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Diffstat (limited to 'src/tools/clippy/src/docs/as_conversions.txt')
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diff --git a/src/tools/clippy/src/docs/as_conversions.txt b/src/tools/clippy/src/docs/as_conversions.txt new file mode 100644 index 000000000..4af479bd8 --- /dev/null +++ b/src/tools/clippy/src/docs/as_conversions.txt @@ -0,0 +1,32 @@ +### What it does +Checks for usage of `as` conversions. + +Note that this lint is specialized in linting *every single* use of `as` +regardless of whether good alternatives exist or not. +If you want more precise lints for `as`, please consider using these separate lints: +`unnecessary_cast`, `cast_lossless/cast_possible_truncation/cast_possible_wrap/cast_precision_loss/cast_sign_loss`, +`fn_to_numeric_cast(_with_truncation)`, `char_lit_as_u8`, `ref_to_mut` and `ptr_as_ptr`. +There is a good explanation the reason why this lint should work in this way and how it is useful +[in this issue](https://github.com/rust-lang/rust-clippy/issues/5122). + +### Why is this bad? +`as` conversions will perform many kinds of +conversions, including silently lossy conversions and dangerous coercions. +There are cases when it makes sense to use `as`, so the lint is +Allow by default. + +### Example +``` +let a: u32; +... +f(a as u16); +``` + +Use instead: +``` +f(a.try_into()?); + +// or + +f(a.try_into().expect("Unexpected u16 overflow in f")); +```
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