Rollup merge of #106360 - estebank:remove-borrow-suggestion, r=compiler-errors
Tweak E0277 `&`-removal suggestions Fix #64068, fix #84837.
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commit
54f6fea818
17 changed files with 253 additions and 76 deletions
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@ -1361,57 +1361,117 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
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err: &mut Diagnostic,
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trait_pred: ty::PolyTraitPredicate<'tcx>,
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) -> bool {
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let span = obligation.cause.span;
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let mut span = obligation.cause.span;
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let mut trait_pred = trait_pred;
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let mut code = obligation.cause.code();
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while let Some((c, Some(parent_trait_pred))) = code.parent() {
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// We want the root obligation, in order to detect properly handle
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// `for _ in &mut &mut vec![] {}`.
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code = c;
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trait_pred = parent_trait_pred;
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}
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while span.desugaring_kind().is_some() {
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// Remove all the hir desugaring contexts while maintaining the macro contexts.
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span.remove_mark();
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}
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let mut expr_finder = super::FindExprBySpan::new(span);
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let Some(hir::Node::Expr(body)) = self.tcx.hir().find(obligation.cause.body_id) else {
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return false;
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};
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expr_finder.visit_expr(&body);
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let mut maybe_suggest = |suggested_ty, count, suggestions| {
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// Remapping bound vars here
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let trait_pred_and_suggested_ty =
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trait_pred.map_bound(|trait_pred| (trait_pred, suggested_ty));
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let mut suggested = false;
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if let Ok(snippet) = self.tcx.sess.source_map().span_to_snippet(span) {
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let refs_number =
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snippet.chars().filter(|c| !c.is_whitespace()).take_while(|c| *c == '&').count();
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if let Some('\'') = snippet.chars().filter(|c| !c.is_whitespace()).nth(refs_number) {
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// Do not suggest removal of borrow from type arguments.
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return false;
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let new_obligation = self.mk_trait_obligation_with_new_self_ty(
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obligation.param_env,
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trait_pred_and_suggested_ty,
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);
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if self.predicate_may_hold(&new_obligation) {
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let msg = if count == 1 {
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"consider removing the leading `&`-reference".to_string()
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} else {
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format!("consider removing {count} leading `&`-references")
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};
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err.multipart_suggestion_verbose(
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&msg,
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suggestions,
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Applicability::MachineApplicable,
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);
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true
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} else {
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false
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}
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};
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// Skipping binder here, remapping below
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let mut suggested_ty = trait_pred.self_ty().skip_binder();
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// Maybe suggest removal of borrows from types in type parameters, like in
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// `src/test/ui/not-panic/not-panic-safe.rs`.
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let mut count = 0;
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let mut suggestions = vec![];
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// Skipping binder here, remapping below
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let mut suggested_ty = trait_pred.self_ty().skip_binder();
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if let Some(mut hir_ty) = expr_finder.ty_result {
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while let hir::TyKind::Ref(_, mut_ty) = &hir_ty.kind {
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count += 1;
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let span = hir_ty.span.until(mut_ty.ty.span);
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suggestions.push((span, String::new()));
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for refs_remaining in 0..refs_number {
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let ty::Ref(_, inner_ty, _) = suggested_ty.kind() else {
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break;
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};
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suggested_ty = *inner_ty;
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// Remapping bound vars here
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let trait_pred_and_suggested_ty =
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trait_pred.map_bound(|trait_pred| (trait_pred, suggested_ty));
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hir_ty = mut_ty.ty;
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let new_obligation = self.mk_trait_obligation_with_new_self_ty(
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obligation.param_env,
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trait_pred_and_suggested_ty,
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);
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if self.predicate_may_hold(&new_obligation) {
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let sp = self
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.tcx
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.sess
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.source_map()
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.span_take_while(span, |c| c.is_whitespace() || *c == '&');
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let remove_refs = refs_remaining + 1;
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let msg = if remove_refs == 1 {
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"consider removing the leading `&`-reference".to_string()
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} else {
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format!("consider removing {} leading `&`-references", remove_refs)
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};
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err.span_suggestion_short(sp, &msg, "", Applicability::MachineApplicable);
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suggested = true;
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break;
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if maybe_suggest(suggested_ty, count, suggestions.clone()) {
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return true;
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}
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}
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}
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suggested
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// Maybe suggest removal of borrows from expressions, like in `for i in &&&foo {}`.
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let Some(mut expr) = expr_finder.result else { return false; };
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let mut count = 0;
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let mut suggestions = vec![];
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// Skipping binder here, remapping below
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let mut suggested_ty = trait_pred.self_ty().skip_binder();
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'outer: loop {
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while let hir::ExprKind::AddrOf(_, _, borrowed) = expr.kind {
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count += 1;
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let span = if expr.span.eq_ctxt(borrowed.span) {
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expr.span.until(borrowed.span)
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} else {
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expr.span.with_hi(expr.span.lo() + BytePos(1))
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};
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suggestions.push((span, String::new()));
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let ty::Ref(_, inner_ty, _) = suggested_ty.kind() else {
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break 'outer;
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};
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suggested_ty = *inner_ty;
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expr = borrowed;
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if maybe_suggest(suggested_ty, count, suggestions.clone()) {
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return true;
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}
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}
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if let hir::ExprKind::Path(hir::QPath::Resolved(None, path)) = expr.kind
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&& let hir::def::Res::Local(hir_id) = path.res
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&& let Some(hir::Node::Pat(binding)) = self.tcx.hir().find(hir_id)
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&& let Some(hir::Node::Local(local)) = self.tcx.hir().find_parent(binding.hir_id)
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&& let None = local.ty
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&& let Some(binding_expr) = local.init
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{
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expr = binding_expr;
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} else {
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break 'outer;
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}
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}
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false
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}
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fn suggest_remove_await(&self, obligation: &PredicateObligation<'tcx>, err: &mut Diagnostic) {
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