{"record":{"id":"6130f1a02684ed7b","repo":"bevyengine/bevy","slug":"can-t-downcast-result-of-access-to-the-given-type","errorCode":null,"errorMessage":"Can't downcast result of access to the given type","messagePattern":"Can't downcast result of access to the given type","errorType":"exception","errorClass":"ReflectPathError","httpStatus":null,"severity":"error","filePath":"crates/bevy_reflect/src/path/mod.rs","lineNumber":29,"sourceCode":"use crate::{PartialReflect, Reflect};\nuse alloc::borrow::Cow;\nuse alloc::vec::Vec;\nuse core::fmt;\nuse derive_more::derive::From;\nuse thiserror::Error;\n\ntype PathResult<'a, T> = Result<T, ReflectPathError<'a>>;\n\n/// An error returned from a failed path string query.\n#[derive(Error, Debug, PartialEq, Eq)]\npub enum ReflectPathError<'a> {\n    /// An error caused by trying to access a path that's not able to be accessed,\n    /// see [`AccessError`] for details.\n    #[error(transparent)]\n    InvalidAccess(AccessError<'a>),\n\n    /// An error that occurs when a type cannot downcast to a given type.\n    #[error(\"Can't downcast result of access to the given type\")]\n    InvalidDowncast,\n\n    /// An error caused by an invalid path string that couldn't be parsed.\n    #[error(\"Encountered an error at offset {offset} while parsing `{path}`: {error}\")]\n    ParseError {\n        /// Position in `path`.\n        offset: usize,\n        /// The path that the error occurred in.\n        path: &'a str,\n        /// The underlying error.\n        error: ParseError<'a>,\n    },\n}\n\nimpl<'a> From<AccessError<'a>> for ReflectPathError<'a> {\n    fn from(value: AccessError<'a>) -> Self {\n        ReflectPathError::InvalidAccess(value)\n    }","sourceCodeStart":11,"sourceCodeEnd":47,"githubUrl":"https://github.com/bevyengine/bevy/blob/396ca727080776bd313bb892423b7d94e03b81b4/crates/bevy_reflect/src/path/mod.rs#L11-L47","documentation":"ReflectPathError::InvalidDowncast is returned by the typed path APIs (GetPath::path::<T>/path_mut::<T> and friends in bevy_reflect::path) when the path string resolves successfully to an element, but that element cannot be downcast to the requested type T. The untyped access succeeds; only the final conversion to &T / &mut T fails.","triggerScenarios":"Calling value.path::<Transform>(\"child.transform\") where the field at that path is of a different type (e.g. GlobalTransform), or querying with the wrong T for a path that resolves to a sibling field of the same name.","commonSituations":"Reflect-path lookups written against older component shapes; copy-pasted paths pointing at fields whose types changed; generic query helpers parameterized with the wrong target type; scene tooling addressing nested fields by string.","solutions":["Verify the target type at the path with the untyped API first: root.path(segment).map(|e| e.represents::<T>()) before the typed call.","Fix the requested T or the path so they agree (check the struct definition at the path's parent).","Use pattern/field access on the typed struct directly when compile-time checking is possible.","Handle the Err arm of path::<T> and report the mismatch instead of unwrap."],"exampleFix":"// before\nlet t = entity.path::<GlobalTransform>(\"transform\").unwrap(); // field is Transform -> InvalidDowncast\n\n// after\nlet t = entity.path::<Transform>(\"transform\").unwrap();","handlingStrategy":"type-guard","validationCode":"use bevy_reflect::GetPath;\n\nlet ok = root.reflect_path(\"transform.scale\")\n    .map(|el| el.represents::<f32>())\n    .unwrap_or(false);\nif ok { let v = root.path::<f32>(\"transform.scale\"); }","typeGuard":"use bevy_reflect::{PartialReflect, Reflect};\n\nfn path_is<T: Reflect>(root: &dyn PartialReflect, path: &str) -> bool {\n    root.reflect_path(path)\n        .map(|el| el.represents::<T>())\n        .unwrap_or(false)\n}","tryCatchPattern":"match entity.path::<Transform>(path_str) {\n    Ok(t) => { /* use &Transform */ }\n    Err(ReflectPathError::InvalidDowncast) => warn!(\"type at '{path_str}' is not Transform\"),\n    Err(ReflectPathError::InvalidAccess(e)) => warn!(\"bad access: {e}\"),\n    Err(ReflectPathError::ParseError { offset, path, .. }) => warn!(\"parse error at {offset} in {path}\"),\n}","preventionTips":["Prefer compile-time field access when types are known; reserve path::<T> for dynamic addressing.","Validate represents::<T>() on the untyped element before the typed query.","Re-verify reflect paths after changing field types."],"tags":["rust","bevy","bevy-reflect","path","downcast","getpath"],"backgroundTag":"invalid-downcast","analyzedSha":"396ca727080776bd313bb892423b7d94e03b81b4","analyzedAt":"2026-08-20T16:12:39.808Z","contentChangedAt":"2026-08-20T16:12:39.808Z","schemaVersion":2},"datasetVersion":"2026-09-14T05:17:10.506Z"}