Fixes #1004

derive/src/input_object.rs

@@ -102,7 +102,7 @@ pub fn generate(object_args: &args::InputObject) -> GeneratorResult<TokenStream>
 
             schema_fields.push(quote! {
                 #crate_name::static_assertions::assert_impl_one!(#ty: #crate_name::InputObjectType);
-                #ty::create_type_info(registry);
+                <#ty as  #crate_name::InputType>::create_type_info(registry);
                 if let #crate_name::registry::MetaType::InputObject { input_fields, .. } =
                     registry.create_fake_input_type::<#ty>() {
                     fields.extend(input_fields);

derive/src/simple_object.rs

@@ -180,7 +180,7 @@ pub fn generate(object_args: &args::SimpleObject) -> GeneratorResult<TokenStream
             });
         } else {
             schema_fields.push(quote! {
-                #ty::create_type_info(registry);
+                <#ty as #crate_name::OutputType>::create_type_info(registry);
                 if let #crate_name::registry::MetaType::Object { fields: obj_fields, .. } =
                     registry.create_fake_output_type::<#ty>() {
                     fields.extend(obj_fields);

tests/input_object.rs

@@ -449,6 +449,51 @@ pub fn test_both_input_output_with_same_name() {
     Schema::new(Query, EmptyMutation, EmptySubscription);
 }
 
+#[tokio::test]
+pub async fn test_both_input_output_flatten() {
+    #[derive(SimpleObject, InputObject)]
+    #[graphql(input_name = "ABCInput")]
+    #[graphql(name = "ABC")]
+    struct ABC {
+        a: i32,
+        #[graphql(flatten)]
+        bc: BC,
+    }
+
+    #[derive(SimpleObject, InputObject)]
+    #[graphql(input_name = "BCInput")]
+    struct BC {
+        b: i32,
+        c: i32,
+    }
+
+    struct Query;
+
+    #[Object]
+    impl Query {
+        async fn obj(&self, input: ABC) -> ABC {
+            input
+        }
+    }
+
+    let schema = Schema::new(Query, EmptyMutation, EmptySubscription);
+    assert_eq!(
+        schema
+            .execute("{ obj(input: { a: 1, b: 2, c: 3 }) { a b c } }")
+            .await
+            .into_result()
+            .unwrap()
+            .data,
+        value!({
+            "obj": {
+                "a": 1,
+                "b": 2,
+                "c": 3
+            }
+        })
+    );
+}
+
 #[tokio::test]
 pub async fn test_skip_input() {
     #[derive(SimpleObject, InputObject)]