Array.map (or other untyped Array returns) cast to typed array

main.gd

var things: Array[Vector2] = [
    Vector2(1,1), Vector2(2,2), Vector2(3,3),
]

var double := func(v: Vector2) -> Vector2:
    return v * 2

# step 1: declare a typed empty array
var doubled_things: Array[Vector2] = []
# step 2: use the assign method to automatically match the type. This is only needed
# for GDScript or Godot built-ins which are typed as Array or Array[Variant]
doubled_things.assign(things.map(double))

print("is Array: ", doubled_things is Array)
print("is Array[Vector2]: ", doubled_things is Array[Vector2])

for t in doubled_things:
    prints(t)



...

is Array: true
is Array[Vector2]: true
(2, 2)
(4, 4)
(6, 6)