diff --git a/mlir/lib/TableGen/Interfaces.cpp b/mlir/lib/TableGen/Interfaces.cpp
--- a/mlir/lib/TableGen/Interfaces.cpp
+++ b/mlir/lib/TableGen/Interfaces.cpp
@@ -85,7 +85,7 @@
   auto *basesInit =
       dyn_cast<llvm::ListInit>(def->getValueInit("baseInterfaces"));
   // Chained inheritance will produce duplicates in the base interface set.
-  StringSet<llvm::MallocAllocator> basesAdded;
+  StringSet<> basesAdded;
   llvm::unique_function<void(Interface)> addBaseInterfaceFn =
       [&](const Interface &baseInterface) {
         // Inherit any base interfaces.