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use rustc_infer::infer::canonical::{Canonical, QueryResponse};
use rustc_infer::infer::TyCtxtInferExt;
use rustc_infer::traits::TraitEngineExt as _;
use rustc_middle::ty::query::Providers;
use rustc_middle::ty::{ParamEnvAnd, TyCtxt};
use rustc_trait_selection::infer::InferCtxtBuilderExt;
use rustc_trait_selection::traits::query::{
normalize::NormalizationResult, CanonicalProjectionGoal, NoSolution,
};
use rustc_trait_selection::traits::{self, ObligationCause, SelectionContext};
use std::sync::atomic::Ordering;
pub(crate) fn provide(p: &mut Providers) {
*p = Providers { normalize_projection_ty, ..*p };
}
fn normalize_projection_ty<'tcx>(
tcx: TyCtxt<'tcx>,
goal: CanonicalProjectionGoal<'tcx>,
) -> Result<&'tcx Canonical<'tcx, QueryResponse<'tcx, NormalizationResult<'tcx>>>, NoSolution> {
debug!("normalize_provider(goal={:#?})", goal);
tcx.sess.perf_stats.normalize_projection_ty.fetch_add(1, Ordering::Relaxed);
tcx.infer_ctxt().enter_canonical_trait_query(
&goal,
|infcx, fulfill_cx, ParamEnvAnd { param_env, value: goal }| {
let selcx = &mut SelectionContext::new(infcx);
let cause = ObligationCause::dummy();
let mut obligations = vec![];
let answer = traits::normalize_projection_type(
selcx,
param_env,
goal,
cause,
0,
&mut obligations,
);
fulfill_cx.register_predicate_obligations(infcx, obligations);
// FIXME(associated_const_equality): All users of normalize_projection_ty expected
// a type, but there is the possibility it could've been a const now. Maybe change
// it to a Term later?
Ok(NormalizationResult { normalized_ty: answer.ty().unwrap() })
},
)
}
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