[clang] [LifetimeSafety] Implement a basic use-after-free diagnostic (PR #149731)

[Gábor Horváth via cfe-commits]

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@@ -492,7 +522,8 @@ class FactGenerator : public ConstStmtVisitor<FactGenerator> {
       // Check if the loan is for a stack variable and if that variable
       // is the one being destructed.
       if (LoanPath.D == DestructedVD)
-        CurrentBlockFacts.push_back(FactMgr.createFact<ExpireFact>(L.ID));
+        CurrentBlockFacts.push_back(FactMgr.createFact<ExpireFact>(
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Xazax-hun wrote:

Random optimization idea to consider for the future: in many cases like end of statement for temporaries or end of scope for locals we have potentially many objects with ending lifetime at the same location. Maybe we do not actually need to create a separate `ExpireFact` for all of them, we could reuse the same fact? Not sure if that could cause any trouble. 

https://github.com/llvm/llvm-project/pull/149731