#![allow(clippy::no_effect, clippy::unnecessary_operation, dead_code)] #![warn(clippy::cast_lossless)] type I64 = i64; type U128 = u128; fn main() { // Test clippy::cast_lossless with casts to integer types let _ = i16::from(1i8); let _ = i32::from(1i8); let _ = i64::from(1i8); let _ = i16::from(1u8); let _ = i32::from(1u8); let _ = i64::from(1u8); let _ = u16::from(1u8); let _ = u32::from(1u8); let _ = u64::from(1u8); let _ = i32::from(1i16); let _ = i64::from(1i16); let _ = i32::from(1u16); let _ = i64::from(1u16); let _ = u32::from(1u16); let _ = u64::from(1u16); let _ = i64::from(1i32); let _ = i64::from(1u32); let _ = u64::from(1u32); // Test with an expression wrapped in parens let _ = u16::from(1u8 + 1u8); let _ = I64::from(1i8); // Do not lint if destination type is u128 // see https://github.com/rust-lang/rust-clippy/issues/12492 let _ = 1u8 as u128; let _ = 1u8 as U128; } // The lint would suggest using `f64::from(input)` here but the `XX::from` function is not const, // so we skip the lint if the expression is in a const fn. // See #3656 const fn abc(input: u16) -> u32 { input as u32 } // Same as the above issue. We can't suggest `::from` in const fns in impls mod cast_lossless_in_impl { struct A; impl A { pub const fn convert(x: u32) -> u64 { x as u64 } } } #[derive(PartialEq, Debug)] #[repr(i64)] enum Test { A = u32::MAX as i64 + 1, } fn issue11458() { macro_rules! sign_cast { ($var: ident, $src: ty, $dest: ty) => { <$dest>::from_ne_bytes(($var as $src).to_ne_bytes()) }; } let x = 10_u128; let _ = i32::from(sign_cast!(x, u8, i8)); let _ = i32::from(sign_cast!(x, u8, i8) + 1); }