925ec0d3c7
Specifically, change `Ty` from this:
```
pub struct Predicate<'tcx> { inner: &'tcx PredicateInner<'tcx> }
```
to this:
```
pub struct Predicate<'tcx>(&'tcx Interned<PredicateS<'tcx>>)
```
where `PredicateInner` is renamed as `PredicateS`.
This (plus a few other minor changes) makes the parallels with `Ty` and
`TyS` much clearer, and makes the uniqueness more explicit.
75 lines
3.0 KiB
Rust
75 lines
3.0 KiB
Rust
use rustc_infer::infer::TyCtxtInferExt;
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use rustc_middle::traits::query::NoSolution;
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use rustc_middle::ty::query::Providers;
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use rustc_middle::ty::{self, ParamEnvAnd, TyCtxt, TypeFoldable};
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use rustc_trait_selection::traits::query::normalize::AtExt;
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use rustc_trait_selection::traits::{Normalized, ObligationCause};
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use std::sync::atomic::Ordering;
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crate fn provide(p: &mut Providers) {
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*p = Providers {
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try_normalize_generic_arg_after_erasing_regions: |tcx, goal| {
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debug!("try_normalize_generic_arg_after_erasing_regions(goal={:#?}", goal);
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tcx.sess
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.perf_stats
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.normalize_generic_arg_after_erasing_regions
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.fetch_add(1, Ordering::Relaxed);
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try_normalize_after_erasing_regions(tcx, goal)
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},
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try_normalize_mir_const_after_erasing_regions: |tcx, goal| {
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try_normalize_after_erasing_regions(tcx, goal)
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},
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..*p
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};
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}
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#[instrument(level = "debug", skip(tcx))]
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fn try_normalize_after_erasing_regions<'tcx, T: TypeFoldable<'tcx> + PartialEq + Copy>(
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tcx: TyCtxt<'tcx>,
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goal: ParamEnvAnd<'tcx, T>,
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) -> Result<T, NoSolution> {
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let ParamEnvAnd { param_env, value } = goal;
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tcx.infer_ctxt().enter(|infcx| {
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let cause = ObligationCause::dummy();
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match infcx.at(&cause, param_env).normalize(value) {
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Ok(Normalized { value: normalized_value, obligations: normalized_obligations }) => {
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// We don't care about the `obligations`; they are
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// always only region relations, and we are about to
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// erase those anyway:
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debug_assert_eq!(
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normalized_obligations.iter().find(|p| not_outlives_predicate(p.predicate)),
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None,
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);
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let resolved_value = infcx.resolve_vars_if_possible(normalized_value);
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// It's unclear when `resolve_vars` would have an effect in a
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// fresh `InferCtxt`. If this assert does trigger, it will give
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// us a test case.
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debug_assert_eq!(normalized_value, resolved_value);
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let erased = infcx.tcx.erase_regions(resolved_value);
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debug_assert!(!erased.needs_infer(), "{:?}", erased);
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Ok(erased)
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}
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Err(NoSolution) => Err(NoSolution),
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}
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})
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}
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fn not_outlives_predicate<'tcx>(p: ty::Predicate<'tcx>) -> bool {
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match p.kind().skip_binder() {
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ty::PredicateKind::RegionOutlives(..) | ty::PredicateKind::TypeOutlives(..) => false,
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ty::PredicateKind::Trait(..)
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| ty::PredicateKind::Projection(..)
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| ty::PredicateKind::WellFormed(..)
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| ty::PredicateKind::ObjectSafe(..)
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| ty::PredicateKind::ClosureKind(..)
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| ty::PredicateKind::Subtype(..)
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| ty::PredicateKind::Coerce(..)
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| ty::PredicateKind::ConstEvaluatable(..)
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| ty::PredicateKind::ConstEquate(..)
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| ty::PredicateKind::TypeWellFormedFromEnv(..) => true,
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}
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}
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