bjoernager/rust
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Move impl constness into impl trait header

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This commit is contained in:
Oli Scherer 2024-12-10 10:12:36 +00:00
parent c0e0d8f874
commit 2ffe3b1e70
8 changed files with 35 additions and 33 deletions
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21
compiler/rustc_const_eval/src/const_eval/fn_queries.rs
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@ -4,16 +4,21 @@ use rustc_hir::def_id::{DefId, LocalDefId};
use rustc_middle::query::Providers;
use rustc_middle::ty::TyCtxt;
fn is_parent_const_impl_raw(tcx: TyCtxt<'_>, def_id: LocalDefId) -> bool {
fn parent_impl_constness(tcx: TyCtxt<'_>, def_id: LocalDefId) -> hir::Constness {
let parent_id = tcx.local_parent(def_id);
matches!(tcx.def_kind(parent_id), DefKind::Impl { .. })
&& tcx.constness(parent_id) == hir::Constness::Const
if matches!(tcx.def_kind(parent_id), DefKind::Impl { .. })
&& let Some(header) = tcx.impl_trait_header(parent_id)
{
header.constness
} else {
hir::Constness::NotConst
}
}
/// Checks whether an item is considered to be `const`. If it is a constructor, anonymous const,
/// const block, const item or associated const, it is const. If it is a trait impl/function,
/// Checks whether an item is considered to be `const`. If it is a constructor, it is const.
/// If it is an assoc method or function,
/// return if it has a `const` modifier. If it is an intrinsic, report whether said intrinsic
/// has a `rustc_const_{un,}stable` attribute. Otherwise, return `Constness::NotConst`.
/// has a `rustc_const_{un,}stable` attribute. Otherwise, panic.
fn constness(tcx: TyCtxt<'_>, def_id: LocalDefId) -> hir::Constness {
let node = tcx.hir_node_by_def_id(def_id);
@ -22,7 +27,6 @@ fn constness(tcx: TyCtxt<'_>, def_id: LocalDefId) -> hir::Constness {
| hir::Node::ImplItem(hir::ImplItem { kind: hir::ImplItemKind::Const(..), .. }) => {
hir::Constness::Const
}
hir::Node::Item(hir::Item { kind: hir::ItemKind::Impl(impl_), .. }) => impl_.constness,
hir::Node::ForeignItem(_) => {
// Foreign items cannot be evaluated at compile-time.
hir::Constness::NotConst
@ -36,8 +40,7 @@ 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 it resides in a const trait impl.
let is_const = is_parent_const_impl_raw(tcx, def_id);
if is_const { hir::Constness::Const } else { hir::Constness::NotConst }
parent_impl_constness(tcx, def_id)
} else {
tcx.dcx().span_bug(
tcx.def_span(def_id),