[clang] Propagate lifetimebound from formal parameters to those in the canonical declaration and use that for analysis (PR #107627)

[Ilya Biryukov via cfe-commits]

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@@ -499,6 +499,7 @@ static bool isNormalAssignmentOperator(const FunctionDecl *FD) {
 }
 
 bool implicitObjectParamIsLifetimeBound(const FunctionDecl *FD) {
+  FD = FD->getMostRecentDecl();
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ilya-biryukov wrote:

It would be great to explain the need for `getMostRecentDecl()`, either:
- (my preferred option) with a function with descriptive name that calls `getMostRecentDecl`, e.g. `getDeclWithLifetimeBound(...)`
- with a comment at each call site.

https://github.com/llvm/llvm-project/pull/107627