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Stop being so bail-y in candidate assembly

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This commit is contained in:
Michael Goulet 2024-11-21 01:34:50 +00:00
parent 2d0ea7956c
commit 0465f71d60
39 changed files with 328 additions and 240 deletions
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28
compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs
View file

@ -91,14 +91,6 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
} else if tcx.is_lang_item(def_id, LangItem::Sized) {
// Sized is never implementable by end-users, it is
// always automatically computed.
// FIXME: Consider moving this check to the top level as it
// may also be useful for predicates other than `Sized`
// Error type cannot possibly implement `Sized` (fixes #123154)
if let Err(e) = obligation.predicate.skip_binder().self_ty().error_reported() {
return Err(SelectionError::Overflow(e.into()));
}
let sized_conditions = self.sized_conditions(obligation);
self.assemble_builtin_bound_candidates(sized_conditions, &mut candidates);
} else if tcx.is_lang_item(def_id, LangItem::Unsize) {
@ -230,13 +222,6 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
) -> Result<(), SelectionError<'tcx>> {
debug!(?stack.obligation);
// An error type will unify with anything. So, avoid
// matching an error type with `ParamCandidate`.
// This helps us avoid spurious errors like issue #121941.
if stack.obligation.predicate.references_error() {
return Ok(());
}
let bounds = stack
.obligation
.param_env
@ -563,19 +548,6 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
obligation: &PolyTraitObligation<'tcx>,
candidates: &mut SelectionCandidateSet<'tcx>,
) {
// Essentially any user-written impl will match with an error type,
// so creating `ImplCandidates` isn't useful. However, we might
// end up finding a candidate elsewhere (e.g. a `BuiltinCandidate` for `Sized`)
// This helps us avoid overflow: see issue #72839
// Since compilation is already guaranteed to fail, this is just
// to try to show the 'nicest' possible errors to the user.
// We don't check for errors in the `ParamEnv` - in practice,
// it seems to cause us to be overly aggressive in deciding
// to give up searching for candidates, leading to spurious errors.
if obligation.predicate.references_error() {
return;
}
let drcx = DeepRejectCtxt::relate_rigid_infer(self.tcx());
let obligation_args = obligation.predicate.skip_binder().trait_ref.args;
self.tcx().for_each_relevant_impl(

4
compiler/rustc_trait_selection/src/traits/select/mod.rs
View file

@ -2487,10 +2487,6 @@ impl<'tcx> SelectionContext<'_, 'tcx> {
let impl_args = self.infcx.fresh_args_for_item(obligation.cause.span, impl_def_id);
let trait_ref = impl_trait_header.trait_ref.instantiate(self.tcx(), impl_args);
if trait_ref.references_error() {
return Err(());
}
debug!(?impl_trait_header);
let Normalized { value: impl_trait_ref, obligations: mut nested_obligations } =