[sass-convert] Multiple parent selectors with double-colon pseudoelements problem

[reinmarm]

Conversion from CSS to .sass/.scss produces wrong output when sass-convert combines a parent selector with double-colon-notation (CSS3) pseudoelements via &. This only occurs when there are more than one selectors with pseudoelements. See my example with the aelement below.

Result:

1. The parent::pseudoelement selectors appear one level too deep.
2. One colon gets stripped, resulting in parent:pseudoelement.
3. At the level where they should be, a lone &: appears, throwing Syntax error: Invalid CSS after "&:": expected pseudoclass or pseudoelement, was "" when trying to compile back to CSS.

/* input.css */

a {
    color: #111;
}
a::foo,
a::bar {
    color: #222;
}

b {
    color: #111;
}
b:foo,
b:bar {
    color: #222;
}

p {
    color: #111;
}
p::foo {
    color: #222;
}

/* output.sass */

// double-colon notation, more than one selector: wrong
a
  color: #111
  &:
    &:foo, &:bar
      color: #222

// single-colon notation: as expected
b
  color: #111
  &:foo, &:bar
    color: #222

// double-colon notation, but only one selector: also as expected
p
  color: #111
  &::foo
    color: #222