QC crash when indexing finishes

Steps to reproduce:

• have clangd enabled
• have a couple of older projects inside your recent projects
• open a small project
• open another one
• close all while parsing and indexing is triggered
• back on the welcome screen, re-open the project you opened the as the last one
• while parsing close all projects

Not sure if related: these projects had not been used with clangd before. Reproducible mostly with qmake based projects. I think with qbs this did not happen so far.

See attached backtrace.