bjoernager/rust
bjoernager/rust
1
Fork 0
Code Activity

Don't point at Self type if we can't find an infer variable in ambiguous trait predicate

Browse source
This commit is contained in:
Michael Goulet 2022-06-25 10:42:23 -07:00
parent ca0105ba4e
commit 12ab6bfafd
15 changed files with 94 additions and 57 deletions
Download patch file Download diff file Expand all files Collapse all files

63
compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs
View file

@ -1970,13 +1970,31 @@ impl<'a, 'tcx> InferCtxtPrivExt<'a, 'tcx> for InferCtxt<'a, 'tcx> {
// Pick the first substitution that still contains inference variables as the one
// we're going to emit an error for. If there are none (see above), fall back to
// the substitution for `Self`.
let subst = {
let substs = data.trait_ref.substs;
substs
.iter()
.find(|s| s.has_infer_types_or_consts())
.unwrap_or_else(|| substs[0])
// a more general error.
let subst = data.trait_ref.substs.iter().find(|s| s.has_infer_types_or_consts());
let mut err = if let Some(subst) = subst {
let impl_candidates = self
.find_similar_impl_candidates(trait_ref)
.into_iter()
.map(|candidate| candidate.trait_ref)
.collect();
self.emit_inference_failure_err(
body_id,
span,
subst,
impl_candidates,
ErrorCode::E0283,
true,
)
} else {
struct_span_err!(
self.tcx.sess,
span,
E0283,
"type annotations needed: cannot satisfy `{}`",
predicate,
)
};
// This is kind of a hack: it frequently happens that some earlier
@ -1999,30 +2017,17 @@ impl<'a, 'tcx> InferCtxtPrivExt<'a, 'tcx> for InferCtxt<'a, 'tcx> {
self.emit_inference_failure_err(
body_id,
span,
subst,
trait_ref.self_ty().skip_binder().into(),
vec![],
ErrorCode::E0282,
false,
)
.emit();
}
err.cancel();
return;
}
let impl_candidates = self
.find_similar_impl_candidates(trait_ref)
.into_iter()
.map(|candidate| candidate.trait_ref)
.collect();
let mut err = self.emit_inference_failure_err(
body_id,
span,
subst,
impl_candidates,
ErrorCode::E0283,
true,
);
let obligation = Obligation::new(
obligation.cause.clone(),
obligation.param_env,
@ -2136,17 +2141,20 @@ impl<'a, 'tcx> InferCtxtPrivExt<'a, 'tcx> for InferCtxt<'a, 'tcx> {
)
}
ty::PredicateKind::Projection(data) => {
let self_ty = data.projection_ty.self_ty();
let term = data.term;
if predicate.references_error() || self.is_tainted_by_errors() {
return;
}
if self_ty.needs_infer() && term.needs_infer() {
// We do this for the `foo.collect()?` case to produce a suggestion.
let subst = data
.projection_ty
.substs
.iter()
.chain(Some(data.term.into_arg()))
.find(|g| g.has_infer_types_or_consts());
if let Some(subst) = subst {
let mut err = self.emit_inference_failure_err(
body_id,
span,
self_ty.into(),
subst,
vec![],
ErrorCode::E0284,
true,
@ -2154,6 +2162,7 @@ impl<'a, 'tcx> InferCtxtPrivExt<'a, 'tcx> for InferCtxt<'a, 'tcx> {
err.note(&format!("cannot satisfy `{}`", predicate));
err
} else {
// If we can't find a substitution, just print a generic error
let mut err = struct_span_err!(
self.tcx.sess,
span,