Dependent Haskell has been desired in the community of Haskell programmers for a long time. Our goal of this project is to make the core language of Haskell, known as System FC, dependently typed, as steps are taken towards dependent Haskell.

This is a working-in-progress project. As a small step towards our final goal, the focus of this talk is on coercion quantification. Coercion quantification is necessary to support homogeneous equality, which simplifies the core and is important for meta-theories of dependently typed core.

Coercion quantification is interesting for both people working in core and for Haskell users. For GHC hackers, the patch to core formalization is worth attention. Adding coercion quantification involves refactor to lots of files in the compilation pipeline and introduces several subtleties. For Haskell users, coercion quantification opens up new questions to the design space in source Haskell, which requires non-trivial extension of the solver. We would want Haskell users to answer if this feature is ever desired in their development.

In this talk, we will share the high-level story-line of the dependently typed core, our low-level progress in implementing coercion quantification, as well as the involving design space, and seek feedbacks from the broader community.