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use infer::canonical::{Canonical, Canonicalized, CanonicalizedQueryResult, QueryRegionConstraint,
QueryResult};
use infer::{InferCtxt, InferOk};
use rustc_data_structures::small_vec::SmallVec;
use std::fmt;
use std::rc::Rc;
use traits::query::Fallible;
use traits::ObligationCause;
use ty::fold::TypeFoldable;
use ty::{Lift, ParamEnvAnd, TyCtxt};
pub mod custom;
pub mod eq;
pub mod normalize;
pub mod outlives;
pub mod prove_predicate;
use self::prove_predicate::ProvePredicate;
pub mod subtype;
pub trait TypeOp<'gcx, 'tcx>: Sized + fmt::Debug {
type Output;
fn fully_perform(
self,
infcx: &InferCtxt<'_, 'gcx, 'tcx>,
) -> Fallible<(Self::Output, Option<Rc<Vec<QueryRegionConstraint<'tcx>>>>)>;
}
pub trait QueryTypeOp<'gcx: 'tcx, 'tcx>:
fmt::Debug + Sized + TypeFoldable<'tcx> + Lift<'gcx>
{
type QueryResult: TypeFoldable<'tcx> + Lift<'gcx>;
fn try_fast_path(
tcx: TyCtxt<'_, 'gcx, 'tcx>,
key: &ParamEnvAnd<'tcx, Self>,
) -> Option<Self::QueryResult>;
fn perform_query(
tcx: TyCtxt<'_, 'gcx, 'tcx>,
canonicalized: Canonicalized<'gcx, ParamEnvAnd<'tcx, Self>>,
) -> Fallible<CanonicalizedQueryResult<'gcx, Self::QueryResult>>;
fn shrink_to_tcx_lifetime(
lifted_query_result: &'a CanonicalizedQueryResult<'gcx, Self::QueryResult>,
) -> &'a Canonical<'tcx, QueryResult<'tcx, Self::QueryResult>>;
fn fully_perform_into(
query_key: ParamEnvAnd<'tcx, Self>,
infcx: &InferCtxt<'_, 'gcx, 'tcx>,
output_query_region_constraints: &mut Vec<QueryRegionConstraint<'tcx>>,
) -> Fallible<Self::QueryResult> {
if let Some(result) = QueryTypeOp::try_fast_path(infcx.tcx, &query_key) {
return Ok(result);
}
let mut canonical_var_values = SmallVec::new();
let canonical_self =
infcx.canonicalize_hr_query_hack(&query_key, &mut canonical_var_values);
let canonical_result = Self::perform_query(infcx.tcx, canonical_self)?;
let canonical_result = Self::shrink_to_tcx_lifetime(&canonical_result);
let param_env = query_key.param_env;
let InferOk { value, obligations } = infcx
.instantiate_nll_query_result_and_region_obligations(
&ObligationCause::dummy(),
param_env,
&canonical_var_values,
canonical_result,
output_query_region_constraints,
)?;
for obligation in obligations {
let () = ProvePredicate::fully_perform_into(
obligation
.param_env
.and(ProvePredicate::new(obligation.predicate)),
infcx,
output_query_region_constraints,
)?;
}
Ok(value)
}
}
impl<'gcx: 'tcx, 'tcx, Q> TypeOp<'gcx, 'tcx> for ParamEnvAnd<'tcx, Q>
where
Q: QueryTypeOp<'gcx, 'tcx>,
{
type Output = Q::QueryResult;
fn fully_perform(
self,
infcx: &InferCtxt<'_, 'gcx, 'tcx>,
) -> Fallible<(Self::Output, Option<Rc<Vec<QueryRegionConstraint<'tcx>>>>)> {
let mut qrc = vec![];
let r = Q::fully_perform_into(self, infcx, &mut qrc)?;
let opt_qrc = if qrc.is_empty() {
None
} else {
Some(Rc::new(qrc))
};
Ok((r, opt_qrc))
}
}