Methods of const traits are const

This commit is contained in:
Oli Scherer 2025-01-15 10:50:07 +00:00
parent 2776bdfe42
commit a61cd86a4e
2 changed files with 13 additions and 12 deletions

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@ -4,14 +4,18 @@ use rustc_hir::def_id::{DefId, LocalDefId};
use rustc_middle::query::Providers; use rustc_middle::query::Providers;
use rustc_middle::ty::TyCtxt; use rustc_middle::ty::TyCtxt;
fn parent_impl_constness(tcx: TyCtxt<'_>, def_id: LocalDefId) -> hir::Constness { fn parent_impl_or_trait_constness(tcx: TyCtxt<'_>, def_id: LocalDefId) -> hir::Constness {
let parent_id = tcx.local_parent(def_id); let parent_id = tcx.local_parent(def_id);
if matches!(tcx.def_kind(parent_id), DefKind::Impl { .. }) match tcx.def_kind(parent_id) {
&& let Some(header) = tcx.impl_trait_header(parent_id) DefKind::Impl { of_trait: true } => tcx.impl_trait_header(parent_id).unwrap().constness,
{ DefKind::Trait => {
header.constness if tcx.is_const_trait(parent_id.into()) {
} else { hir::Constness::Const
hir::Constness::NotConst } else {
hir::Constness::NotConst
}
}
_ => hir::Constness::NotConst,
} }
} }
@ -34,7 +38,7 @@ fn constness(tcx: TyCtxt<'_>, def_id: LocalDefId) -> hir::Constness {
// If the function itself is not annotated with `const`, it may still be a `const fn` // If the function itself is not annotated with `const`, it may still be a `const fn`
// if it resides in a const trait impl. // if it resides in a const trait impl.
parent_impl_constness(tcx, def_id) parent_impl_or_trait_constness(tcx, def_id)
} else { } else {
tcx.dcx().span_bug( tcx.dcx().span_bug(
tcx.def_span(def_id), tcx.def_span(def_id),

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@ -360,10 +360,7 @@ impl<'tcx> interpret::Machine<'tcx> for CompileTimeMachine<'tcx> {
// sensitive check here. But we can at least rule out functions that are not const at // sensitive check here. But we can at least rule out functions that are not const at
// all. That said, we have to allow calling functions inside a trait marked with // all. That said, we have to allow calling functions inside a trait marked with
// #[const_trait]. These *are* const-checked! // #[const_trait]. These *are* const-checked!
// FIXME(const_trait_impl): why does `is_const_fn` not classify them as const? if !ecx.tcx.is_const_fn(def) || ecx.tcx.has_attr(def, sym::rustc_do_not_const_check) {
if (!ecx.tcx.is_const_fn(def) && !ecx.tcx.is_const_default_method(def))
|| ecx.tcx.has_attr(def, sym::rustc_do_not_const_check)
{
// We certainly do *not* want to actually call the fn // We certainly do *not* want to actually call the fn
// though, so be sure we return here. // though, so be sure we return here.
throw_unsup_format!("calling non-const function `{}`", instance) throw_unsup_format!("calling non-const function `{}`", instance)