Xcode 11 Error: "Unknown argument type '__attribute__' in method -[RCTAppState getCurrentAppState:error:]. Extend RCTConvert to support this type."
According the official issue : https://github.com/facebook/react-native/issues/25138 iOS build fails to run in with Xcode 11.0 beta This is a 0.59 version bug. If you have want to fix it by youself, please check this out: https://github.com/facebook/react-native/pull/25146. react-native/React/Base/RCTModuleMethod.mm line94: RCTReadString(input, "__attribute__((__unused__))") ||