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

   1 #![allow(
   2     dead_code,
   3     clippy::borrow_as_ptr,
   4     clippy::needless_lifetimes,
   5     clippy::missing_transmute_annotations
   6 )]
   7 //@no-rustfix
   8 extern crate core;
   9
  10 use std::mem::transmute as my_transmute;
  11 use std::vec::Vec as MyVec;
  12
  13 fn my_int() -> Usize {
  14     Usize(42)
  15 }
  16
  17 fn my_vec() -> MyVec<i32> {
  18     vec![]
  19 }
  20
  21 #[allow(clippy::needless_lifetimes, clippy::transmute_ptr_to_ptr)]
  22 #[warn(clippy::useless_transmute)]
  23 unsafe fn _generic<'a, T, U: 'a>(t: &'a T) {
  24     // FIXME: should lint
  25     // let _: &'a T = core::intrinsics::transmute(t);
  26
  27     let _: &'a U = core::intrinsics::transmute(t);
  28
  29     let _: *const T = core::intrinsics::transmute(t);
  30     //~^ ERROR: transmute from a reference to a pointer
  31     //~| NOTE: `-D clippy::useless-transmute` implied by `-D warnings`
  32
  33     let _: *mut T = core::intrinsics::transmute(t);
  34     //~^ ERROR: transmute from a reference to a pointer
  35
  36     let _: *const U = core::intrinsics::transmute(t);
  37     //~^ ERROR: transmute from a reference to a pointer
  38 }
  39
  40 #[warn(clippy::useless_transmute)]
  41 fn useless() {
  42     unsafe {
  43         let _: Vec<i32> = core::intrinsics::transmute(my_vec());
  44         //~^ ERROR: transmute from a type (`std::vec::Vec<i32>`) to itself
  45
  46         let _: Vec<i32> = core::mem::transmute(my_vec());
  47         //~^ ERROR: transmute from a type (`std::vec::Vec<i32>`) to itself
  48
  49         let _: Vec<i32> = std::intrinsics::transmute(my_vec());
  50         //~^ ERROR: transmute from a type (`std::vec::Vec<i32>`) to itself
  51
  52         let _: Vec<i32> = std::mem::transmute(my_vec());
  53         //~^ ERROR: transmute from a type (`std::vec::Vec<i32>`) to itself
  54
  55         let _: Vec<i32> = my_transmute(my_vec());
  56         //~^ ERROR: transmute from a type (`std::vec::Vec<i32>`) to itself
  57
  58         let _: *const usize = std::mem::transmute(5_isize);
  59         //~^ ERROR: transmute from an integer to a pointer
  60
  61         let _ = 5_isize as *const usize;
  62
  63         let _: *const usize = std::mem::transmute(1 + 1usize);
  64         //~^ ERROR: transmute from an integer to a pointer
  65
  66         let _ = (1 + 1_usize) as *const usize;
  67     }
  68
  69     unsafe fn _f<'a, 'b>(x: &'a u32) -> &'b u32 {
  70         std::mem::transmute(x)
  71     }
  72
  73     unsafe fn _f2<'a, 'b>(x: *const (dyn Iterator<Item = u32> + 'a)) -> *const (dyn Iterator<Item = u32> + 'b) {
  74         std::mem::transmute(x)
  75     }
  76
  77     unsafe fn _f3<'a, 'b>(x: fn(&'a u32)) -> fn(&'b u32) {
  78         std::mem::transmute(x)
  79     }
  80
  81     unsafe fn _f4<'a, 'b>(x: std::borrow::Cow<'a, str>) -> std::borrow::Cow<'b, str> {
  82         std::mem::transmute(x)
  83     }
  84 }
  85
  86 struct Usize(usize);
  87
  88 #[warn(clippy::crosspointer_transmute)]
  89 fn crosspointer() {
  90     let mut int: Usize = Usize(0);
  91     let int_const_ptr: *const Usize = &int as *const Usize;
  92     let int_mut_ptr: *mut Usize = &mut int as *mut Usize;
  93
  94     unsafe {
  95         let _: Usize = core::intrinsics::transmute(int_const_ptr);
  96         //~^ ERROR: transmute from a type (`*const Usize`) to the type that it points to (
  97         //~| NOTE: `-D clippy::crosspointer-transmute` implied by `-D warnings`
  98
  99         let _: Usize = core::intrinsics::transmute(int_mut_ptr);
 100         //~^ ERROR: transmute from a type (`*mut Usize`) to the type that it points to (`U
 101
 102         let _: *const Usize = core::intrinsics::transmute(my_int());
 103         //~^ ERROR: transmute from a type (`Usize`) to a pointer to that type (`*const Usi
 104
 105         let _: *mut Usize = core::intrinsics::transmute(my_int());
 106         //~^ ERROR: transmute from a type (`Usize`) to a pointer to that type (`*mut Usize
 107     }
 108 }
 109
 110 #[warn(clippy::transmute_int_to_bool)]
