Trait rustc_typeck::outlives::outlives_bounds::InferCtxtExt[−][src]

pub trait InferCtxtExt<'tcx> {
    fn implied_outlives_bounds(
        &self, 
        param_env: ParamEnv<'tcx>, 
        body_id: HirId, 
        ty: Ty<'tcx>, 
        span: Span
    ) -> 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.
  • span, a span to use when normalizing, hopefully not important, might be useful if a bug! occurs.

Implementors