Pattern groups with GADT

[ncannasse]

Only patterns having the same type should be allowed to be grouped:

enum A<T> {
    X : A<Bool>;
    Y : A<Int>;
    Z : A<Int>;
}

class Test {

    static function foo<T>( a : A<T> ) : T {
        return switch( a ) {
        case X,Y: false; // should not be allowed
        case Z: 0; // we should still be allowed to have Y,Z
        }
    }

    static function main() {
        trace([foo(X),foo(Y),foo(Z)]);      
    }
}