At least, I've never seen someone use the `$` operator and put the right operand without any spacing in between. Not only would it cause errors on activating Template Haskell because GHC would interpret it as a TH splice[1], but also it would be weird to read because one tends to use the `$` operator when they have a multi-term expression they would otherwise not want to parenthesize. For example, take a look at this line in Yesod[2]:
$logInfo $ pack $ show (a, b, c)
The one without a space is a Template Haskell splice and the ones with a space are using the function application operator. If logInfo didn't need to be expanded by Template Haskell and we deactivate that extension, we could write:
logInfo $pack $show (a, b, c)
But I doubt anyone would because the implied parentheses around those operators are:
[2] https://github.com/yesodweb/yesod/blob/c8aeb61ace568cdc2bc81...