1 use rustc_infer::infer::{DefiningAnchor, TyCtxtInferExt};
2 use rustc_middle::ty::query::Providers;
3 use rustc_middle::ty::{ParamEnvAnd, TyCtxt};
4 use rustc_span::source_map::DUMMY_SP;
5 use rustc_trait_selection::traits::query::CanonicalPredicateGoal;
6 use rustc_trait_selection::traits::{
7 EvaluationResult, Obligation, ObligationCause, OverflowError, SelectionContext, TraitQueryMode,
10 pub(crate) fn provide(p: &mut Providers) {
11 *p = Providers { evaluate_obligation, ..*p };
14 fn evaluate_obligation<'tcx>(
16 canonical_goal: CanonicalPredicateGoal<'tcx>,
17 ) -> Result<EvaluationResult, OverflowError> {
18 debug!("evaluate_obligation(canonical_goal={:#?})", canonical_goal);
19 // HACK This bubble is required for this tests to pass:
20 // impl-trait/issue99642.rs
21 tcx.infer_ctxt().with_opaque_type_inference(DefiningAnchor::Bubble).enter_with_canonical(
24 |ref infcx, goal, _canonical_inference_vars| {
25 debug!("evaluate_obligation: goal={:#?}", goal);
26 let ParamEnvAnd { param_env, value: predicate } = goal;
28 let mut selcx = SelectionContext::with_query_mode(&infcx, TraitQueryMode::Canonical);
29 let obligation = Obligation::new(ObligationCause::dummy(), param_env, predicate);
31 selcx.evaluate_root_obligation(&obligation)