diff --git a/src/components/script/dom/bindings/codegen/CodegenRust.py b/src/components/script/dom/bindings/codegen/CodegenRust.py
index 1fa4b47e8e4..ea5aac30305 100644
--- a/src/components/script/dom/bindings/codegen/CodegenRust.py
+++ b/src/components/script/dom/bindings/codegen/CodegenRust.py
@@ -628,14 +628,14 @@ def getJSToNativeConversionTemplate(type, descriptorProvider, failureCode=None,
                     "(${val}).to_object()"))
 
         declType = CGGeneric(descriptor.nativeType)
-        if type.nullable() or isOptional:
+        if type.nullable():
             templateBody = "Some(%s)" % templateBody
             declType = CGWrapper(declType, pre="Option<", post=">")
 
         templateBody = wrapObjectTemplate(templateBody, isDefinitelyObject,
                                           type, failureCode)
 
-        return (templateBody, declType, isOptional, "None" if isOptional else None)
+        return handleOptional(templateBody, declType, isOptional)
 
     if type.isSpiderMonkeyInterface():
         raise TypeError("Can't handle SpiderMonkey interface arguments yet")
diff --git a/src/components/script/dom/testbinding.rs b/src/components/script/dom/testbinding.rs
index a441cbddcd2..031ee0a9259 100644
--- a/src/components/script/dom/testbinding.rs
+++ b/src/components/script/dom/testbinding.rs
@@ -145,7 +145,7 @@ impl TestBinding {
     pub fn PassOptionalNullableDouble(&self, _: Option<Option<f64>>) {}
     pub fn PassOptionalNullableString(&self, _: Option<Option<DOMString>>) {}
     // pub fn PassOptionalNullableEnum(&self, _: Option<Option<TestEnum>>) {}
-    // pub fn PassOptionalNullableInterface(&self, _: Option<Option<JS<Blob>>>) {}
+    pub fn PassOptionalNullableInterface(&self, _: Option<Option<JS<Blob>>>) {}
     pub fn PassOptionalNullableUnion(&self, _: Option<Option<HTMLElementOrLong>>) {}
 
     pub fn PassOptionalBooleanWithDefault(&self, _: bool) {}
diff --git a/src/components/script/dom/webidls/TestBinding.webidl b/src/components/script/dom/webidls/TestBinding.webidl
index e2a236e9199..5749214fba3 100644
--- a/src/components/script/dom/webidls/TestBinding.webidl
+++ b/src/components/script/dom/webidls/TestBinding.webidl
@@ -150,7 +150,7 @@ interface TestBinding {
   void passOptionalNullableDouble(optional double? arg);
   void passOptionalNullableString(optional DOMString? arg);
   // void passOptionalNullableEnum(optional TestEnum? arg);
-  // void passOptionalNullableInterface(optional Blob? arg);
+  void passOptionalNullableInterface(optional Blob? arg);
   void passOptionalNullableUnion(optional (HTMLElement or long)? arg);
 
   void passOptionalBooleanWithDefault(optional boolean arg = false);