C Error on invalid uint -> set cast

[Wh1teDuke]

Test

let 
  a = {'a', 'b'}
  b = cast[uint8](a)
  c = cast[set[char]](b)  # Error here

Result

error: cast specifies array type
  memcpy((void*)c_97014, (NIM_CONST void*)((TY82458) (b_97008)), 32);
                                           ^

---

>nim -v
Nim Compiler Version 0.12.1 (2015-11-07) [Windows: i386]
Copyright (c) 2006-2015 by Andreas Rumpf

git hash: c83e4390d863ab1f2d0ad4ab5417352f1ffd8f04
active boot switches: -d:release