Bug 434672

SUMMARY
Kdevelop's syntax highlighter stops working under some circumstances.

STEPS TO REPRODUCE
1. write some C/C++ code
2. mismatch brackets, write something wrong.
3. 

OBSERVED RESULT
Sometimes, hard to tell exactly when, but it seems when particular errors are present such as mismatched brackets, the syntax highlighter stops working and the code is all black. 

EXPECTED RESULT
Syntax highlighting should go on working regardless of code errors, just like in Kwrite.

SOFTWARE/OS VERSIONS
Windows: 
macOS: 
Linux/KDE Plasma: fc33
(available in About System)
KDE Plasma Version: 5.20.5
KDE Frameworks Version: 5.79
Qt Version: 5.15.2

ADDITIONAL INFORMATION
When this situation occurs, the code is highlighted again if I remove (undo) the last written text, which is the one that caused the error. But from then on, even moving one line of code up or down, makes the highlighter stop working again.

I ultimately have to reload the file or close and reopen kdevelop. At which point, the highlighter works ok meaning the source code itself causes no problems.