@lehins the lts 22 and 23 builds of QuickCheck are apparently buggy (don't include 2.15.0.1, rather 2.15.0?). Perhaps this should be brought to the attention of the lts maintainers? Anyway, I've included lts 24 and nightly here because that appears to work.

The QuickCheck issue was resolved by skipping some tests on old QuickCheck versions.

the lts 22 and 23 builds of QuickCheck are apparently buggy (don't include 2.15.0.1, rather 2.15.0?).

This is not a bug, this is a feature. Both LTS-22 and 23 will forever include QuickCheck-2.14.3: https://www.stackage.org/lts-23.28/package/QuickCheck-2.14.3

It was only LTS-24 that started including QuickCheck-2.15 major version.
The way LTSs on stackage work is once a major version is included in the first snapshot, it will never switch to a new major version of a package, because that would bring breaking changes wit it and thus invalidate the concept of LTS.

Looks nice! https://coveralls.io/github/input-output-hk/constrained-generators

We might wanna include a badge somewhere in the README:

[![Coverage Status](https://coveralls.io/repos/github/input-output-hk/constrained-generators/badge.svg?branch=master)](https://coveralls.io/github/input-output-hk/constrained-generators?branch=master)