WIP blog article

Author: anatoliykmetyuk

docs/blog/_posts/2020-06-16-25th-dotty-milestone-release.md

@@ -0,0 +1,85 @@
+---
+layout: blog-page
+title: Announcing Dotty 0.25.0-RC2 - speed-up of givens, progress on Scala 2 macro compat
+author: Anatolii Kmetiuk
+authorImg: /images/anatolii.png
+date: 2020-06-16
+---
+
+Hello! We are excited to announce 0.25.0-RC2 of Dotty. In this version, following feedback of the community, we have improved compilation speeds when programming with givens. We have also made progress towards better cross-compilation of macro definitions between Scala 2 and Scala 3.
+
+You can try out this version right now, from the comfort of your SBT, by visiting the [home page](https://dotty.epfl.ch/) and scrolling down to the "Create a Dotty Project" section.
+
+Alternatively, you can try this version of Scala online via [Scastie](https://scastie.scala-lang.org/). Once you're there, click "Build Settings" and set "Target" to "Dotty".
+
+Enjoy the ride🚀!
+
+<!--more-->
+# Progress on macro compatibility with Scala 2
+One of the most challenging parts of the migration from Scala 2 to Scala 3 are macros. Scala 3 has re-implementing the entire metaprogramming mechanism from scratch, and so all the Scala 2 macros must also be rewritten from scratch using the Scala 3 metaprogramming capabilities.
+
+Under these conditions, cross-compilation of a library between Scala 2 and Scala 3 also becomes more challenging since you need to split your sources between the two versions.
+
+To address this challenge, we are currently working on a solution to allow macro definitions of Scala 2 and Scala 3 macros to reside in the same file. This co-habitation will look as follows:
+
+```scala
+object Macro1 {
+  import scala.language.experimental.macros
+  def lineNumber: Int = macro LineNumberMacroScala2.thisLineNumberImpl
+  inline def lineNumber: Int = ${ LineNumberMacroScala3.thisLineNumberExpr }
+}
+```
+
+Currently, this is a work in progress. You can dive deeper into the current state of things by looking at PR [#8811](https://github.com/lampepfl/dotty/pull/8811).
+
+# Speed up the compiler when programming with givens
+Dotty brings to the user an enhanced error reporting when it comes to programming with givens. This better error reporting, however, proved to be a trade-off. Sometimes it takes an unreasonable amount of time and space to compute a quality suggestion to the end user.
+
+A number of users reported considerable slowdowns when it comes to programming with implicits. To address this issue, we have modified the logic for given imports suggestion. We introduced a per-run budget of 10 seconds, so it is guaranteed that it won't take longer than that time to compute all the given imports.
+
+This default budget is configurable via a compiler flag `-Ximport-suggestion-timeout`.
+
+This change should speed-up the compiler when it comes to programming with givens.
+
+For more information, see PR [#9167](https://github.com/lampepfl/dotty/pull/9167).
+
+# Let us know what you think!
+
+If you have questions or any sort of feedback, feel free to send us a message on our
+[Gitter channel](https://gitter.im/lampepfl/dotty). If you encounter a bug, please
+[open an issue on GitHub](https://github.com/lampepfl/dotty/issues/new).
+
+## Contributing
+
+TODO
+
+If you want to get your hands dirty and contribute to Dotty, now is a good time to get involved!
+Head to our [Getting Started page for new contributors](https://dotty.epfl.ch/docs/contributing/getting-started.html),
+and have a look at some of the [good first issues](https://github.com/lampepfl/dotty/issues?q=is%3Aissue+is%3Aopen+label%3Aexp%3Anovice).
+They make perfect entry points into hacking on the compiler.
+
+We are looking forward to having you join the team of contributors.
+
+## Library authors: Join our community build
+
+Dotty now has a set of widely-used community libraries that are built against every nightly Dotty
+snapshot. Currently, this includes shapeless, ScalaPB, algebra, scalatest, scopt and squants.
+Join our [community build](https://github.com/lampepfl/dotty/tree/master/community-build)
+to make sure that our regression suite includes your library.
+
+[Scastie]: https://scastie.scala-lang.org/?target=dotty
+
+[@odersky]: https://github.com/odersky
+[@DarkDimius]: https://github.com/DarkDimius
+[@smarter]: https://github.com/smarter
+[@felixmulder]: https://github.com/felixmulder
+[@nicolasstucki]: https://github.com/nicolasstucki
+[@liufengyun]: https://github.com/liufengyun
+[@OlivierBlanvillain]: https://github.com/OlivierBlanvillain
+[@biboudis]: https://github.com/biboudis
+[@allanrenucci]: https://github.com/allanrenucci
+[@Blaisorblade]: https://github.com/Blaisorblade
+[@Duhemm]: https://github.com/Duhemm
+[@AleksanderBG]: https://github.com/AleksanderBG
+[@milessabin]: https://github.com/milessabin
+[@anatoliykmetyuk]: https://github.com/anatoliykmetyuk