barbararamiro reported an issue where in the Boost Advanced Settings referencing a SASS variable in the Raw SCSS would produce an error.

The error was initially encountered on a MoodleCloud site, however I verified with basbrands the error is prevalent on the current master branch.

To reproduce it:

1. Build SASSC library following the docs in https://github.com/sass/sassc 
2. Login as admin.
3. Go to "Site administration > Development > Experimental settings".
4. Set "Path to SassC" with the proper path to the sassc binary file built in step #1.
5. Go to Boost > Advanced Settings and:
   • Enter $moodle-test: #FF00FF; as "Raw initial SCSS"
   • Referenced that variable in the "Raw SCSS" section with:

.crmpicco {

   border-color: $moodle-test;

}

Saving this form produced the error:

Coding error detected, it must be fixed by a programmer: Error: Undefined variable: "$moodle-test". on line 2 of stdin >> border-colour: $moodle-test; ---------------^

More information about this error
Debug info:
Error code: codingerror
Stack trace:

line 138 of /lib/classes/scss.php: coding_exception thrown
line 10574 of /lib/adminlib.php: call to core_scss->compile()
line 2242 of /lib/adminlib.php: call to admin_setting_scsscode->validate()
line 8187 of /lib/adminlib.php: call to admin_setting_configtext->write_setting()
line 44 of /admin/settings.php: call to admin_write_settings()

The pathtosassc config setting is set to /usr/local/bin/sassc on Cloud. If pathtosassc is removed, the error is not displayed (so this error is only caused when using the SASSC to compile SCSS).

See attached screenshots.