Function dispatch_query

fn dispatch_query<R>(
    genv: GlobalEnv<'_, '_>,
    def_id: DefId,
    local: impl FnOnce(MaybeExternId) -> R,
    external: impl FnOnce(DefId) -> Option<R>,
    default: impl FnOnce(DefId) -> R,
) -> R

Resolve the def_id and dispatch it to a provider (local, external, or default).