Hi,
It's because of the default value of array elements. See the end of this
section: https://docs.perl6.org/language/list#Typing
my @a;
say @a.of.perl; # Mu
say @a.default.perl; # Any
say @a[0]; # (Any)
role Foo {};
my Foo @a;
say @a.of.perl; # Foo
say @a.default.perl; # Foo
say @a[0] # (Foo)
On 2017-01-03 10:59:34 GMT, Martin Barth wrote:
> Hi There,
>
> I am not sure if my RoleType @array; is correct, or if there is a better
> way to declare such an array. But I find the error that is happening
> when there are no elements in the array confusing on the first sight. It
> took me a while to realize that my array was empty and therefore it
> "means" the class/role itself.
>
>
> > perl6 -e 'role Foo {method n{...}}; class Bar does Foo {method
> n{"n"}}; my Foo@a = (); @a.push: Bar.new; say @a[0].n'
> n
>
> > perl6 -e 'role Foo {method n{...}}; class Bar does Foo {method
> n{"n"}}; my Foo@a = (); say @a[0].n'
> Method 'n' must be implemented by Foo because it is required by a role
> in any compose_method_table at gen/moar/m-Metamodel.nqp line 2824
> in any apply at gen/moar/m-Metamodel.nqp line 2834
> in any compose at gen/moar/m-Metamodel.nqp line 3006
> in any make_pun at gen/moar/m-Metamodel.nqp line 1692
> in any find_method at gen/moar/m-Metamodel.nqp line 1720
> in block <unit> at -e line 1
>
> > perl6 -e 'role Foo {method n{...}}; class Bar does Foo {method
> n{"n"}}; my @a = (); say @a[0].n'
> No such method 'n' for invocant of type 'Any'
> in block <unit> at -e line 1
