This page lists the projects that the Scala Center will work on during the current quarter. You can find more information about our completed projects in the quarterly activity reports.

Roadmap for 2022 Q3

The following sections present our plan for the current quarter. Every project description is followed by the concrete results we will deliver, and their expected outcome on the Scala community.

Make Scala tooling seamless for newcomers, and provide robust foundations for the Scala ecosystem

Smarter “Step Into” when debugging

The “step-into” feature in Metals is hard to use because it often goes to synthetic methods (getter, setter, bridge, mixin-forwarder), that do not exist in the source code. We will improve the implementation of the scala-debug-adapter to address this issue.

Implement JSR-45 in Scala 2 and Scala 3 compilers

We want to improve the debugging experience by implementing JSR-45 in both Scala 2 and Scala 3. This was requested by an Advisory Board Proposal. Some work has already been done, but it needs a final push.

GitHub Security Alerts

We want to harden the security of the Scala ecosystem by implementing Security Alerts for Scala projects using the GitHub API. We will publish a GitHub action that can be used by library maintainers to get notified about vulnerabilities in their sbt projects.

TASTy-query and TASTy-MiMa

TASTy-query is a work-in-progress library to read TASTy files, explore them, and ask semantic questions about them. It is independent from the compiler, and can be used as a building block to implement tools performing static analyses of Scala programs. An example is TASTY-MiMa, an upcoming tool “like MiMa, but for TASTy”.

We plan to implement support for semantic queries such as “are two types equivalent?”, “is a type a subtype of another one?”, etc., and to publish a prototype of TASTy-MiMa.

You can read the full roadmap here.


Scaladex is an index of the Scala ecosystem.

Beside being an index of Scala libraries, we believe scaladex can be a place where Scala programmers can find open-source libraries to contribute to. We will implement new features on scaladex to allow library authors to highlight how new contributors could help them, and for new contributors to easily find projects to contribute to.

Last, we would like to formalize the scaladex HTTP API. Scaladex exposes a public HTTP API that can be used by third-party tools to search for libraries. However, this API is not documented, and it may change. We will formalize it, and document it.

Metals and Bloop

Bloop has recently been updated to use the latest version of Zinc. However, in the process we had to remove “pipelining”, which parallelizes better the compilation process. We will add back pipelining to Bloop.

Other than that, we will continue working on the remaining issues towards a release of Metals 1.0.0.

Add Support for Binary Compatible Evolutions to Case Classes

Case classes are popular to achieve domain modeling. However, they come with an important drawback: it is impossible to apply any evolution (adding/removing fields on a case class) in a backward binary compatible way. This forces library authors to manually re-implement the features of case classes that they need (typically, structural equality) at the price of more verbosity. Other solutions include tools generating code (e.g. contraband), or experimental macro annotations (e.g. data-class, scalameta).

We started a “pre-SIP” discussion, which received some support and comments from the community. Based on the collected feedback, we will submit a concrete Scala Improvement Proposal to support, at the language-level, data types with structural equality that can evolve in a binary compatible way.

Education and Documentation

Alternative online learning platform with more support for the learners

As part of our mission to produce high-quality education material, we maintain a set of online courses that are published on the platform Coursera. These courses can be used by individuals to acquire new skills for a job, or by companies to train their employees.

We just launched our course Effective Programming in Scala to the Extension School platform. This platform allows us to provide individualized support to the learners, and to offer Scala trainings to companies.

Scala Teachers Community

We believe that Scala is a great language for teaching programming in academia. Several professors already use it, but we would like to grow this community of teachers.

We will add a page to the Scala website to present the community of teachers who use Scala: what are the benefits of using Scala, in which universities it is taught, etc.

Scala Website

We plan to modernize the Scala website, and to integrate better the Scala 2 and Scala 3 documentation.

Following up on the work we did in the previous quarter, we plan to polish further the content of the website.

The next main tasks are:

  • make the content more use-case-oriented rather than features-oriented,
  • make the code examples available in both Scala 2 and Scala 3,
  • reorganize the structure to make it more intuitive according to the reader’s background,
  • create new tutorials to document better how to contribute to the Scala open-source ecosystem.


We will finish the work started in early 2022 to consolidate the Scala.js ecosystem.

With the help of the community, we plan to document the best practices to have a productive development environment in Scala.js.


We will conduct many actions aiming at communicating a positive image of Scala, and making people excited about it.

  • We will publish a five-year report detailing the activities and impact of the Scala Center during the past five years!
  • We will regularly share our achievements and engage the community on our projects via our LinkedIn page,
  • We will create an online shop where individual will be able to give donations to the Scala Center in exchange for goodies,
  • We will speak at tech conferences and local meetups to encourage people to contribute to the Scala ecosystem, and to let non-Scala programmers know about Scala,
  • Currently, Scala doesn’t have much presence in fields other than backend development and data engineering. Given our positioning at EPFL, there are opportunities for collaborations with scientists and industries to expand in other domains. We plan to organize a workshop to introduce Scala to a team of scientists in the field of space. We expect to learn more about the possible barriers to the adoption of Scala to conduct scientific experiments,
  • We will publish two new videos in the series Let’s talk about Scala 3 to highlight the strengths of Scala 3.

Community, Sustainability, and Governance

Scala 3 Compiler Academy

We believe that the pool of knowledgeable people about the Scala 3 compiler implementation is too small. We will create a self-sustaining knowledge hub for the compiler where others can come and be effectively mentored to be compiler contributors.

We are continuously adding content to the Scala 3 Compiler Academy YouTube channel, and we run regular events to onboard external contributors on the compiler codebase. In case you are interested in contributing to the Scala 3 compiler, please register by filling this form.

Google Summer of Code

The Scala Center has been accepted as a mentor organization for Google Summer of Code 2022. We will coordinate discussions between mentees and mentors.

Scala Improvement Process

The Scala Improvement Process is a process for submitting changes to the Scala language. It aims to evolve Scala openly and collaboratively. However, that process was paused in the past couple of years. We overhauled the process itself, and we will now enter the active phase: we will restart the work on reviewing proposals, and we will restart the regular committee meetings.

Promote Simple Scala Solutions

We feel that, currently, the Scala ecosystem has a focus on advanced expert-level tools and libraries, favouring power and flexibility over familiarity and ease of onboarding. We believe that newcomers don’t need to learn advanced concepts such as pure functional programming or reactive programming to be productive in Scala.

In partnership with VirtusLab, we will contribute to the creation of tutorials demonstrating how to solve typical programming tasks in a more approachable programming style.

Maintenance Work

We will also spend a small part of our time reviewing pull requests, triaging issues, and sometimes implementing pull requests for the following projects, to make sure important points are addressed:

  • Scala 3 compiler
  • Scala 2 TASTy reader
  • Scaladex
  • Coursier

Advisory Board Proposals

For reference, you can see here the list of Advisory Board proposals and their respective status.