> ## Documentation Index
> Fetch the complete documentation index at: https://docs.sifr.sh/llms.txt
> Use this file to discover all available pages before exploring further.

# SIFR-RUST-CB-0001: Rust callback lifetime, threading, or policy contract is invalid.

> Rust callback lifetime, threading, or policy contract is invalid.

`SIFR-RUST-CB-0001` belongs to the **Rust callbacks** diagnostic family. It means: rust callback lifetime, threading, or policy contract is invalid.

## Why It Happens

A Rust callback lifetime, threading, or backpressure contract was violated.

<Info>
  Use `sifr --explain SIFR-RUST-CB-0001` locally to see the renderer's exact message template and any machine-applicable suggestions for the compiler version you are running.
</Info>

## Details

| Field                  | Value                                                                                                                              |
| ---------------------- | ---------------------------------------------------------------------------------------------------------------------------------- |
| Code                   | `SIFR-RUST-CB-0001`                                                                                                                |
| Family                 | `RUST-CB`                                                                                                                          |
| Severity               | Error                                                                                                                              |
| Stability              | stable                                                                                                                             |
| Owner                  | `sifr_driver::build::rust_interop`                                                                                                 |
| Representative fixture | `crates/sifr_driver/src/build/rust_interop_callback_contract_tests.rs::package_rust_interop_rejects_callback_missing_backpressure` |

See the [Error Codes index](/diagnostics/error-codes) for the complete catalog.