diff --git a/mlir/examples/toy/Ch2/include/toy/MLIRGen.h b/mlir/examples/toy/Ch2/include/toy/MLIRGen.h
--- a/mlir/examples/toy/Ch2/include/toy/MLIRGen.h
+++ b/mlir/examples/toy/Ch2/include/toy/MLIRGen.h
@@ -18,7 +18,9 @@
 
 namespace mlir {
 class MLIRContext;
-class OwningModuleRef;
+template <typename OpTy>
+class OwningOpRef;
+class ModuleOp;
 } // namespace mlir
 
 namespace toy {
@@ -26,7 +28,8 @@
 
 /// Emit IR for the given Toy moduleAST, returns a newly created MLIR module
 /// or nullptr on failure.
-mlir::OwningModuleRef mlirGen(mlir::MLIRContext &context, ModuleAST &moduleAST);
+mlir::OwningOpRef<mlir::ModuleOp> mlirGen(mlir::MLIRContext &context,
+                                          ModuleAST &moduleAST);
 } // namespace toy
 
 #endif // TOY_MLIRGEN_H
diff --git a/mlir/examples/toy/Ch2/mlir/MLIRGen.cpp b/mlir/examples/toy/Ch2/mlir/MLIRGen.cpp
--- a/mlir/examples/toy/Ch2/mlir/MLIRGen.cpp
+++ b/mlir/examples/toy/Ch2/mlir/MLIRGen.cpp
@@ -443,8 +443,8 @@
 namespace toy {
 
 // The public API for codegen.
-mlir::OwningModuleRef mlirGen(mlir::MLIRContext &context,
-                              ModuleAST &moduleAST) {
+mlir::OwningOpRef<mlir::ModuleOp> mlirGen(mlir::MLIRContext &context,
+                                          ModuleAST &moduleAST) {
   return MLIRGenImpl(context).mlirGen(moduleAST);
 }
 
diff --git a/mlir/examples/toy/Ch2/toyc.cpp b/mlir/examples/toy/Ch2/toyc.cpp
--- a/mlir/examples/toy/Ch2/toyc.cpp
+++ b/mlir/examples/toy/Ch2/toyc.cpp
@@ -78,7 +78,7 @@
     auto moduleAST = parseInputFile(inputFilename);
     if (!moduleAST)
       return 6;
-    mlir::OwningModuleRef module = mlirGen(context, *moduleAST);
+    mlir::OwningOpRef<mlir::ModuleOp> module = mlirGen(context, *moduleAST);
     if (!module)
       return 1;
 
@@ -97,7 +97,8 @@
   // Parse the input mlir.
   llvm::SourceMgr sourceMgr;
   sourceMgr.AddNewSourceBuffer(std::move(*fileOrErr), llvm::SMLoc());
-  mlir::OwningModuleRef module = mlir::parseSourceFile(sourceMgr, &context);
+  mlir::OwningOpRef<mlir::ModuleOp> module =
+      mlir::parseSourceFile(sourceMgr, &context);
   if (!module) {
     llvm::errs() << "Error can't load file " << inputFilename << "\n";
     return 3;
diff --git a/mlir/examples/toy/Ch3/include/toy/MLIRGen.h b/mlir/examples/toy/Ch3/include/toy/MLIRGen.h
--- a/mlir/examples/toy/Ch3/include/toy/MLIRGen.h
+++ b/mlir/examples/toy/Ch3/include/toy/MLIRGen.h
@@ -18,7 +18,9 @@
 
 namespace mlir {
 class MLIRContext;
-class OwningModuleRef;
+template <typename OpTy>
+class OwningOpRef;
+class ModuleOp;
 } // namespace mlir
 
 namespace toy {
@@ -26,7 +28,8 @@
 
 /// Emit IR for the given Toy moduleAST, returns a newly created MLIR module
 /// or nullptr on failure.
-mlir::OwningModuleRef mlirGen(mlir::MLIRContext &context, ModuleAST &moduleAST);
+mlir::OwningOpRef<mlir::ModuleOp> mlirGen(mlir::MLIRContext &context,
+                                          ModuleAST &moduleAST);
 } // namespace toy
 
 #endif // TOY_MLIRGEN_H
diff --git a/mlir/examples/toy/Ch3/mlir/MLIRGen.cpp b/mlir/examples/toy/Ch3/mlir/MLIRGen.cpp
--- a/mlir/examples/toy/Ch3/mlir/MLIRGen.cpp
+++ b/mlir/examples/toy/Ch3/mlir/MLIRGen.cpp
@@ -443,8 +443,8 @@
 namespace toy {
 
 // The public API for codegen.
-mlir::OwningModuleRef mlirGen(mlir::MLIRContext &context,
-                              ModuleAST &moduleAST) {
+mlir::OwningOpRef<mlir::ModuleOp> mlirGen(mlir::MLIRContext &context,
+                                          ModuleAST &moduleAST) {
   return MLIRGenImpl(context).mlirGen(moduleAST);
 }
 
diff --git a/mlir/examples/toy/Ch3/toyc.cpp b/mlir/examples/toy/Ch3/toyc.cpp
--- a/mlir/examples/toy/Ch3/toyc.cpp
+++ b/mlir/examples/toy/Ch3/toyc.cpp
@@ -72,7 +72,7 @@
 }
 
 int loadMLIR(llvm::SourceMgr &sourceMgr, mlir::MLIRContext &context,
-             mlir::OwningModuleRef &module) {
+             mlir::OwningOpRef<mlir::ModuleOp> &module) {
   // Handle '.toy' input to the compiler.
   if (inputType != InputType::MLIR &&
       !llvm::StringRef(inputFilename).endswith(".mlir")) {
@@ -106,7 +106,7 @@
   // Load our Dialect in this MLIR Context.
   context.getOrLoadDialect<mlir::toy::ToyDialect>();
 
