diff --git a/mlir/include/mlir/IR/Builders.h b/mlir/include/mlir/IR/Builders.h
index 424eb980cd33a..0dcf4daf656fd 100644
--- a/mlir/include/mlir/IR/Builders.h
+++ b/mlir/include/mlir/IR/Builders.h
@@ -374,6 +374,10 @@ class OpBuilder : public Builder {
   template <typename OpTy, typename... Args>
   OpTy create(Location location, Args &&... args) {
     OperationState state(location, OpTy::getOperationName());
+    if (!state.name.getAbstractOperation())
+      llvm::report_fatal_error("Building op `" +
+                               state.name.getStringRef().str() +
+                               "` but it isn't registered in this MLIRContext");
     OpTy::build(*this, state, std::forward<Args>(args)...);
     auto *op = createOperation(state);
     auto result = dyn_cast<OpTy>(op);
@@ -390,6 +394,10 @@ class OpBuilder : public Builder {
     // Create the operation without using 'createOperation' as we don't want to
     // insert it yet.
     OperationState state(location, OpTy::getOperationName());
+    if (!state.name.getAbstractOperation())
+      llvm::report_fatal_error("Building op `" +
+                               state.name.getStringRef().str() +
+                               "` but it isn't registered in this MLIRContext");
     OpTy::build(*this, state, std::forward<Args>(args)...);
     Operation *op = Operation::create(state);
 
diff --git a/mlir/include/mlir/IR/MLIRContext.h b/mlir/include/mlir/IR/MLIRContext.h
index da0b0bd826ced..8e75bb6244493 100644
--- a/mlir/include/mlir/IR/MLIRContext.h
+++ b/mlir/include/mlir/IR/MLIRContext.h
@@ -85,6 +85,9 @@ class MLIRContext {
   /// directly.
   std::vector<AbstractOperation *> getRegisteredOperations();
 
+  /// Return true if this operation name is registered in this context.
+  bool isOperationRegistered(StringRef name);
+
   // This is effectively private given that only MLIRContext.cpp can see the
   // MLIRContextImpl type.
   MLIRContextImpl &getImpl() { return *impl; }
diff --git a/mlir/include/mlir/IR/OpDefinition.h b/mlir/include/mlir/IR/OpDefinition.h
index bf5bd70c2b7fe..e92d54ec84f9b 100644
--- a/mlir/include/mlir/IR/OpDefinition.h
+++ b/mlir/include/mlir/IR/OpDefinition.h
@@ -1235,7 +1235,10 @@ class Op : public OpState,
   static bool classof(Operation *op) {
     if (auto *abstractOp = op->getAbstractOperation())
       return TypeID::get<ConcreteType>() == abstractOp->typeID;
-    return op->getName().getStringRef() == ConcreteType::getOperationName();
+    assert(op->getContext()->isOperationRegistered(
+               ConcreteType::getOperationName()) &&
+           "Casting attempt to an unregistered operation");
+    return false;
   }
 
   /// This is the hook used by the AsmParser to parse the custom form of this
diff --git a/mlir/lib/IR/MLIRContext.cpp b/mlir/lib/IR/MLIRContext.cpp
index 0728f294be861..da607a2319bfc 100644
--- a/mlir/lib/IR/MLIRContext.cpp
+++ b/mlir/lib/IR/MLIRContext.cpp
@@ -543,6 +543,13 @@ std::vector<AbstractOperation *> MLIRContext::getRegisteredOperations() {
   return result;
 }
 
+bool MLIRContext::isOperationRegistered(StringRef name) {
+  // Lock access to the context registry.
+  ScopedReaderLock registryLock(impl->contextMutex, impl->threadingIsEnabled);
+
+  return impl->registeredOperations.count(name);
+}
+
 void Dialect::addOperation(AbstractOperation opInfo) {
   assert((getNamespace().empty() ||
           opInfo.name.split('.').first == getNamespace()) &&
@@ -621,8 +628,9 @@ Identifier Identifier::get(StringRef str, MLIRContext *context) {
 static Dialect &lookupDialectForSymbol(MLIRContext *ctx, TypeID typeID) {
   auto &impl = ctx->getImpl();
   auto it = impl.registeredDialectSymbols.find(typeID);
-  assert(it != impl.registeredDialectSymbols.end() &&
-         "symbol is not registered.");
+  if (it == impl.registeredDialectSymbols.end())
+    llvm::report_fatal_error(
+        "Trying to create a type that was not registered in this MLIRContext.");
   return *it->second;
 }