[clang] [clang-tools-extra] [clang] Improve nested name specifier AST representation (PR #147835)

[Andrey Ali Khan Bolshakov via cfe-commits]

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@@ -2586,8 +2561,9 @@ bool CXXNameMangler::mangleUnresolvedTypeOrSimpleId(QualType Ty,
   }
 
   case Type::InjectedClassName:
-    mangleSourceNameWithAbiTags(
-        cast<InjectedClassNameType>(Ty)->getDecl());
+    mangleSourceNameWithAbiTags(cast<InjectedClassNameType>(Ty)
+                                    ->getOriginalDecl()
+                                    ->getDefinitionOrSelf());
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bolshakov-a wrote:

Is this `getDefinitionOrSelf()` call necessary here? Shouldn't `InjectedClassNameType` always refer to the definition where the class name is injected to?

https://github.com/llvm/llvm-project/pull/147835