How can I use structs in a named enum?

[simendsjo]

On Wed, 29 Feb 2012 12:15:35 +0100, simendsjo <simendsjo at gmail.com> wrote:

> .. That is >> enum E : Struct {}
>
> struct S {
>      int a;
> }
>
> // ok
> enum E : S {
>      a = S(1),
> }
>
> // Error: need member function opCmp() for struct S to compare
> /*
> enum E2 : S {
>      a = S(1),
>      b = S(2)
> }
> */
>
> struct S2 {
>      int a;
>      int opCmp(ref const S2 other)
>      {
>          return a == other.a ? 0 : (a < other.a ? -1 : 1);
>      }
> }
>
> // Error: function opcmp.S2.opCmp (ref const(S2) other) is not callable  
> using argument types (E3)
> // Error: cast(const(S2))S2(1) is not an lvalue
> // Error: function opcmp.S2.opCmp (ref const(S2) other) is not callable  
> using argument types (E3)
> // Error: cast(const(S2))S2(1) is not an lvalue
> enum E3 : S2 {
>      a = S2(1),
>      b = S2(2)
> }
>
> void main() {
> }
>
>
> So E3 is passed as the parameter to S2.opCmp..?

Hmm.. By removing ref const in opCmp, it works as expected