[PATCH] D103949: Only consider built-in compound assignment operators for -Wunused-but-set-*

[Stephan Bergmann via Phabricator via cfe-commits]

sberg added inline comments.


================
Comment at: clang/lib/Sema/SemaExprCXX.cpp:7794-7798
+    if (BO->getLHS()->getType()->isDependentType() ||
+        BO->getRHS()->getType()->isDependentType())
+    {
+      if (BO->getOpcode() != BO_Assign)
+        return;
----------------
mbenfield wrote:
> Would you mind elaborating on the need for this code? IIUC, you're concerned about overloaded operators, but won't such operators always be covered by the `CXXOperatorCallExpr` case below? 
That's what I would initially have thought too (see my unanswered <https://lists.llvm.org/pipermail/llvm-dev/2021-June/150875.html> "[llvm-dev] BinaryOperator vs. CXXOperatorCallExpr in template code"; but which, I notice now, I accidentally sent to llvm-dev rather than cfe-dev).

But e.g. the template `f4` test code in `warn-unused-but-set-variables-cpp.cpp` turns the `+=` into a `BinaryOperator`.


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  https://reviews.llvm.org/D103949/new/

https://reviews.llvm.org/D103949