Access the sixteenth constructor of a sum type.
Where Control.Lens._16 is the sixteenth projection out of a product, _I16 is the sixteenth
injection into a sum.
The default implementation is the prism to the sixteenth constructor of a
Generic type, injection (Proxy :: Proxy 15).
data T = C1 | C2 | C3 | C4 | C5 | C6 | C7 | C8 | C9 | C10 | C11 | C12 | C13 | C14 | C15 | C16 Int | C17 deriving (Show, Generic)instance Injection16 T T Int IntC16 1 ^? _I16Just 1
C17 ^? _I16Nothing
_I16 # 1 :: TC16 1