[clang] [dataflow] CXXOperatorCallExpr equal operator might not be a glvalue (PR #80991)

[via cfe-commits]

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@@ -535,7 +535,19 @@ class TransferVisitor : public ConstStmtVisitor<TransferVisitor> {
         return;
 
       copyRecord(*LocSrc, *LocDst, Env);
-      Env.setStorageLocation(*S, *LocDst);
+
+      // If the expr is a glvalue, we can reasonably assume the operator is
+      // returning T& and thus we can assign it `LocDst`.
+      if (S->isGLValue()) {
+        Env.setStorageLocation(*S, *LocDst);
+      } else if (S->getType()->isRecordType()) {
+        // If the expr is a prvalue, we cannot really assume anything regarding
+        // the new value being created. We should just propagate it to ensure a
+        // `RecordValue` exist for it.
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martinboehme wrote:

The "propagate" wording is misleading. Here's a suggestion based on the equivalent code in `VisitCallExpr()`:

```suggestion
        // Make sure that we have a `RecordValue` for this expression so that
        // `Environment::getResultObjectLocation()` is able to return a location
        // for it.
```

https://github.com/llvm/llvm-project/pull/80991