6.3.5. Writing qualified in postpositive position



ImportQualifiedPost allows the syntax import M qualified, that is, to annotate a module as qualified by writing qualified after the module name.

To import a qualified module usually you must specify qualified in prepositive position : import qualified M. This often leads to a “hanging indent” (which is automatically inserted by some autoformatters and common in many code bases. For example:

import qualified A
import           B
import           C

The ImportQualifiedPost extension allows qualified to appear in postpositive position : import M qualified. With this extension enabled, one can write:

import A qualified
import B
import C

It is an error if qualified appears in both pre and postpositive positions.

The warning -Wprepositive-qualified-syntax (off by default) reports on any occurrences of imports annotated qualified using prepositive syntax.