This is surely a bug in the Sass, in the latest version (gem install sass --pre
) your code expands to
.cc_sidebar .btn,
.cc_popup .btn {
display: inline-block;
cursor: pointer; }
.cc_sidebar .btn, .cc_popup .btn--icon, .cc_sidebar .btn, .cc_popup .btn--icon {
width: 25px; }
And you can see duplicated .cc_sidebar .btn, .cc_popup .btn--icon
.cc_sidebar .btn, .cc_popup .btn--icon
part, so it looks like a bug.
I actually tested it a bit and, yes, there are two bugs actually! I filled them up in the Sass issues: https://github.com/nex3/sass/issues/1003 and https://github.com/nex3/sass/issues/1004, so you could use your code when they would be fixed.
As the problem is with multiple selectors, the only workaround is not to use them :(