Google Summer of Code 2026 Wrap-up

The Haskell.org committee is pleased to present the results of Haskell's participation in the Google Summer of Code 2026. This marks our 15th time taking part in GSoC!

Of the four projects alloted to our organization, three concluded successfully:

• Case Split Plugin for Haskell Language Server
• Restoring Typeclass Refinement Support in Liquid Haskell
• Goto Dependency Definition

Congratulations to all the contributors and a huge thank you to our wonderful mentors!

Case Split Plugin for Haskell Language Server

• Contributor: Enrico Maria De Angelis
• Mentors: Fendor, MangoIV, Andreas Klebinger

This project produced a plugin for the Haskell Language Server (HLS) that implements case splitting functionality. This provides users with a code action that automatically inserts any missing pattern matches in case statements.

Read more in the final code submission.

Restoring Typeclass Refinement Support in Liquid Haskell

• Contributor: Juan Pablo Yamamoto
• Mentor: Facundo Domínguez

This project restores type class elaboration in Liquid Haskell. This allows for verification of type class laws and instances, for example proving that a Monoid instance adheres to the identity and associativity laws.

Read more in the project results write-up.

Goto Dependency Definition

• Contributor: Vidit Odedra
• Mentor: Fendor, Zubin Duggal

The goal is this project is to extend the goto definition functionality in Haskell Language Server (HLS) to work for external dependencies. Although the pull request implementing it is still under review, the ground work has been laid for this oft-requested feature.

Read more in the final code submission.