[perl #64022] fails with ::MySig ::= :(Num, Str)

[via RT]

# New Ticket Created by  Hojung Yoon 
# Please include the string:  [perl #64022]
# in the subject line of all future correspondence about this issue. 
# <URL: http://rt.perl.org/rt3/Ticket/Display.html?id=64022 >


<amoc> rakudo: my ::MyType ::= :(Num, Str)
<p6eval> rakudo c26021: OUTPUT«ResizablePMCArray: Can't pop from an empty
array!␤current instr.: 'parrot;Perl6;Grammar;Actions;typename' pc -3015048
((unknown file):-1)␤»

<amoc> rakudo: ::MyType ::= :(Num, Str)
<p6eval> rakudo c26021: OUTPUT«too few arguments passed (0) - 2 params
expected␤current instr.: '_block14' pc 40 (EVAL_18:28)␤»

<amoc> rakudo: ::MyType := Int
<p6eval> rakudo c26021: RESULT«Int»

<jnthn> rakudo: ::MyType := Int; my MyType $x = 42; say "ok"; $x = "OMG";
say $x;
<p6eval> rakudo c26021: OUTPUT«ok␤Type mismatch in assignment.␤current
instr.: 'die' pc 15960 (src/builtins/control.pir:204)␤»


but from: http://perlcabal.org/syn/S02.html#Names_and_Variables

A signature object (Signature) may be created with colon-prefixed parens:
    my ::MySig ::= :(Int, Num, Complex, Status)