 111 fn int_to_bool() {
 112     let _: bool = unsafe { std::mem::transmute(0_u8) };
 113     //~^ ERROR: transmute from a `u8` to a `bool`
 114     //~| NOTE: `-D clippy::transmute-int-to-bool` implied by `-D warnings`
 115 }
 116
 117 #[warn(clippy::transmute_int_to_float)]
 118 mod int_to_float {
 119     fn test() {
 120         let _: f32 = unsafe { std::mem::transmute(0_u32) };
 121         //~^ ERROR: transmute from a `u32` to a `f32`
 122         //~| NOTE: `-D clippy::transmute-int-to-float` implied by `-D warnings`
 123         let _: f32 = unsafe { std::mem::transmute(0_i32) };
 124         //~^ ERROR: transmute from a `i32` to a `f32`
 125         let _: f64 = unsafe { std::mem::transmute(0_u64) };
 126         //~^ ERROR: transmute from a `u64` to a `f64`
 127         let _: f64 = unsafe { std::mem::transmute(0_i64) };
 128         //~^ ERROR: transmute from a `i64` to a `f64`
 129     }
 130
 131     mod issue_5747 {
 132         const VALUE32: f32 = unsafe { std::mem::transmute(0_u32) };
 133         const VALUE64: f64 = unsafe { std::mem::transmute(0_i64) };
 134
 135         const fn from_bits_32(v: i32) -> f32 {
 136             unsafe { std::mem::transmute(v) }
 137         }
 138
 139         const fn from_bits_64(v: u64) -> f64 {
 140             unsafe { std::mem::transmute(v) }
 141         }
 142     }
 143 }
 144
 145 mod num_to_bytes {
 146     fn test() {
 147         unsafe {
 148             let _: [u8; 1] = std::mem::transmute(0u8);
 149             //~^ ERROR: transmute from a `u8` to a `[u8; 1]`
 150             //~| NOTE: `-D clippy::transmute-num-to-bytes` implied by `-D warnings`
 151             let _: [u8; 4] = std::mem::transmute(0u32);
 152             //~^ ERROR: transmute from a `u32` to a `[u8; 4]`
 153             let _: [u8; 16] = std::mem::transmute(0u128);
 154             //~^ ERROR: transmute from a `u128` to a `[u8; 16]`
 155             let _: [u8; 1] = std::mem::transmute(0i8);
 156             //~^ ERROR: transmute from a `i8` to a `[u8; 1]`
 157             let _: [u8; 4] = std::mem::transmute(0i32);
 158             //~^ ERROR: transmute from a `i32` to a `[u8; 4]`
 159             let _: [u8; 16] = std::mem::transmute(0i128);
 160             //~^ ERROR: transmute from a `i128` to a `[u8; 16]`
 161             let _: [u8; 4] = std::mem::transmute(0.0f32);
 162             //~^ ERROR: transmute from a `f32` to a `[u8; 4]`
 163             let _: [u8; 8] = std::mem::transmute(0.0f64);
 164             //~^ ERROR: transmute from a `f64` to a `[u8; 8]`
 165         }
 166     }
 167     const fn test_const() {
 168         unsafe {
 169             let _: [u8; 1] = std::mem::transmute(0u8);
 170             //~^ ERROR: transmute from a `u8` to a `[u8; 1]`
 171             let _: [u8; 4] = std::mem::transmute(0u32);
 172             //~^ ERROR: transmute from a `u32` to a `[u8; 4]`
 173             let _: [u8; 16] = std::mem::transmute(0u128);
 174             //~^ ERROR: transmute from a `u128` to a `[u8; 16]`
 175             let _: [u8; 1] = std::mem::transmute(0i8);
 176             //~^ ERROR: transmute from a `i8` to a `[u8; 1]`
 177             let _: [u8; 4] = std::mem::transmute(0i32);
 178             //~^ ERROR: transmute from a `i32` to a `[u8; 4]`
 179             let _: [u8; 16] = std::mem::transmute(0i128);
 180             //~^ ERROR: transmute from a `i128` to a `[u8; 16]`
 181             let _: [u8; 4] = std::mem::transmute(0.0f32);
 182             let _: [u8; 8] = std::mem::transmute(0.0f64);
 183         }
 184     }
 185 }
 186
 187 fn bytes_to_str(mb: &mut [u8]) {
 188     const B: &[u8] = b"";
 189
 190     let _: &str = unsafe { std::mem::transmute(B) };
 191     //~^ ERROR: transmute from a `&[u8]` to a `&str`
 192     //~| NOTE: `-D clippy::transmute-bytes-to-str` implied by `-D warnings`
 193     let _: &mut str = unsafe { std::mem::transmute(mb) };
 194     //~^ ERROR: transmute from a `&mut [u8]` to a `&mut str`
 195     const _: &str = unsafe { std::mem::transmute(B) };
 196     //~^ ERROR: transmute from a `&[u8]` to a `&str`
 197 }
 198
 199 fn main() {}