[clang] [LifetimeSafety] Track origins through std::function (PR #191123)

[Gábor Horváth via cfe-commits]

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@@ -130,7 +130,9 @@ class ExpireFact : public Fact {
 
 class OriginFlowFact : public Fact {
   OriginID OIDDest;
-  OriginID OIDSrc;
+  // The source origin to flow from. Absent when only clearing the destination's
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Xazax-hun wrote:

Hmm, we probably have a lot of flow facts and making the Src optional will increase the size of this type. I wonder if it would be more efficient to have a new OriginKillFact instead. @usx95 what do you think?

https://github.com/llvm/llvm-project/pull/191123