang#122195 I added a "caller chooses ty for type param" note for when the return expression type a.k.a. found type does not match the expected return type. rust-lang#126547 found that this note was confusing when the found return type *contains* the expected type, e.g. ```rs fn f<T>(t: &T) -> T { t } ``` because the found return type `&T` will *always* be different from the expected return type `T`, so the note was needlessly redundant and confusing. This PR addresses that by not making the note if the found return type contains the expected return type. r? `@fmease` (since you reviewed the original PR) Fixesrust-lang#126547

bors · 2024-06-18T20:33:20Z

☔ The latest upstream changes (presumably #126623) made this pull request unmergeable. Please resolve the merge conflicts.

…ram" note - Avoid "caller chooses ty for type param" note if the found type a.k.a. the return expression type *contains* the type parameter, because e.g. `&T` will always be different from `T` (i.e. "well duh"). - Rename `note_caller_chooses_ty_for_ty_param` to `try_note_caller_chooses_ty_for_ty_param` because the note is not always made. Issue: rust-lang#126547

jieyouxu · 2024-06-18T21:28:46Z

Rebased for diag.subdiagnostic() improvements that removed need for passing dcx() (hecc yeah) and cleaned up the tracing debug usages. EDIT: ui tests pass locally.

…llaumeGomez Rollup of 9 pull requests Successful merges: - rust-lang#123782 (Test that opaque types can't have themselves as a hidden type with incompatible lifetimes) - rust-lang#124580 (Suggest removing unused tuple fields if they are the last fields) - rust-lang#125852 (improve tip for inaccessible traits) - rust-lang#126422 (Suggest using a standalone doctest for non-local impl defs) - rust-lang#126427 (Rewrite `intrinsic-unreachable`, `sepcomp-cci-copies`, `sepcomp-inlining` and `sepcomp-separate` `run-make` tests to rmake.rs) - rust-lang#126493 (safe transmute: support non-ZST, variantful, uninhabited enums) - rust-lang#126572 (override user defined channel when using precompiled rustc) - rust-lang#126615 (Add `rustc-ice*` to `.gitignore`) - rust-lang#126632 (Replace `move||` with `move ||`) Failed merges: - rust-lang#126558 (hir_typeck: be more conservative in making "note caller chooses ty param" note) r? `@ghost` `@rustbot` modify labels: rollup

jieyouxu · 2024-06-18T22:08:54Z

@rustbot review

fmease · 2024-06-18T22:13:43Z

@bors r+

bors · 2024-06-18T22:13:46Z

📌 Commit 939026c has been approved by fmease

It is now in the queue for this repository.

hir_typeck: be more conservative in making "note caller chooses ty param" note In rust-lang#122195 I added a "caller chooses ty for type param" note for when the return expression type a.k.a. found type does not match the expected return type. rust-lang#126547 found that this note was confusing when the found return type *contains* the expected type, e.g. ```rs fn f<T>(t: &T) -> T { t } ``` because the found return type `&T` will *always* be different from the expected return type `T`, so the note was needlessly redundant and confusing. This PR addresses that by not making the note if the found return type contains the expected return type. r? `@fmease` (since you reviewed the original PR) Fixesrust-lang#126547

Rollup of 10 pull requests Successful merges: - rust-lang#124135 (delegation: Implement glob delegation) - rust-lang#125078 (fix: break inside async closure has incorrect span for enclosing closure) - rust-lang#125293 (Place tail expression behind terminating scope) - rust-lang#126422 (Suggest using a standalone doctest for non-local impl defs) - rust-lang#126493 (safe transmute: support non-ZST, variantful, uninhabited enums) - rust-lang#126504 (Sync fuchsia test runner with clang test runner) - rust-lang#126558 (hir_typeck: be more conservative in making "note caller chooses ty param" note) - rust-lang#126586 (Add `@badboy` and `@BlackHoleFox` as Mac Catalyst maintainers) - rust-lang#126615 (Add `rustc-ice*` to `.gitignore`) - rust-lang#126632 (Replace `move||` with `move ||`) r? `@ghost` `@rustbot` modify labels: rollup

Rollup merge of rust-lang#126558 - jieyouxu:caller-chooses-ty, r=fmease hir_typeck: be more conservative in making "note caller chooses ty param" note In rust-lang#122195 I added a "caller chooses ty for type param" note for when the return expression type a.k.a. found type does not match the expected return type. rust-lang#126547 found that this note was confusing when the found return type *contains* the expected type, e.g. ```rs fn f<T>(t: &T) -> T { t } ``` because the found return type `&T` will *always* be different from the expected return type `T`, so the note was needlessly redundant and confusing. This PR addresses that by not making the note if the found return type contains the expected return type. r? ``@fmease`` (since you reviewed the original PR) Fixesrust-lang#126547

rustbot assigned fmease Jun 16, 2024

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels Jun 16, 2024

jieyouxu mentioned this pull request Jun 16, 2024
Confusing "the caller chooses a type which can be different" [E308] #126547
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fmease approved these changes Jun 18, 2024
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bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Jun 18, 2024

This was referenced Jun 18, 2024
Rollup of 10 pull requests #126635
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Rollup of 9 pull requests #126642
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bors added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. labels Jun 18, 2024

jieyouxu added 2 commits June 18, 2024 21:05

tests: update tests for more conservative return ty mismatch note
939026c

rust-cloud-vmsBotforce-pushed the caller-chooses-ty branch from a5eff62 to 939026cCompare June 18, 2024 21:07

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Jun 18, 2024

fmease approved these changes Jun 18, 2024
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bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Jun 18, 2024

jieyouxu mentioned this pull request Jun 19, 2024
Rollup of 20 pull requests #126653
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jieyouxu mentioned this pull request Jun 19, 2024
Rollup of 10 pull requests #126655
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bors merged commit bf841c4 into rust-lang:masterJun 19, 2024

rustbot added this to the 1.81.0 milestone Jun 19, 2024

jieyouxu deleted the caller-chooses-ty branch June 29, 2024 08:18

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hir_typeck: be more conservative in making "note caller chooses ty param" note - #126558

hir_typeck: be more conservative in making "note caller chooses ty param" note#126558
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