I know I must be missing something, but can't figure out what. When I create a scala project, following the scala-plugin instructions, not a single syntax error is detected. For example:
object MyApp {
val aNumber: Int = "hello"
}
does not detect any error. If I right-click and ask it to compile, then I get the expected type mismatch error from the scala compiler. This is just a silly example, no syntax errors are being flagged. For regular Java projects it works fine, so it must be scala specific.
I have a clean install of IDEA 10 CE on a OSX 10.6 and Scala 2.8.1 final. I have set up the jdk in the project settings as well as the scala home when creating the project. I have the latest version of the plugin (12/2010).
Any hint on what I'm missing?
You have to enable error highlighting. Turn on Settings/Code Style/Scala/Other settings/Enable experimental error highlighting
Works here too (IntelliJ 10.0.1, Scala 2.8.1, OpenJDK, Ubuntu 10.10 64bit).
If you want more type checking you can also tick "Enable experimental error highlighting (possibly shows many wrong red code)" in the Settings, but this shouldn't make a difference in your case, although it works perfectly in my case for a large code base.
In project structure > modules > [your project name] > dependencies tab, do you have scala-compiler-[some version] listed?
See the Exploring the Project Structure here
intelliJ IDEA 10.0.1 + scala 2.8.1 on Ubuntu 10.10 64bit.
It shows a type mismatch error
For 2019.1 CE on Mac OS:
Preferences | Build, Execution, Deployment | Compiler | Scala Compiler
Checked the option:
Features->Experimental Features
Related
while building through Intellij Idea, I got the following message:
Error:scalac: 'jvm-1.10' is not a valid choice for '-target'
Error:scalac: bad option: '-target:jvm-1.10'
later, after a Java upgrade
Build, Execution, Deployment -> Build Tools -> Gradle -> Gradle JVM:
1.8 Build, Execution, Deployment -> Complier -> Scala Complier -> Scala Compile Server -> JDK: 1.8
in build.gradle
compileScala.targetCompatibility = 1.8
ScalaCompileOptions.metaClass.useAnt = false
Nothing helps!
upd:
this helps: in build.gradle
tasks.withType(ScalaCompile) {
scalaCompileOptions.useAnt = false
}
not needed:
compileScala.targetCompatibility = 1.8
ScalaCompileOptions.metaClass.useAnt = false
"Error:scalac: 'jvm-1.10' is not a valid choice for '-target' Error:scalac: bad option: '-target:jvm-1.10'"
In the JDK compatibility notes as mentioned below, it also indicates
that the Java 10 is not fully supporting Scala 2.12.6 JDK 9 & 10
compatibility notes
As you were saying you build this through IntelliJ IDEA, I suspect
you haven't configure your java version (Java 10) or scala version
(2.12.6) inside running configuration project settings.
And also please try out building/compile your application through
commandline in order to check whether you are getting the same error
with that (Otherwise this is just bad configuration in IDEA tht you
need to change)
JDK 9 & 10 compatibility notes (Mentioned in Scala Docs)
JDK 9 & 10 compatibility notes
As of Scala 2.12.6 and 2.11.12, JDK 9 & 10 support is incomplete. Notably, scalac will not enforce the restrictions of the Java Platform Module System, which means that code that typechecks may incur linkage errors at runtime.
JDK 9 & 10 support requires minimum sbt version 1.1.0, or 0.13.17 in the 0.13.x series.
For more information on JDK 9 & 10 compatibility, watch the “Support JDK 9” issue on GitHub.
The same issue can happen with mixed multi-module gradle projects that use java 11 and scala 2.12.10.
In that case, it may help to reconfigure IntelliJ (2019.2) via
Settings > Build, Execution, Deployment > Scala Compiler
by removing the targets defined in Additional compiler options for the affected scala modules.
I stumbled over this issue when having the same problem with Java 11. The reconfiguration comment of Roland Ewald solved the problem. It is important to mention, that this reconfiguration has to be made for all modules of the project (at least for me this was necessary) as well as that IntelliJ sometimes hides parts of the Additional compiler options, so be sure to click on expand even if they seem empty or correct.
I just set up a Scala project in Eclipse (Oxygen 4.7.3a, on Ubuntu 18.04) with the Scala-IDE plugin (4.7.0.v-2_12-201709291352-71a28d0) with a simple HelloWorld object. If I set "Properties -> Scala Compiler" to 2.12 everything works as expected: the project compiles and runs. But if I choose any other version (for instance, "Latest 2.10 bundle (dynamic)" I get prompted to do a full rebuild (as expected) but when I go to "Project -> Build" nothing happens. If I have errors in my code, the editor underlines them, but they won't show in "Problems". If I try to run it I get a class not found error.
I get the feeling that it is not actually compiling. Any ideas on what I need to configure differently?
I finally solved it by removing openjdk-11 and installing openjdk-8. After doing that and reinstalling Eclipse and Scala-IDE everything works fine.
