Selectors inside of &:not() are duplicated in output

[bkistyping]

These styles:

.a, .b {
  &:not(.c) { background: red; }
}

Compile to:

.a:not(.c, .c), .b:not(.c, .c) {
  background: red; }

Expected:

.a:not(.c), .b:not(.c) {
  background: red; }

The selector inside of :not() seems to be duplicated for every selector it is nested inside of. Sort of hilariously, doing something like:

.a, .b, .c {
  .d, .e {
    &:not(.f) { background: red; }
  }
}

Compiles to .a .d:not(.f, .f, .f, .f, .f, .f),, etc.

Using sassc 3.3.0, libsass 3.3.3, sass2scss 1.0.5. I know there’s another issue about this but it’s old now and wasn't labeled very clearly. Sorry!

[bkistyping]

Oops, this is a libsass bug and not in sassc: sass/libsass#1901