bjoernager/rust
bjoernager/rust
1
Fork 0
Code Activity

Don't project specializable RPITIT projection

Browse source
This commit is contained in:
Michael Goulet 2023-02-21 18:27:17 +00:00
parent 02b3664766
commit 9bf32c40b4
3 changed files with 119 additions and 5 deletions
Download patch file Download diff file Expand all files Collapse all files

27
compiler/rustc_trait_selection/src/traits/project.rs
View file

@ -1307,21 +1307,38 @@ fn assemble_candidate_for_impl_trait_in_trait<'cx, 'tcx>(
let _ = selcx.infcx.commit_if_ok(|_| {
match selcx.select(&obligation.with(tcx, trait_predicate)) {
Ok(Some(super::ImplSource::UserDefined(data))) => {
candidate_set.push_candidate(ProjectionCandidate::ImplTraitInTrait(data));
Ok(())
let Ok(leaf_def) = specialization_graph::assoc_def(tcx, data.impl_def_id, trait_fn_def_id) else {
return Err(());
};
// Only reveal a specializable default if we're past type-checking
// and the obligation is monomorphic, otherwise passes such as
// transmute checking and polymorphic MIR optimizations could
// get a result which isn't correct for all monomorphizations.
if leaf_def.is_final()
|| (obligation.param_env.reveal() == Reveal::All
&& !selcx
.infcx
.resolve_vars_if_possible(obligation.predicate.trait_ref(tcx))
.still_further_specializable())
{
candidate_set.push_candidate(ProjectionCandidate::ImplTraitInTrait(data));
Ok(())
} else {
Err(())
}
}
Ok(None) => {
candidate_set.mark_ambiguous();
return Err(());
Err(())
}
Ok(Some(_)) => {
// Don't know enough about the impl to provide a useful signature
return Err(());
Err(())
}
Err(e) => {
debug!(error = ?e, "selection error");
candidate_set.mark_error(e);
return Err(());
Err(())
}
}
});