Function resolve_ty_ident 

fn resolve_ty_ident<'tcx>(
    tcx: TyCtxt<'tcx>,
    def_id: DefId,
    name: &str,
) -> Option<Ty<'tcx>>

Resolve a type identifier to a Ty, handling the Self keyword (which match_ty_with_ident does not understand) by delegating to resolve_type_name.