[clang] [Clang] Fix UB in #131515 (PR #132091)

[Florian Mayer via cfe-commits]

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@@ -1681,7 +1681,7 @@ std::optional<unsigned> Sema::GetDecompositionElementCount(QualType T,
   llvm::APSInt TupleSize(Ctx.getTypeSize(Ctx.getSizeType()));
   switch (isTupleLike(*this, Loc, T, TupleSize)) {
   case IsTupleLike::Error:
-    return {};
+    return std::nullopt;
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fmayer wrote:

doesn't the change on 1709 change the return value?

https://github.com/llvm/llvm-project/pull/132091