Scala 2.10.4-RC1 is now available!

We are very happy to announce the first release candidate of Scala 2.10.4! If no serious blocking issues are found this will become the final 2.10.4 version.

The release is available for download from scala-lang.org or from Maven Central.

The Scala team and contributors fixed 23 issues since 2.10.3!

In total, 39 RC1 pull requests were merged on GitHub.

Known Issues

Before reporting a bug, please have a look at these known issues.

Scala IDE for Eclipse

The Scala IDE with this release built right in is available through the following update-site:

• for Eclipse 4.2/4.3 (Juno/Kepler)

Have a look at the getting started guide for more info.

New features in the 2.10 series

Since 2.10.4 is strictly a bug-fix release, here’s an overview of the most prominent new features and improvements as introduced in 2.10.0:

• Value Classes

  • A class may now extend AnyVal to make it behave like a struct type (restrictions apply).

  • https://docs.scala-lang.org/overviews/core/value-classes.html

• Implicit Classes

  • The implicit modifier now also applies to class definitions to reduce the boilerplate of implicit wrappers.

  • https://docs.scala-lang.org/sips/implicit-classes.html

• String Interpolation

  • val what = "awesome"; println(s"string interpolation is ${what.toUpperCase}!")

  • https://docs.scala-lang.org/overviews/core/string-interpolation.html

• Futures and Promises

  • Asynchronously get some JSON: for (req <- WS.url(restApiUrl).get()) yield (req.json \ "users").as[List[User]] (uses play!)

  • https://docs.scala-lang.org/overviews/core/futures.html

• Dynamic and applyDynamic

  • x.foo becomes x.applyDynamic("foo") if x’s type does not define a foo, but is a subtype of Dynamic

  • https://docs.scala-lang.org/sips/type-dynamic.html

• Dependent method types:

  • def identity(x: AnyRef): x.type = x // the return type says we return exactly what we got

• New ByteCode emitter based on ASM

  • Can target JDK 1.5, 1.6 and 1.7

  • Emits 1.6 bytecode by default

  • Old 1.5 backend is deprecated

• A new Pattern Matcher

  • rewritten from scratch to generate more robust code (no more exponential blow-up!)

  • code generation and analyses are now independent (the latter can be turned off with -Xno-patmat-analysis)

• Scaladoc Improvements

  • Implicits (-implicits flag)

  • Diagrams (-diagrams flag, requires graphviz)

  • Groups (-groups)

• Modularized Language features

  • Get on top of the advanced Scala features used in your codebase by explicitly importing them.

  • https://docs.scala-lang.org/sips/modularizing-language-features.html

• Parallel Collections are now configurable with custom thread pools

  • https://docs.scala-lang.org/overviews/parallel-collections/overview.html

• Akka Actors now part of the distribution

  • scala.actors have been deprecated and the akka implementation is now included in the distribution.

• Performance Improvements

  • Faster inliner

  • Range#sum is now O(1)

  • Update of ForkJoin library

  • Fixes in immutable TreeSet/TreeMap

  • Improvements to PartialFunctions

• Addition of ??? and NotImplementedError
• Addition of IsTraversableOnce + IsTraversableLike type classes for extension methods

• Deprecations and cleanup

  • Floating point and octal literal syntax deprecation

  • Removed scala.dbc

Experimental features

• Scala Reflection

  • https://docs.scala-lang.org/overviews/reflection/overview.html

• Macros

  • https://docs.scala-lang.org/overviews/macros/overview.html

The API is subject to (possibly major) changes in the 2.11.x series, but don’t let that stop you from experimenting with them! A lot of developers have already come up with very cool applications for them. Some examples can be seen at hxxp://scalamacros.org/news/2012/11/05/status-update.html.

A big thank you to all the contributors!

#	Author
16	Jason Zaugg
15	Adriaan Moors
3	Simon Schaefer
3	Eugene Burmako
3	Luc Bourlier
2	Som Snytt
2	Paul Phillips
2	Mirco Dotta
1	Mark Harrah
1	Vlad Ureche
1	Heather Miller
1	FrancÃßois Garillot
1	Roberto Tyley

