38 lines
1.3 KiB
Rust
38 lines
1.3 KiB
Rust
use crate::infer::canonical::{Canonicalized, CanonicalizedQueryResponse};
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use crate::traits::query::Fallible;
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use rustc::ty::{ParamEnvAnd, Predicate, TyCtxt};
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pub use rustc::traits::query::type_op::ProvePredicate;
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impl<'tcx> super::QueryTypeOp<'tcx> for ProvePredicate<'tcx> {
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type QueryResponse = ();
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fn try_fast_path(
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tcx: TyCtxt<'tcx>,
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key: &ParamEnvAnd<'tcx, Self>,
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) -> Option<Self::QueryResponse> {
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// Proving Sized, very often on "obviously sized" types like
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// `&T`, accounts for about 60% percentage of the predicates
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// we have to prove. No need to canonicalize and all that for
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// such cases.
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if let Predicate::Trait(trait_ref, _) = key.value.predicate {
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if let Some(sized_def_id) = tcx.lang_items().sized_trait() {
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if trait_ref.def_id() == sized_def_id {
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if trait_ref.skip_binder().self_ty().is_trivially_sized(tcx) {
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return Some(());
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}
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}
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}
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}
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None
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}
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fn perform_query(
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tcx: TyCtxt<'tcx>,
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canonicalized: Canonicalized<'tcx, ParamEnvAnd<'tcx, Self>>,
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) -> Fallible<CanonicalizedQueryResponse<'tcx, ()>> {
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tcx.type_op_prove_predicate(canonicalized)
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}
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}
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