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Auto merge of #101986 - WaffleLapkin:move_lint_note_to_the_bottom, r=estebank

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Move lint level source explanation to the bottom

So, uhhhhh

r? `@estebank`

## User-facing change

"note: `#[warn(...)]` on by default" and such are moved to the bottom of the diagnostic:
```diff
-   = note: `#[warn(unsupported_calling_conventions)]` on by default
   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
   = note: for more information, see issue #87678 <https://github.com/rust-lang/rust/issues/87678>
+   = note: `#[warn(unsupported_calling_conventions)]` on by default
```

Why warning is enabled is the least important thing, so it shouldn't be the first note the user reads, IMO.

## Developer-facing change

`struct_span_lint` and similar methods have a different signature.

Before: `..., impl for<'a> FnOnce(LintDiagnosticBuilder<'a, ()>)`
After: `..., impl Into<DiagnosticMessage>, impl for<'a, 'b> FnOnce(&'b mut DiagnosticBuilder<'a, ()>) -> &'b mut DiagnosticBuilder<'a, ()>`

The reason for this is that `struct_span_lint` needs to edit the diagnostic _after_ `decorate` closure is called. This also makes lint code a little bit nicer in my opinion.

Another option is to use `impl for<'a> FnOnce(LintDiagnosticBuilder<'a, ()>) -> DiagnosticBuilder<'a, ()>` altough I don't _really_ see reasons to do `let lint = lint.build(message)` everywhere.

## Subtle problem

By moving the message outside of the closure (that may not be called if the lint is disabled) `format!(...)` is executed earlier, possibly formatting `Ty` which may call a query that trims paths that crashes the compiler if there were no warnings...

I don't think it's that big of a deal, considering that we move from `format!(...)` to `fluent` (which is lazy by-default) anyway, however this required adding a workaround which is unfortunate.

## P.S.

I'm sorry, I do not how to make this PR smaller/easier to review. Changes to the lint API affect SO MUCH 😢
This commit is contained in:
bors
2022-10-01 10:44:25 +00:00
parent 277bb6653b b5b3ffe3fc
commit 744e397d88
827 changed files with 3370 additions and 3210 deletions
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57
compiler/rustc_hir_analysis/src/astconv/mod.rs
View File

@@ -2010,30 +2010,35 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
tcx.check_stability(item.def_id, Some(hir_ref_id), span, None);
if let Some(variant_def_id) = variant_resolution {
tcx.struct_span_lint_hir(AMBIGUOUS_ASSOCIATED_ITEMS, hir_ref_id, span, |lint| {
let mut err = lint.build("ambiguous associated item");
let mut could_refer_to = |kind: DefKind, def_id, also| {
let note_msg = format!(
"`{}` could{} refer to the {} defined here",
assoc_ident,
also,
kind.descr(def_id)
tcx.struct_span_lint_hir(
AMBIGUOUS_ASSOCIATED_ITEMS,
hir_ref_id,
span,
"ambiguous associated item",
|lint| {
let mut could_refer_to = |kind: DefKind, def_id, also| {
let note_msg = format!(
"`{}` could{} refer to the {} defined here",
assoc_ident,
also,
kind.descr(def_id)
);
lint.span_note(tcx.def_span(def_id), &note_msg);
};
could_refer_to(DefKind::Variant, variant_def_id, "");
could_refer_to(kind, item.def_id, " also");
lint.span_suggestion(
span,
"use fully-qualified syntax",
format!("<{} as {}>::{}", qself_ty, tcx.item_name(trait_did), assoc_ident),
Applicability::MachineApplicable,
);
err.span_note(tcx.def_span(def_id), &note_msg);
};
could_refer_to(DefKind::Variant, variant_def_id, "");
could_refer_to(kind, item.def_id, " also");
err.span_suggestion(
span,
"use fully-qualified syntax",
format!("<{} as {}>::{}", qself_ty, tcx.item_name(trait_did), assoc_ident),
Applicability::MachineApplicable,
);
err.emit();
});
lint
},
);
}
Ok((ty, kind, item.def_id))
}
@@ -3079,15 +3084,15 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
BARE_TRAIT_OBJECTS,
self_ty.hir_id,
self_ty.span,
msg,
|lint| {
let mut diag = lint.build(msg);
diag.multipart_suggestion_verbose(
lint.multipart_suggestion_verbose(
"use `dyn`",
sugg,
Applicability::MachineApplicable,
);
self.maybe_lint_blanket_trait_impl(&self_ty, &mut diag);
diag.emit();
self.maybe_lint_blanket_trait_impl(&self_ty, lint);
lint
},
);
}