Revision control
Copy as Markdown
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
use std::fmt::Display;
use error_support::{handle_error, ErrorHandling, GetErrorHandling};
#[derive(Debug, thiserror::Error)]
struct Error {}
impl Display for Error {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
write!(f, "Internal Error!")
}
}
#[derive(Debug, thiserror::Error)]
struct ExternalError {}
impl Display for ExternalError {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
write!(f, "External Error!")
}
}
impl GetErrorHandling for Error {
type ExternalError = ExternalError;
fn get_error_handling(&self) -> error_support::ErrorHandling<Self::ExternalError> {
ErrorHandling::convert(ExternalError {})
}
}
#[handle_error(Error)]
fn func() -> ::std::result::Result<String, ExternalError> {
Err(Error{})
}
#[handle_error(Error)]
fn func2() -> Result<String, ExternalError> {
Err(Error{})
}
type MyResult<T, E = ExternalError> = std::result::Result<T, E>;
#[handle_error(Error)]
fn func3() -> MyResult<String> {
Err(Error{})
}
type FullyAliasedResult<T = String, E = ExternalError> = std::result::Result<T, E>;
#[handle_error(Error)]
fn func4() -> FullyAliasedResult {
Err(Error{})
}
mod submodule {
#[super::handle_error(super::Error)]
pub(super) fn func() -> ::std::result::Result<String, super::ExternalError> {
Err(super::Error{})
}
}
fn main() {
// We verify that all functions now return Result<T, ExternalError>
let _: Vec<ExternalError> = vec![
func().unwrap_err(),
func2().unwrap_err(),
func3().unwrap_err(),
func4().unwrap_err(),
submodule::func().unwrap_err(),
];
}