-  mlir::OwningModuleRef module;
+  mlir::OwningOpRef<mlir::ModuleOp> module;
   llvm::SourceMgr sourceMgr;
   mlir::SourceMgrDiagnosticHandler sourceMgrHandler(sourceMgr, &context);
   if (int error = loadMLIR(sourceMgr, context, module))
diff --git a/mlir/examples/toy/Ch4/include/toy/MLIRGen.h b/mlir/examples/toy/Ch4/include/toy/MLIRGen.h
--- a/mlir/examples/toy/Ch4/include/toy/MLIRGen.h
+++ b/mlir/examples/toy/Ch4/include/toy/MLIRGen.h
@@ -18,7 +18,9 @@
 
 namespace mlir {
 class MLIRContext;
-class OwningModuleRef;
+template <typename OpTy>
+class OwningOpRef;
+class ModuleOp;
 } // namespace mlir
 
 namespace toy {
@@ -26,7 +28,8 @@
 
 /// Emit IR for the given Toy moduleAST, returns a newly created MLIR module
 /// or nullptr on failure.
-mlir::OwningModuleRef mlirGen(mlir::MLIRContext &context, ModuleAST &moduleAST);
+mlir::OwningOpRef<mlir::ModuleOp> mlirGen(mlir::MLIRContext &context,
+                                          ModuleAST &moduleAST);
 } // namespace toy
 
 #endif // TOY_MLIRGEN_H
diff --git a/mlir/examples/toy/Ch4/mlir/MLIRGen.cpp b/mlir/examples/toy/Ch4/mlir/MLIRGen.cpp
--- a/mlir/examples/toy/Ch4/mlir/MLIRGen.cpp
+++ b/mlir/examples/toy/Ch4/mlir/MLIRGen.cpp
@@ -447,8 +447,8 @@
 namespace toy {
 
 // The public API for codegen.
-mlir::OwningModuleRef mlirGen(mlir::MLIRContext &context,
-                              ModuleAST &moduleAST) {
+mlir::OwningOpRef<mlir::ModuleOp> mlirGen(mlir::MLIRContext &context,
+                                          ModuleAST &moduleAST) {
   return MLIRGenImpl(context).mlirGen(moduleAST);
 }
 
diff --git a/mlir/examples/toy/Ch4/toyc.cpp b/mlir/examples/toy/Ch4/toyc.cpp
--- a/mlir/examples/toy/Ch4/toyc.cpp
+++ b/mlir/examples/toy/Ch4/toyc.cpp
@@ -73,7 +73,7 @@
 }
 
 int loadMLIR(llvm::SourceMgr &sourceMgr, mlir::MLIRContext &context,
-             mlir::OwningModuleRef &module) {
+             mlir::OwningOpRef<mlir::ModuleOp> &module) {
   // Handle '.toy' input to the compiler.
   if (inputType != InputType::MLIR &&
       !llvm::StringRef(inputFilename).endswith(".mlir")) {
@@ -107,7 +107,7 @@
   // Load our Dialect in this MLIR Context.
   context.getOrLoadDialect<mlir::toy::ToyDialect>();
 
-  mlir::OwningModuleRef module;
+  mlir::OwningOpRef<mlir::ModuleOp> module;
   llvm::SourceMgr sourceMgr;
   mlir::SourceMgrDiagnosticHandler sourceMgrHandler(sourceMgr, &context);
   if (int error = loadMLIR(sourceMgr, context, module))
diff --git a/mlir/examples/toy/Ch5/include/toy/MLIRGen.h b/mlir/examples/toy/Ch5/include/toy/MLIRGen.h
--- a/mlir/examples/toy/Ch5/include/toy/MLIRGen.h
+++ b/mlir/examples/toy/Ch5/include/toy/MLIRGen.h
@@ -18,7 +18,9 @@
 
 namespace mlir {
 class MLIRContext;
-class OwningModuleRef;
+template <typename OpTy>
+class OwningOpRef;
+class ModuleOp;
 } // namespace mlir
 
 namespace toy {
@@ -26,7 +28,8 @@
 
 /// Emit IR for the given Toy moduleAST, returns a newly created MLIR module
 /// or nullptr on failure.
-mlir::OwningModuleRef mlirGen(mlir::MLIRContext &context, ModuleAST &moduleAST);
+mlir::OwningOpRef<mlir::ModuleOp> mlirGen(mlir::MLIRContext &context,
+                                          ModuleAST &moduleAST);
 } // namespace toy
 
 #endif // TOY_MLIRGEN_H
diff --git a/mlir/examples/toy/Ch5/mlir/MLIRGen.cpp b/mlir/examples/toy/Ch5/mlir/MLIRGen.cpp
--- a/mlir/examples/toy/Ch5/mlir/MLIRGen.cpp
+++ b/mlir/examples/toy/Ch5/mlir/MLIRGen.cpp
@@ -447,8 +447,8 @@
 namespace toy {
 
 // The public API for codegen.
-mlir::OwningModuleRef mlirGen(mlir::MLIRContext &context,
-                              ModuleAST &moduleAST) {
+mlir::OwningOpRef<mlir::ModuleOp> mlirGen(mlir::MLIRContext &context,
+                                          ModuleAST &moduleAST) {
   return MLIRGenImpl(context).mlirGen(moduleAST);
 }
 
diff --git a/mlir/examples/toy/Ch5/toyc.cpp b/mlir/examples/toy/Ch5/toyc.cpp
--- a/mlir/examples/toy/Ch5/toyc.cpp
+++ b/mlir/examples/toy/Ch5/toyc.cpp
@@ -77,7 +77,7 @@
 }
 
 int loadMLIR(llvm::SourceMgr &sourceMgr, mlir::MLIRContext &context,
-             mlir::OwningModuleRef &module) {
+             mlir::OwningOpRef<mlir::ModuleOp> &module) {
   // Handle '.toy' input to the compiler.
   if (inputType != InputType::MLIR &&
       !llvm::StringRef(inputFilename).endswith(".mlir")) {
@@ -111,7 +111,7 @@
   // Load our Dialect in this MLIR Context.
   context.getOrLoadDialect<mlir::toy::ToyDialect>();
 
