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use crate::infer::canonical::{Canonical, CanonicalQueryResponse};
use crate::traits::query::dropck_outlives::{trivial_dropck_outlives, DropckOutlivesResult};
use crate::traits::query::Fallible;
use rustc_middle::ty::{ParamEnvAnd, Ty, TyCtxt};
#[derive(Copy, Clone, Debug, HashStable, TypeFoldable, TypeVisitable, Lift)]
pub struct DropckOutlives<'tcx> {
dropped_ty: Ty<'tcx>,
}
impl<'tcx> DropckOutlives<'tcx> {
pub fn new(dropped_ty: Ty<'tcx>) -> Self {
DropckOutlives { dropped_ty }
}
}
impl<'tcx> super::QueryTypeOp<'tcx> for DropckOutlives<'tcx> {
type QueryResponse = DropckOutlivesResult<'tcx>;
fn try_fast_path(
tcx: TyCtxt<'tcx>,
key: &ParamEnvAnd<'tcx, Self>,
) -> Option<Self::QueryResponse> {
if trivial_dropck_outlives(tcx, key.value.dropped_ty) {
Some(DropckOutlivesResult::default())
} else {
None
}
}
fn perform_query(
tcx: TyCtxt<'tcx>,
canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, Self>>,
) -> Fallible<CanonicalQueryResponse<'tcx, Self::QueryResponse>> {
// Subtle: note that we are not invoking
// `infcx.at(...).dropck_outlives(...)` here, but rather the
// underlying `dropck_outlives` query. This same underlying
// query is also used by the
// `infcx.at(...).dropck_outlives(...)` fn. Avoiding the
// wrapper means we don't need an infcx in this code, which is
// good because the interface doesn't give us one (so that we
// know we are not registering any subregion relations or
// other things).
// FIXME convert to the type expected by the `dropck_outlives`
// query. This should eventually be fixed by changing the
// *underlying query*.
let canonicalized = canonicalized.unchecked_map(|ParamEnvAnd { param_env, value }| {
let DropckOutlives { dropped_ty } = value;
param_env.and(dropped_ty)
});
tcx.dropck_outlives(canonicalized)
}
}
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