86 lines
2.0 KiB
Rust
86 lines
2.0 KiB
Rust
// Copyright 2014-2018 The Rust Project Developers. See the COPYRIGHT
|
|
// file at the top-level directory of this distribution.
|
|
//
|
|
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
|
|
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
|
|
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
|
|
// option. This file may not be copied, modified, or distributed
|
|
// except according to those terms.
|
|
|
|
#![deny(clippy::fallible_impl_from)]
|
|
|
|
// docs example
|
|
struct Foo(i32);
|
|
impl From<String> for Foo {
|
|
fn from(s: String) -> Self {
|
|
Foo(s.parse().unwrap())
|
|
}
|
|
}
|
|
|
|
struct Valid(Vec<u8>);
|
|
|
|
impl<'a> From<&'a str> for Valid {
|
|
fn from(s: &'a str) -> Valid {
|
|
Valid(s.to_owned().into_bytes())
|
|
}
|
|
}
|
|
impl From<usize> for Valid {
|
|
fn from(i: usize) -> Valid {
|
|
Valid(Vec::with_capacity(i))
|
|
}
|
|
}
|
|
|
|
struct Invalid;
|
|
|
|
impl From<usize> for Invalid {
|
|
fn from(i: usize) -> Invalid {
|
|
if i != 42 {
|
|
panic!();
|
|
}
|
|
Invalid
|
|
}
|
|
}
|
|
|
|
impl From<Option<String>> for Invalid {
|
|
fn from(s: Option<String>) -> Invalid {
|
|
let s = s.unwrap();
|
|
if !s.is_empty() {
|
|
panic!(42);
|
|
} else if s.parse::<u32>().unwrap() != 42 {
|
|
panic!("{:?}", s);
|
|
}
|
|
Invalid
|
|
}
|
|
}
|
|
|
|
trait ProjStrTrait {
|
|
type ProjString;
|
|
}
|
|
impl<T> ProjStrTrait for Box<T> {
|
|
type ProjString = String;
|
|
}
|
|
impl<'a> From<&'a mut <Box<u32> as ProjStrTrait>::ProjString> for Invalid {
|
|
fn from(s: &'a mut <Box<u32> as ProjStrTrait>::ProjString) -> Invalid {
|
|
if s.parse::<u32>().ok().unwrap() != 42 {
|
|
panic!("{:?}", s);
|
|
}
|
|
Invalid
|
|
}
|
|
}
|
|
|
|
struct Unreachable;
|
|
|
|
impl From<String> for Unreachable {
|
|
fn from(s: String) -> Unreachable {
|
|
if s.is_empty() {
|
|
return Unreachable;
|
|
}
|
|
match s.chars().next() {
|
|
Some(_) => Unreachable,
|
|
None => unreachable!(), // do not lint the unreachable macro
|
|
}
|
|
}
|
|
}
|
|
|
|
fn main() {}
|