-  mlir::OwningModuleRef module;
+  mlir::OwningOpRef<mlir::ModuleOp> module;
   llvm::SourceMgr sourceMgr;
   mlir::SourceMgrDiagnosticHandler sourceMgrHandler(sourceMgr, &context);
   if (int error = loadMLIR(sourceMgr, context, module))
diff --git a/mlir/examples/toy/Ch6/include/toy/MLIRGen.h b/mlir/examples/toy/Ch6/include/toy/MLIRGen.h
--- a/mlir/examples/toy/Ch6/include/toy/MLIRGen.h
+++ b/mlir/examples/toy/Ch6/include/toy/MLIRGen.h
@@ -18,7 +18,9 @@
 
 namespace mlir {
 class MLIRContext;
-class OwningModuleRef;
+template <typename OpTy>
+class OwningOpRef;
+class ModuleOp;
 } // namespace mlir
 
 namespace toy {
@@ -26,7 +28,8 @@
 
 /// Emit IR for the given Toy moduleAST, returns a newly created MLIR module
 /// or nullptr on failure.
-mlir::OwningModuleRef mlirGen(mlir::MLIRContext &context, ModuleAST &moduleAST);
+mlir::OwningOpRef<mlir::ModuleOp> mlirGen(mlir::MLIRContext &context,
+                                          ModuleAST &moduleAST);
 } // namespace toy
 
 #endif // TOY_MLIRGEN_H
diff --git a/mlir/examples/toy/Ch6/mlir/MLIRGen.cpp b/mlir/examples/toy/Ch6/mlir/MLIRGen.cpp
--- a/mlir/examples/toy/Ch6/mlir/MLIRGen.cpp
+++ b/mlir/examples/toy/Ch6/mlir/MLIRGen.cpp
@@ -447,8 +447,8 @@
 namespace toy {
 
 // The public API for codegen.
-mlir::OwningModuleRef mlirGen(mlir::MLIRContext &context,
-                              ModuleAST &moduleAST) {
+mlir::OwningOpRef<mlir::ModuleOp> mlirGen(mlir::MLIRContext &context,
+                                          ModuleAST &moduleAST) {
   return MLIRGenImpl(context).mlirGen(moduleAST);
 }
 
diff --git a/mlir/examples/toy/Ch6/toyc.cpp b/mlir/examples/toy/Ch6/toyc.cpp
--- a/mlir/examples/toy/Ch6/toyc.cpp
+++ b/mlir/examples/toy/Ch6/toyc.cpp
@@ -96,7 +96,8 @@
   return parser.parseModule();
 }
 
-int loadMLIR(mlir::MLIRContext &context, mlir::OwningModuleRef &module) {
+int loadMLIR(mlir::MLIRContext &context,
+             mlir::OwningOpRef<mlir::ModuleOp> &module) {
   // Handle '.toy' input to the compiler.
   if (inputType != InputType::MLIR &&
       !llvm::StringRef(inputFilename).endswith(".mlir")) {
@@ -127,7 +128,7 @@
 }
 
 int loadAndProcessMLIR(mlir::MLIRContext &context,
-                       mlir::OwningModuleRef &module) {
+                       mlir::OwningOpRef<mlir::ModuleOp> &module) {
   if (int error = loadMLIR(context, module))
     return error;
 
@@ -267,7 +268,7 @@
   // Load our Dialect in this MLIR Context.
   context.getOrLoadDialect<mlir::toy::ToyDialect>();
 
-  mlir::OwningModuleRef module;
+  mlir::OwningOpRef<mlir::ModuleOp> module;
   if (int error = loadAndProcessMLIR(context, module))
     return error;
 
diff --git a/mlir/examples/toy/Ch7/include/toy/MLIRGen.h b/mlir/examples/toy/Ch7/include/toy/MLIRGen.h
--- a/mlir/examples/toy/Ch7/include/toy/MLIRGen.h
+++ b/mlir/examples/toy/Ch7/include/toy/MLIRGen.h
@@ -18,7 +18,9 @@
 
 namespace mlir {
 class MLIRContext;
-class OwningModuleRef;
+template <typename OpTy>
+class OwningOpRef;
+class ModuleOp;
 } // namespace mlir
 
 namespace toy {
@@ -26,7 +28,8 @@
 
 /// Emit IR for the given Toy moduleAST, returns a newly created MLIR module
 /// or nullptr on failure.
-mlir::OwningModuleRef mlirGen(mlir::MLIRContext &context, ModuleAST &moduleAST);
+mlir::OwningOpRef<mlir::ModuleOp> mlirGen(mlir::MLIRContext &context,
+                                          ModuleAST &moduleAST);
 } // namespace toy
 
 #endif // TOY_MLIRGEN_H
diff --git a/mlir/examples/toy/Ch7/mlir/MLIRGen.cpp b/mlir/examples/toy/Ch7/mlir/MLIRGen.cpp
--- a/mlir/examples/toy/Ch7/mlir/MLIRGen.cpp
+++ b/mlir/examples/toy/Ch7/mlir/MLIRGen.cpp
@@ -669,8 +669,8 @@
 namespace toy {
 
