c3f9403f59
Such structures may contain self-references, in which case the same location may be accessible through a pointer that is not based-on the noalias pointer. This is still grey area as far as language semantics are concerned, but checking for !Unpin as an indicator for self-referential sturctures seems like a good approach for the meantime.
52 lines
1.4 KiB
Rust
52 lines
1.4 KiB
Rust
//! Queries for checking whether a type implements one of a few common traits.
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use rustc_hir::lang_items::LangItem;
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use rustc_infer::infer::TyCtxtInferExt;
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use rustc_middle::ty::{self, Ty, TyCtxt};
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use rustc_span::DUMMY_SP;
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use rustc_trait_selection::traits;
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fn is_copy_raw<'tcx>(tcx: TyCtxt<'tcx>, query: ty::ParamEnvAnd<'tcx, Ty<'tcx>>) -> bool {
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is_item_raw(tcx, query, LangItem::Copy)
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}
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fn is_sized_raw<'tcx>(tcx: TyCtxt<'tcx>, query: ty::ParamEnvAnd<'tcx, Ty<'tcx>>) -> bool {
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is_item_raw(tcx, query, LangItem::Sized)
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}
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fn is_freeze_raw<'tcx>(tcx: TyCtxt<'tcx>, query: ty::ParamEnvAnd<'tcx, Ty<'tcx>>) -> bool {
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is_item_raw(tcx, query, LangItem::Freeze)
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}
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fn is_unpin_raw<'tcx>(tcx: TyCtxt<'tcx>, query: ty::ParamEnvAnd<'tcx, Ty<'tcx>>) -> bool {
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is_item_raw(tcx, query, LangItem::Unpin)
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}
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fn is_item_raw<'tcx>(
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tcx: TyCtxt<'tcx>,
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query: ty::ParamEnvAnd<'tcx, Ty<'tcx>>,
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item: LangItem,
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) -> bool {
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let (param_env, ty) = query.into_parts();
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let trait_def_id = tcx.require_lang_item(item, None);
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tcx.infer_ctxt().enter(|infcx| {
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traits::type_known_to_meet_bound_modulo_regions(
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&infcx,
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param_env,
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ty,
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trait_def_id,
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DUMMY_SP,
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)
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})
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}
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pub(crate) fn provide(providers: &mut ty::query::Providers) {
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*providers = ty::query::Providers {
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is_copy_raw,
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is_sized_raw,
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is_freeze_raw,
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is_unpin_raw,
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..*providers
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};
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}
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