I think this is because .WHAT is a special case. It's not really a method
which is what you need to make *.method work. *.WHAT will always return
(Whatever) immediately.
There is an odd what of working around this:
perl6 -e 'sub foo(\a where *.&WHAT === Int ) { say "Hello"; }; foo(10); #
works
using the &WHAT sub with postfix syntax you get around the special casing.
I'm not sure if .WHAT special casing is considered a bug. I haven't been
able to find a pre-existing ticket wrt to it.
On Sat, Sep 24, 2016 at 4:42 PM Itsuki Toyota <perl6-bugs-follo...@perl.org>
wrote:
> # New Ticket Created by Itsuki Toyota
> # Please include the string: [perl #129346]
> # in the subject line of all future correspondence about this issue.
> # <URL: https://rt.perl.org/Ticket/Display.html?id=129346 >
>
>
> See the following results
>
> $ perl6 -e 'sub foo(\a where { *.WHAT === Int } ) { say "Hello"; };
> foo(10);'
> Constraint type check failed for parameter 'a'
> in sub foo at -e line 1
> in block <unit> at -e line 1
>
> $ perl6 -e 'sub foo(\a where -> \e { \e.WHAT === Int } ) { say "Hello"; };
> foo(10);'
> Constraint type check failed for parameter 'a'
> in sub foo at -e line 1
> in block <unit> at -e line 1
>
> $ perl6 -e 'sub foo(\a where -> \e { e.WHAT === Int } ) { say "Hello"; };
> foo(10);'
> Hello
>
> It seems that "Whatever *" cannot handle sigilless values correctly.
> I think that the 1st example should return the same result as the 3rd
> example.
>
>
>
> $ perl6 --version
> This is Rakudo version 2016.08.1-202-g78393dd built on MoarVM version
> 2016.08-47-g2eedba8
> implementing Perl 6.c.
>
