[perl #75868] Infinite recursion when using Match object as hash key

[via RT]

# New Ticket Created by  Moritz Lenz 
# Please include the string:  [perl #75868]
# in the subject line of all future correspondence about this issue. 
# <URL: http://rt.perl.org/rt3/Ticket/Display.html?id=75868 >


./perl6 -e 'my %h = a => 1; "a" ~~ /./; say %h{$/}'
maximum recursion depth exceeded
  in 'postcircumfix:<{ }>' at line 1
  in 'postcircumfix:<{ }>' at line 1
  in 'postcircumfix:<{ }>' at line 1
  in 'postcircumfix:<{ }>' at line 1
  in 'postcircumfix:<{ }>' at line 1
...