bevyengine/bevy · error · ReflectCloneError

expected downcast to `{expected}`, but received `{received}`

Error message

expected downcast to `{expected}`, but received `{received}`

What it means

ReflectCloneError::FieldNotCloneable — while cloning a reflected container, a specific field (identified by FieldId, optional variant name, and container type path) could not be cloned, typically because it lacks a #[reflect(clone)] attribute. Add the attribute or a clone registration for that field's type.

Source

Thrown at crates/bevy_reflect/src/error.rs:54

    /// [deriving `Reflect`]: derive@crate::Reflect
    #[error(
        "field `{}` cannot be made cloneable for `PartialReflect::reflect_clone` (are you missing a `#[reflect(clone)]` attribute?)",
        full_path(.field, .variant.as_deref(), .container_type_path)
    )]
    FieldNotCloneable {
        /// Struct field or enum variant field which cannot be cloned.
        field: FieldId,
        /// Variant this field is part of if the container is an enum, otherwise [`None`].
        variant: Option<Cow<'static, str>>,
        /// Fully qualified path of the type containing this field.
        container_type_path: Cow<'static, str>,
    },
    /// Could not downcast to the expected type.
    ///
    /// Realistically this should only occur when a type has incorrectly implemented [`Reflect`].
    ///
    /// [`Reflect`]: crate::Reflect
    #[error("expected downcast to `{expected}`, but received `{received}`")]
    FailedDowncast {
        /// The fully qualified path of the type that was expected.
        expected: Cow<'static, str>,
        /// The fully qualified path of the type that was received.
        received: Cow<'static, str>,
    },
}

fn full_path(
    field: &FieldId,
    variant: Option<&str>,
    container_type_path: &str,
) -> alloc::string::String {
    match variant {
        Some(variant) => format!("{container_type_path}::{variant}::{field}"),
        None => format!("{container_type_path}::{field}"),
    }
}

View on GitHub (pinned to 396ca72708)

Solutions

1. Downcast to the actual received type instead
2. Check represents::<T>() or reflect_type_path() before downcasting
3. Fix registration so the expected and actual types agree

When it happens

Trigger: Thrown at crates/bevy_reflect/src/error.rs:54 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of bevyengine/bevy@396ca72708 (2026-08-20). Data as JSON: /api/errors/550fd7f334733e80. Report an issue: GitHub.