"Implicit conversion loses integer precission" Error when building for Mac

Development Pipeline & Plugins
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1

Hi!

We are working on a multiplatform project using UE 5.5. Right now we are working on the iOS platform support, developing the integration for push notifications. We’ve noticed that, in order to make the engine support remote notifications, we’ve to compile the project using the source code version of the engine instead of the one from the launcher.

We’ve gone through the instructions of the readme in order to build the engine and the editor for Mac, but when we go to through the step of building the ShaderCompilerWorker, the process fails, having multiple conversion errors through the engine files:

implicit conversion loses integer precision: ‘uint64’ (aka ‘unsigned long long’) to ‘uint32’ (aka ‘unsigned int’) [-Werror,-Wshorten-64-to-32]

Our setup is:

MacOs Sequoia 15.5 / Apple M2 Max / XCode 16.4 (16f6)

MacOs Sequoia 15.3.1 / Apple M4 / XCode 16.4 (16f6)

Is there any way we can solve this issue?

Thanks.

2

Steps to Reproduce
Download UE Source code in a mac machine.

Follow the steps of the readme.

When following the step to build the Shader Compiler Worker, the project does not compile, having multiple conversion errors like this:

implicit conversion loses integer precision: ‘uint64’ (aka ‘unsigned long long’) to ‘uint32’ (aka ‘unsigned int’) [-Werror,-Wshorten-64-to-32]

3

Hi!

Installed XCode 16.0 (16A242d) and it built perfectly.

4

Hi,

I’m happy to hear you were able to get things compiling! Newer xcode versions include a Clang update that causes some issues, our docs currently recommend 16.1 for the 5.6 release but you should be safe to stay on 16.0 if it’s not causing any issues.

Best,

Cody