I got similar issues when I wanted to set maven submodules with scala in intelliJ. I eventually succeed with particular pom.xml. You may investigate this way.
Just for information I'll give you some extracts from my pom.xml that might be useful to you :
Parent pom.xml
<pluginManagement>
<plugins>
<!-- configure scala style -->
<plugin>
<groupId>org.scalastyle</groupId>
<artifactId>scalastyle-maven-plugin</artifactId>
<version>0.8.0</version>
<executions>
<execution>
<goals>
<goal>check</goal>
</goals>
</execution>
</executions>
<configuration>
<verbose>false</verbose>
<failOnViolation>true</failOnViolation>
<includeTestSourceDirectory>true</includeTestSourceDirectory>
<failOnWarning>false</failOnWarning>
<sourceDirectory>${basedir}/src/main/scala</sourceDirectory>
<testSourceDirectory>${basedir}/src/test/scala</testSourceDirectory>
<outputFile>${project.basedir}/target/scalastyle-output.xml</outputFile>
<outputEncoding>UTF-8</outputEncoding>
</configuration>
</plugin>
<!-- set scala maven plugin version -->
<plugin>
<groupId>net.alchim31.maven</groupId>
<artifactId>scala-maven-plugin</artifactId>
<version>3.2.2</version>
<configuration>
<scalaCompatVersion>${scala.binary.version}</scalaCompatVersion>
<scalaVersion>${scala.version}</scalaVersion>
</configuration>
</plugin>
</plugins>
</pluginManagement>
Child pom.xml
<build>
<plugins>
<!-- Scala Compiler -->
<plugin>
<groupId>net.alchim31.maven</groupId>
<artifactId>scala-maven-plugin</artifactId>
<executions>
<!-- Run scala compiler in the process-resources phase, so that dependencies on
scala classes can be resolved later in the (Java) compile phase -->
<execution>
<id>scala-compile-first</id>
<phase>process-resources</phase>
<goals>
<goal>compile</goal>
</goals>
</execution>
</executions>
<configuration>
<jvmArgs>
<jvmArg>-Xms128m</jvmArg>
<jvmArg>-Xmx512m</jvmArg>
</jvmArgs>
</configuration>
</plugin>
<!-- Adding scala source directories to build path -->
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>build-helper-maven-plugin</artifactId>
<version>1.7</version>
<executions>
<!-- Add src/main/scala to eclipse build path -->
<execution>
<id>add-source</id>
<phase>generate-sources</phase>
<goals>
<goal>add-source</goal>
</goals>
<configuration>
<sources>
<source>src/main/scala</source>
</sources>
</configuration>
</execution>
<!-- Add src/test/scala to eclipse build path -->
<execution>
<id>add-test-source</id>
<phase>generate-test-sources</phase>
<goals>
<goal>add-test-source</goal>
</goals>
<configuration>
<sources>
<source>src/test/scala</source>
</sources>
</configuration>
</execution>
</executions>
</plugin>
<!-- Scala Code Style, most of the configuration done via plugin management -->
<plugin>
<groupId>org.scalastyle</groupId>
<artifactId>scalastyle-maven-plugin</artifactId>
<configuration>
<configLocation>${project.basedir}/../../tools/maven/scalastyle-config.xml</configLocation>
</configuration>
</plugin>
Unfortunately I couldn't say exactly which part is fondamental. Hope it could help.
