[clang] [analyzer] Implement binary operations on LazyCompoundVals (PR #106982)

[Donát Nagy via cfe-commits]

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@@ -538,7 +541,8 @@ ProgramStateRef CStringChecker::checkInit(CheckerContext &C,
     OS << ") in the ";
     printIdxWithOrdinalSuffix(OS, Buffer.ArgumentIndex + 1);
     OS << " argument is undefined";
-    emitUninitializedReadBug(C, State, Buffer.Expression, OS.str());
+    emitUninitializedReadBug(C, State, Buffer.Expression,
+                             FirstElementVal->getAsRegion(), OS.str());
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NagyDonat wrote:

```suggestion
                             LastElementVal->getAsRegion(), OS.str());
```

https://github.com/llvm/llvm-project/pull/106982