1 use rustc::traits::query::CanonicalPredicateGoal;
3 EvaluationResult, Obligation, ObligationCause, OverflowError, SelectionContext, TraitQueryMode,
5 use rustc::ty::query::Providers;
6 use rustc::ty::{ParamEnvAnd, TyCtxt};
7 use syntax::source_map::DUMMY_SP;
9 crate fn provide(p: &mut Providers<'_>) {
10 *p = Providers { evaluate_obligation, ..*p };
13 fn evaluate_obligation<'tcx>(
15 canonical_goal: CanonicalPredicateGoal<'tcx>,
16 ) -> Result<EvaluationResult, OverflowError> {
17 debug!("evaluate_obligation(canonical_goal={:#?})", canonical_goal);
18 tcx.infer_ctxt().enter_with_canonical(
21 |ref infcx, goal, _canonical_inference_vars| {
22 debug!("evaluate_obligation: goal={:#?}", goal);
23 let ParamEnvAnd { param_env, value: predicate } = goal;
25 let mut selcx = SelectionContext::with_query_mode(&infcx, TraitQueryMode::Canonical);
26 let obligation = Obligation::new(ObligationCause::dummy(), param_env, predicate);
28 selcx.evaluate_root_obligation(&obligation)