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Rollup merge of #99671 - TaKO8Ki:suggest-dereferencing-index, r=compiler-errors

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Suggest dereferencing index when trying to use a reference of usize as index

fixes #96678
This commit is contained in:
Yuki Okushi 2022-07-30 07:39:50 +09:00 • committed by GitHub
commit 4a44efae14
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GPG key ID: 4AEE18F83AFDEB23
12 changed files with 111 additions and 32 deletions
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1
compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs
View file

@ -531,6 +531,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
}
self.suggest_floating_point_literal(&obligation, &mut err, &trait_ref);
self.suggest_dereferencing_index(&obligation, &mut err, trait_predicate);
let mut suggested =
self.suggest_dereferences(&obligation, &mut err, trait_predicate);
suggested |= self.suggest_fn_call(&obligation, &mut err, trait_predicate);

28
compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
View file

@ -320,6 +320,13 @@ pub trait InferCtxtExt<'tcx> {
err: &mut Diagnostic,
trait_pred: ty::PolyTraitPredicate<'tcx>,
);
fn suggest_dereferencing_index(
&self,
obligation: &PredicateObligation<'tcx>,
err: &mut Diagnostic,
trait_pred: ty::PolyTraitPredicate<'tcx>,
);
}
fn predicate_constraint(generics: &hir::Generics<'_>, pred: String) -> (Span, String) {
@ -2895,6 +2902,27 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
);
}
}
fn suggest_dereferencing_index(
&self,
obligation: &PredicateObligation<'tcx>,
err: &mut Diagnostic,
trait_pred: ty::PolyTraitPredicate<'tcx>,
) {
if let ObligationCauseCode::ImplDerivedObligation(_) = obligation.cause.code()
&& self.tcx.is_diagnostic_item(sym::SliceIndex, trait_pred.skip_binder().trait_ref.def_id)
&& let ty::Slice(_) = trait_pred.skip_binder().trait_ref.substs.type_at(1).kind()
&& let ty::Ref(_, inner_ty, _) = trait_pred.skip_binder().self_ty().kind()
&& let ty::Uint(ty::UintTy::Usize) = inner_ty.kind()
{
err.span_suggestion_verbose(
obligation.cause.span.shrink_to_lo(),
"dereference this index",
'*',
Applicability::MachineApplicable,
);
}
}
}
/// Collect all the returned expressions within the input expression.