Function rustc_trait_selection::solve::assembly::structural_traits::coroutine_closure_to_certain_coroutine

fn coroutine_closure_to_certain_coroutine<'tcx>(
    tcx: TyCtxt<'tcx>,
    goal_kind: ClosureKind,
    goal_region: Region<'tcx>,
    def_id: DefId,
    args: CoroutineClosureArgs<'tcx>,
    sig: CoroutineClosureSignature<'tcx>
) -> Ty<'tcx>

Given a coroutine-closure, project to its returned coroutine when we are certain that the closure’s kind is compatible with the goal.