Implicit conversion from enumeration type 'enum CGImageAlphaInfo' to different enumeration type 'CGBitmapinfo' (aka) 'enum CGBitmapInfo')
From the docs:
The constants for specifying the alpha channel information are declared with the CGImageAlphaInfo type but can be passed to this parameter safely.
So you can just use a cast to suppress the warning:
CGBitmapInfo bitmapInfo = (CGBitmapInfo) kBitmapInfo;