pub trait GenericArgsExt {
// Required methods
fn box_args(&self) -> (&Ty, &Ty);
fn to_rustc<'tcx>(&self, tcx: TyCtxt<'tcx>) -> GenericArgsRef<'tcx>;
fn rebase_onto(
&self,
tcx: &TyCtxt<'_>,
source_ancestor: DefId,
target_args: &GenericArgs,
) -> List<GenericArg>;
}