Generated by SassMeister.com.

SassMeister-input.sass

// ----
// Sass (v3.4.13)
// Compass (v1.0.3)
// ----

.block
  color: red
  &__element
    color: yellow
  &--modifier
    color: blue
    .block__element
      color: green

SassMeister-output.css

.block {
  color: red;
}
.block__element {
  color: yellow;
}
.block--modifier {
  color: blue;
}
.block--modifier .block__element {
  color: green;
}