Scala's wrong forward reference error

Question

private def foo(a:A):B = a match{
    case A(...) =>
        val x = a.b //error: wrong forward reference a
        ...
}

Where b is not mentioned in A(...), if that matters.

I've tried my luck on Google, but I seem to find only posts of people having errors involving forward references but no explanation of what this particular error actually means.

Would appreciate it if somebody could help me out.

Answer 1

Well, don't I feel stupid now...

private def foo(a:A):B = a match{
    case A(...) =>
        val x = a.b //error: wrong forward reference a
        ...
        val a = ... //<-- THAT's the reason for the error
        ...
}

So a simple rename will resolve the issue:

private def foo(aa:A):B = aa match{
    case A(...) =>
        val x = aa.b
        ...
        val a = ...
        ...
}