[clang] [LifetimeSafety] Detect use-after-return (PR #165370)

[Utkarsh Saxena via cfe-commits]

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@@ -43,7 +43,7 @@ struct LivenessInfo {
   /// multiple uses along different paths, this will point to the use appearing
   /// earlier in the translation unit.
   /// This is 'null' when the origin is not live.
-  const UseFact *CausingUseFact;
+  const Fact *CausingFact;
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usx95 wrote:

We can use `llvm::PointerUnion<UseFact*, OriginEscapeFact* >` to be explicit what can appear here.

https://github.com/llvm/llvm-project/pull/165370