[clang] [Clang] Refactor instantiation of declarations within concepts (PR #221707)

[Yanzuo Liu via cfe-commits]

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@@ -530,7 +530,9 @@ class HashParameterMapping : public RecursiveASTVisitor<HashParameterMapping> {
     }
   }
 };
+} // namespace
 
+namespace clang {
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zwuis wrote:

Unrelated changes? Ditto for `SubstituteParameterMappings`.

https://github.com/llvm/llvm-project/pull/221707