78 lines
1.6 KiB
Rust
78 lines
1.6 KiB
Rust
#![deny(clippy::fallible_impl_from)]
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#![allow(clippy::if_then_panic)]
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// docs example
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struct Foo(i32);
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impl From<String> for Foo {
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fn from(s: String) -> Self {
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Foo(s.parse().unwrap())
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}
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}
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struct Valid(Vec<u8>);
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impl<'a> From<&'a str> for Valid {
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fn from(s: &'a str) -> Valid {
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Valid(s.to_owned().into_bytes())
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}
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}
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impl From<usize> for Valid {
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fn from(i: usize) -> Valid {
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Valid(Vec::with_capacity(i))
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}
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}
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struct Invalid;
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impl From<usize> for Invalid {
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fn from(i: usize) -> Invalid {
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if i != 42 {
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panic!();
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}
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Invalid
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}
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}
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impl From<Option<String>> for Invalid {
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fn from(s: Option<String>) -> Invalid {
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let s = s.unwrap();
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if !s.is_empty() {
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panic!("42");
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} else if s.parse::<u32>().unwrap() != 42 {
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panic!("{:?}", s);
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}
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Invalid
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}
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}
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trait ProjStrTrait {
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type ProjString;
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}
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impl<T> ProjStrTrait for Box<T> {
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type ProjString = String;
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}
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impl<'a> From<&'a mut <Box<u32> as ProjStrTrait>::ProjString> for Invalid {
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fn from(s: &'a mut <Box<u32> as ProjStrTrait>::ProjString) -> Invalid {
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if s.parse::<u32>().ok().unwrap() != 42 {
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panic!("{:?}", s);
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}
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Invalid
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}
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}
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struct Unreachable;
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impl From<String> for Unreachable {
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fn from(s: String) -> Unreachable {
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if s.is_empty() {
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return Unreachable;
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}
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match s.chars().next() {
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Some(_) => Unreachable,
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None => unreachable!(), // do not lint the unreachable macro
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}
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}
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}
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fn main() {}
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