src/tools/clippy/tests/ui/transmute.rs

   1 #![allow(dead_code, clippy::borrow_as_ptr)]
   2
   3 extern crate core;
   4
   5 use std::mem::transmute as my_transmute;
   6 use std::vec::Vec as MyVec;
   7
   8 fn my_int() -> Usize {
   9     Usize(42)
  10 }
  11
  12 fn my_vec() -> MyVec<i32> {
  13     vec![]
  14 }
  15
  16 #[allow(clippy::needless_lifetimes, clippy::transmute_ptr_to_ptr)]
  17 #[warn(clippy::useless_transmute)]
  18 unsafe fn _generic<'a, T, U: 'a>(t: &'a T) {
  19     // FIXME: should lint
  20     // let _: &'a T = core::intrinsics::transmute(t);
  21
  22     let _: &'a U = core::intrinsics::transmute(t);
  23
  24     let _: *const T = core::intrinsics::transmute(t);
  25
  26     let _: *mut T = core::intrinsics::transmute(t);
  27
  28     let _: *const U = core::intrinsics::transmute(t);
  29 }
  30
  31 #[warn(clippy::useless_transmute)]
  32 fn useless() {
  33     unsafe {
  34         let _: Vec<i32> = core::intrinsics::transmute(my_vec());
  35
  36         let _: Vec<i32> = core::mem::transmute(my_vec());
  37
  38         let _: Vec<i32> = std::intrinsics::transmute(my_vec());
  39
  40         let _: Vec<i32> = std::mem::transmute(my_vec());
  41
  42         let _: Vec<i32> = my_transmute(my_vec());
  43
  44         let _: *const usize = std::mem::transmute(5_isize);
  45
  46         let _ = 5_isize as *const usize;
  47
  48         let _: *const usize = std::mem::transmute(1 + 1usize);
  49
  50         let _ = (1 + 1_usize) as *const usize;
  51     }
  52
  53     unsafe fn _f<'a, 'b>(x: &'a u32) -> &'b u32 {
  54         std::mem::transmute(x)
  55     }
  56
  57     unsafe fn _f2<'a, 'b>(x: *const (dyn Iterator<Item = u32> + 'a)) -> *const (dyn Iterator<Item = u32> + 'b) {
  58         std::mem::transmute(x)
  59     }
  60
  61     unsafe fn _f3<'a, 'b>(x: fn(&'a u32)) -> fn(&'b u32) {
  62         std::mem::transmute(x)
  63     }
  64
  65     unsafe fn _f4<'a, 'b>(x: std::borrow::Cow<'a, str>) -> std::borrow::Cow<'b, str> {
  66         std::mem::transmute(x)
  67     }
  68 }
  69
  70 struct Usize(usize);
  71
  72 #[warn(clippy::crosspointer_transmute)]
  73 fn crosspointer() {
  74     let mut int: Usize = Usize(0);
  75     let int_const_ptr: *const Usize = &int as *const Usize;
  76     let int_mut_ptr: *mut Usize = &mut int as *mut Usize;
  77
  78     unsafe {
  79         let _: Usize = core::intrinsics::transmute(int_const_ptr);
  80
  81         let _: Usize = core::intrinsics::transmute(int_mut_ptr);
  82
  83         let _: *const Usize = core::intrinsics::transmute(my_int());
  84
  85         let _: *mut Usize = core::intrinsics::transmute(my_int());
  86     }
  87 }
  88
  89 #[warn(clippy::transmute_int_to_char)]
  90 fn int_to_char() {
  91     let _: char = unsafe { std::mem::transmute(0_u32) };
  92     let _: char = unsafe { std::mem::transmute(0_i32) };
  93
  94     // These shouldn't warn
  95     const _: char = unsafe { std::mem::transmute(0_u32) };
  96     const _: char = unsafe { std::mem::transmute(0_i32) };
  97 }
  98
  99 #[warn(clippy::transmute_int_to_bool)]
 100 fn int_to_bool() {
 101     let _: bool = unsafe { std::mem::transmute(0_u8) };
 102 }
 103
 104 #[warn(clippy::transmute_int_to_float)]
 105 mod int_to_float {
 106     fn test() {
 107         let _: f32 = unsafe { std::mem::transmute(0_u32) };
 108         let _: f32 = unsafe { std::mem::transmute(0_i32) };
 109         let _: f64 = unsafe { std::mem::transmute(0_u64) };
 110         let _: f64 = unsafe { std::mem::transmute(0_i64) };
 111     }
 112
 113     mod issue_5747 {
 114         const VALUE32: f32 = unsafe { std::mem::transmute(0_u32) };
 115         const VALUE64: f64 = unsafe { std::mem::transmute(0_i64) };
 116
 117         const fn from_bits_32(v: i32) -> f32 {
 118             unsafe { std::mem::transmute(v) }
 119         }
 120
 121         const fn from_bits_64(v: u64) -> f64 {
 122             unsafe { std::mem::transmute(v) }
 123         }
 124     }
 125 }
 126
 127 mod num_to_bytes {
 128     fn test() {
 129         unsafe {
 130             let _: [u8; 1] = std::mem::transmute(0u8);
 131             let _: [u8; 4] = std::mem::transmute(0u32);
 132             let _: [u8; 16] = std::mem::transmute(0u128);
 133             let _: [u8; 1] = std::mem::transmute(0i8);
 134             let _: [u8; 4] = std::mem::transmute(0i32);
 135             let _: [u8; 16] = std::mem::transmute(0i128);
 136             let _: [u8; 4] = std::mem::transmute(0.0f32);
 137             let _: [u8; 8] = std::mem::transmute(0.0f64);
 138         }
 139     }
 140     const fn test_const() {
 141         unsafe {
 142             let _: [u8; 1] = std::mem::transmute(0u8);
 143             let _: [u8; 4] = std::mem::transmute(0u32);
 144             let _: [u8; 16] = std::mem::transmute(0u128);
 145             let _: [u8; 1] = std::mem::transmute(0i8);
 146             let _: [u8; 4] = std::mem::transmute(0i32);
 147             let _: [u8; 16] = std::mem::transmute(0i128);
 148             let _: [u8; 4] = std::mem::transmute(0.0f32);
 149             let _: [u8; 8] = std::mem::transmute(0.0f64);
 150         }
 151     }
 152 }
 153
 154 fn bytes_to_str(mb: &mut [u8]) {
 155     const B: &[u8] = b"";
 156
 157     let _: &str = unsafe { std::mem::transmute(B) };
 158     let _: &mut str = unsafe { std::mem::transmute(mb) };
 159     const _: &str = unsafe { std::mem::transmute(B) };
 160 }
 161
 162 fn main() {}