Regression: freezes after duplicating a class

Inside a namespace I inserted a copy of a derived concrete class and the program freezes.

This happens for dailies of the last couples of days.

(for qt-creator-opensource-linux-x86_64-4.8.0-beta2_2598.run   and

qt-creator-opensource-linux-x86_64-4.8.0-beta2_2600.run)

I reinstall

qt-creator-opensource-linux-x86_64-4.8.0-beta2_2584.run 

(Qt Creator 4.8.0-beta2 (4.7.83)

Based on Qt 5.11.2 (GCC 5.3.1 20160406 (Red Hat 5.3.1-6), 64 bit)

Built on Nov 7 2018 07:37:41

From revision 077953b923 )

and it did not freeze.