map -is:exact -package:bytestring -package:ghc -package:charset -package:basement -package:imports -package:base-prelude -package:filepath -package:base -package:containers 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.