map -package:containers -package:conduit -package:aeson -package:case-insensitive -package:base -package:monoidal-containers -package:ghc -package:blaze-html package:hedgehog is:exact

Generates a map using a Range to determine the length. This may fail to generate anything if the keys produced by the generator do not account for a large enough number of unique items to satify the required map size.