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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<EvaluationResult, OverflowError> {
debug!("evaluate_obligation(canonical_goal={:#?})", canonical_goal);
// HACK This bubble is required for this tests to pass:
// impl-trait/issue99642.rs
tcx.infer_ctxt().with_opaque_type_inference(DefiningAnchor::Bubble).enter_with_canonical(
DUMMY_SP,
&canonical_goal,
|ref infcx, goal, _canonical_inference_vars| {
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(ObligationCause::dummy(), param_env, predicate);
selcx.evaluate_root_obligation(&obligation)
},
)
}
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