bjoernager/rust
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Suggest mutable borrows correctly

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This commit is contained in:
Michael Goulet 2023-01-25 19:17:46 +00:00
parent 800f1f3513
commit b83ab0ce96
2 changed files with 20 additions and 10 deletions
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26
compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
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@ -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());