Apple Swift version 5.0.1 (swiftlang-1001.0.82.4 clang-1001.0.46.5)
Additional Detail from JIRA
When printing an error created from an Obj-C NS_ERROR_ENUM declaration, the imported error has a bizarre synthesized description that looks like "related decl 'e' for <desc>" (where <desc> is the actual expected description).
@mikeash, any opinions? (Or Lily, for that matter.) I wrote the original code here but only to fit imported errors into the existing demangling framework, not because I was finessing the output to some spec.
Yeah, I'm not thrilled at the _nsError: output but it's at least understandable and clearly a field of the type. The "related decl 'e' for" is just confusing, and if it were removed but everything else left as-is that would be fine (and would match how e.g. CocoaError is printed).
Though I'd also suggest that the __C_Synthesized. prefix on the debug description should go away as well.