Auto merge of #5068 - JohnTitor:split-up-transmute, r=phansch

Split up `transmute` ui test

Part of #2038

changelog: none

Author: bors

clippy_dev/src/stderr_length_check.rs

@@ -7,7 +7,7 @@ use std::io::prelude::*;
 // The maximum length allowed for stderr files.
 //
 // We limit this because small files are easier to deal with than bigger files.
-const LIMIT: usize = 275;
+const LIMIT: usize = 245;
 
 pub fn check() {
     let stderr_files = stderr_files();

tests/ui/transmute.rs

@@ -27,46 +27,6 @@ unsafe fn _generic<'a, T, U: 'a>(t: &'a T) {
     let _: *const U = core::intrinsics::transmute(t);
 }
 
-#[warn(clippy::transmute_ptr_to_ref)]
-unsafe fn _ptr_to_ref<T, U>(p: *const T, m: *mut T, o: *const U, om: *mut U) {
-    let _: &T = std::mem::transmute(p);
-    let _: &T = &*p;
-
-    let _: &mut T = std::mem::transmute(m);
-    let _: &mut T = &mut *m;
-
-    let _: &T = std::mem::transmute(m);
-    let _: &T = &*m;
-
-    let _: &mut T = std::mem::transmute(p as *mut T);
-    let _ = &mut *(p as *mut T);
-
-    let _: &T = std::mem::transmute(o);
-    let _: &T = &*(o as *const T);
-
-    let _: &mut T = std::mem::transmute(om);
-    let _: &mut T = &mut *(om as *mut T);
-
-    let _: &T = std::mem::transmute(om);
-    let _: &T = &*(om as *const T);
-}
-
-#[warn(clippy::transmute_ptr_to_ref)]
-fn issue1231() {
-    struct Foo<'a, T> {
-        bar: &'a T,
-    }
-
-    let raw = 42 as *const i32;
-    let _: &Foo<u8> = unsafe { std::mem::transmute::<_, &Foo<_>>(raw) };
-
-    let _: &Foo<&u8> = unsafe { std::mem::transmute::<_, &Foo<&_>>(raw) };
-
-    type Bar<'a> = &'a u8;
-    let raw = 42 as *const i32;
-    unsafe { std::mem::transmute::<_, Bar>(raw) };
-}
-
 #[warn(clippy::useless_transmute)]
 fn useless() {
     unsafe {
@@ -131,58 +91,4 @@ fn bytes_to_str(b: &[u8], mb: &mut [u8]) {
     let _: &mut str = unsafe { std::mem::transmute(mb) };
 }
 
-// Make sure we can modify lifetimes, which is one of the recommended uses
-// of transmute
-
-// Make sure we can do static lifetime transmutes
-#[warn(clippy::transmute_ptr_to_ptr)]
-unsafe fn transmute_lifetime_to_static<'a, T>(t: &'a T) -> &'static T {
-    std::mem::transmute::<&'a T, &'static T>(t)
-}
-
-// Make sure we can do non-static lifetime transmutes
-#[warn(clippy::transmute_ptr_to_ptr)]
-unsafe fn transmute_lifetime<'a, 'b, T>(t: &'a T, u: &'b T) -> &'b T {
-    std::mem::transmute::<&'a T, &'b T>(t)
-}
-
-struct LifetimeParam<'a> {
-    s: &'a str,
-}
-
-struct GenericParam<T> {
-    t: T,
-}
-
-#[warn(clippy::transmute_ptr_to_ptr)]
-fn transmute_ptr_to_ptr() {
-    let ptr = &1u32 as *const u32;
-    let mut_ptr = &mut 1u32 as *mut u32;
-    unsafe {
-        // pointer-to-pointer transmutes; bad
-        let _: *const f32 = std::mem::transmute(ptr);
-        let _: *mut f32 = std::mem::transmute(mut_ptr);
-        // ref-ref transmutes; bad
-        let _: &f32 = std::mem::transmute(&1u32);
-        let _: &f64 = std::mem::transmute(&1f32);
-        // ^ this test is here because both f32 and f64 are the same TypeVariant, but they are not
-        // the same type
-        let _: &mut f32 = std::mem::transmute(&mut 1u32);
-        let _: &GenericParam<f32> = std::mem::transmute(&GenericParam { t: 1u32 });
-    }
-
-    // these are recommendations for solving the above; if these lint we need to update
-    // those suggestions
-    let _ = ptr as *const f32;
-    let _ = mut_ptr as *mut f32;
-    let _ = unsafe { &*(&1u32 as *const u32 as *const f32) };
-    let _ = unsafe { &mut *(&mut 1u32 as *mut u32 as *mut f32) };
-
-    // transmute internal lifetimes, should not lint
-    let s = "hello world".to_owned();
-    let lp = LifetimeParam { s: &s };
-    let _: &LifetimeParam<'static> = unsafe { std::mem::transmute(&lp) };
-    let _: &GenericParam<&LifetimeParam<'static>> = unsafe { std::mem::transmute(&GenericParam { t: &lp }) };
-}
-
 fn main() {}

tests/ui/transmute.stderr

@@ -24,223 +24,123 @@ error: transmute from a reference to a pointer
 LL |     let _: *const U = core::intrinsics::transmute(t);
    |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `t as *const T as *const U`
 
