Undefined symbol - but what symbol?

I just switched from another IDE to Xcode. I last used Xcode about six years ago, and things have changed.

When i build, I get told that there was a compile error, but no errors are shown. When I switch to the Report Navigator, I can see there the error is a missing symbol. But it doesn't tell me what that symbol is. It just says "Undefined symbols:"... and that's it. No info on the symbol involved.

How do I get actionable info from a build failure? Where is the complete compiler output?

Undefined symbol - but what symbol?
 
 
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