Improve diagnostic output of `non_local_definitions` lint #125089

Urgau · 2024-05-13T20:01:24Z

This PR improves (or at least tries to improve) the diagnostic output of non_local_definitions lint, by simplifying the wording, by adding a "sort of" explanation of bounds interaction that leak the impl...

This PR is best reviewed commit by commit and is voluntarily made a bit vague as to have a starting point to improve on.

Related to https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/non_local_defs.20wording.20improvements

Fixes #125068
Fixes #124396
cc @workingjubilee
r? @estebank

workingjubilee

feel free to "nah actually" I am just trying to throw a couple wording ideas at the wall.

compiler/rustc_lint/messages.ftl

compiler/rustc_lint/src/non_local_def.rs

Urgau · 2024-05-14T16:56:02Z

I pushed several more commits that tries to improve the clarity the message were are trying to pass, mainly by moving the "move help message" to a separate span with some labels.

warning: non-local `impl` definition, `impl` blocks should be written at the same level as their item
  --> $DIR/consts.rs:43:5
   |
LL |     impl Test {
   |     ^^^^^^^^^
   |
   = note: methods and assoc const are still usable outside the current expression, only `impl Local` and `impl dyn Local` are local and only if the `Local` type is at the same nesting as the `impl` block
help: move this `impl` block and outside the of the current function `main`
  --> $DIR/consts.rs:43:5
   |
LL |       impl Test {
   |       ^    ---- may need to be moved as well
   |  _____|
   | |
LL | |
LL | |         fn foo() {}
LL | |     }
   | |_____^
   = note: this lint may become deny-by-default in the edition 2024 and higher, see the tracking issue <https://github.com/rust-lang/rust/issues/120363>

compiler/rustc_lint/messages.ftl

rustbot · 2024-05-15T17:13:10Z

These commits modify the Cargo.lock file. Unintentional changes to Cargo.lock can be introduced when switching branches and rebasing PRs.

If this was unintentional then you should revert the changes before this PR is merged.
Otherwise, you can ignore this comment.

Urgau · 2024-05-15T17:17:36Z

I continued to improved the diagnostic output by adding labels that points to Self type and Trait to better put emphasis on the fact that they are non-local for the lint.

With the example in #125068 (comment), it now gives:

warning: non-local `impl` definition, `impl` blocks should be written at the same level as their item
 --> a.rs:6:5
  |
6 |     impl Trait for Option<Local> {}
  |     ^^^^^-----^^^^^------^^^^^^^
  |          |         |
  |          |         `Option` is not local
  |          `Trait` is not local
  |
  = note: `impl` may be usable in bounds, etc. from outside the expression, which might e.g. make something constructible that previously wasn't, because it's still on a publicly-visible type
  = note: an `impl` is never scoped, even when it is nested inside an item, as it may impact type checking outside of that item, which can be the case if neither the trait or the self type are at the same nesting level as the `impl`
help: move this `impl` block outside of the current function `main`
 --> a.rs:6:5
  |
6 |     impl Trait for Option<Local> {}
  |     ^^^^^^^^^^^^^^^^^^^^^^-----^^^^
  |                           |
  |                           may need to be moved as well
  = note: this lint may become deny-by-default in the edition 2024 and higher, see the tracking issue <https://github.com/rust-lang/rust/issues/120363>
  = note: `#[warn(non_local_definitions)]` on by default

with colors

estebank

There's quite a bit of code that I need to continue reviewing, but I have some nitpicks based on the output.

tests/ui/lint/non-local-defs/weird-exprs.stderr

tests/ui/lint/non-local-defs/suggest-moving-inner.stderr

compiler/rustc_lint/src/non_local_def.rs

estebank · 2024-05-17T23:41:47Z

tests/ui/lint/non-local-defs/cargo-update.stderr

+warning: non-local `impl` definition, `impl` blocks should be written at the same level as their item
  --> $DIR/cargo-update.rs:17:1
   |
 LL | non_local_macro::non_local_impl!(LocalStruct);
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   | |
+   | `LocalStruct` is not local
+   | `Debug` is not local


We should customize the error when involving macros, because the suggestion to move the impl out of a const is not actionable for users in this case. Even further, it is likely that we shouldn't emit the lint if it comes from a foreign macro (do not deal with that in this PR).

I agree it would be good if we could have a specialized version of the diagnostic for macro-generated code, but I have no idea what it would look like.

Even further, it is likely that we shouldn't emit the lint if it comes from a foreign macro (do not deal with that in this PR).

We must still emit the warning in macro-generated code, since the goal is to make the lint deny-by-default and then hard-error in a future edition, and without the warn it would go straight to hard-error which is not good.

As follow up work (not this PR), we should still customize the error to state "the macro needs to be changed".

Urgau · 2024-05-20T17:30:41Z

All the review comments have been addressed or have been replied to.

@rustbot ready

bors · 2024-05-22T00:47:52Z

☔ The latest upstream changes (presumably #124417) made this pull request unmergeable. Please resolve the merge conflicts.

Urgau · 2024-05-27T11:34:57Z

@estebank could you give this PR another review.

compiler/rustc_lint/messages.ftl

estebank

Minor nitpick in wording, beyond that this is ready to land.

- Restrict const-anon exception diag to relevant places - Invoke bounds (and type-inference) in non_local_defs - Specialize diagnostic for impl without Trait

- Remove wrong exception text for non-local macro_rules! - Simplify anonymous const exception note

estebank · 2024-05-28T03:16:55Z

@bors r+

bors · 2024-05-28T03:16:58Z

📌 Commit c7d3004 has been approved by estebank

It is now in the queue for this repository.

