I'm trying to bring some really old C++ code back online, using Xcode 12. Lots of errors and warnings. And...although each shows a filename (in red) and line number, when I double-click on the warning the corresponding code does not open. Compiler found the file but the IDE doesn't. (Thief.h, shown in black, is found OK.)
I imagine there's some path or setting in my ancient Xcode project file that is out of date, but I don't know where to look. How do you fix this?