It would have been helpful having some feedback from Eclipse regarding what was not working. I figured it out because I tried to build with SBT and the error lead to this SO question: Failed to initialize compiler: object java.lang.Object in compiler mirror not found
I tried the update-alternatives option (also changing the Java path in eclipse.ini) but then I got the "object java.lang.Object in compiler mirror not found" error in Eclipse problems. Since I didn't need openjdk-11 anyway I simply switched to openjdk-8.
I have use the IntelliJ Scala plugin before, in 13 and 13.1. I upgraded to 14, and it doesn't work anymore for my SBT project.
For all Scala standard lib stuff, I see errors like "Cannot find symbol scala.Option".
at scala project, compiler error - Cannot resolve symbol List? says I need to have the Scala facet for my module. I looked in facets, and Scala wasn't an option.
I've uninstalled IntelliJ and the Scala plugin and my settings and the projects files multiple times, but still happens.
How do I fix this?
the new scala plugin for intellij 14 removed the facet and replaced it with Scala SDK library, see blog
for sbt project, I guess the best bet is to re-create your project by:
File -> open -> select the build.sbt of your project in popup -> delete existing project and import
I had a similar issue when a Java module calls an Scala object. The issue was from the wrong setup in Source Folders; the Scala source was in src/main/scala/..., but in the Project Structure, the Source Folders were setup as src by default. When I changed it as src/main/scala, the Java module can find the Scala object correctly.
I fixed this by using the nightly builds of the Scala plugin.
The fixes have now been incorporated into the stable versions.
In my case i just had to reload the IDE...
Environment: Play 2.3.0/Scala 2.11.1/IntelliJ 13.1
I used Typesafe Activator 1.2.1 to create a new project with Scala 2.11.1. After the project was created, I ran gen-idea. The generated IDEA project fails to compile with the error:
Error: scala: No 'scala-library*.jar' in Scala compiler library in test
Am I doing something wrong? Workaround?
Open File -> Project Structures -> Libraries, remove any scala sdk in it, e.g. scala-sdk-2.11.8 in the following image.
Click on +, then Scala SDK.
Select the right Scala SDK from the list, for me, it's Ivy-Scala-2.11.8 shown in the picture.
Select the current project(mine is spark-test), click OK.
Then click OK to close it.
Run again, it should work now.
Since IDEA 13 you should use SBT support which is bundled with Scala plugin.
With it there is no need to add third-party SBT plugins and run special commands; just import the project using "File -> Import project..." menu item, and it will automatically load SBT project structure and its dependencies.
I had the same issue with the .idea files generated by ./activator idea with play 2.3. A quick fix is to look in "Project Structure->modules" and note the name of the compiler library. For me it was "SBT: scala2.11.1". The look in "Project Structure->Libraries" and check the contents of this library. It should contain scala-compiler.jar, scala-library.jar, scala-reflect.jar. If this libraries are not present, add them (in my case they are located in ~/.sbt/boot/scala-2.11.1/lib).
For IDEA 15 and project exported from Activator 1.3.5 only Russell's solution helped at the moment.
I have fixed scala compiler library with adding 3 libraries located in ~/.sbt/boot/scala-2.11.1/lib to library's compiler classpath and classes. After indexing project I moved this library to global libraries of IDEA and it was saved there.
I had the same issue.
If you are building your project using external sbt i.e sbt compile then it will create or add dependencies in libraries(all external dependency also) and scala sdk will be added as SBT:scala* based on version of your scala.
So you can remove SDK with SBT as prefix and add proper SDK through Intellij.
File->Project Structure->Libraries
Remove SBT SDK and add it manually.
For me with IDEA 12, I fixed this issue when I unchecked the box for "Use external build" in Settings.Compiler.
now is 2021 year, in Mac, use IntelliJ to run scala:
core logic
Mac: brew install scala
IntelliJ: open *.scala file, then according notice to auto config java JDK and Scala SDK
detailed steps: pls refer another post's answer
I'm an absolute Scala beginner. I was wanting to get up and running. I needed to create a Scala project, not a Java project with Scala library:
I'm trying to develop on the Scala compiler project with the help of ScalaIDE. I followed this guide to set up the development environment. When I now try to build the mentioned projects, the reflect project won't get built. Instead, I get the following error via the console output:
uncaught exception during compilation: scala.reflect.internal.MissingRequirementError reflect Unknown Scala Problem
Having tried the provided ANT script of the project via the console, everything seems to work fine.
Does anyone know if I'm missing a hidden compiler flag, dependency or something like this?
Thanks!
With the IDE for Scala 2.10 you can only build the 2.10.x branch of the Scala compiler. If you want to work on master, you need to install a 2.11-based version of the IDE. We don't publicise IDE for 2.11 nightlies yet, but they are available at:
http://download.scala-ide.org/nightly/scala-ide-master-2.11.0-SNAPSHOT/