Trait rustc_typeck::outlives::outlives_bounds::InferCtxtExt

source · [−]
pub trait InferCtxtExt<'tcx> {
    fn implied_outlives_bounds(
        &self,
        param_env: ParamEnv<'tcx>,
        body_id: HirId,
        ty: Ty<'tcx>
    ) -> Vec<OutlivesBound<'tcx>>;
}

Required Methods

Implementations on Foreign Types

Implied bounds are region relationships that we deduce automatically. The idea is that (e.g.) a caller must check that a function’s argument types are well-formed immediately before calling that fn, and hence the callee can assume that its argument types are well-formed. This may imply certain relationships between generic parameters. For example:

fn foo<'a,T>(x: &'a T) {}

can only be called with a 'a and T such that &'a T is WF. For &'a T to be WF, T: 'a must hold. So we can assume T: 'a.

Parameters
  • param_env, the where-clauses in scope
  • body_id, the body-id to use when normalizing assoc types. Note that this may cause outlives obligations to be injected into the inference context with this body-id.
  • ty, the type that we are supposed to assume is WF.

Implementors