Example code:
  class wExtendedElementList extends List {
    wExtendedElementList.from(List elements) : super.from(elements){}
  }
This uses a factory constructor as the super-constructor in the initializer list. The error message given is:

  Error: line 2 pos 48: super class constructor 'List.from' not found
      wExtendedElementList.from(List elements) : super.from(elements){}

This error message is misleading, going on incorrect, since List.from is a constructor. The error isn't that it doesn't exist, but that it is a factory constructor instead of a generative constructor.
(It's technically true that the compiler didn't find List.from, but that's because it was looking in the wrong place).