Set different indent policy for preamble

[yutotakano]

I'd love it if it were possible to use IndentPolicyFree on the module preamble, but IndentPolicyLeft on the body code.

IndentPolicyFree

import           Control.Monad                  ( guard
                                                , unless
                                                , void
                                                )
import           Control.Monad.IO.Class         ( MonadIO )
import           Data.Maybe                     ( catMaybes )

item = Item
    { aField       = "mhm"
    , anotherField = \x ->
                         case
                                 complexFunction
                                     123
                                     (anotherComplexFunction x Nothing)
                             of
                                 Left  e -> Nothing
                                 Right y -> Just [y]
    }

IndentPolicyLeft & IndentPolicyMultiple

import Control.Monad (guard, unless, void)
import Control.Monad.IO.Class (MonadIO)
import Data.Maybe (catMaybes)

item = Item
    { aField       = "mhm"
    , anotherField = \x ->
        case complexFunction 123 (anotherComplexFunction x Nothing) of
            Left  e -> Nothing
            Right y -> Just [y]
    }

My goal is to achieve the import list of the former, with the body formatted as the latter. Specifically, I dislike how in the former result, complexFunction and the Left/Right are indented to (4n + 1) spaces! It looks like a hanging indent from \x, but this is quite ugly.