// Copyright 2022 Parity Technologies (UK) Ltd. // This file is part of Polkadot. // Polkadot is free software: you can redistribute it and/or modify // it under the terms of the GNU General Public License as published by // the Free Software Foundation, either version 3 of the License, or // (at your option) any later version. // Polkadot is distributed in the hope that it will be useful, // but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the // GNU General Public License for more details. // You should have received a copy of the GNU General Public License // along with Polkadot. If not, see . use fatality::fatality; use assert_matches::assert_matches; #[derive(Debug, thiserror::Error)] #[error("We tried")] struct Fatal; #[derive(Debug, thiserror::Error)] #[error("Get a dinosaur bandaid")] struct Bobo; #[fatality] enum Kaboom { #[error(transparent)] Iffy(#[from] Fatal), #[error(transparent)] Bobo(#[from] Bobo), #[error("Message {0}")] Eh(char), } fn iffy() -> Result<(), Kaboom> { Err(Fatal)? } fn bobo() -> Result<(), Kaboom> { Err(Bobo)? } fn oh_canada() -> Result<(), Kaboom> { Ok(Err(Kaboom::Eh('?'))?) } fn main() { if let Err(fatal) = iffy() { assert_matches!(fatal, Kaboom::Iffy(_)); } if let Err(bobo) = bobo() { assert_matches!(bobo, Kaboom::Bobo(_)); } if let Err(eh) = oh_canada() { assert_matches!(eh, Kaboom::Eh(_)); } }