[clang] [clang] Fix missing check for nullptr in CallExpr::getUnusedResultAttr (PR #118636)

[Yanzuo Liu via cfe-commits]

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@@ -1619,8 +1619,9 @@ std::pair<const NamedDecl *, const Attr *>
 CallExpr::getUnusedResultAttr(const ASTContext &Ctx) const {
   // If the callee is marked nodiscard, return that attribute
   const Decl *D = getCalleeDecl();
-  if (const auto *A = D->getAttr<WarnUnusedResultAttr>())
-    return {nullptr, A};
+  if (D != nullptr)
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zwuis wrote:

```suggestion
  if (const Decl *D = getCalleeDecl())
```


https://github.com/llvm/llvm-project/pull/118636