private static Func <TIn, TOut> CompileFromFingerprint(Expression <Func <TIn, TOut> > expr) { var fingerprint = FingerprintingExpressionVisitor.GetFingerprintChain(expr, out var capturedConstants); if (fingerprint != null) { var del = _fingerprintedCache.GetOrAdd(fingerprint, _ => { // Fingerprinting succeeded, but there was a cache miss. Rewrite the expression // and add the rewritten expression to the cache. var hoistedExpr = HoistingExpressionVisitor <TIn, TOut> .Hoist(expr); return(hoistedExpr.Compile()); }); return(model => del(model, capturedConstants)); } // couldn't be fingerprinted return(null); }