Currently it says this:
Use of uninitialized value of type Any in numeric context
in block at line 1
As well as complains about sink context in non-repl:
Useless use of "**" in expression "$_**2" in sink context (line 1)
I see no problem with it. Except that it no longer says which variable
# New Ticket Created by Siddhant Saraf
# Please include the string: [perl #112986]
# in the subject line of all future correspondence about this issue.
# URL: https://rt.perl.org:443/rt3/Ticket/Display.html?id=112986
sisar r: $_**2;
p6eval rakudo 45679a: OUTPUTĀ«use of uninitialized variable