Description of problem:

An attempt to run the current updates in rawhide has the following effects:

 Problem 1: problem with installed package yum-3.4.3-518.fc29.noarch
  - package dnf-yum-2.7.5-16.fc29.noarch conflicts with yum provided by yum-3.4.3-518.fc29.noarch
  - cannot install the best update candidate for package dnf-yum-2.7.5-12.fc29.noarch
 Problem 2: problem with installed package yum-utils-1.1.31-515.fc29.noarch
  - package yum-utils-1.1.31-515.fc29.noarch requires yum >= 3.4.3-148, but none of the providers can be installed
  - package dnf-yum-2.7.5-16.fc29.noarch conflicts with yum provided by yum-3.4.3-518.fc29.noarch
  - problem with installed package dnf-yum-2.7.5-12.fc29.noarch
  - package dnf-yum-2.7.5-12.fc29.noarch requires dnf = 2.7.5-12.fc29, but none of the providers can be installed
  - cannot install both dnf-2.7.5-16.fc29.noarch and dnf-2.7.5-12.fc29.noarch
  - cannot install the best update candidate for package dnf-2.7.5-12.fc29.noarch

Version-Release number of selected component (if applicable):
yum-3.4.3-518.fc29

Additional info:
Adding to an update command '--allowerasing' results in a proposition to delete 'dnf-yum'.  If that package is indeed obsolete then maybe dnf should mark it as such.  On the other hand the only executable provided by 'dnf-yum' is a quite simple script /usr/bin/yum, which is not a part of 'yum' package, so this looks like too strict versioning in requirements.