Compile Error under JDK9-167

I got a simple test program. A little Hello World. One Main class in package demo. One module-info.java in the root package. With a JDK9 166 this little program compiles fine and writes "Hello World". Now I installed JDK9-167, set it as SDK in IntelliJ, try to compile but I get errors like this :

H:\Projects\SW\java\jdk9test\src\main\java\module-info.java

Error:(4, 1) java: file should be on source path, or on patch path for module

H:\Projects\SW\java\jdk9test\src\main\java\demo\Main.java

Error:(1, 1) java: file should be on source path, or on patch path for module

Any Ideas here ?