 // The public API for codegen.
-mlir::OwningModuleRef mlirGen(mlir::MLIRContext &context,
-                              ModuleAST &moduleAST) {
+mlir::OwningOpRef<mlir::ModuleOp> mlirGen(mlir::MLIRContext &context,
+                                          ModuleAST &moduleAST) {
   return MLIRGenImpl(context).mlirGen(moduleAST);
 }
 
diff --git a/mlir/examples/toy/Ch7/toyc.cpp b/mlir/examples/toy/Ch7/toyc.cpp
--- a/mlir/examples/toy/Ch7/toyc.cpp
+++ b/mlir/examples/toy/Ch7/toyc.cpp
@@ -96,7 +96,8 @@
   return parser.parseModule();
 }
 
-int loadMLIR(mlir::MLIRContext &context, mlir::OwningModuleRef &module) {
+int loadMLIR(mlir::MLIRContext &context,
+             mlir::OwningOpRef<mlir::ModuleOp> &module) {
   // Handle '.toy' input to the compiler.
   if (inputType != InputType::MLIR &&
       !llvm::StringRef(inputFilename).endswith(".mlir")) {
@@ -127,7 +128,7 @@
 }
 
 int loadAndProcessMLIR(mlir::MLIRContext &context,
-                       mlir::OwningModuleRef &module) {
+                       mlir::OwningOpRef<mlir::ModuleOp> &module) {
   if (int error = loadMLIR(context, module))
     return error;
 
@@ -268,7 +269,7 @@
   // Load our Dialect in this MLIR Context.
   context.getOrLoadDialect<mlir::toy::ToyDialect>();
 
-  mlir::OwningModuleRef module;
+  mlir::OwningOpRef<mlir::ModuleOp> module;
   if (int error = loadAndProcessMLIR(context, module))
     return error;
 
diff --git a/mlir/include/mlir/IR/BuiltinOps.h b/mlir/include/mlir/IR/BuiltinOps.h
--- a/mlir/include/mlir/IR/BuiltinOps.h
+++ b/mlir/include/mlir/IR/BuiltinOps.h
@@ -31,23 +31,6 @@
 #define GET_OP_CLASSES
 #include "mlir/IR/BuiltinOps.h.inc"
 
-//===----------------------------------------------------------------------===//
-// Dialect Utilities
-//===----------------------------------------------------------------------===//
-
-namespace mlir {
-/// This class acts as an owning reference to a module, and will automatically
-/// destroy the held module on destruction if the held module is valid.
-// TODO: Remove this class in favor of using OwningOpRef directly.
-class OwningModuleRef : public OwningOpRef<ModuleOp> {
-public:
-  using OwningOpRef<ModuleOp>::OwningOpRef;
-  OwningModuleRef() = default;
-  OwningModuleRef(OwningOpRef<ModuleOp> &&other)
-      : OwningOpRef<ModuleOp>(std::move(other)) {}
-};
-} // namespace mlir
-
 namespace llvm {
 /// Allow stealing the low bits of FuncOp.
 template <>
diff --git a/mlir/include/mlir/IR/PatternMatch.h b/mlir/include/mlir/IR/PatternMatch.h
--- a/mlir/include/mlir/IR/PatternMatch.h
+++ b/mlir/include/mlir/IR/PatternMatch.h
@@ -612,7 +612,7 @@
   PDLPatternModule() = default;
 
   /// Construct a PDL pattern with the given module.
-  PDLPatternModule(OwningModuleRef pdlModule)
+  PDLPatternModule(OwningOpRef<ModuleOp> pdlModule)
       : pdlModule(std::move(pdlModule)) {}
 
   /// Merge the state in `other` into this pattern module.
@@ -669,7 +669,7 @@
 
 private:
   /// The module containing the `pdl.pattern` operations.
-  OwningModuleRef pdlModule;
+  OwningOpRef<ModuleOp> pdlModule;
 
   /// The external functions referenced from within the PDL module.
   llvm::StringMap<PDLConstraintFunction> constraintFunctions;
diff --git a/mlir/include/mlir/Parser.h b/mlir/include/mlir/Parser.h
--- a/mlir/include/mlir/Parser.h
+++ b/mlir/include/mlir/Parser.h
@@ -206,21 +206,21 @@
 
 /// TODO: These methods are deprecated in favor of the above template versions.
 /// They should be removed when usages have been updated.
-inline OwningModuleRef parseSourceFile(const llvm::SourceMgr &sourceMgr,
-                                       MLIRContext *context) {
+inline OwningOpRef<ModuleOp> parseSourceFile(const llvm::SourceMgr &sourceMgr,
+                                             MLIRContext *context) {
   return parseSourceFile<ModuleOp>(sourceMgr, context);
 }
-inline OwningModuleRef parseSourceFile(llvm::StringRef filename,
-                                       MLIRContext *context) {
+inline OwningOpRef<ModuleOp> parseSourceFile(llvm::StringRef filename,
+                                             MLIRContext *context) {
   return parseSourceFile<ModuleOp>(filename, context);
 }
-inline OwningModuleRef parseSourceFile(llvm::StringRef filename,
-                                       llvm::SourceMgr &sourceMgr,
-                                       MLIRContext *context) {
+inline OwningOpRef<ModuleOp> parseSourceFile(llvm::StringRef filename,
+                                             llvm::SourceMgr &sourceMgr,
+                                             MLIRContext *context) {
   return parseSourceFile<ModuleOp>(filename, sourceMgr, context);
 }
-inline OwningModuleRef parseSourceString(llvm::StringRef moduleStr,
-                                         MLIRContext *context) {
+inline OwningOpRef<ModuleOp> parseSourceString(llvm::StringRef moduleStr,
+                                               MLIRContext *context) {
   return parseSourceString<ModuleOp>(moduleStr, context);
 }
 
diff --git a/mlir/include/mlir/Target/LLVMIR/Import.h b/mlir/include/mlir/Target/LLVMIR/Import.h
--- a/mlir/include/mlir/Target/LLVMIR/Import.h
+++ b/mlir/include/mlir/Target/LLVMIR/Import.h
@@ -25,14 +25,14 @@
 namespace mlir {
 
 class DialectRegistry;
-class OwningModuleRef;
+
 class MLIRContext;
 
