diff options
Diffstat (limited to '')
-rw-r--r-- | compiler/rustc_trait_selection/src/traits/query/type_op/implied_outlives_bounds.rs | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/compiler/rustc_trait_selection/src/traits/query/type_op/implied_outlives_bounds.rs b/compiler/rustc_trait_selection/src/traits/query/type_op/implied_outlives_bounds.rs new file mode 100644 index 000000000..2a3319f0f --- /dev/null +++ b/compiler/rustc_trait_selection/src/traits/query/type_op/implied_outlives_bounds.rs @@ -0,0 +1,42 @@ +use crate::infer::canonical::{Canonicalized, CanonicalizedQueryResponse}; +use crate::traits::query::Fallible; +use rustc_infer::traits::query::OutlivesBound; +use rustc_middle::ty::{self, ParamEnvAnd, Ty, TyCtxt}; + +#[derive(Copy, Clone, Debug, HashStable, TypeFoldable, TypeVisitable, Lift)] +pub struct ImpliedOutlivesBounds<'tcx> { + pub ty: Ty<'tcx>, +} + +impl<'tcx> super::QueryTypeOp<'tcx> for ImpliedOutlivesBounds<'tcx> { + type QueryResponse = Vec<OutlivesBound<'tcx>>; + + fn try_fast_path( + _tcx: TyCtxt<'tcx>, + key: &ParamEnvAnd<'tcx, Self>, + ) -> Option<Self::QueryResponse> { + // Don't go into the query for things that can't possibly have lifetimes. + match key.value.ty.kind() { + ty::Tuple(elems) if elems.is_empty() => Some(vec![]), + ty::Never | ty::Str | ty::Bool | ty::Char | ty::Int(_) | ty::Uint(_) | ty::Float(_) => { + Some(vec![]) + } + _ => None, + } + } + + fn perform_query( + tcx: TyCtxt<'tcx>, + canonicalized: Canonicalized<'tcx, ParamEnvAnd<'tcx, Self>>, + ) -> Fallible<CanonicalizedQueryResponse<'tcx, Self::QueryResponse>> { + // FIXME this `unchecked_map` is only necessary because the + // query is defined as taking a `ParamEnvAnd<Ty>`; it should + // take an `ImpliedOutlivesBounds` instead + let canonicalized = canonicalized.unchecked_map(|ParamEnvAnd { param_env, value }| { + let ImpliedOutlivesBounds { ty } = value; + param_env.and(ty) + }); + + tcx.implied_outlives_bounds(canonicalized) + } +} |