Of the following lines, Haskell seems to have problems only with the last one. The error when I load the file in GHCi is error: parse error on input ‘♟’.
xK = '♔'
xK = '♕'
xR = '♖'
xB = '♗'
xN = '♘'
xP = '♙'
xk = '♚'
xk = '♛'
xr = '♜'
xb = '♝'
xn = '♞'
xp = '♟︎'
Whatever the reason is, I find so strange that everything is just fine with the other 11 characters.
Might be important: I copied the characters straight from Wikipedia.