bevyengine/bevy · error · ArgError

expected {expected} value but received {received} value (@ a

Error message

expected {expected} value but received {received} value (@ argument index {index})

What it means

ArgError::InvalidOwnership — the argument was provided with the wrong ownership (Owned/Ref/Mut) for the parameter, e.g. passing a shared ref where an owned value is consumed. Payloads: argument index, expected and received Ownership.

Source

Thrown at crates/bevy_reflect/src/func/args/error.rs:23

use crate::func::args::Ownership;

/// An error that occurs when converting an [argument].
///
/// [argument]: crate::func::args::Arg
#[derive(Debug, Error, PartialEq)]
pub enum ArgError {
    /// The argument is not the expected type.
    #[error("expected `{expected}` but received `{received}` (@ argument index {index})")]
    UnexpectedType {
        /// Argument index.
        index: usize,
        /// Expected argument type path.
        expected: Cow<'static, str>,
        /// Received argument type path.
        received: Cow<'static, str>,
    },
    /// The argument has the wrong ownership.
    #[error("expected {expected} value but received {received} value (@ argument index {index})")]
    InvalidOwnership {
        /// Argument index.
        index: usize,
        /// Expected ownership.
        expected: Ownership,
        /// Received ownership.
        received: Ownership,
    },
    /// Occurs when attempting to access an argument from an empty [`ArgList`].
    ///
    /// [`ArgList`]: crate::func::args::ArgList
    #[error("expected an argument but received none")]
    EmptyArgList,
}

/// The given argument count is out of bounds.
#[derive(Debug, Error, PartialEq)]
#[error("argument count out of bounds: {0}")]

View on GitHub (pinned to 396ca72708)

Solutions

1. Pass the value with the ownership the signature expects (owned vs reference vs mutable reference)
2. Adjust the function signature to accept the provided ownership

When it happens

Trigger: Thrown at crates/bevy_reflect/src/func/args/error.rs:23 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/d152680036df95a2. Report an issue: GitHub.