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Rollup merge of #120164 - trevyn:is_downgradable, r=compiler-errors

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`maybe_lint_impl_trait`: separate `is_downgradable` from `is_object_safe`

https://github.com/rust-lang/rust/pull/119752 leveraged and overloaded `is_object_safe` to prevent an ICE, but accurate object safety information is needed for precise suggestions. This separates out `is_downgradable`, used for the ICE prevention, and `is_object_safe`, which returns to its original meaning.
This commit is contained in:
Matthias Krüger 2024-01-22 16:54:59 +01:00 • committed by GitHub
commit 6e4933f94f
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3 changed files with 65 additions and 53 deletions
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16
compiler/rustc_hir_analysis/src/astconv/lint.rs
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@ -94,15 +94,17 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
return false;
};
let impl_sugg = vec![(self_ty.span.shrink_to_lo(), "impl ".to_string())];
let mut is_downgradable = true;
let is_object_safe = match self_ty.kind {
hir::TyKind::TraitObject(objects, ..) => {
objects.iter().all(|o| match o.trait_ref.path.res {
Res::Def(DefKind::Trait, id) if Some(id) == owner => {
// When we're dealing with a recursive trait, we don't want to downgrade
// the error, so we consider them to be object safe always. (#119652)
true
Res::Def(DefKind::Trait, id) => {
if Some(id) == owner {
// For recursive traits, don't downgrade the error. (#119652)
is_downgradable = false;
}
tcx.check_is_object_safe(id)
}
Res::Def(DefKind::Trait, id) => tcx.check_is_object_safe(id),
_ => false,
})
}
@ -130,7 +132,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
],
Applicability::MachineApplicable,
);
} else if diag.is_error() {
} else if diag.is_error() && is_downgradable {
// We'll emit the object safety error already, with a structured suggestion.
diag.downgrade_to_delayed_bug();
}
@ -156,7 +158,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
}
if !is_object_safe {
diag.note(format!("`{trait_name}` it is not object safe, so it can't be `dyn`"));
if diag.is_error() {
if diag.is_error() && is_downgradable {
// We'll emit the object safety error already, with a structured suggestion.
diag.downgrade_to_delayed_bug();
}