Direction of tree-walkign in the compiler PluginPhase

[rssh]

I'm trying to write a small compiler plugin phase, which should apply to DefDefs transformation from top to bottom.
But I see default evaluation sequence is from bottom to top:

I.e, during processing next code:

object X {
  def a(): A=>B = {
     a => b
  }
}

transformDefDef at first applied to internal lambda function. X.a.$anonfun then to X.a

So, question - is it possible to change tree-walking strategy for compiler phase ?

//.btw, find a way to process only top-level defdefs

Thanks!

[rssh]

Answer to self after reading sources of MiniPhase/MegaPhase: no. (i.e. for excluding child nodes need to have analyzer or selection phase before our phase).