diff --git a/mlir/include/mlir/IR/MLIRContext.h b/mlir/include/mlir/IR/MLIRContext.h
--- a/mlir/include/mlir/IR/MLIRContext.h
+++ b/mlir/include/mlir/IR/MLIRContext.h
@@ -98,9 +98,6 @@
         }));
   }
 
-  /// Return true if the given dialect is currently loading.
-  bool isDialectLoading(StringRef dialectNamespace);
-
   /// Load a dialect in the context.
   template <typename Dialect>
   void loadDialect() {
@@ -239,6 +236,9 @@
   llvm::hash_code getRegistryHash();
 
 private:
+  /// Return true if the given dialect is currently loading.
+  bool isDialectLoading(StringRef dialectNamespace);
+
   const std::unique_ptr<MLIRContextImpl> impl;
 
   MLIRContext(const MLIRContext &) = delete;
diff --git a/mlir/lib/IR/MLIRContext.cpp b/mlir/lib/IR/MLIRContext.cpp
--- a/mlir/lib/IR/MLIRContext.cpp
+++ b/mlir/lib/IR/MLIRContext.cpp
@@ -430,10 +430,10 @@
           "the PassManager): this can indicate a "
           "missing `dependentDialects` in a pass for example.");
 #endif // NDEBUG
-    // nullptr indicates that the dialect is currently being loaded.
-    impl.loadedDialects[dialectNamespace] = nullptr;
-    std::unique_ptr<Dialect> &dialect = impl.loadedDialects[dialectNamespace] =
-        ctor();
+    // loadedDialects entry is initialized to nullptr, indicating that the
+    // dialect is currently being loaded.
+    std::unique_ptr<Dialect> &dialect = impl.loadedDialects[dialectNamespace];
+    dialect = ctor();
     assert(dialect && "dialect ctor failed");
 
     // Refresh all the identifiers dialect field, this catches cases where a