bjoernager/rust
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Make &-removal suggestion verbose

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This commit is contained in:
Esteban Küber 2023-01-01 18:43:47 -08:00
parent b22c152958
commit 2024aa48b4
10 changed files with 113 additions and 53 deletions
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71
compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
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@ -1358,26 +1358,41 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
err: &mut Diagnostic,
trait_pred: ty::PolyTraitPredicate<'tcx>,
) -> bool {
let span = obligation.cause.span;
let mut span = obligation.cause.span;
while span.desugaring_kind().is_some() {
// Remove all the hir desugaring contexts while maintaining the macro contexts.
span.remove_mark();
}
let mut suggested = false;
if let Ok(snippet) = self.tcx.sess.source_map().span_to_snippet(span) {
let refs_number =
snippet.chars().filter(|c| !c.is_whitespace()).take_while(|c| *c == '&').count();
if let Some('\'') = snippet.chars().filter(|c| !c.is_whitespace()).nth(refs_number) {
// Do not suggest removal of borrow from type arguments.
return false;
}
// Skipping binder here, remapping below
let mut suggested_ty = trait_pred.self_ty().skip_binder();
let mut expr_finder = super::FindExprBySpan { span, result: None };
let Some(hir::Node::Expr(body)) = self.tcx.hir().find(obligation.cause.body_id) else {
return false;
};
expr_finder.visit_expr(&body);
let mut count = 0;
let mut suggestions = vec![];
let Some(mut expr) = expr_finder.result else { return false; };
// Skipping binder here, remapping below
let mut suggested_ty = trait_pred.self_ty().skip_binder();
'outer: loop {
while let hir::ExprKind::AddrOf(_, _, borrowed) = expr.kind {
count += 1;
let span = if expr.span.eq_ctxt(borrowed.span) {
expr.span.until(borrowed.span)
} else {
expr.span.with_hi(expr.span.lo() + BytePos(1))
};
suggestions.push((span, String::new()));
for refs_remaining in 0..refs_number {
let ty::Ref(_, inner_ty, _) = suggested_ty.kind() else {
break;
};
suggested_ty = *inner_ty;
expr = borrowed;
// Remapping bound vars here
let trait_pred_and_suggested_ty =
trait_pred.map_bound(|trait_pred| (trait_pred, suggested_ty));
@ -1388,25 +1403,33 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
);
if self.predicate_may_hold(&new_obligation) {
let sp = self
.tcx
.sess
.source_map()
.span_take_while(span, |c| c.is_whitespace() || *c == '&');
let remove_refs = refs_remaining + 1;
let msg = if remove_refs == 1 {
let msg = if count == 1 {
"consider removing the leading `&`-reference".to_string()
} else {
format!("consider removing {} leading `&`-references", remove_refs)
format!("consider removing {count} leading `&`-references")
};
err.span_suggestion_short(sp, &msg, "", Applicability::MachineApplicable);
err.multipart_suggestion_verbose(
&msg,
suggestions,
Applicability::MachineApplicable,
);
suggested = true;
break;
break 'outer;
}
}
if let hir::ExprKind::Path(hir::QPath::Resolved(None, path)) = expr.kind
&& let hir::def::Res::Local(hir_id) = path.res
&& let Some(hir::Node::Pat(binding)) = self.tcx.hir().find(hir_id)
&& let parent_hir_id = self.tcx.hir().get_parent_node(binding.hir_id)
&& let Some(hir::Node::Local(local)) = self.tcx.hir().find(parent_hir_id)
&& let None = local.ty
&& let Some(binding_expr) = local.init
{
expr = binding_expr;
} else {
break 'outer;
}
}
suggested
}