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