 /// Convert the given LLVM module into MLIR's LLVM dialect.  The LLVM context is
 /// extracted from the registered LLVM IR dialect. In case of error, report it
 /// to the error handler registered with the MLIR context, if any (obtained from
 /// the MLIR module), and return `{}`.
-OwningModuleRef
+OwningOpRef<ModuleOp>
 translateLLVMIRToModule(std::unique_ptr<llvm::Module> llvmModule,
                         MLIRContext *context);
 
diff --git a/mlir/include/mlir/Translation.h b/mlir/include/mlir/Translation.h
--- a/mlir/include/mlir/Translation.h
+++ b/mlir/include/mlir/Translation.h
@@ -25,21 +25,22 @@
 struct LogicalResult;
 class MLIRContext;
 class ModuleOp;
-class OwningModuleRef;
+template <typename OpTy>
+class OwningOpRef;
 
 /// Interface of the function that translates the sources managed by `sourceMgr`
 /// to MLIR. The source manager has at least one buffer. The implementation
 /// should create a new MLIR ModuleOp in the given context and return a pointer
 /// to it, or a nullptr in case of any error.
-using TranslateSourceMgrToMLIRFunction =
-    std::function<OwningModuleRef(llvm::SourceMgr &sourceMgr, MLIRContext *)>;
+using TranslateSourceMgrToMLIRFunction = std::function<OwningOpRef<ModuleOp>(
+    llvm::SourceMgr &sourceMgr, MLIRContext *)>;
 
 /// Interface of the function that translates the given string to MLIR. The
 /// implementation should create a new MLIR ModuleOp in the given context. If
 /// source-related error reporting is required from within the function, use
 /// TranslateSourceMgrToMLIRFunction instead.
 using TranslateStringRefToMLIRFunction =
-    std::function<OwningModuleRef(llvm::StringRef, MLIRContext *)>;
+    std::function<OwningOpRef<ModuleOp>(llvm::StringRef, MLIRContext *)>;
 
 /// Interface of the function that translates MLIR to a different format and
 /// outputs the result to a stream. It is allowed to modify the module.
diff --git a/mlir/lib/CAPI/IR/IR.cpp b/mlir/lib/CAPI/IR/IR.cpp
--- a/mlir/lib/CAPI/IR/IR.cpp
+++ b/mlir/lib/CAPI/IR/IR.cpp
@@ -177,7 +177,8 @@
 }
 
 MlirModule mlirModuleCreateParse(MlirContext context, MlirStringRef module) {
-  OwningModuleRef owning = parseSourceString(unwrap(module), unwrap(context));
+  OwningOpRef<ModuleOp> owning =
+      parseSourceString(unwrap(module), unwrap(context));
   if (!owning)
     return MlirModule{nullptr};
   return MlirModule{owning.release().getOperation()};
@@ -192,8 +193,9 @@
 }
 
 void mlirModuleDestroy(MlirModule module) {
-  // Transfer ownership to an OwningModuleRef so that its destructor is called.
-  OwningModuleRef(unwrap(module));
+  // Transfer ownership to an OwningOpRef<ModuleOp> so that its destructor is
+  // called.
+  OwningOpRef<ModuleOp>(unwrap(module));
 }
 
 MlirOperation mlirModuleGetOperation(MlirModule module) {
diff --git a/mlir/lib/ExecutionEngine/JitRunner.cpp b/mlir/lib/ExecutionEngine/JitRunner.cpp
--- a/mlir/lib/ExecutionEngine/JitRunner.cpp
+++ b/mlir/lib/ExecutionEngine/JitRunner.cpp
@@ -110,8 +110,8 @@
 
 } // namespace
 
-static OwningModuleRef parseMLIRInput(StringRef inputFilename,
-                                      MLIRContext *context) {
+static OwningOpRef<ModuleOp> parseMLIRInput(StringRef inputFilename,
+                                            MLIRContext *context) {
   // Set up the input file.
   std::string errorMessage;
   auto file = openInputFile(inputFilename, &errorMessage);
@@ -122,7 +122,7 @@
 
   llvm::SourceMgr sourceMgr;
   sourceMgr.AddNewSourceBuffer(std::move(file), SMLoc());
-  return OwningModuleRef(parseSourceFile(sourceMgr, context));
+  return OwningOpRef<ModuleOp>(parseSourceFile(sourceMgr, context));
 }
 
 static inline Error makeStringError(const Twine &message) {
diff --git a/mlir/lib/Support/MlirOptMain.cpp b/mlir/lib/Support/MlirOptMain.cpp
--- a/mlir/lib/Support/MlirOptMain.cpp
+++ b/mlir/lib/Support/MlirOptMain.cpp
@@ -59,7 +59,7 @@
 
   // Parse the input file and reset the context threading state.
   TimingScope parserTiming = timing.nest("Parser");
-  OwningModuleRef module(parseSourceFile(sourceMgr, context));
+  OwningOpRef<ModuleOp> module(parseSourceFile(sourceMgr, context));
   context->enableMultithreading(wasThreadingEnabled);
   if (!module)
     return failure();
diff --git a/mlir/lib/Target/LLVMIR/ConvertFromLLVMIR.cpp b/mlir/lib/Target/LLVMIR/ConvertFromLLVMIR.cpp
--- a/mlir/lib/Target/LLVMIR/ConvertFromLLVMIR.cpp
+++ b/mlir/lib/Target/LLVMIR/ConvertFromLLVMIR.cpp
@@ -854,11 +854,11 @@
   return success();
 }
 
