[perl #128936] X::Placeholder::NonPlaceholder is unused

[via RT]

# New Ticket Created by  Zoffix Znet 
# Please include the string:  [perl #128936]
# in the subject line of all future correspondence about this issue. 
# <URL: https://rt.perl.org/Ticket/Display.html?id=128936 >


It appears that X::Placeholder::NonPlaceholder exists in the code but is unused 
anywhere. Dead code likely should be removed:

This is all the output I get:
$ grep -nR X::Placeholder::NonPlaceholder                                       
                  
src/core/Exception.pm:826:my class X::Placeholder::NonPlaceholder does X::Comp {