1 #![feature(tool_lints)]
8 use std::mem::transmute as my_transmute;
9 use std::vec::Vec as MyVec;
11 fn my_int() -> Usize {
15 fn my_vec() -> MyVec<i32> {
19 #[allow(clippy::needless_lifetimes, clippy::transmute_ptr_to_ptr)]
20 #[warn(clippy::useless_transmute)]
21 unsafe fn _generic<'a, T, U: 'a>(t: &'a T) {
22 let _: &'a T = core::intrinsics::transmute(t);
24 let _: &'a U = core::intrinsics::transmute(t);
26 let _: *const T = core::intrinsics::transmute(t);
28 let _: *mut T = core::intrinsics::transmute(t);
30 let _: *const U = core::intrinsics::transmute(t);
33 #[warn(clippy::transmute_ptr_to_ref)]
34 unsafe fn _ptr_to_ref<T, U>(p: *const T, m: *mut T, o: *const U, om: *mut U) {
35 let _: &T = std::mem::transmute(p);
38 let _: &mut T = std::mem::transmute(m);
39 let _: &mut T = &mut *m;
41 let _: &T = std::mem::transmute(m);
44 let _: &mut T = std::mem::transmute(p as *mut T);
45 let _ = &mut *(p as *mut T);
47 let _: &T = std::mem::transmute(o);
48 let _: &T = &*(o as *const T);
50 let _: &mut T = std::mem::transmute(om);
51 let _: &mut T = &mut *(om as *mut T);
53 let _: &T = std::mem::transmute(om);
54 let _: &T = &*(om as *const T);
57 #[warn(clippy::transmute_ptr_to_ref)]
59 struct Foo<'a, T: 'a> {
63 let raw = 42 as *const i32;
64 let _: &Foo<u8> = unsafe { std::mem::transmute::<_, &Foo<_>>(raw) };
66 let _: &Foo<&u8> = unsafe { std::mem::transmute::<_, &Foo<&_>>(raw) };
68 type Bar<'a> = &'a u8;
69 let raw = 42 as *const i32;
70 unsafe { std::mem::transmute::<_, Bar>(raw) };
73 #[warn(clippy::useless_transmute)]
76 let _: Vec<i32> = core::intrinsics::transmute(my_vec());
78 let _: Vec<i32> = core::mem::transmute(my_vec());
80 let _: Vec<i32> = std::intrinsics::transmute(my_vec());
82 let _: Vec<i32> = std::mem::transmute(my_vec());
84 let _: Vec<i32> = my_transmute(my_vec());
86 let _: Vec<u32> = core::intrinsics::transmute(my_vec());
87 let _: Vec<u32> = core::mem::transmute(my_vec());
88 let _: Vec<u32> = std::intrinsics::transmute(my_vec());
89 let _: Vec<u32> = std::mem::transmute(my_vec());
90 let _: Vec<u32> = my_transmute(my_vec());
92 let _: *const usize = std::mem::transmute(5_isize);
94 let _ = 5_isize as *const usize;
96 let _: *const usize = std::mem::transmute(1+1usize);
98 let _ = (1+1_usize) as *const usize;
104 #[warn(clippy::crosspointer_transmute)]
106 let mut int: Usize = Usize(0);
107 let int_const_ptr: *const Usize = &int as *const Usize;
108 let int_mut_ptr: *mut Usize = &mut int as *mut Usize;
111 let _: Usize = core::intrinsics::transmute(int_const_ptr);
113 let _: Usize = core::intrinsics::transmute(int_mut_ptr);
115 let _: *const Usize = core::intrinsics::transmute(my_int());
117 let _: *mut Usize = core::intrinsics::transmute(my_int());
121 #[warn(clippy::transmute_int_to_char)]
123 let _: char = unsafe { std::mem::transmute(0_u32) };
124 let _: char = unsafe { std::mem::transmute(0_i32) };
127 #[warn(clippy::transmute_int_to_bool)]
129 let _: bool = unsafe { std::mem::transmute(0_u8) };
132 #[warn(clippy::transmute_int_to_float)]
134 let _: f32 = unsafe { std::mem::transmute(0_u32) };
135 let _: f32 = unsafe { std::mem::transmute(0_i32) };
138 fn bytes_to_str(b: &[u8], mb: &mut [u8]) {
139 let _: &str = unsafe { std::mem::transmute(b) };
140 let _: &mut str = unsafe { std::mem::transmute(mb) };
143 // Make sure we can modify lifetimes, which is one of the recommended uses
146 // Make sure we can do static lifetime transmutes
147 #[warn(clippy::transmute_ptr_to_ptr)]
148 unsafe fn transmute_lifetime_to_static<'a, T>(t: &'a T) -> &'static T {
149 std::mem::transmute::<&'a T, &'static T>(t)
152 // Make sure we can do non-static lifetime transmutes
153 #[warn(clippy::transmute_ptr_to_ptr)]
154 unsafe fn transmute_lifetime<'a, 'b, T>(t: &'a T, u: &'b T) -> &'b T {
155 std::mem::transmute::<&'a T, &'b T>(t)
158 struct LifetimeParam<'a> {
162 struct GenericParam<T> {
166 #[warn(clippy::transmute_ptr_to_ptr)]
167 fn transmute_ptr_to_ptr() {
168 let ptr = &1u32 as *const u32;
169 let mut_ptr = &mut 1u32 as *mut u32;
171 // pointer-to-pointer transmutes; bad
172 let _: *const f32 = std::mem::transmute(ptr);
173 let _: *mut f32 = std::mem::transmute(mut_ptr);
174 // ref-ref transmutes; bad
175 let _: &f32 = std::mem::transmute(&1u32);
176 let _: &f64 = std::mem::transmute(&1f32);
177 // ^ this test is here because both f32 and f64 are the same TypeVariant, but they are not
179 let _: &mut f32 = std::mem::transmute(&mut 1u32);
180 let _: &GenericParam<f32> = std::mem::transmute(&GenericParam { t: 1u32 });
183 // these are recommendations for solving the above; if these lint we need to update
185 let _ = ptr as *const f32;
186 let _ = mut_ptr as *mut f32;
187 let _ = unsafe { &*(&1u32 as *const u32 as *const f32) };
188 let _ = unsafe { &mut *(&mut 1u32 as *mut u32 as *mut f32) };
190 // transmute internal lifetimes, should not lint
191 let s = "hello world".to_owned();
192 let lp = LifetimeParam { s: &s };
193 let _: &LifetimeParam<'static> = unsafe { std::mem::transmute(&lp) };
194 let _: &GenericParam<&LifetimeParam<'static>> = unsafe {
195 std::mem::transmute(&GenericParam { t: &lp})