34 lines
1.4 KiB
Rust
34 lines
1.4 KiB
Rust
use rustc_infer::infer::TyCtxtInferExt;
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use rustc_middle::query::Providers;
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use rustc_middle::traits::DefiningAnchor;
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use rustc_middle::ty::{ParamEnvAnd, TyCtxt};
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use rustc_span::source_map::DUMMY_SP;
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use rustc_trait_selection::traits::query::CanonicalPredicateGoal;
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use rustc_trait_selection::traits::{
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EvaluationResult, Obligation, ObligationCause, OverflowError, SelectionContext, TraitQueryMode,
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};
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pub(crate) fn provide(p: &mut Providers) {
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*p = Providers { evaluate_obligation, ..*p };
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}
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fn evaluate_obligation<'tcx>(
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tcx: TyCtxt<'tcx>,
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canonical_goal: CanonicalPredicateGoal<'tcx>,
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) -> Result<EvaluationResult, OverflowError> {
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assert!(!tcx.next_trait_solver_globally());
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debug!("evaluate_obligation(canonical_goal={:#?})", canonical_goal);
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// HACK This bubble is required for this tests to pass:
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// impl-trait/issue99642.rs
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let (ref infcx, goal, _canonical_inference_vars) = tcx
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.infer_ctxt()
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.with_opaque_type_inference(DefiningAnchor::Bubble)
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.build_with_canonical(DUMMY_SP, &canonical_goal);
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debug!("evaluate_obligation: goal={:#?}", goal);
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let ParamEnvAnd { param_env, value: predicate } = goal;
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let mut selcx = SelectionContext::with_query_mode(&infcx, TraitQueryMode::Canonical);
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let obligation = Obligation::new(tcx, ObligationCause::dummy(), param_env, predicate);
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selcx.evaluate_root_obligation(&obligation)
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}
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