-OwningModuleRef
+OwningOpRef<ModuleOp>
 mlir::translateLLVMIRToModule(std::unique_ptr<llvm::Module> llvmModule,
                               MLIRContext *context) {
   context->loadDialect<LLVMDialect>();
-  OwningModuleRef module(ModuleOp::create(
+  OwningOpRef<ModuleOp> module(ModuleOp::create(
       FileLineColLoc::get(context, "", /*line=*/0, /*column=*/0)));
 
   Importer deserializer(context, module.get());
@@ -876,8 +876,8 @@
 
 // Deserializes the LLVM bitcode stored in `input` into an MLIR module in the
 // LLVM dialect.
-OwningModuleRef translateLLVMIRToModule(llvm::SourceMgr &sourceMgr,
-                                        MLIRContext *context) {
+OwningOpRef<ModuleOp> translateLLVMIRToModule(llvm::SourceMgr &sourceMgr,
+                                              MLIRContext *context) {
   llvm::SMDiagnostic err;
   llvm::LLVMContext llvmContext;
   std::unique_ptr<llvm::Module> llvmModule = llvm::parseIR(
diff --git a/mlir/lib/Target/SPIRV/TranslateRegistration.cpp b/mlir/lib/Target/SPIRV/TranslateRegistration.cpp
--- a/mlir/lib/Target/SPIRV/TranslateRegistration.cpp
+++ b/mlir/lib/Target/SPIRV/TranslateRegistration.cpp
@@ -35,8 +35,8 @@
 
 // Deserializes the SPIR-V binary module stored in the file named as
 // `inputFilename` and returns a module containing the SPIR-V module.
-static OwningModuleRef deserializeModule(const llvm::MemoryBuffer *input,
-                                         MLIRContext *context) {
+static OwningOpRef<ModuleOp> deserializeModule(const llvm::MemoryBuffer *input,
+                                               MLIRContext *context) {
   context->loadDialect<spirv::SPIRVDialect>();
 
   // Make sure the input stream can be treated as a stream of SPIR-V words
@@ -56,7 +56,7 @@
   if (!spirvModule)
     return {};
 
-  OwningModuleRef module(ModuleOp::create(FileLineColLoc::get(
+  OwningOpRef<ModuleOp> module(ModuleOp::create(FileLineColLoc::get(
       context, input->getBufferIdentifier(), /*line=*/0, /*column=*/0)));
   module->getBody()->push_front(spirvModule.release());
 
@@ -147,7 +147,7 @@
     return failure();
 
   // Wrap around in a new MLIR module.
-  OwningModuleRef dstModule(ModuleOp::create(
+  OwningOpRef<ModuleOp> dstModule(ModuleOp::create(
       FileLineColLoc::get(&deserializationContext,
                           /*filename=*/"", /*line=*/0, /*column=*/0)));
   dstModule->getBody()->push_front(spirvModule.release());
diff --git a/mlir/lib/Translation/Translation.cpp b/mlir/lib/Translation/Translation.cpp
--- a/mlir/lib/Translation/Translation.cpp
+++ b/mlir/lib/Translation/Translation.cpp
@@ -62,7 +62,7 @@
     StringRef name, const TranslateSourceMgrToMLIRFunction &function) {
   auto wrappedFn = [function](llvm::SourceMgr &sourceMgr, raw_ostream &output,
                               MLIRContext *context) {
-    OwningModuleRef module = function(sourceMgr, context);
+    OwningOpRef<ModuleOp> module = function(sourceMgr, context);
     if (!module || failed(verify(*module)))
       return failure();
     module->print(output);
@@ -101,7 +101,7 @@
     DialectRegistry registry;
     dialectRegistration(registry);
     context->appendDialectRegistry(registry);
-    auto module = OwningModuleRef(parseSourceFile(sourceMgr, context));
+    auto module = OwningOpRef<ModuleOp>(parseSourceFile(sourceMgr, context));
     if (!module || failed(verify(*module)))
       return failure();
     return function(module.get(), output);
diff --git a/mlir/unittests/ExecutionEngine/Invoke.cpp b/mlir/unittests/ExecutionEngine/Invoke.cpp
--- a/mlir/unittests/ExecutionEngine/Invoke.cpp
+++ b/mlir/unittests/ExecutionEngine/Invoke.cpp
@@ -63,7 +63,7 @@
   registerAllDialects(registry);
   registerLLVMDialectTranslation(registry);
   MLIRContext context(registry);
-  OwningModuleRef module = parseSourceString(moduleStr, &context);
+  OwningOpRef<ModuleOp> module = parseSourceString(moduleStr, &context);
   ASSERT_TRUE(!!module);
   ASSERT_TRUE(succeeded(lowerToLLVMDialect(*module)));
   auto jitOrError = ExecutionEngine::create(*module);
@@ -88,7 +88,7 @@
   registerAllDialects(registry);
   registerLLVMDialectTranslation(registry);
   MLIRContext context(registry);
-  OwningModuleRef module = parseSourceString(moduleStr, &context);
+  OwningOpRef<ModuleOp> module = parseSourceString(moduleStr, &context);
   ASSERT_TRUE(!!module);
   ASSERT_TRUE(succeeded(lowerToLLVMDialect(*module)));
   auto jitOrError = ExecutionEngine::create(*module);
@@ -207,7 +207,7 @@
   registerAllDialects(registry);
   registerLLVMDialectTranslation(registry);
   MLIRContext context(registry);
-  OwningModuleRef module = parseSourceString(moduleStr, &context);
+  OwningOpRef<ModuleOp> module = parseSourceString(moduleStr, &context);
   ASSERT_TRUE(!!module);
   ASSERT_TRUE(succeeded(lowerToLLVMDialect(*module)));
   auto jitOrError = ExecutionEngine::create(*module);
diff --git a/mlir/unittests/Interfaces/ControlFlowInterfacesTest.cpp b/mlir/unittests/Interfaces/ControlFlowInterfacesTest.cpp
--- a/mlir/unittests/Interfaces/ControlFlowInterfacesTest.cpp
+++ b/mlir/unittests/Interfaces/ControlFlowInterfacesTest.cpp
@@ -83,7 +83,7 @@
   registry.insert<CFTestDialect>();
   MLIRContext ctx(registry);
 
