I just wanted to highlight how bizarre this discussion has become in general (nothing against you, it seems to be a common theme):

    “““
    I'm unhappy with Scala's compatibility guarantees,
    therefore I'll pick a language which

    a) does not provide any binary compatibility guarantees
       at all,
    b) has no tool to figure out whether incompatible 
       changes have actually happened,
    c) lacks any sort of guidance to figure out if library 
       A is compatible with library B short of downloading
       and executing them together,
    d) provides no clean way to cross-compile libraries 
       against multiple versions.

    But hey, let's bash Scala for caring about these issues 
    and deride them for shipping actual, working
    solutions addressing those issues.
    ”””

Scala guarantees:

    - Source compatibility between major versions
    - Source and binary compatibility (both backward and 
      forward) for all minor and update releases of that 
      major version

People will have a hard time to find another modern language which gives them these guarantees.

Hypocrisy and cognitive dissonance FTW, I guess.