xtoHash and xopEquals are generated by the compiler automatically.Curiously those two symbol names are not demangling.Given this, I suspect the best thing to do is file a bug report with ldc with the code that generated the linker error.
Oh the <_My_struct> part is my simplification, it is mangled as something like : _D6..<_My_struct>..__xtoHashFNbNeKxSQBlQBoQBiZm