CustomFloat.opBinary

real opBinary(string op, T)(T b) if (__traits(compiles, mixin(`get!real` ~ op ~ `b.get!real`))) const

ditto

real opBinary(string op, T)(T b) if (  __traits(compiles,  mixin(`get!real` ~ op ~ `b`))  &&
        !__traits(compiles,  mixin(`get!real` ~ op ~ `b.get!real`)))

const

ditto