From the mailing list:
I wanted to compile a custom theme for my OO 9.3.1 installation, using the provided compile_theme.sh script. I have the latest SASS 3.3.4. Compiling a child theme based on the openolat default theme, this SASS error from the core theme pops up:
I did a quick&dirty fix by removing the @extend in _basemod.scss and replacing it with the rules for .b_with_small_icon_right from _icons.scss.