[clang-tools-extra] [clangd] forward clang-tidy's readability-identifier-naming fix to textDocument/rename (PR #78454)

[Nathan Ridge via cfe-commits]

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@@ -648,6 +649,27 @@ tweakSelection(const Range &Sel, const InputsAndAST &AST,
   return std::move(Result);
 }
 
+// Some fixes may perform local renaming, we want to convert those to clangd
+// rename commands, such that we can leverage the index for more accurate
+// results.
+std::optional<ClangdServer::CodeActionResult::Rename>
+TryConvertToRename(const Diag *Diag, const ClangdServer::DiagRef &DR,
+                   const Fix &Fix) {
+  bool IsClangTidyRename = Diag->Source == Diag::ClangTidy &&
+                           Diag->Name == "readability-identifier-naming" &&
+                           !Fix.Edits.empty();
+  if (IsClangTidyRename) {
+    ClangdServer::CodeActionResult::Rename R;
+    R.NewName = Fix.Edits.front().newText;
+    R.Diag = DR;
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HighCommander4 wrote:

(for simplicity, consider omitting the `DR` parameter, and just construct a `DiagRef` here as `{Diag->Range, Diag->Message}`, which is how a `DiagRef` is constructed [elsewhere](https://searchfox.org/llvm/rev/33c6b77d2a18862fb5b16160ef9d600382e93f19/clang-tools-extra/clangd/ClangdLSPServer.cpp#1763))

https://github.com/llvm/llvm-project/pull/78454