bjoernager/rust
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Account for type params

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This commit is contained in:
Esteban Küber 2023-01-01 19:35:53 -08:00
parent 2024aa48b4
commit ce83be4af8
4 changed files with 81 additions and 38 deletions
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88
compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
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@ -1363,19 +1363,70 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
// Remove all the hir desugaring contexts while maintaining the macro contexts.
span.remove_mark();
}
let mut suggested = false;
let mut expr_finder = super::FindExprBySpan { span, result: None };
let mut expr_finder = super::FindExprBySpan::new(span);
let Some(hir::Node::Expr(body)) = self.tcx.hir().find(obligation.cause.body_id) else {
return false;
};
expr_finder.visit_expr(&body);
let mut maybe_suggest = |suggested_ty, count, suggestions| {
// Remapping bound vars here
let trait_pred_and_suggested_ty =
trait_pred.map_bound(|trait_pred| (trait_pred, suggested_ty));
let new_obligation = self.mk_trait_obligation_with_new_self_ty(
obligation.param_env,
trait_pred_and_suggested_ty,
);
if self.predicate_may_hold(&new_obligation) {
let msg = if count == 1 {
"consider removing the leading `&`-reference".to_string()
} else {
format!("consider removing {count} leading `&`-references")
};
err.multipart_suggestion_verbose(
&msg,
suggestions,
Applicability::MachineApplicable,
);
true
} else {
false
}
};
// Maybe suggest removal of borrows from types in type parameters, like in
// `src/test/ui/not-panic/not-panic-safe.rs`.
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();
if let Some(mut hir_ty) = expr_finder.ty_result {
while let hir::TyKind::Ref(_, mut_ty) = &hir_ty.kind {
count += 1;
let span = hir_ty.span.until(mut_ty.ty.span);
suggestions.push((span, String::new()));
let ty::Ref(_, inner_ty, _) = suggested_ty.kind() else {
break;
};
suggested_ty = *inner_ty;
hir_ty = mut_ty.ty;
if maybe_suggest(suggested_ty, count, suggestions.clone()) {
return true;
}
}
}
// Maybe suggest removal of borrows from expressions, like in `for i in &&&foo {}`.
let Some(mut expr) = expr_finder.result else { return false; };
let mut count = 0;
let mut suggestions = vec![];
// 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;
@ -1387,35 +1438,14 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
suggestions.push((span, String::new()));
let ty::Ref(_, inner_ty, _) = suggested_ty.kind() else {
break;
break 'outer;
};
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));
let new_obligation = self.mk_trait_obligation_with_new_self_ty(
obligation.param_env,
trait_pred_and_suggested_ty,
);
if self.predicate_may_hold(&new_obligation) {
let msg = if count == 1 {
"consider removing the leading `&`-reference".to_string()
} else {
format!("consider removing {count} leading `&`-references")
};
err.multipart_suggestion_verbose(
&msg,
suggestions,
Applicability::MachineApplicable,
);
suggested = true;
break 'outer;
if maybe_suggest(suggested_ty, count, suggestions.clone()) {
return true;
}
}
if let hir::ExprKind::Path(hir::QPath::Resolved(None, path)) = expr.kind
@ -1431,7 +1461,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
break 'outer;
}
}
suggested
false
}
fn suggest_remove_await(&self, obligation: &PredicateObligation<'tcx>, err: &mut Diagnostic) {