Bad class file due to value with constant type that overrides a specialized trait method

[scabug]

trait A[@specialized(Int) T] {
  def f: T = ???
}

object B extends A[Int] {
  override final val f = 0
}

will cause the following error when B is loaded:

Exception in thread "main" java.lang.ClassFormatError: Duplicate method name&signature in class file test/B$
	at java.lang.ClassLoader.defineClass1(Native Method)
	at java.lang.ClassLoader.defineClass(ClassLoader.java:760)
	at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
	at java.net.URLClassLoader.defineClass(URLClassLoader.java:467)
	at java.net.URLClassLoader.access$100(URLClassLoader.java:73)
	at java.net.URLClassLoader$1.run(URLClassLoader.java:368)
	at java.net.URLClassLoader$1.run(URLClassLoader.java:362)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.net.URLClassLoader.findClass(URLClassLoader.java:361)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
	at java.lang.Class.getDeclaredMethods0(Native Method)
	at java.lang.Class.privateGetDeclaredMethods(Class.java:2701)
	at java.lang.Class.privateGetMethodRecursive(Class.java:3048)
	at java.lang.Class.getMethod0(Class.java:3018)
	at java.lang.Class.getMethod(Class.java:1784)
	at com.intellij.rt.execution.application.AppMain.main(AppMain.java:125)

Interestingly, if we removed the "final" marker in object B, the code will run properly.

[scabug]

Imported From: https://issues.scala-lang.org/browse/SI-9486?orig=1
Reporter: Tongfei Chen (ctongfei)
Affected Versions: 2.11.7, 2.12.0-M2

[scabug]

@soc said (edited on Sep 25, 2015 5:04:25 PM UTC):
My first guess¹ would be that this is caused by the compiler's behavior of treating definitions of values with literals as constant types: some check in an earlier phase doesn't take this into account and then in the backend the constant type is again erased to the same signature as the other method from the parent.

¹ adding a type ascription also "fixes" the crash

[som-snytt]

duplicated by #12301