diff options
| -rw-r--r-- | compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs | 26 | ||||
| -rw-r--r-- | tests/ui/suggestions/late-bound-in-borrow-closure-sugg.stderr | 4 |
2 files changed, 20 insertions, 10 deletions
diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs index 3028242781c..64f19aa0097 100644 --- a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs +++ b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs @@ -3775,12 +3775,12 @@ fn hint_missing_borrow<'tcx>( let args = fn_decl.inputs.iter().map(|ty| ty); - fn get_deref_type_and_refs(mut ty: Ty<'_>) -> (Ty<'_>, usize) { - let mut refs = 0; + fn get_deref_type_and_refs(mut ty: Ty<'_>) -> (Ty<'_>, Vec<hir::Mutability>) { + let mut refs = vec![]; - while let ty::Ref(_, new_ty, _) = ty.kind() { + while let ty::Ref(_, new_ty, mutbl) = ty.kind() { ty = *new_ty; - refs += 1; + refs.push(*mutbl); } (ty, refs) @@ -3794,11 +3794,21 @@ fn hint_missing_borrow<'tcx>( let (expected_ty, expected_refs) = get_deref_type_and_refs(*expected_arg); if infcx.can_eq(param_env, found_ty, expected_ty).is_ok() { - if found_refs < expected_refs { - to_borrow.push((arg.span.shrink_to_lo(), "&".repeat(expected_refs - found_refs))); - } else if found_refs > expected_refs { + // FIXME: This could handle more exotic cases like mutability mismatches too! + if found_refs.len() < expected_refs.len() + && found_refs[..] == expected_refs[expected_refs.len() - found_refs.len()..] + { + to_borrow.push(( + arg.span.shrink_to_lo(), + expected_refs[..expected_refs.len() - found_refs.len()] + .iter() + .map(|mutbl| format!("&{}", mutbl.prefix_str())) + .collect::<Vec<_>>() + .join(""), + )); + } else if found_refs.len() > expected_refs.len() { let mut span = arg.span.shrink_to_lo(); - let mut left = found_refs - expected_refs; + let mut left = found_refs.len() - expected_refs.len(); let mut ty = arg; while let hir::TyKind::Ref(_, mut_ty) = &ty.kind && left > 0 { span = span.with_hi(mut_ty.ty.span.lo()); diff --git a/tests/ui/suggestions/late-bound-in-borrow-closure-sugg.stderr b/tests/ui/suggestions/late-bound-in-borrow-closure-sugg.stderr index 4fb5c65235c..6820af1fd45 100644 --- a/tests/ui/suggestions/late-bound-in-borrow-closure-sugg.stderr +++ b/tests/ui/suggestions/late-bound-in-borrow-closure-sugg.stderr @@ -18,8 +18,8 @@ LL | pub fn set_closure(&mut self, function: impl Fn(&mut Trader) + 'a) { | ^^^^^^^^^^^^^^^ required by this bound in `Trader::<'a>::set_closure` help: consider borrowing the argument | -LL | let closure = |trader : &Trader| { - | + +LL | let closure = |trader : &mut Trader| { + | ++++ error: aborting due to previous error |