Your bug report

#75580: 30.0.93;  statements inside string interpolation for csharp modes
 are fontified incorrectly

which was filed against the emacs package, has been closed.

The explanation is attached below, along with your original report.
If you require more details, please reply to 75580@debbugs.gnu.org.

-- 
75580: https://debbugs.gnu.org/cgi/bugreport.cgi?bug=75580
GNU Bug Tracking System
Contact help-debbugs@gnu.org with problems