[clang] nonblocking/nonallocating attributes: 2nd pass caller/callee analysis (PR #99656)

[via cfe-commits]

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@@ -78,22 +78,19 @@ class ViolationSite {
 // be inferred as holding that effect.
 struct Violation {
   FunctionEffect Effect;
-  FunctionEffect
+  std::optional<FunctionEffect>
       CalleeEffectPreventingInference; // Only for certain IDs; can be None.
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Sirraide wrote:

```suggestion
      CalleeEffectPreventingInference; // Only for certain IDs; can be nullopt.
```
Comment still needs updating

https://github.com/llvm/llvm-project/pull/99656