Release Notes 2.0

Dec 20 2011

We released the Scala IDE V2.0 for Eclipse today! After 9 months of intensive work by the community contributors, users and the IDE team we are really proud to release the new version. Not only is it robust and reliable but also comes with much improved performance and responsiveness. There are a whole lot of new features that make it a real pleasure to use, Report errors as you type, Project builder with dependency tracking, Definition Hyperlinking and Inferred type hovers, Code completion and better integration with Java build tools, and lots more. You can learn more about them all below. We hope you will enjoy using the new version and continue to help us with ideas and improvement suggestions, or just contribute them.

While working on V2.0 the team has been listening hard to what the IDE users need. Simply stated faster compilation, better debugging and better integration with established Java tools like Maven. The good news is the team is ready for and excited by the challenge. Doing V2.0 we learned a lot about the build process and now understand what is needed to make significant gains in large project compile times. This and providing a solid debugging capability will be the main thrust of the next IDE development cycle. More details will be laid out as we go through the project planning phase and establish milestones. Contributors will be most welcome and we have made it a lot easier to be one. So if you want us to get the next version faster, come and help!

A lot of effort has gone into this version of the IDE and we would like to recognize the people who have contributed so much time and energy to the success of the project.

A bit of history

The Scala IDE project began a few years back, when Miles Sabin laid down the foundations of the open source project and an enthusiastic community formed around the effort to create a free, open-source, Eclipse-based IDE for Scala. In late 2010 the Typesafe team decided to support the open source project, and in September Eugene Vigdorchik became the first full-time engineer to work on the project, supported part-time by Hubert Plociniczak from the EPFL team. Typesafe founder and Scala creator Martin Odersky led the redesign of the Scala presentation compiler, the engine behind the IDE semantic actions.

Version 2.0

For version 2.0 we had some tough decisions to take, and development started with a very limited number of features, aiming for a very reliable core. Naturally, this raised the need for early and frequent feedback from our users: on March 28 we had the first beta of the upcoming 2.0 release. This was followed by a stream of betas (12 in total!), packing around 300 closed tickets over the next months. As Eugene moved on to other projects, several other Typesafe engineers joined the IDE team: Iulian Dragos and Mirco Dotta, followed by Luc Bourlier in September. Together with the great community (Mirko Stocker and Matt Russell just to name a few), the IDE took great strides to reach its first production-ready release.


As things moved forward and the 2.0 branch became the main version in use, it became clear that we needed to have more than one IDE version: 2.0 remained the rock-solid branch, where only bug-fixing happens, while 2.1 is the place where new features, such as semantic highlighting or implicit highlighting are developed.

Besides the two IDE versions, we support three versions of the Scala compiler: 2.8.x, 2.9.x and 2.10 (Scala trunk), with nightlies for all of them, so you can choose what suits you the best: the latest IDE developments on a stable Scala compiler, the stable IDE on the bleeding edge Scala compiler, or even the latest and greatest of both – like the core Scala team, who uses the Eclipse IDE for their daily scalac development! The choice is yours.


While the IDE always had a vibrant community around it, contributing to the project itself was sometimes challenging for newcomers. On October 4 we moved the project to Github, leading to a much simpler process for contributors. In just a few weeks we had 17 forks, some of which are extremely interesting developments in their own right (check out ScalaGWT, who brings Scala to the GWT framework).


Today we also release a redesign of the Scala IDE website, along with reworked documentation, including screencasts. Thanks Heather for the awesome work (also, check out the screencasts)! We believe that the current version is not only pretty, but makes it much easier to find documentation, both for users and contributors (and everyone is a potential contributor!). The website is backed by Github too, so you can contribute by using the awesome Pull Request button!

A look at the future

Even though it’s been a long ride, today’s release is not the end of the road, but rather a beginning. We can now look at adding new features on a solid base, and great things will come, such as /find references/, or a Scala /debugger/. Suggest your favorite feature, and help us build the next great IDE!

After the 2.0.0 release we will continue to support the 2.0 branch with maintenance releases including important bug fixes. However, the focus will shift to the 2.1 development, and concentrate on the upcoming features. Also, 2.0.0 is the last version that supports the 2.8 compiler. This decision was not taken lightly, but the effort to support 2.8 is way too high and slowed us down too much. We believe that 2.0.0 is a solid release that can help people who cannot upgrade to 2.9.x in the immediate future.


Scala IDE version 2 improves developer productivity through a large number of features. Below we highlight the main ones, but don’t forget to check out the full list on the website, and watch the screencast to see them in action.

Report errors as you type

The IDE saves you time by type-checking your program as you type, and notifying you of errors before you build. This greatly reduces the number of times you need to build your project.

Project builder with dependency tracking

The IDE saves you time even when you do have to build your project: by using Sbt’s engine for tracking dependencies between source files (even between dependent projects), the IDE only builds the sources that need to be built. This is often much less than all the sources in your project.

Definition Hyperlinking

Ctrl-click on an identifier to navigate to its definition. This allows you to concentrate on your program, since you don’t need to remember in what source file a certain definition lies. Try it out surfing through the Scala collection library!

Code Completion

Hit Ctrl-space to see a list of all members you could invoke at a certain point in your program. Even members added through implicit conversions are available. Moreover, you can find a class on your classpath, even if it wasn’t imported in your file yet (and the completion engine takes care of adding the import).

Inferred type hovers

Hover with the mouse over an identifier to see its type. This comes in handy when the compiler infers a different type than what you expect.

And there is more! Check out the full list of features, and download Scala IDE 2.0 today at!