Build error: Ambiguous occurrence ‘mapMaybe’

[dimchansky]

Build failed with the following output:

src/Alder/Reconcile.hs:29:32:
    Ambiguous occurrence ‘mapMaybe’
    It could refer to either ‘HashMap.mapMaybe’,
                             imported from ‘Data.HashMap.Strict’ at src/Alder/Reconcile.hs:10:1-47
                          or ‘Data.Maybe.mapMaybe’,
                             imported from ‘Data.Maybe’ at src/Alder/Reconcile.hs:11:1-27

src/Alder/Reconcile.hs:43:41:
    Ambiguous occurrence ‘mapMaybe’
    It could refer to either ‘HashMap.mapMaybe’,
                             imported from ‘Data.HashMap.Strict’ at src/Alder/Reconcile.hs:10:1-47
                          or ‘Data.Maybe.mapMaybe’,
                             imported from ‘Data.Maybe’ at src/Alder/Reconcile.hs:11:1-27