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use query boilerplate for subtype

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This commit is contained in:
Niko Matsakis 2018-06-27 06:48:52 -04:00
parent fa71af4192
commit ac40d73c6f
1 changed files with 14 additions and 14 deletions
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28
src/librustc_traits/type_op_subtype.rs
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@ -11,25 +11,25 @@
use rustc::infer::canonical::{Canonical, QueryResult};
use rustc::traits::query::type_op::subtype::Subtype;
use rustc::traits::query::NoSolution;
use rustc::traits::{FulfillmentContext, ObligationCause};
use rustc::traits::ObligationCause;
use rustc::ty::TyCtxt;
use rustc_data_structures::sync::Lrc;
use syntax::codemap::DUMMY_SP;
crate fn type_op_subtype<'tcx>(
tcx: TyCtxt<'_, 'tcx, 'tcx>,
canonicalized: Canonical<'tcx, Subtype<'tcx>>,
) -> Result<Lrc<Canonical<'tcx, QueryResult<'tcx, ()>>>, NoSolution> {
let tcx = tcx.global_tcx();
tcx.infer_ctxt().enter(|ref infcx| {
let (Subtype { param_env, sub, sup }, canonical_inference_vars) =
infcx.instantiate_canonical_with_fresh_inference_vars(DUMMY_SP, &canonicalized);
let fulfill_cx = &mut FulfillmentContext::new();
let obligations = match infcx.at(&ObligationCause::dummy(), param_env).sup(sup, sub) {
Ok(v) => v.into_obligations(),
Err(_) => return Err(NoSolution),
};
fulfill_cx.register_predicate_obligations(infcx, obligations);
infcx.make_canonicalized_query_result(canonical_inference_vars, (), fulfill_cx)
})
tcx.infer_ctxt().enter_canonical_trait_query(
&canonicalized,
|infcx,
Subtype {
param_env,
sub,
sup,
}| {
Ok(infcx
.at(&ObligationCause::dummy(), param_env)
.sup(sup, sub)?)
},
)
}