+ /// Checks whether `expected` is a subtype of `actual`: `expected <: actual`.
+ pub fn sub<T: ToTrace<'tcx>>(
+ &self,
+ cause: &ObligationCause<'tcx>,
+ param_env: ty::ParamEnv<'tcx>,
+ expected: T,
+ actual: T,
+ ) -> Result<(), TypeError<'tcx>> {
+ self.infcx
+ .at(cause, param_env)
+ .sup(expected, actual)
+ .map(|infer_ok| self.register_infer_ok_obligations(infer_ok))
+ }
+
+ /// Checks whether `expected` is a supertype of `actual`: `expected :> actual`.