Primary parent via ampersand (SASS). How?

Question

css

Good time!
I am learning how to use BEM correctly in my projects.
There is a button with an icon and text.
I want to indent the left of the text if there is an icon, i.e. like .btn__ico + .btn__text:

// example 1
.btn
  &__ico
    position: absolute
  &__ico + &__text
    margin-left: 29px

// example 2
.btn
  &__ico
    position: absolute
    + .btn__text
      margin-left: 29px

Which of these methods is correct?
And is there a third?
Tried like this:

.btn
  &__ico
    position: absolute
    & + &__text
      margin-left: 29px

But it doesn't work as expected.
It is desirable with arguments, so that I understand why this is so.

Answer 1

Personally, I always use the second option.
Your attempt doesn't work because & refers to the parent, so when you try to write &__text in a &__ico block, you write something like this: &__ico__text.

Answer 2

You can try like this...

.btn
  $b: &
  &__ico
    position: absolute
    + #{$b}__text
      margin-left: 29px