-  OwningModuleRef module = parseSourceString(ir, &ctx);
+  OwningOpRef<ModuleOp> module = parseSourceString(ir, &ctx);
   Operation *testOp = &module->getBody()->getOperations().front();
   Operation *op1 = &testOp->getRegion(0).front().front();
   Operation *op2 = &testOp->getRegion(1).front().front();
@@ -104,7 +104,7 @@
   registry.insert<CFTestDialect>();
   MLIRContext ctx(registry);
 
-  OwningModuleRef module = parseSourceString(ir, &ctx);
+  OwningOpRef<ModuleOp> module = parseSourceString(ir, &ctx);
   Operation *testOp = &module->getBody()->getOperations().front();
   Operation *op1 = &testOp->getRegion(0).front().front();
   Operation *op2 = &testOp->getRegion(1).front().front();
@@ -131,7 +131,7 @@
   registry.insert<CFTestDialect>();
   MLIRContext ctx(registry);
 
-  OwningModuleRef module = parseSourceString(ir, &ctx);
+  OwningOpRef<ModuleOp> module = parseSourceString(ir, &ctx);
   Operation *testOp = &module->getBody()->getOperations().front();
   Operation *op1 =
       &testOp->getRegion(0).front().front().getRegion(0).front().front();
diff --git a/mlir/unittests/Interfaces/DataLayoutInterfacesTest.cpp b/mlir/unittests/Interfaces/DataLayoutInterfacesTest.cpp
--- a/mlir/unittests/Interfaces/DataLayoutInterfacesTest.cpp
+++ b/mlir/unittests/Interfaces/DataLayoutInterfacesTest.cpp
@@ -236,7 +236,7 @@
   registry.insert<DLTIDialect, DLTestDialect>();
   MLIRContext ctx(registry);
 
-  OwningModuleRef module = parseSourceString(ir, &ctx);
+  OwningOpRef<ModuleOp> module = parseSourceString(ir, &ctx);
   DataLayout layout(module.get());
   EXPECT_EQ(layout.getTypeSize(IntegerType::get(&ctx, 42)), 6u);
   EXPECT_EQ(layout.getTypeSize(Float16Type::get(&ctx)), 2u);
@@ -257,7 +257,7 @@
   registry.insert<DLTIDialect, DLTestDialect>();
   MLIRContext ctx(registry);
 
-  OwningModuleRef module = parseSourceString(ir, &ctx);
+  OwningOpRef<ModuleOp> module = parseSourceString(ir, &ctx);
   auto op =
       cast<DataLayoutOpInterface>(module->getBody()->getOperations().front());
   DataLayout layout(op);
@@ -280,7 +280,7 @@
   registry.insert<DLTIDialect, DLTestDialect>();
   MLIRContext ctx(registry);
 
-  OwningModuleRef module = parseSourceString(ir, &ctx);
+  OwningOpRef<ModuleOp> module = parseSourceString(ir, &ctx);
   auto op =
       cast<DataLayoutOpInterface>(module->getBody()->getOperations().front());
   DataLayout layout(op);
@@ -306,7 +306,7 @@
   registry.insert<DLTIDialect, DLTestDialect>();
   MLIRContext ctx(registry);
 
-  OwningModuleRef module = parseSourceString(ir, &ctx);
+  OwningOpRef<ModuleOp> module = parseSourceString(ir, &ctx);
   auto op =
       cast<DataLayoutOpInterface>(module->getBody()->getOperations().front());
   DataLayout layout(op);
@@ -338,7 +338,7 @@
   registry.insert<DLTIDialect, DLTestDialect>();
   MLIRContext ctx(registry);
 
-  OwningModuleRef module = parseSourceString(ir, &ctx);
+  OwningOpRef<ModuleOp> module = parseSourceString(ir, &ctx);
   auto op =
       cast<DataLayoutOpInterface>(module->getBody()->getOperations().front());
   DataLayout layout(op);
@@ -369,7 +369,7 @@
   registry.insert<DLTIDialect, DLTestDialect>();
   MLIRContext ctx(registry);
 
-  OwningModuleRef module = parseSourceString(ir, &ctx);
+  OwningOpRef<ModuleOp> module = parseSourceString(ir, &ctx);
   auto op =
       cast<DataLayoutOpInterface>(module->getBody()->getOperations().front());
   DataLayout layout(op);
@@ -395,7 +395,7 @@
   registry.insert<DLTIDialect, DLTestDialect>();
   MLIRContext ctx(registry);
 
-  OwningModuleRef module = parseSourceString(ir, &ctx);
+  OwningOpRef<ModuleOp> module = parseSourceString(ir, &ctx);
   auto op =
       cast<DataLayoutOpInterface>(module->getBody()->getOperations().front());
   DataLayout layout(op);
@@ -414,7 +414,7 @@
   registry.insert<DLTIDialect, DLTestDialect>();
   MLIRContext ctx(registry);
 
-  OwningModuleRef module = parseSourceString(ir, &ctx);
+  OwningOpRef<ModuleOp> module = parseSourceString(ir, &ctx);
   auto op =
       cast<DataLayoutOpInterface>(module->getBody()->getOperations().front());
   DataLayout layout(op);
diff --git a/mlir/unittests/Interfaces/InferTypeOpInterfaceTest.cpp b/mlir/unittests/Interfaces/InferTypeOpInterfaceTest.cpp
--- a/mlir/unittests/Interfaces/InferTypeOpInterfaceTest.cpp
+++ b/mlir/unittests/Interfaces/InferTypeOpInterfaceTest.cpp
@@ -47,7 +47,7 @@
 
