[llvm] [llvm] Errorize DebuginfodFetcher::fetch() for inspection at call-sites (NFC) (PR #191191)

[Stefan Gränitz via llvm-commits]

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@@ -108,5 +109,8 @@ std::optional<std::string> BuildIDFetcher::fetch(BuildIDRef BuildID) const {
         return std::string(Path);
     }
   }
-  return std::nullopt;
+  return createStringError(
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weliveindetail wrote:

I guess we would need a `raw_ostream &operator<<(raw_ostream &, const BuildIDRef &)` for that and we don't have one. Personally, I prefer the explicit notation.

https://github.com/llvm/llvm-project/pull/191191