Struct FunctionalVariances 

struct FunctionalVariances<'tcx> {
    tcx: TyCtxt<'tcx>,
    variances: FxHashMap<DefId, Variance>,
    ambient_variance: Variance,
    generics: &'tcx Generics,
}

Computes the variances of regions that appear in the type, but considering late-bound regions too, which don’t have their variance computed usually.

Like generalization, this is a unary operation implemented on top of the binary relation infrastructure, mostly because it’s much easier to have the relation track the variance for you, rather than having to do it yourself.

Fields

tcx: TyCtxt<'tcx>

variances: FxHashMap<DefId, Variance>

ambient_variance: Variance

generics: &'tcx Generics

Trait Implementations

impl<'tcx> TypeRelation<TyCtxt<'tcx>> for FunctionalVariances<'tcx>

fn cx(&self) -> TyCtxt<'tcx>

fn relate_ty_args( &mut self, a_ty: Ty<'tcx>, _: Ty<'tcx>, def_id: DefId, a_args: GenericArgsRef<'tcx>, b_args: GenericArgsRef<'tcx>, _: impl FnOnce(GenericArgsRef<'tcx>) -> Ty<'tcx>, ) -> RelateResult<'tcx, Ty<'tcx>>

fn relate_with_variance<T: Relate<TyCtxt<'tcx>>>( &mut self, variance: Variance, _: VarianceDiagInfo<TyCtxt<'tcx>>, a: T, b: T, ) -> RelateResult<'tcx, T>

Switch variance for the purpose of relating a and b.

fn tys(&mut self, a: Ty<'tcx>, b: Ty<'tcx>) -> RelateResult<'tcx, Ty<'tcx>>

fn regions( &mut self, a: Region<'tcx>, _: Region<'tcx>, ) -> RelateResult<'tcx, Region<'tcx>>

fn consts( &mut self, a: Const<'tcx>, b: Const<'tcx>, ) -> RelateResult<'tcx, Const<'tcx>>

fn binders<T>( &mut self, a: Binder<'tcx, T>, b: Binder<'tcx, T>, ) -> RelateResult<'tcx, Binder<'tcx, T>>

where T: Relate<TyCtxt<'tcx>>,

fn relate<T>(&mut self, a: T, b: T) -> Result<T, TypeError<I>>

where T: Relate<I>,

Generic relation routine suitable for most anything.

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 56 bytes