Commits and the issues they fixed since v2.10.3

Issue(s)	Commit	Message
SI-6426	47562e7adb	Revert "SI-6426, importable _."
SI-8062	f0d913b51d	SI-8062 Fix inliner cycle with recursion, separate compilation
SI-7912	006e2f2aad	SI-7912 Be defensive calling `toString` in `MatchError#getMessage`
SI-8060	bb427a3416	SI-8060 Avoid infinite loop with higher kinded type alias
SI-7995	5ed834e251	SI-7995 completion imported vars and vals
SI-8019	c955cf4c2e	SI-8019 Make Publisher check PartialFunction is defined for Event
SI-8029	fdcc262070	SI-8029 Avoid multi-run cyclic error with companions, package object
SI-7439	8d74fa0242	[backport] SI-7439 Avoid NPE in `isMonomorphicType` with stub symbols.
SI-8010	9036f774bc	SI-8010 Fix regression in erasure double definition checks
SI-7982	7d4109486b	SI-7982 Changed contract of askLoadedType to unload units by default
SI-6913	70634395a4	SI-6913 Fixing semantics of Future fallbackTo to be according to docs
SI-7458	02308c9691	SI-7458 Pres. compiler must not observe trees in silent mode
SI-7548	652b3b4b9d	SI-7548 Test to demonstrate residual exploratory typing bug
SI-7548	b7509c922f	SI-7548 askTypeAt returns the same type whether the source was fully or targeted
SI-8005	3629b645cc	SI-8005 Fixes NoPositon error for updateDynamic calls
SI-8004	696545d53f	SI-8004 Resolve NoPosition error for applyDynamicNamed method call
SI-7463, SI-8003	b915f440eb	SI-7463,SI-8003 Correct wrong position for {select,apply}Dynamic calls
SI-7280	053a2744c6	[nomaster] SI-7280 Scope completion not returning members provided by imports
SI-7915	04df2e48e4	SI-7915 Corrected range positions created during default args expansion
SI-7776	d15ed081ef	[backport] SI-7776 post-erasure signature clashes are now macro-aware
SI-6546	075f6f260c	SI-6546 InnerClasses attribute refers to absent class
SI-7638, SI-4012	e09a8a2b7f	SI-4012 Mixin and specialization work well
SI-7519	50c8b39ec4	SI-7519: Additional test case covering sbt/sbt#914
SI-7519	ce74bb0060	[nomaster] SI-7519 Less brutal attribute resetting in adapt fallback
SI-4936, SI-6026	e350bd2cbc	[nomaster] SI-6026 backport getResource bug fix
SI-6026	2bfe0e797c	SI-6026 REPL checks for javap before tools.jar
SI-7295	25bcba59ce	SI-7295 Fix windows batch file with args containing parentheses
SI-7020	7b560213cb	Disable tests for SI-7020
SI-7783	2ccbfa5778	SI-7783 Don't issue deprecation warnings for inferred TypeTrees
SI-7815	733b3220c9	SI-7815 Dealias before deeming method type as dependent

Complete commit list!

sha	Title
3fa2c97853	Report error on code size overflow, log method name.
2aa9da578e	Partially revert f8d8f7d08d.
47562e7adb	Revert "SI-6426, importable _."
f0d913b51d	SI-8062 Fix inliner cycle with recursion, separate compilation
9cdbe28c00	Fixup #3248 missed a spot in pack.xml
006e2f2aad	SI-7912 Be defensive calling `toString` in `MatchError#getMessage`
bb427a3416	SI-8060 Avoid infinite loop with higher kinded type alias
27a38602de	Update README, include doc/licenses in distro
139ba9d875	Add attribution for Typesafe.
e555106070	Remove docs/examples; they reside at scala/scala-dist
dc6dd58d9d	Remove unused android test and corresponding license.
f8d8f7d08d	Do not distribute partest and its dependencies.
5ed834e251	SI-7995 completion imported vars and vals
c955cf4c2e	SI-8019 Make Publisher check PartialFunction is defined for Event
fdcc262070	SI-8029 Avoid multi-run cyclic error with companions, package object
8d74fa0242	[backport] SI-7439 Avoid NPE in `isMonomorphicType` with stub symbols.
9036f774bc	SI-8010 Fix regression in erasure double definition checks
3faa2eedd8	[nomaster] better error messages for various macro definition errors
7d4109486b	SI-7982 Changed contract of askLoadedType to unload units by default
70634395a4	SI-6913 Fixing semantics of Future fallbackTo to be according to docs
02308c9691	SI-7458 Pres. compiler must not observe trees in silent mode
652b3b4b9d	SI-7548 Test to demonstrate residual exploratory typing bug
b7509c922f	SI-7548 askTypeAt returns the same type whether the source was fully or targeted
0c963c9085	[nomaster] teaches toolbox about -Yrangepos
3629b645cc	SI-8005 Fixes NoPositon error for updateDynamic calls
696545d53f	SI-8004 Resolve NoPosition error for applyDynamicNamed method call
b915f440eb	SI-7463,SI-8003 Correct wrong position for {select,apply}Dynamic calls
053a2744c6	[nomaster] SI-7280 Scope completion not returning members provided by imports
eb9f0f7975	[nomaster] Adds test cases for scope completion
3a8796da1a	[nomaster] Test infrastructure for scope completion
04df2e48e4	SI-7915 Corrected range positions created during default args expansion
ec89b59717	Upgrade pax-url-aether to 1.6.0.
1d29c0a08b	[backport] Add buildcharacter.properties to .gitignore.
31ead67a30	IDE needs swing/actors/continuations
852a9479d0	Allow retrieving STARR from non-standard repo for PR validation
40af1e0c44	Allow publishing only core (pr validation)
ba0718fd1d	Render relevant properties to buildcharacter.properties
d15ed081ef	[backport] SI-7776 post-erasure signature clashes are now macro-aware
6045a05b83	Fix completion after application with implicit arguments
075f6f260c	SI-6546 InnerClasses attribute refers to absent class
e09a8a2b7f	SI-4012 Mixin and specialization work well
50c8b39ec4	SI-7519: Additional test case covering sbt/sbt#914
ce74bb0060	[nomaster] SI-7519 Less brutal attribute resetting in adapt fallback
e350bd2cbc	[nomaster] SI-6026 backport getResource bug fix
2bfe0e797c	SI-6026 REPL checks for javap before tools.jar
25bcba59ce	SI-7295 Fix windows batch file with args containing parentheses
7b560213cb	Disable tests for SI-7020
8986ee4fd5	Disable flaky presentation compiler test.
2ccbfa5778	SI-7783 Don't issue deprecation warnings for inferred TypeTrees
ee9138e99e	Bump version to 2.10.4 for nightlies
733b3220c9	SI-7815 Dealias before deeming method type as dependent