diff options
Diffstat (limited to 'src/tools/clippy/tests/ui/useless_conversion.rs')
-rw-r--r-- | src/tools/clippy/tests/ui/useless_conversion.rs | 92 |
1 files changed, 92 insertions, 0 deletions
diff --git a/src/tools/clippy/tests/ui/useless_conversion.rs b/src/tools/clippy/tests/ui/useless_conversion.rs new file mode 100644 index 000000000..f2444a8f4 --- /dev/null +++ b/src/tools/clippy/tests/ui/useless_conversion.rs @@ -0,0 +1,92 @@ +// run-rustfix + +#![deny(clippy::useless_conversion)] +#![allow(clippy::unnecessary_wraps)] + +fn test_generic<T: Copy>(val: T) -> T { + let _ = T::from(val); + val.into() +} + +fn test_generic2<T: Copy + Into<i32> + Into<U>, U: From<T>>(val: T) { + // ok + let _: i32 = val.into(); + let _: U = val.into(); + let _ = U::from(val); +} + +fn test_questionmark() -> Result<(), ()> { + { + let _: i32 = 0i32.into(); + Ok(Ok(())) + }??; + Ok(()) +} + +fn test_issue_3913() -> Result<(), std::io::Error> { + use std::fs; + use std::path::Path; + + let path = Path::new("."); + for _ in fs::read_dir(path)? {} + + Ok(()) +} + +fn test_issue_5833() -> Result<(), ()> { + let text = "foo\r\nbar\n\nbaz\n"; + let lines = text.lines(); + if Some("ok") == lines.into_iter().next() {} + + Ok(()) +} + +fn main() { + test_generic(10i32); + test_generic2::<i32, i32>(10i32); + test_questionmark().unwrap(); + test_issue_3913().unwrap(); + test_issue_5833().unwrap(); + + let _: String = "foo".into(); + let _: String = From::from("foo"); + let _ = String::from("foo"); + #[allow(clippy::useless_conversion)] + { + let _: String = "foo".into(); + let _ = String::from("foo"); + let _ = "".lines().into_iter(); + } + + let _: String = "foo".to_string().into(); + let _: String = From::from("foo".to_string()); + let _ = String::from("foo".to_string()); + let _ = String::from(format!("A: {:04}", 123)); + let _ = "".lines().into_iter(); + let _ = vec![1, 2, 3].into_iter().into_iter(); + let _: String = format!("Hello {}", "world").into(); + + // keep parentheses around `a + b` for suggestion (see #4750) + let a: i32 = 1; + let b: i32 = 1; + let _ = i32::from(a + b) * 3; + + // see #7205 + let s: Foo<'a'> = Foo; + let _: Foo<'b'> = s.into(); + let s2: Foo<'a'> = Foo; + let _: Foo<'a'> = s2.into(); + let s3: Foo<'a'> = Foo; + let _ = Foo::<'a'>::from(s3); + let s4: Foo<'a'> = Foo; + let _ = vec![s4, s4, s4].into_iter().into_iter(); +} + +#[derive(Copy, Clone)] +struct Foo<const C: char>; + +impl From<Foo<'a'>> for Foo<'b'> { + fn from(_s: Foo<'a'>) -> Self { + Foo + } +} |