bjoernager/rust
bjoernager/rust
1
Fork 0
Code Activity

Rollup merge of #107306 - compiler-errors:correct-sugg-for-closure-arg-needs-borrow, r=oli-obk

Browse source 
Correct suggestions for closure arguments that need a borrow

Fixes #107301 by dealing with binders correctly
Fixes another issue where we were suggesting adding just `&` when we expected `&mut _` in a closure arg
This commit is contained in:
Matthias Krüger 2023-01-28 05:20:18 +01:00 • committed by GitHub
commit fa2cd945af
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23
3 changed files with 74 additions and 10 deletions
Download patch file Download diff file Expand all files Collapse all files

30
compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
View file

@ -3807,13 +3807,13 @@ fn hint_missing_borrow<'tcx>(
err: &mut Diagnostic,
) {
let found_args = match found.kind() {
ty::FnPtr(f) => f.inputs().skip_binder().iter(),
ty::FnPtr(f) => infcx.replace_bound_vars_with_placeholders(*f).inputs().iter(),
kind => {
span_bug!(span, "found was converted to a FnPtr above but is now {:?}", kind)
}
};
let expected_args = match expected.kind() {
ty::FnPtr(f) => f.inputs().skip_binder().iter(),
ty::FnPtr(f) => infcx.replace_bound_vars_with_placeholders(*f).inputs().iter(),
kind => {
span_bug!(span, "expected was converted to a FnPtr above but is now {:?}", kind)
}
@ -3824,12 +3824,12 @@ 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)
@ -3843,11 +3843,21 @@ 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());