Kotlin Blog

We’re happy to announce that we’ve just released Kotlin 1.0.5, which continues the series of bugfix and tooling updates for Kotlin 1.0.

We’d like to thank our external contributors whose pull requests were included in this release: Kirill Rakhman, Vladislav Golub, Vsevolod Tolstopyatov, Yoshinori Isogai, takahirom and gitreelike. Thanks to everyone who tried the EAP builds and sent us feedback, too!

The complete list of changes in the release can be found in the changelog. Some of the changes worth highlighting are:

Loop to Lambda Conversion

The IntelliJ IDEA plugin can now detect many cases where imperative for loops can be rewritten in a more compact and idiomatic manner using standard library functions such as filter and map. As a simple example, the following snippet:

…will be automatically converted to:

To trigger the conversion, put the caret on the for keyword and press Alt-Enter.
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We’re happy to announce the second milestone release of Kotlin 1.1. This release brings one long-awaited new language feature, destructuring in lambdas, as well as many improvements to features introduced in 1.1-M1, including type aliases, coroutines and bound references. The new release also includes all tooling features introduced in Kotlin 1.0.4 and 1.0.5-eap-66, and is fully compatible with IntelliJ IDEA 2016.3 EAP and Android Studio 2.2.

As with Kotlin 1.1-M01, we give no backward compatibility guarantees for new language and library features. Anything introduced in milestone releases of 1.1 is subject to change before the final 1.1 release.

And once again: please do share your feedback regarding the new language features or any problems that you may run into with this release, via YouTrack, forums and Slack.

The full changelog for 1.1-M02 is available here.

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We’re happy to announce the release of a new bugfix and tooling update of Kotlin, version 1.0.4. This version brings many improvements related to the IDE and build tools, as well as JavaScript support.

Once again we’d like to thank our external contributors who implemented some of the features in this release, Kirill Rakhman and Yoshinori Isogai, as well as everyone who tried the EAP builds of 1.0.4 and sent us feedback.

You can find the full list of fixes and improvements in the changelog. Some of the changes deserve special mention:

Language Change: Assignment of ‘val’ in try/catch

In versions of Kotlin before 1.0.4, you could initialize the same val both in the try and catch branches of a try/catch statement. For example, the following code was allowed:

In effect, a final variable could be assigned twice, and it was possible to observe two different values for it (for example, if the value in the try statement was captured in a lambda). In Java, the equivalent code is not allowed.

To maintain consistent semantics, the code which assigns the same val in both try and catch branches becomes a warning in Kotlin 1.0.4 and will become an error in version 1.0.5. In most cases, the code can be easily fixed by converting the code to an expression form, and the IDE will offer a quickfix to convert this code automatically. The above example would be converted to:

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