Xcode 7.3: "Ambiguous expansion of macro" when re-defining macro in prefix file Xcode 7.3: "Ambiguous expansion of macro" when re-defining macro in prefix file xcode xcode

Xcode 7.3: "Ambiguous expansion of macro" when re-defining macro in prefix file


This is a bug in Xcode; we'd appreciate if you could file a bug report at https://bugreport.apple.com and leave the bug # in a comment here. Your options for working around this bug in the meantime are:

  • You could use a different name than "assert" for this macro.
  • You could set the GCC_PRECOMPILE_PREFIX_HEADER build setting to NO, since PCH don’t provide a lot of benefit when you already have modules. The prefix header will still work, it just won’t be turned into a PCH.
  • You could turn off modules.