[clang] [clang] Support 'this' position for lifetimebound attribute (PR #115021)

[Saleem Abdulrasool via cfe-commits]

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@@ -730,7 +731,9 @@ class YAMLConverter {
     }
   }
 
-  void convertParams(const ParamsSeq &Params, FunctionInfo &OutInfo) {
+  std::optional<ParamInfo> convertParams(const ParamsSeq &Params,
+                                         FunctionInfo &OutInfo) {
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compnerd wrote:

While currently we only apply a note to a single implicit parameter (`this` or `self`), what if we were to extend this in the future? Does it make sense to take a reference to a `std::optional<ParamInfo>` that we setup as the implicit instance parameter?

https://github.com/llvm/llvm-project/pull/115021