static if(is(typeof(&T) : R function(in Y, ref X, RCIAllocator), Y, X, R) || is(typeof(&T) : R delegate(in Y, ref X, RCIAllocator), Y, X, R) || is(typeof(T) : R function(in Y, ref X, RCIAllocator), Y, X, R) || is(typeof(T) : R delegate(in Y, ref X, RCIAllocator), Y, X, R))