error-const-inc-2.ck:4:3: error: cannot chuck/assign '+=>' to 'Math.PI'...
[4] 2 +=> Math.PI;
      ^
error-const-inc-2.ck:4:7: error: ...(reason: 'Math.PI' is a constant, and is not assignable)
[4] 2 +=> Math.PI;
          ^
