#derive #set #target #failing #try-from #type #derive-debug

macro tryfromfail

Derive failing TryFrom for a set of target types

1 unstable release

Uses old Rust 2015

0.1.0 Apr 20, 2018

#17 in #try-from

MIT license

5KB
51 lines

tryfromfail

Latest Version Documentation

Custom derive failing TryFrom implementations for a set of target types.

Returns the original value as Err(value).

Example

#[macro_use]
extern crate tryfromfail;

use std::convert::TryInto;

#[derive(Debug, PartialEq, FailingTryFrom)]
#[FailingTryFrom(OtherType)]
struct SomeType {}

#[derive(Debug, PartialEq)]
struct OtherType {}

#[test]
fn works() {
    let val = OtherType {};
    let failed_try_from: Result<SomeType, OtherType> = val.try_into();
    assert_eq!(failed_try_from, Err(OtherType {}));
}

Dependencies

~2MB
~46K SLoC