[clang] [Clang] enhance diagnostic by attaching source location to deduced type in trailing return without auto (PR #115786)

[Mariya Podchishchaeva via cfe-commits]

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@@ -652,6 +652,7 @@ Bug Fixes to C++ Support
   an implicitly instantiated class template specialization. (#GH51051)
 - Fixed an assertion failure caused by invalid enum forward declarations. (#GH112208)
 - Name independent data members were not correctly initialized from default member initializers. (#GH114069)
+- Clang now uses deduced type locations in trailing return without auto diagnostics. (#GH78694)
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Fznamznon wrote:

How about
```suggestion
- Clang now uses valid deduced type locations when diagnosing functions with trailing return type missing placeholder return type. (#GH78694)
```

https://github.com/llvm/llvm-project/pull/115786