diff --git a/servo/src/components/script/dom/bindings/codegen/CodegenRust.py b/servo/src/components/script/dom/bindings/codegen/CodegenRust.py
index cb9dd7036049..a14358d99c68 100644
--- a/servo/src/components/script/dom/bindings/codegen/CodegenRust.py
+++ b/servo/src/components/script/dom/bindings/codegen/CodegenRust.py
@@ -877,8 +877,6 @@ def getJSToNativeConversionTemplate(type, descriptorProvider, failureCode=None,
     if not type.isPrimitive():
         raise TypeError("Need conversion for argument type '%s'" % str(type))
 
-    typeName = builtinNames[type.tag()]
-
     conversionBehavior = "eDefault"
     if isEnforceRange:
         conversionBehavior = "eEnforceRange"
@@ -898,10 +896,12 @@ def getJSToNativeConversionTemplate(type, descriptorProvider, failureCode=None,
         "  Err(_) => { %s }\n"
         "}" % (successVal, exceptionCode))
 
+    declType = CGGeneric(builtinNames[type.tag()])
     if type.nullable():
-        declType = CGGeneric("Option<" + typeName + ">")
-    else:
-        declType = CGGeneric(typeName)
+        declType = CGWrapper(declType, pre="Option<", post=">")
+
+    if isOptional:
+        declType = CGWrapper(declType, pre="Option<", post=">")
 
     if defaultValue is not None:
         if isinstance(defaultValue, IDLNullValue):
@@ -925,10 +925,7 @@ def getJSToNativeConversionTemplate(type, descriptorProvider, failureCode=None,
                                    "  ${declName} = %s;\n"
                                    "}" % defaultStr)).define()
 
-    initialVal = "false" if typeName == "bool" else ("0 as %s" % typeName)
-    if type.nullable():
-        initialVal = "Some(%s)" % initialVal
-    return (template, declType, None, isOptional, initialVal)
+    return (template, declType, None, isOptional, "None" if isOptional else None)
 
 def instantiateJSToNativeConversionTemplate(templateTuple, replacements,
                                             argcAndIndex=None):
diff --git a/servo/src/components/script/dom/blob.rs b/servo/src/components/script/dom/blob.rs
index f1c4f677cf3d..df665bc6d47e 100644
--- a/servo/src/components/script/dom/blob.rs
+++ b/servo/src/components/script/dom/blob.rs
@@ -43,7 +43,7 @@ impl Blob {
         ~""
     }
 
-    pub fn Slice(&self, _start: i64, _end: i64, _contentType: Option<DOMString>) -> JS<Blob> {
+    pub fn Slice(&self, _start: Option<i64>, _end: Option<i64>, _contentType: Option<DOMString>) -> JS<Blob> {
         Blob::new(&self.window)
     }
 
diff --git a/servo/src/components/script/dom/testbinding.rs b/servo/src/components/script/dom/testbinding.rs
index 514260c5c10c..4dd9f190b03e 100644
--- a/servo/src/components/script/dom/testbinding.rs
+++ b/servo/src/components/script/dom/testbinding.rs
@@ -74,33 +74,32 @@ impl TestBinding {
     pub fn GetInterfaceAttributeNullable(&self) -> Option<JS<Blob>> { Some(Blob::new(&self.window)) }
     pub fn SetInterfaceAttributeNullable(&self, _: Option<JS<Blob>>) {}
 
-    // FIXME (issue #1813) Doesn't currently compile.
-    // pub fn PassOptionalBoolean(&self, _: Option<bool>) {}
-    // pub fn PassOptionalByte(&self, _: Option<i8>) {}
-    // pub fn PassOptionalOctet(&self, _: Option<u8>) {}
-    // pub fn PassOptionalShort(&self, _: Option<i16>) {}
-    // pub fn PassOptionalUnsignedShort(&self, _: Option<u16>) {}
-    // pub fn PassOptionalLong(&self, _: Option<i32>) {}
-    // pub fn PassOptionalUnsignedLong(&self, _: Option<u32>) {}
-    // pub fn PassOptionalLongLong(&self, _: Option<i64>) {}
-    // pub fn PassOptionalUnsignedLongLong(&self, _: Option<u64>) {}
-    // pub fn PassOptionalFloat(&self, _: Option<f32>) {}
-    // pub fn PassOptionalDouble(&self, _: Option<f64>) {}
+    pub fn PassOptionalBoolean(&self, _: Option<bool>) {}
+    pub fn PassOptionalByte(&self, _: Option<i8>) {}
+    pub fn PassOptionalOctet(&self, _: Option<u8>) {}
+    pub fn PassOptionalShort(&self, _: Option<i16>) {}
+    pub fn PassOptionalUnsignedShort(&self, _: Option<u16>) {}
+    pub fn PassOptionalLong(&self, _: Option<i32>) {}
+    pub fn PassOptionalUnsignedLong(&self, _: Option<u32>) {}
+    pub fn PassOptionalLongLong(&self, _: Option<i64>) {}
+    pub fn PassOptionalUnsignedLongLong(&self, _: Option<u64>) {}
+    pub fn PassOptionalFloat(&self, _: Option<f32>) {}
+    pub fn PassOptionalDouble(&self, _: Option<f64>) {}
     pub fn PassOptionalString(&self, _: Option<DOMString>) {}
     pub fn PassOptionalInterface(&self, _: Option<JS<Blob>>) {}
     pub fn PassOptionalAny(&self, _: *JSContext, _: Option<JSVal>) {}
 
