NoSuchMethodError on java.lang.Enum.getEnumConstants

[nicolasstucki]

dotty> classOf[java.nio.file.AccessMode].getEnumConstants
java.lang.NoSuchMethodError: java.lang.Class.getEnumConstants()Ljava/lang/Object;
    at .<init>(<console>:8)
    at .<clinit>(<console>)
    at RequestResult$.<init>(<console>:3)
    at RequestResult$.<clinit>(<console>)
    at RequestResult$result(<console>)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java...

This happens with any java enum class.

[DarkDimius]

is it indeed a java.lang.Class.getEnumConstants()Ljava/lang/Object;? for some reason [ is missing.

[DarkDimius]

        0: ldc           #15                 // class java/nio/file/AccessMode
         2: invokevirtual #21                 // Method java/lang/Class.getEnumConstants:()Ljava/lang/Object;
         5: checkcast     #23                 // class "[Ljava/nio/file/AccessMode;"
         8: areturn

result of For.scala after TreeTransform:{vcInlineMethods, isInstanceOfEvaluator, seqLiterals, intercepted, getters, elimByName, augmentScala2Traits, resolveSuper, arrayConstructors}:
package <empty> {
  @dotty.annotation.internal.SourceFile("For.scala") class FooR() extends Object
    (
  ) {
    def foo: Array[java.nio.file.AccessMode] =
      classOf[class AccessMode].getEnumConstants()
  }
}
result of For.scala after erasure:
package <empty> {
  @dotty.annotation.internal.SourceFile("For.scala") class FooR() extends Object
    (
  ) {
    def foo(): java.nio.file.AccessMode[] =
      classOf[class AccessMode].getEnumConstants().asInstanceOf[
        java.nio.file.AccessMode[]
      ]
  }
}

Seems like the problem is caused by incorrect erasure of getEnumConstants.

[smarter]

Our handling of Java T[] is known to be broken: #533

[smarter]

The culprit is indeed eraseArray which doesn't know that generic arrays coming from Java should be erased to Object[] instead of Object like Scala

[odersky]

Fixed by #1391.