[perl #79642] [BUG] When a hash isn't bound to an optional %-sigilled parameter, something weird ends up in it in Rakudo

[Carl Mäsak]

# New Ticket Created by  "Carl Mäsak" 
# Please include the string:  [perl #79642]
# in the subject line of all future correspondence about this issue. 
# <URL: http://rt.perl.org/rt3/Ticket/Display.html?id=79642 >


<masak> rakudo: sub foo($a, %h?) { bar($a, %h) }; sub bar($a, %h?) {
say "alive!" }; foo(42)
<p6eval> rakudo : OUTPUT«Method 'HOW' not found for invocant of class
'Hash'␤  in 'bar' at line 1 [...]
<masak> rakudo: sub foo($a, %h?) { say %h.WHAT }; foo(42)
<p6eval> rakudo : OUTPUT«Method 'WHAT' not found for invocant of class
'Hash'␤  in 'foo' at line 22:/tmp/qK5WsYzzEI␤  in main program body at
line 22:/tmp/qK5WsYzzEI␤»
* masak submits rakudobug
<colomon> masak++
<masak> bug brought to you courtesy of a November being brought back
from the Mostly Dead.

Further experimenting reveals that the %h coming in through &foo
claims to be a Hash, but it has no methods at all, so you can't do
anything with it, not even pass it to &bar.