Error: not a property - ?

[Era Scarecrow]

  This is an unexpected error; Seems it's the result of not 
down-casting a variable-type. Is this a bug? Or just need a 
better error message?

Version: DMD32 D Compiler v2.061


   struct S {
     void test(uint v) @property {}
     void test2(ulong v) @property {}
   }

   ulong x;
   S s;

   s.test2 = x;
   s.test = x;  //s.test is not a property