You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: errors.rs
    path of file: ./repos/crates.io/src/util
    
    the code of the file until where you have to start completion: //! This module implements several error types and traits.
//!
//! The suggested usage in returned results is as follows:
//!
//! * The concrete `util::concrete::Error` type (re-exported as `util::Error`) is great for code
//!   that is not part of the request/response lifecycle.  It avoids pulling in the unnecessary
//!   infrastructure to convert errors into a user facing JSON responses (relative to `AppError`).
//! * `diesel::QueryResult` - There is a lot of code that only deals with query errors.  If only
//!   one type of error is possible in a function, using that specific error is preferable to the
//!   more general `util::Error`.  This is especially common in model code.
//! * `util::errors::AppResult` - Some failures should be conve
    
    fn http_error_responses() {
        use crate::serde::de::Error;

        // Types for handling common error status codes
        assert_eq!(bad_request("").response().status(), StatusCode::BAD_REQUEST);
        assert_eq!(forbidden().response().status(), StatusCode::FORBIDDEN);
        assert_eq!(
            BoxedAppError::from(DieselError::NotFound)
                .response()
                .status(),
            StatusCode::NOT_FOUND
        );
        assert_eq!(not_found().response().status(), StatusCode::NOT_FOUND);

        // All other error types are converted to internal server errors
        assert_eq!(
            internal("").response().status(),
            StatusCode::INTERNAL_SERVER_ERROR
        );
        assert_eq!(
            BoxedAppError::from(serde_json::Error::custom("ExpectedColon"))
                .response()
                .status(),
            StatusCode::INTERNAL_SERVER_ERROR
        );
        assert_eq!(
            BoxedAppError::from(::std::io::Error::new(::std::io::ErrorKind::Other, ""))
                .response()
                .status(),
            StatusCode::INTERNAL_SERVER_ERROR
        );
    }