pub fn try_get_cached<Tcx, C>(
    tcx: Tcx,
    cache: &C,
    key: &C::Key
) -> Option<C::Value>where
    C: QueryCache,
    Tcx: DepContext,
Expand description

Checks if the query is already computed and in the cache. It returns the shard index and a lock guard to the shard, which will be used if the query is not in the cache and we need to compute it.