Qt Creator Clang Code Model problems collection

aha_1980 · 15 Mar 2019, 13:30

Hi all,

I've created this topic to track all problems that are SOLVED by deactivating the Clang Code Model with Help > About Plugins > Clang Code Model.

I regularly see these, and like to collect them to make the developers aware of these problems. After all, the build in code model will be removed some time in the future and till then Clang needs to be rock stable and fast.

So please, add a comment here whenever you encounter a topic that is just SOLVED by disabling Clang.

Thanks!

koahnig · 15 Mar 2019, 13:35

@aha_1980

That is certainly a good idea, but would this not fit better with jira?
Or are you considering this more like a pre-screening before jira is overloaded?

aha_1980 · wrote on 15 Mar 2019, 13:35

@koahnig Absolutely ACK to both points.

I just like to have a collection/polling first, before creating a JIRA ticket.

And of course that makes it easier for most people here to help ;)

Regards

J.Hilk · 15 Mar 2019, 16:04

@aha_1980
ohho, where to start ?

Let me list the 2 major ones, why I turned the plugin of by default on my working pc.

speed

Classes with large line count ( could thousand < 15000 in my case ) Slow down horribly. Auto complete, ctrl-left-click etc can take up about 30 secs to happen. -> Meanwhile Clang backend process takes up 1 core to 100% load (noticed on a 2016 iMac) - Completely disappears with a deactivation of the plugin

Auto complete is worse with the new code model

Especially noticeable during QObject::connect writing. In the old model, writing a &would call forth the auto complete of the correct class name - connect(this, &...) - where as with the new model all included classes are listed
The new code model also does not differentiate between signals and slot during the auto complete, and simply lists everything

koahnig · 15 Mar 2019, 16:38

@J.Hilk @aha_1980

Speed and blocked cores are certainly a problem.

Therefore, it would be handy to have a fast switch for the code model. Basically a definable key stroke for de- and activation would be great. If there a time limit for either settings would be wonderful.
Or is the key stroke already possible with some macro?

aha_1980 · wrote on 15 Mar 2019, 16:38

@koahnig

I've already created QTCREATORBUG-21407 for that, so please comment and vote there.

For me, that would really be helpful as I have some projects that definitely not work with Clang.

My other observation is, that Clang overall works better and faster on Linux than in Windows. However, with every Creator update some of my projects break in one or another use case and it's no fun finding the reason for that again and again.

J.Hilk · wrote on 22 Mar 2019, 09:51

One more for the list, turning clang code model off helped here as well

https://forum.qt.io/topic/100408/qt-creator-strange-behaviour-how-to-fix-it/10

rudag · 4 Apr 2019, 17:02

I had the same problem as this one:

https://forum.qt.io/topic/74385/qt-creator-autocomplete-not-updating-for-new-ui-widgets-until-re-compile/4

And I solved it by turning clang code model off.

aha_1980 · 8 Apr 2019, 12:47

Hi @rudag, thanks for your comment.

I think this specific bug has been fixed recently. Which version did you try?

rudag · wrote on 8 Apr 2019, 12:47

@aha_1980

4.8.2 (4.8.0)
I just updated Qt Creator

Maxxii · 15 Apr 2019, 07:42

I had issue with autocompetion of inherited function parameters here:
https://forum.qt.io/topic/101748/autocompletion-doesn-t-suggest-function-parameters-inherited-from-parent-class

And it is solved by turning off clang code model.

aha_1980 · M Maxxii 13 Apr 2019, 21:22

Hi @Maxxii,

thanks for adding your problem here. I think your specific problem can be turned in a report at bugreports.qt.io - as we already have a reproducible example. Would you mind doing that? (and adding a link here?)

Thanks!

Maxxii · wrote on 15 Apr 2019, 15:42

@aha_1980 Actually, I made a bug report even before making that thread ;) And then decided to ask on forums to be sure. It's here. I also added comment to this bug, noticing it is solved by turning off clang code model.

aha_1980 · wrote on 27 Apr 2019, 09:55

https://forum.qt.io/topic/102198/many-incomprehensible-errors looks like another candidate...

aha_1980 · wrote on 30 Apr 2019, 03:51

https://forum.qt.io/topic/102266/autocomplete-on-a-hello-world-basic-project-doesn-t-works/4

aha_1980 · wrote on 1 May 2019, 05:02

https://forum.qt.io/topic/102272/using-qt-project-code-with-earlier-versions/10 also looks like a candidate

aha_1980 · 21 May 2019, 05:08

And another one: https://forum.qt.io/topic/102999/strange-variable-has-incomplete-type-and-forward-declaration-of-qapplication-issues

aha_1980 · wrote on 21 May 2019, 05:00

And one more: https://forum.qt.io/topic/103006/linux-qtcreator-and-qt5-9-6-compiling-gnu-c-libraries

J.Hilk · 21 May 2019, 05:19

@aha_1980

And another one: https://forum.qt.io/topic/102999/strange-variable-has-incomplete-type-and-forward-declaration-of-qapplication-issues

oh! I run into that as well, didn't think about turning off the code model as potential solution.

I ended up forwarding a class instance pointer several levels up in the hierarchy ....

This is stupid.

aha_1980 · J J.Hilk 21 May 2019, 05:08

Hi @J.Hilk,

oh! I run into that as well, didn't think about turning off the code model as potential solution.

Well I don't think turning off the code model is a solution. But most of these problems collected here have in common, that Clang has parse problems in a header which then propagate in every file that is including the header.

Tracking down these problems, however, is a tedious task.