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~const trait or projection bounds do not imply non-const bounds

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This commit is contained in:
Michael Goulet 2024-01-07 22:53:50 +00:00
parent 0ee9cfd54d
commit e44b11f695
11 changed files with 214 additions and 83 deletions
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18
compiler/rustc_hir_analysis/src/bounds.rs
View file

@ -45,24 +45,6 @@ impl<'tcx> Bounds<'tcx> {
polarity: ty::ImplPolarity,
) {
self.push_trait_bound_inner(tcx, trait_ref, span, polarity);
// push a non-const (`host = true`) version of the bound if it is `~const`.
if tcx.features().effects
&& let Some(host_effect_idx) = tcx.generics_of(trait_ref.def_id()).host_effect_index
&& trait_ref.skip_binder().args.const_at(host_effect_idx) != tcx.consts.true_
{
let generics = tcx.generics_of(trait_ref.def_id());
let Some(host_index) = generics.host_effect_index else { return };
let trait_ref = trait_ref.map_bound(|mut trait_ref| {
trait_ref.args =
tcx.mk_args_from_iter(trait_ref.args.iter().enumerate().map(|(n, arg)| {
if host_index == n { tcx.consts.true_.into() } else { arg }
}));
trait_ref
});
self.push_trait_bound_inner(tcx, trait_ref, span, polarity);
}
}
fn push_trait_bound_inner(

38
compiler/rustc_hir_analysis/src/collect/predicates_of.rs
View file

@ -11,7 +11,7 @@ use rustc_hir::intravisit::{self, Visitor};
use rustc_middle::ty::{self, Ty, TyCtxt};
use rustc_middle::ty::{GenericPredicates, ImplTraitInTraitData, ToPredicate};
use rustc_span::symbol::Ident;
use rustc_span::{sym, Span, DUMMY_SP};
use rustc_span::{Span, DUMMY_SP};
/// Returns a list of all type predicates (explicit and implicit) for the definition with
/// ID `def_id`. This includes all predicates returned by `predicates_defined_on`, plus
@ -38,38 +38,12 @@ pub(super) fn predicates_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::GenericPredic
// an obligation and instead be skipped. Otherwise we'd use
// `tcx.def_span(def_id);`
let span = rustc_span::DUMMY_SP;
let non_const_bound = if tcx.features().effects && tcx.has_attr(def_id, sym::const_trait) {
// when `Self` is a const trait, also add `Self: Trait<.., true>` as implied bound,
// because only implementing `Self: Trait<.., false>` is currently not possible.
Some((
ty::TraitRef::new(
tcx,
def_id,
ty::GenericArgs::for_item(tcx, def_id, |param, _| {
if param.is_host_effect() {
tcx.consts.true_.into()
} else {
tcx.mk_param_from_def(param)
}
}),
)
.to_predicate(tcx),
result.predicates =
tcx.arena.alloc_from_iter(result.predicates.iter().copied().chain(std::iter::once((
ty::TraitRef::identity(tcx, def_id).to_predicate(tcx),
span,
))
} else {
None
};
result.predicates = tcx.arena.alloc_from_iter(
result
.predicates
.iter()
.copied()
.chain(std::iter::once((
ty::TraitRef::identity(tcx, def_id).to_predicate(tcx),
span,
)))
.chain(non_const_bound),
);
))));
}
debug!("predicates_of(def_id={:?}) = {:?}", def_id, result);
result