Is rindex broken or does my brain need a reboot?

[Frederik Schwarzer]

Hi,

I had a little problem with rindex and wrote a small demo code that 
shows what I found.

The code is:
use v6;

my $string = "perl";
say $string;                                                                    
                                                                                
                      
say $string.WHAT;                                                               
                                                                                
                      
say $string.index("e");                                                         
                                                                                
                      
say $string.rindex("e");                                                        
                                                                                
                      
                                                                                
                                                                                
                      
say "";                                                                         
                                                                                
                      
say @*ARGS[0];                                                                  
                                                                                
                      
say @*ARGS[0].WHAT;                                                             
                                                                                
                      
say @*ARGS[0].index("e");                                                       
                                                                                
                      
say @*ARGS[0].rindex("e");                                                      
                                                                                
                      

When run, I see the following (with a two-week old build of Rakudo 
master):
$ perl6 index.pl perl
perl
Str()
1
1

perl
Str()
1
Failure.new(exception => X::AdHoc.new(payload => "substring not 
found"))

Do I miss something? Any help is appreciated.

Regards