Problem found with dmd 2.042. This code works at runtime if you move the enum line inside the main, but as it is crashes the compiler:


struct Searcher(T) {
    T[] data;
    bool opBinaryRight(string Op:"in")(T item) {
        return false;
    }
}
auto searcher(T)(T[] arr) {
    return Searcher!T(arr);
}
enum bool b = 1 in searcher([1]);
void main() {}


Errors printed:
test.d(10): Error: forward reference to inferred return type of function call searcher([1])
test.d(10): Error: rvalue of in expression must be an associative array, not int


(Please add the latest dmd2 version to drop-down menu, I don't know how to do it).