Function resolve_region_name 

pub(crate) fn resolve_region_name<'tcx>(
    tcx: TyCtxt<'tcx>,
    def_id: DefId,
    name: &str,
) -> Option<Region<'tcx>>

Resolve a lifetime name from a contract (e.g. "a", "static") to a concrete Region. name is the raw ident, without the leading '.