import std;

​

void main()

{

    static assert(longestMemberName!Foo == "bbb".length);

}

​

struct Foo

{

    string s;

    int ii;

    bool bbb;

    deprecated("Use `s`")

    string zzzz;

}

​

private template longestMemberName(T)

if (is(T == struct))

{

    enum longestMemberName = ()

    {

        size_t maxLength;

        T thing;  // need a `this`

​

        foreach (immutable i, immutable member; thing.tupleof)

        {

            static if (!__traits(isDeprecated, thing.tupleof[i]) &&

                       !isType!(thing.tupleof[i]))

            {

                enum name = __traits(identifier, thing.tupleof[i]);

                maxLength = max(maxLength, name.length);

            }

        }

​

        return maxLength;

    }();

}