Documentation for method List assembled from the following pages:

Class: Any §

From Any

(Any) method List §

Defined as:

method List(--> List:D) is nodal

Coerces the invocant to List, using the list method.

Class: Slip §

From Slip

(Slip) method List §

Defined as:

multi method List(Slip:D: --> List:D)

Turns it into a list.

Class: Array §

From Array

(Array) method List §

Defined as:

multi method List(Array:D:)

Converts the array to a List

my @array= [1];
@array[3]=3;
say @array.List;       # OUTPUT: «(1 Nil Nil 3)␤» 

The holes will show up as Nil.