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

[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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cor3ntin wrote:

Yes, it should not have, as was pointed out in the original PR (and it's clearly bogus).
I edited the commit message to clarify.
Thanks!

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