rust-clippy/tests/ui/fallible_impl_from.rs

81 lines
1.8 KiB
Rust

#![deny(clippy::fallible_impl_from)]
#![allow(clippy::uninlined_format_args)]
// docs example
struct Foo(i32);
impl From<String> for Foo {
//~^ ERROR: consider implementing `TryFrom` instead
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 {
//~^ ERROR: consider implementing `TryFrom` instead
fn from(i: usize) -> Invalid {
if i != 42 {
panic!();
}
Invalid
}
}
impl From<Option<String>> for Invalid {
//~^ ERROR: consider implementing `TryFrom` instead
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 {
//~^ ERROR: consider implementing `TryFrom` instead
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() {}