bevyengine/bevy · error · ReflectedRonSerializeError::ValueNotReflect

Subasset type was not registered in the TypeRegistry…

Error message

Subasset type was not registered in the TypeRegistry. Ensure your subasset's type implements Reflect (and if it's generic it needs to be manually registered)

What it means

ReflectedRonSerializeError::ValueNotReflect is thrown when the subasset value's type was not found in the TypeRegistry during reflected RON serialization. The serializer looks up the value's type to obtain reflection data (ReflectSerialize etc.) needed to write it out.

Solutions

1. Call app.register_type::<T>() for the subasset's concrete type
2. For generic types, register the monomorphized instance manually (e.g. app.register_type::<Vec<MyType>>())
3. Ensure the plugin that registers the type runs before the save occurs

Example fix

// before
app.save_asset(&handle, "level.ron");

// after
app.register_type::<LevelConfig>();
app.save_asset(&handle, "level.ron");

fn is_type_registered<T: GetTypeRegistration>(registry: &TypeRegistry) -> bool {
    registry.contains(TypeId::of::<T>())
}

When it happens

Trigger: Saving a RON asset whose concrete subasset type implements Reflect but was never passed to app.register_type::<T>(); generic types like Vec<MyType> or HashMap<K, V> that need manual registration.

Common situations: Generic or newtype-wrapped assets not registered; type registered only in a plugin that isn't active in this app; registering the root type but forgetting nested/container types.

Related errors

• Subasset type does not have ReflectFromPtr registered in…
• Attempted to load type
• Attempted to load type
• Could not parse RON
• Error while trying to read the world file

AI-assisted analysis of bevyengine/bevy@a62cce8c05 (2026-09-19). Data as JSON: /api/errors/0c09794b4872413f. Report an issue: GitHub.

Appendix: source

Thrown at crates/bevy_asset/src/common_loaders/ron.rs:479

}

/// An error type for RON saving.
#[derive(Error, Debug)]
pub enum RonSerializeError {
    #[error(transparent)]
    IoError(#[from] std::io::Error),
    #[error(transparent)]
    Ron(#[from] ron::Error),
}

/// An error type for RON saving using reflection.
#[derive(Error, Debug)]
pub enum ReflectedRonSerializeError {
    #[error(
        "Expected the root LoadedUntypedHandle to hold a handle to its subasset, but it did not have such a subasset"
    )]
    MissingSubasset,
    #[error("Subasset type was not registered in the TypeRegistry. Ensure your subasset's type implements Reflect (and if it's generic it needs to be manually registered)")]
    ValueNotReflect,
    #[error("Subasset type does not have ReflectFromPtr registered in its type data")]
    MissingReflectFromPtr,
    #[error(transparent)]
    Ron(#[from] RonSerializeError),
}

#[cfg(test)]
mod tests {
    use std::path::Path;

    use alloc::{string::String, vec};

    use bevy_ecs::reflect::AppTypeRegistry;
    use bevy_reflect::{Reflect, TypePath};
    use bevy_tasks::{futures::check_ready, IoTaskPool};
    use serde::{Deserialize, Serialize};

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