-    // pub fn PassOptionalNullableBoolean(&self, _: Option<Option<bool>>) {}
-    // pub fn PassOptionalNullableByte(&self, _: Option<Option<i8>>) {}
-    // pub fn PassOptionalNullableOctet(&self, _: Option<Option<u8>>) {}
-    // pub fn PassOptionalNullableShort(&self, _: Option<Option<i16>>) {}
-    // pub fn PassOptionalNullableUnsignedShort(&self, _: Option<Option<u16>>) {}
-    // pub fn PassOptionalNullableLong(&self, _: Option<Option<i32>>) {}
-    // pub fn PassOptionalNullableUnsignedLong(&self, _: Option<Option<u32>>) {}
-    // pub fn PassOptionalNullableLongLong(&self, _: Option<Option<i64>>) {}
-    // pub fn PassOptionalNullableUnsignedLongLong(&self, _: Option<Option<u64>>) {}
-    // pub fn PassOptionalNullableFloat(&self, _: Option<Option<f32>>) {}
-    // pub fn PassOptionalNullableDouble(&self, _: Option<Option<f64>>) {}
+    pub fn PassOptionalNullableBoolean(&self, _: Option<Option<bool>>) {}
+    pub fn PassOptionalNullableByte(&self, _: Option<Option<i8>>) {}
+    pub fn PassOptionalNullableOctet(&self, _: Option<Option<u8>>) {}
+    pub fn PassOptionalNullableShort(&self, _: Option<Option<i16>>) {}
+    pub fn PassOptionalNullableUnsignedShort(&self, _: Option<Option<u16>>) {}
+    pub fn PassOptionalNullableLong(&self, _: Option<Option<i32>>) {}
+    pub fn PassOptionalNullableUnsignedLong(&self, _: Option<Option<u32>>) {}
+    pub fn PassOptionalNullableLongLong(&self, _: Option<Option<i64>>) {}
+    pub fn PassOptionalNullableUnsignedLongLong(&self, _: Option<Option<u64>>) {}
+    pub fn PassOptionalNullableFloat(&self, _: Option<Option<f32>>) {}
+    pub fn PassOptionalNullableDouble(&self, _: Option<Option<f64>>) {}
     pub fn PassOptionalNullableString(&self, _: Option<Option<DOMString>>) {}
     // pub fn PassOptionalNullableInterface(&self, _: Option<Option<JS<Blob>>>) {}
 
diff --git a/servo/src/components/script/dom/webidls/TestBinding.webidl b/servo/src/components/script/dom/webidls/TestBinding.webidl
index 3a967f5484a4..1fd5f2424561 100644
--- a/servo/src/components/script/dom/webidls/TestBinding.webidl
+++ b/servo/src/components/script/dom/webidls/TestBinding.webidl
@@ -32,33 +32,32 @@ interface TestBinding {
            attribute DOMString? stringAttributeNullable;
            attribute Blob? interfaceAttributeNullable;
 
-  // FIXME (issue #1813) Doesn't currently compile.
-  // void passOptionalBoolean(optional boolean arg);
-  // void passOptionalByte(optional byte arg);
-  // void passOptionalOctet(optional octet arg);
-  // void passOptionalShort(optional short arg);
-  // void passOptionalUnsignedShort(optional unsigned short arg);
-  // void passOptionalLong(optional long arg);
-  // void passOptionalUnsignedLong(optional unsigned long arg);
-  // void passOptionalLongLong(optional long long arg);
-  // void passOptionalUnsignedLongLong(optional unsigned long long arg);
-  // void passOptionalFloat(optional float arg);
-  // void passOptionalDouble(optional double arg);
+  void passOptionalBoolean(optional boolean arg);
+  void passOptionalByte(optional byte arg);
+  void passOptionalOctet(optional octet arg);
+  void passOptionalShort(optional short arg);
+  void passOptionalUnsignedShort(optional unsigned short arg);
+  void passOptionalLong(optional long arg);
+  void passOptionalUnsignedLong(optional unsigned long arg);
+  void passOptionalLongLong(optional long long arg);
+  void passOptionalUnsignedLongLong(optional unsigned long long arg);
+  void passOptionalFloat(optional float arg);
+  void passOptionalDouble(optional double arg);
   void passOptionalString(optional DOMString arg);
   void passOptionalInterface(optional Blob arg);
   void passOptionalAny(optional any arg);
 
-  // void passOptionalNullableBoolean(optional boolean? arg);
-  // void passOptionalNullableByte(optional byte? arg);
-  // void passOptionalNullableOctet(optional octet? arg);
-  // void passOptionalNullableShort(optional short? arg);
-  // void passOptionalNullableUnsignedShort(optional unsigned short? arg);
-  // void passOptionalNullableLong(optional long? arg);
-  // void passOptionalNullableUnsignedLong(optional unsigned long? arg);
-  // void passOptionalNullableLongLong(optional long long? arg);
-  // void passOptionalNullableUnsignedLongLong(optional unsigned long long? arg);
-  // void passOptionalNullableFloat(optional float? arg);
-  // void passOptionalNullableDouble(optional double? arg);
+  void passOptionalNullableBoolean(optional boolean? arg);
+  void passOptionalNullableByte(optional byte? arg);
+  void passOptionalNullableOctet(optional octet? arg);
+  void passOptionalNullableShort(optional short? arg);
+  void passOptionalNullableUnsignedShort(optional unsigned short? arg);
+  void passOptionalNullableLong(optional long? arg);
+  void passOptionalNullableUnsignedLong(optional unsigned long? arg);
+  void passOptionalNullableLongLong(optional long long? arg);
+  void passOptionalNullableUnsignedLongLong(optional unsigned long long? arg);
+  void passOptionalNullableFloat(optional float? arg);
+  void passOptionalNullableDouble(optional double? arg);
   void passOptionalNullableString(optional DOMString? arg);
   // void passOptionalNullableInterface(optional Blob? arg);