behavior change within 2.6 makes it impossible to override class parameters of "included" parametrized classes

In 2.6.1 the following recipe:

<pre>
class a(
$b_c =

{ 'b' => 'foo' }

) {
notice $a::b_c
if $a::b_c

{ notice $a::b_c['b'] }

}

class b {
class

{'a': b_c => false }

}

class b::c inherits b {
Class['a']{ b_c =>

{ 'b' => 'bleh' }

}
}

class b::d

{ include ::b::c }

include b::d
</pre>

produces the following output:

<pre>
$ puppet foo.pp
notice: Scope(Class[A]): bbleh
notice: Scope(Class[A]): bleh
</pre>

Which is what I expected. However with 2.6.3 it produces the following output:

<pre>

1. puppet foo.pp
   notice: Scope(Class[A]): false
   </pre>

Imho likely the changes for #4778 and #5074 are responsible for that behavior change.

However this makes it impossible to overwrite parameters of a "included" parametrized class in a subclass. There are only ugly workarounds for that problem and I think this should actually work as it did within 2.6.1. Otherwise the usefulness of parametrized classes is quite reduced.