How can I get this UDA at compile time?

[Jack via Digitalmars-d-learn]

I've had a struct like this:

struct Attr
{
        string value;
}
struct Foo
{
        @(Attr("a attr"))
        enum a = Foo(10);

        @(Attr("b attr"))
        enum b = Foo(11);


        int x;
        int y;
        bool doY = true;
        
        int value()
        {

                return x;
        }

}

I'd like to get that atrribute's value at compile time, something 
like this:

        enum s = Foo.a.baa;
        enum s2 = Foo.b.baa;
        writeln(s); // a attr
        writeln(s2); // b attr

I did this:

        string baa()
        {
                import std.traits : getUDAs, hasUDA;

                static foreach(field; __traits(allMembers, Foo))
                {{
                        alias m = __traits(getMember, Foo, field);
                        static if(is(typeof(m) == Foo))
                        {
                                if(m.value == this.value)
                                        return getUDAs!(m, Attr)[0].value;
                        }
                }}

                return null;
        }

that was working fine, but I needed to switch value property from 
Foo struct, so that I can't read this value at CTFE anymore, so 
this fails now:

                        if(m.value == this.value)
                                        return getUDAs!(m, Attr)[0].value;

How can I solve this?