   DialectRegistry registry;
   MLIRContext ctx;
-  OwningModuleRef module;
+  OwningOpRef<ModuleOp> module;
   FuncOp mapFn;
 };
 
diff --git a/mlir/unittests/Pass/AnalysisManagerTest.cpp b/mlir/unittests/Pass/AnalysisManagerTest.cpp
--- a/mlir/unittests/Pass/AnalysisManagerTest.cpp
+++ b/mlir/unittests/Pass/AnalysisManagerTest.cpp
@@ -32,7 +32,7 @@
   MLIRContext context;
 
   // Test fine grain invalidation of the module analysis manager.
-  OwningModuleRef module(ModuleOp::create(UnknownLoc::get(&context)));
+  OwningOpRef<ModuleOp> module(ModuleOp::create(UnknownLoc::get(&context)));
   ModuleAnalysisManager mam(*module, /*passInstrumentor=*/nullptr);
   AnalysisManager am = mam;
 
@@ -54,7 +54,7 @@
   Builder builder(&context);
 
   // Create a function and a module.
-  OwningModuleRef module(ModuleOp::create(UnknownLoc::get(&context)));
+  OwningOpRef<ModuleOp> module(ModuleOp::create(UnknownLoc::get(&context)));
   FuncOp func1 =
       FuncOp::create(builder.getUnknownLoc(), "foo",
                      builder.getFunctionType(llvm::None, llvm::None));
@@ -84,7 +84,7 @@
   Builder builder(&context);
 
   // Create a function and a module.
-  OwningModuleRef module(ModuleOp::create(UnknownLoc::get(&context)));
+  OwningOpRef<ModuleOp> module(ModuleOp::create(UnknownLoc::get(&context)));
   FuncOp func1 =
       FuncOp::create(builder.getUnknownLoc(), "foo",
                      builder.getFunctionType(llvm::None, llvm::None));
@@ -128,7 +128,7 @@
   Builder builder(&context);
 
   // Create a function and a module.
-  OwningModuleRef module(ModuleOp::create(UnknownLoc::get(&context)));
+  OwningOpRef<ModuleOp> module(ModuleOp::create(UnknownLoc::get(&context)));
   ModuleAnalysisManager mam(*module, /*passInstrumentor=*/nullptr);
   AnalysisManager am = mam;
 
@@ -150,7 +150,7 @@
   MLIRContext context;
 
   // Create a module.
-  OwningModuleRef module(ModuleOp::create(UnknownLoc::get(&context)));
+  OwningOpRef<ModuleOp> module(ModuleOp::create(UnknownLoc::get(&context)));
   ModuleAnalysisManager mam(*module, /*passInstrumentor=*/nullptr);
   AnalysisManager am = mam;
 
@@ -174,7 +174,7 @@
   MLIRContext context;
 
   // Create a module.
-  OwningModuleRef module(ModuleOp::create(UnknownLoc::get(&context)));
+  OwningOpRef<ModuleOp> module(ModuleOp::create(UnknownLoc::get(&context)));
   ModuleAnalysisManager mam(*module, /*passInstrumentor=*/nullptr);
   AnalysisManager am = mam;
 
@@ -205,7 +205,7 @@
   MLIRContext context;
 
   // Create a module.
-  OwningModuleRef module(ModuleOp::create(UnknownLoc::get(&context)));
+  OwningOpRef<ModuleOp> module(ModuleOp::create(UnknownLoc::get(&context)));
   ModuleAnalysisManager mam(*module, /*passInstrumentor=*/nullptr);
   AnalysisManager am = mam;
 
@@ -237,7 +237,7 @@
   MLIRContext context;
 
   // Create a module.
-  OwningModuleRef module(ModuleOp::create(UnknownLoc::get(&context)));
+  OwningOpRef<ModuleOp> module(ModuleOp::create(UnknownLoc::get(&context)));
   ModuleAnalysisManager mam(*module, /*passInstrumentor=*/nullptr);
   AnalysisManager am = mam;
 
diff --git a/mlir/unittests/Pass/PassManagerTest.cpp b/mlir/unittests/Pass/PassManagerTest.cpp
--- a/mlir/unittests/Pass/PassManagerTest.cpp
+++ b/mlir/unittests/Pass/PassManagerTest.cpp
@@ -50,7 +50,7 @@
   Builder builder(&context);
 
   // Create a module with 2 functions.
-  OwningModuleRef module(ModuleOp::create(UnknownLoc::get(&context)));
+  OwningOpRef<ModuleOp> module(ModuleOp::create(UnknownLoc::get(&context)));
   for (StringRef name : {"secret", "not_secret"}) {
     FuncOp func =
         FuncOp::create(builder.getUnknownLoc(), name,
@@ -95,7 +95,7 @@
   context.allowUnregisteredDialects();
 
   // Create a module
-  OwningModuleRef module(ModuleOp::create(UnknownLoc::get(&context)));
+  OwningOpRef<ModuleOp> module(ModuleOp::create(UnknownLoc::get(&context)));
 
   // Add a single "invalid_op" operation
   OpBuilder builder(&module->getBodyRegion());
diff --git a/mlir/unittests/Transforms/Canonicalizer.cpp b/mlir/unittests/Transforms/Canonicalizer.cpp
--- a/mlir/unittests/Transforms/Canonicalizer.cpp
+++ b/mlir/unittests/Transforms/Canonicalizer.cpp
@@ -74,7 +74,7 @@
     %1 = "test.foo"() {sym_name = "B"} : () -> (f32)
   )mlir";
 
-  OwningModuleRef module = mlir::parseSourceString(code, &context);
+  OwningOpRef<ModuleOp> module = mlir::parseSourceString(code, &context);
   ASSERT_TRUE(succeeded(mgr.run(*module)));
 
   EXPECT_TRUE(module->lookupSymbol("B"));