Xcode 11.0 build get error - Unknown argument type '__attribute__' in method -[RCTAppState getCurrentAppState:error:]

The solution is to either Upgrade to RN 59.9 or higher OR to apply this patch manually:

  1. go to node_modules/react-native/React/Base/RCTModuleMethod.mm
  2. Add the line from the patch.

Solution for this issue: go to node_modules/react-native/React/Base/RCTModuleMethod.mm and update below code

static BOOL RCTParseUnused(const char **input)
{
  return RCTReadString(input, "__attribute__((unused))") ||
           RCTReadString(input, "__attribute__((__unused__))") ||
           RCTReadString(input, "__unused");
}