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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
commit | 698f8c2f01ea549d77d7dc3338a12e04c11057b9 (patch) | |
tree | 173a775858bd501c378080a10dca74132f05bc50 /compiler/rustc_traits/src/normalize_erasing_regions.rs | |
parent | Initial commit. (diff) | |
download | rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.tar.xz rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.zip |
Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'compiler/rustc_traits/src/normalize_erasing_regions.rs')
-rw-r--r-- | compiler/rustc_traits/src/normalize_erasing_regions.rs | 73 |
1 files changed, 73 insertions, 0 deletions
diff --git a/compiler/rustc_traits/src/normalize_erasing_regions.rs b/compiler/rustc_traits/src/normalize_erasing_regions.rs new file mode 100644 index 000000000..5d394ed22 --- /dev/null +++ b/compiler/rustc_traits/src/normalize_erasing_regions.rs @@ -0,0 +1,73 @@ +use rustc_infer::infer::TyCtxtInferExt; +use rustc_middle::traits::query::NoSolution; +use rustc_middle::ty::query::Providers; +use rustc_middle::ty::{self, ParamEnvAnd, TyCtxt, TypeFoldable}; +use rustc_trait_selection::traits::query::normalize::AtExt; +use rustc_trait_selection::traits::{Normalized, ObligationCause}; +use std::sync::atomic::Ordering; + +pub(crate) fn provide(p: &mut Providers) { + *p = Providers { + try_normalize_generic_arg_after_erasing_regions: |tcx, goal| { + debug!("try_normalize_generic_arg_after_erasing_regions(goal={:#?}", goal); + + tcx.sess + .perf_stats + .normalize_generic_arg_after_erasing_regions + .fetch_add(1, Ordering::Relaxed); + + try_normalize_after_erasing_regions(tcx, goal) + }, + try_normalize_mir_const_after_erasing_regions: |tcx, goal| { + try_normalize_after_erasing_regions(tcx, goal) + }, + ..*p + }; +} + +fn try_normalize_after_erasing_regions<'tcx, T: TypeFoldable<'tcx> + PartialEq + Copy>( + tcx: TyCtxt<'tcx>, + goal: ParamEnvAnd<'tcx, T>, +) -> Result<T, NoSolution> { + let ParamEnvAnd { param_env, value } = goal; + tcx.infer_ctxt().enter(|infcx| { + let cause = ObligationCause::dummy(); + match infcx.at(&cause, param_env).normalize(value) { + Ok(Normalized { value: normalized_value, obligations: normalized_obligations }) => { + // We don't care about the `obligations`; they are + // always only region relations, and we are about to + // erase those anyway: + debug_assert_eq!( + normalized_obligations.iter().find(|p| not_outlives_predicate(p.predicate)), + None, + ); + + let resolved_value = infcx.resolve_vars_if_possible(normalized_value); + // It's unclear when `resolve_vars` would have an effect in a + // fresh `InferCtxt`. If this assert does trigger, it will give + // us a test case. + debug_assert_eq!(normalized_value, resolved_value); + let erased = infcx.tcx.erase_regions(resolved_value); + debug_assert!(!erased.needs_infer(), "{:?}", erased); + Ok(erased) + } + Err(NoSolution) => Err(NoSolution), + } + }) +} + +fn not_outlives_predicate<'tcx>(p: ty::Predicate<'tcx>) -> bool { + match p.kind().skip_binder() { + ty::PredicateKind::RegionOutlives(..) | ty::PredicateKind::TypeOutlives(..) => false, + ty::PredicateKind::Trait(..) + | ty::PredicateKind::Projection(..) + | ty::PredicateKind::WellFormed(..) + | ty::PredicateKind::ObjectSafe(..) + | ty::PredicateKind::ClosureKind(..) + | ty::PredicateKind::Subtype(..) + | ty::PredicateKind::Coerce(..) + | ty::PredicateKind::ConstEvaluatable(..) + | ty::PredicateKind::ConstEquate(..) + | ty::PredicateKind::TypeWellFormedFromEnv(..) => true, + } +} |