…=estebank Improve diagnostic output the `non_local_definitions` lint This PR improves (or at least tries to improve) the diagnostic output the `non_local_definitions` lint, by simplifying the wording, by adding a "sort of" explanation of bounds interaction that leak the impl... This PR is best reviewed commit by commit and is voluntarily made a bit vague as to have a starting point to improve on. Related to https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/non_local_defs.20wording.20improvements Fixes rust-lang#125068 Fixes rust-lang#124396 cc `@workingjubilee` r? `@estebank`

…=estebank Improve diagnostic output the `non_local_definitions` lint This PR improves (or at least tries to improve) the diagnostic output the `non_local_definitions` lint, by simplifying the wording, by adding a "sort of" explanation of bounds interaction that leak the impl... This PR is best reviewed commit by commit and is voluntarily made a bit vague as to have a starting point to improve on. Related to https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/non_local_defs.20wording.20improvements Fixes rust-lang#125068 Fixes rust-lang#124396 cc ``@workingjubilee`` r? ``@estebank``

…kingjubilee Rollup of 4 pull requests Successful merges: - rust-lang#125089 (Improve diagnostic output the `non_local_definitions` lint) - rust-lang#125343 (`-Znext-solver`: eagerly normalize when adding goals) - rust-lang#125411 (check host's libstdc++ version when using ci llvm) - rust-lang#125551 (Stabilise `IpvNAddr::{BITS, to_bits, from_bits}` (`ip_bits`)) r? `@ghost` `@rustbot` modify labels: rollup

…kingjubilee Rollup of 5 pull requests Successful merges: - rust-lang#125089 (Improve diagnostic output the `non_local_definitions` lint) - rust-lang#125343 (`-Znext-solver`: eagerly normalize when adding goals) - rust-lang#125551 (Stabilise `IpvNAddr::{BITS, to_bits, from_bits}` (`ip_bits`)) - rust-lang#125640 (Don't suggest turning non-char-literal exprs of ty `char` into string literals) - rust-lang#125647 (update tracking issue for lazy_cell_consume) r? `@ghost` `@rustbot` modify labels: rollup

Rollup merge of rust-lang#125089 - Urgau:non_local_def-suggestions, r=estebank Improve diagnostic output the `non_local_definitions` lint This PR improves (or at least tries to improve) the diagnostic output the `non_local_definitions` lint, by simplifying the wording, by adding a "sort of" explanation of bounds interaction that leak the impl... This PR is best reviewed commit by commit and is voluntarily made a bit vague as to have a starting point to improve on. Related to https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/non_local_defs.20wording.20improvements Fixes rust-lang#125068 Fixes rust-lang#124396 cc ```@workingjubilee``` r? ```@estebank```

rustbot assigned estebank May 13, 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. T-rustdoc Relevant to the rustdoc team, which will review and decide on the PR/issue. labels May 13, 2024

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Urgau force-pushed the non_local_def-suggestions branch from 0c69265 to 2819950 Compare May 13, 2024 20:20

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Urgau force-pushed the non_local_def-suggestions branch from 9a5bb1f to a39cf37 Compare May 14, 2024 21:41

Urgau mentioned this pull request May 15, 2024

non-local-definitions lint fires for impl using private types #125068

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Urgau force-pushed the non_local_def-suggestions branch from abefe35 to 5044fb6 Compare May 18, 2024 13:10

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Urgau force-pushed the non_local_def-suggestions branch from 5044fb6 to 7236f18 Compare May 22, 2024 05:59

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Urgau added 5 commits May 27, 2024 23:58

non_local_defs: move out from #[derive(LintDiagnostic)] to manual impl

5ad4ad7

non_local_defs: switch to more friendly primary message

06c6a2d

non_local_defs: improve some notes around trait, bounds, consts

de1c122

- Restrict const-anon exception diag to relevant places - Invoke bounds (and type-inference) in non_local_defs - Specialize diagnostic for impl without Trait

non_local_defs: use span of the impl def and not the impl block

26b873d

non_local_defs: use labels to indicate what may need to be moved

22095fb

Urgau added 6 commits May 27, 2024 23:59

non_local_defs: improve exception note for impl and macro_rules!

402580b

- Remove wrong exception text for non-local macro_rules! - Simplify anonymous const exception note

non_local_defs: be more precise about what needs to be moved

d3dfe14

non_local_defs: improve main without a trait note

ab23fd8

non_local_defs: suggest removing leading ref/ptr to make the impl local

b719529

non_local_defs: point to Self and Trait to give more context

98273ec

non_local_defs: point the parent item when appropriate

c7d3004

Urgau force-pushed the non_local_def-suggestions branch from 7236f18 to c7d3004 Compare May 27, 2024 22:01

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 May 28, 2024

matthiaskrgr mentioned this pull request May 28, 2024

Rollup of 4 pull requests #125643

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workingjubilee mentioned this pull request May 28, 2024

Rollup of 4 pull requests #125644

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workingjubilee mentioned this pull request May 28, 2024

Rollup of 5 pull requests #125649

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workingjubilee changed the title ~~Improve diagnostic output the non_local_definitions lint~~ Improve diagnostic output of non_local_definitions lint May 28, 2024

bors merged commit 8e89f83 into rust-lang:master May 28, 2024
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rustbot added this to the 1.80.0 milestone May 28, 2024

Urgau mentioned this pull request May 29, 2024

Indicate in non_local_defs lint that the macro needs to change #125722

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Improve diagnostic output of `non_local_definitions` lint #125089

Improve diagnostic output of `non_local_definitions` lint #125089

Urgau commented May 13, 2024 •

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Improve diagnostic output of non_local_definitions lint #125089

Improve diagnostic output of non_local_definitions lint #125089

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Improve diagnostic output of `non_local_definitions` lint #125089

Improve diagnostic output of `non_local_definitions` lint #125089

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