[clang-tools-extra] [clangd] fix extract-to-function for overloaded operators (PR #81640)

[Nathan Ridge via cfe-commits]

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@@ -104,9 +104,12 @@ bool isRootStmt(const Node *N) {
   // Root statement cannot be partially selected.
   if (N->Selected == SelectionTree::Partial)
     return false;
-  // Only DeclStmt can be an unselected RootStmt since VarDecls claim the entire
-  // selection range in selectionTree.
-  if (N->Selected == SelectionTree::Unselected && !N->ASTNode.get<DeclStmt>())
+  // A DeclStmt can be an unselected RootStmt since VarDecls claim the entire
+  // selection range in selectionTree. Additionally, a CXXOperatorCallExpr of a
+  // binary operation can be unselected because it's children claim the entire
+  // selection range in the selection tree (e.g. <<).
+  if (N->Selected == SelectionTree::Unselected && !N->ASTNode.get<DeclStmt>() &&
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HighCommander4 wrote:

Do we need to make a corresponding change [here](https://searchfox.org/llvm/rev/30213e99b86a078c9d472264c7edeea9aa638dd4/clang-tools-extra/clangd/refactor/tweaks/ExtractFunction.cpp#141-146)? The comment suggests that it's special-casing `DeclStmt` for the same reason as this code.

https://github.com/llvm/llvm-project/pull/81640