functionSig
    -- | first argument
    :: Int
    -- | second argument
    -- with multiline doc
    -> Int
    -- | result
    -> String
functionSigWithForall
    :: forall a
    -- | first argument
     . Int
    -- | second argument
    -- with multiline doc
    -> a
    -- | result
    -> String
functionSigWithContext
    :: (HasCallStack)
    -- | first argument
    => Int
    -- | second argument
    -- with multiline doc
    -> Int
    -- | result
    -> String
functionSigWithForallAndContext
    :: forall a
     . (HasCallStack)
    -- | first argument
    => Int
    -- | second argument
    -- with multiline doc
    -> a
    -- | result
    -> String