Xcode 16.3 and undefined template 'std::char_traits<unsigned char>' prevent building the app

[lorenc-tomasz]

Description

Xcode 16.3 removes the base template for std::char_traits: https://developer.apple.com/documentation/xcode-release-notes/xcode-16_3-release-notes

This prevents to build iOS app with new Xcode 16.3.

Steps to reproduce

Try to build app with Xcode 16.3

React Native Version

0.76.8

Affected Platforms

Build - iOS

Output of npx @react-native-community/cli info

Not needed

Stacktrace or Logs

Not needed

Reproducer

https://github.com/react-native-community/rn-diff-purge/tree/release/0.76.8

Screenshots and Videos

No response

[react-native-bot]

Warning

Missing reproducer: We could not detect a reproducible example in your issue report. Please provide either:

• If your bug is UI related: a Snack
• If your bug is build/upgrade related: a project using our Reproducer Template
• Otherwise send us a Pull Request with the RNTesterPlayground.js edited to reproduce your bug.

[akhaled01]

Im also facing the exact same issue. i tried using react-native@0.78.0 and it builds without issue, but i have not tested the .ipa app to see if it actually works

[xubmuajkub]

Same issue on "react-native": "0.71.7"

[lorenc-tomasz]

"react-native": "0.77.2" seems to be building fine. So issue is up to 0.76.8.

[VanDinh18]

same issue on react native 0.72.17
Implicit instantiation of undefined template 'std::char_traits<fmt::internal::char8_type>'

[wdcs-krunalsatapara]

same issue on react native 0.74.1
Implicit instantiation of undefined template 'std::char_traits'

[tinypal]

Apparantly the new upgrade xcode 16.3 is causing this issue. Downgrade to Xcode 16.2 and it works fine it seems.