Bug 514291 - kdeconnect-25.08.3 and kmymoney-5.2.1 won't compile with Clang due to invalid constexpr in /usr/include/qt6/QtCore/qlist.h
Summary: kdeconnect-25.08.3 and kmymoney-5.2.1 won't compile with Clang due to invalid...
Status: RESOLVED UPSTREAM
Alias: None
Product: kde
Classification: I don't know
Component: general (other bugs)
Version First Reported In: unspecified
Platform: Other Linux
: NOR normal
Target Milestone: ---
Assignee: Unassigned bugs
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2026-01-07 19:31 UTC by Paul Gover
Modified: 2026-01-08 00:11 UTC (History)
1 user (show)

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Description Paul Gover 2026-01-07 19:31:30 UTC
SUMMARY
When updating my Gentoo system, both kdeconnect and kmymoney failed to compile with Clang, with the message:
     /usr/include/qt6/QtCore/qlist.h:449:26: error: constexpr variable 'MaxSize' must be initialized by a constant expression
     constexpr size_t MaxSize = maxSize();
They compile OK with gcc.

I appreciate this is not a failure in either kdeconnect or kmymoney, but I'm not sure how or where to report it.
I raised it on Gentoo (https://bugs.gentoo.org/968397), but they said "upstream", which seems fair.
I would raise it with Qt, but I get the impression they only support paying customers.
I also appreciate that this is down to Clang being more restrictive than gcc, and most people don't compile KDE apps with Clang.  But I thought somebody should be told!

STEPS TO REPRODUCE
1. Wipe your Ubuntu/RedHat/Linux from Scratch system
2.  Install Gentoo
3. Configure /etc/portage/make.conf to use clang in preference to gcc
4. emerge kdeconnect
:-)

OBSERVED RESULT

Failed emerge of kdeconnect, with the above messages in build.log

EXPECTED RESULT
Installation of kdeconnect

SOFTWARE/OS VERSIONS
(available in the Info Center app, or by running `kinfo` in a terminal window)
Linux/KDE Plasma: 
KDE Plasma Version: 6.5.4
KDE Frameworks Version: 6.20.0
Qt Version: 6.10.1
Clang version 21.1.8

ADDITIONAL INFORMATION
Comment 1 Nicolas Fella 2026-01-08 00:11:07 UTC
> I would raise it with Qt, but I get the impression they only support paying customers.

That is not correct, anyone can report bugs to Qt, and you'll have to if you want this fixed.