Index: clangd/global-symbol-builder/GlobalSymbolBuilderMain.cpp
===================================================================
--- clangd/global-symbol-builder/GlobalSymbolBuilderMain.cpp
+++ clangd/global-symbol-builder/GlobalSymbolBuilderMain.cpp
@@ -105,7 +105,17 @@
     llvm::errs() << llvm::toString(std::move(Err)) << "\n";
   }
 
+  // Deduplicate the result by key.
+  // FIXME(ioeric): we need a better way to merge symbols with the same key. For
+  // example, class forward-declarations can have the same key as the class
+  // definition, and we should merge them instead of ignoring one of them. We
+  // would also need to aggregate signals like usage count when they are added.
+  llvm::StringMap<llvm::StringRef> ReducedSymbols;
   Executor->get()->getToolResults()->forEachResult(
-      [](llvm::StringRef, llvm::StringRef Value) { llvm::outs() << Value; });
+      [&ReducedSymbols](llvm::StringRef Key, llvm::StringRef Value) {
+        ReducedSymbols[Key] = Value;
+      });
+  for (const auto &Sym : ReducedSymbols)
+    llvm::outs() << Sym.second;
   return 0;
 }