-error: transmute from a pointer type (`*const T`) to a reference type (`&T`)
-  --> $DIR/transmute.rs:32:17
-   |
-LL |     let _: &T = std::mem::transmute(p);
-   |                 ^^^^^^^^^^^^^^^^^^^^^^ help: try: `&*p`
-   |
-   = note: `-D clippy::transmute-ptr-to-ref` implied by `-D warnings`
-
-error: transmute from a pointer type (`*mut T`) to a reference type (`&mut T`)
-  --> $DIR/transmute.rs:35:21
-   |
-LL |     let _: &mut T = std::mem::transmute(m);
-   |                     ^^^^^^^^^^^^^^^^^^^^^^ help: try: `&mut *m`
-
-error: transmute from a pointer type (`*mut T`) to a reference type (`&T`)
-  --> $DIR/transmute.rs:38:17
-   |
-LL |     let _: &T = std::mem::transmute(m);
-   |                 ^^^^^^^^^^^^^^^^^^^^^^ help: try: `&*m`
-
-error: transmute from a pointer type (`*mut T`) to a reference type (`&mut T`)
-  --> $DIR/transmute.rs:41:21
-   |
-LL |     let _: &mut T = std::mem::transmute(p as *mut T);
-   |                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `&mut *(p as *mut T)`
-
-error: transmute from a pointer type (`*const U`) to a reference type (`&T`)
-  --> $DIR/transmute.rs:44:17
-   |
-LL |     let _: &T = std::mem::transmute(o);
-   |                 ^^^^^^^^^^^^^^^^^^^^^^ help: try: `&*(o as *const T)`
-
-error: transmute from a pointer type (`*mut U`) to a reference type (`&mut T`)
-  --> $DIR/transmute.rs:47:21
-   |
-LL |     let _: &mut T = std::mem::transmute(om);
-   |                     ^^^^^^^^^^^^^^^^^^^^^^^ help: try: `&mut *(om as *mut T)`
-
-error: transmute from a pointer type (`*mut U`) to a reference type (`&T`)
-  --> $DIR/transmute.rs:50:17
-   |
-LL |     let _: &T = std::mem::transmute(om);
-   |                 ^^^^^^^^^^^^^^^^^^^^^^^ help: try: `&*(om as *const T)`
-
-error: transmute from a pointer type (`*const i32`) to a reference type (`&issue1231::Foo<'_, u8>`)
-  --> $DIR/transmute.rs:61:32
-   |
-LL |     let _: &Foo<u8> = unsafe { std::mem::transmute::<_, &Foo<_>>(raw) };
-   |                                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `&*(raw as *const Foo<_>)`
-
-error: transmute from a pointer type (`*const i32`) to a reference type (`&issue1231::Foo<'_, &u8>`)
-  --> $DIR/transmute.rs:63:33
-   |
-LL |     let _: &Foo<&u8> = unsafe { std::mem::transmute::<_, &Foo<&_>>(raw) };
-   |                                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `&*(raw as *const Foo<&_>)`
-
-error: transmute from a pointer type (`*const i32`) to a reference type (`&u8`)
-  --> $DIR/transmute.rs:67:14
-   |
-LL |     unsafe { std::mem::transmute::<_, Bar>(raw) };
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `&*(raw as *const u8)`
-
 error: transmute from a type (`std::vec::Vec<i32>`) to itself
-  --> $DIR/transmute.rs:73:27
+  --> $DIR/transmute.rs:33:27
    |
 LL |         let _: Vec<i32> = core::intrinsics::transmute(my_vec());
    |                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: transmute from a type (`std::vec::Vec<i32>`) to itself
-  --> $DIR/transmute.rs:75:27
+  --> $DIR/transmute.rs:35:27
    |
 LL |         let _: Vec<i32> = core::mem::transmute(my_vec());
    |                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: transmute from a type (`std::vec::Vec<i32>`) to itself
-  --> $DIR/transmute.rs:77:27
+  --> $DIR/transmute.rs:37:27
    |
 LL |         let _: Vec<i32> = std::intrinsics::transmute(my_vec());
    |                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: transmute from a type (`std::vec::Vec<i32>`) to itself
-  --> $DIR/transmute.rs:79:27
+  --> $DIR/transmute.rs:39:27
    |
 LL |         let _: Vec<i32> = std::mem::transmute(my_vec());
    |                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: transmute from a type (`std::vec::Vec<i32>`) to itself
-  --> $DIR/transmute.rs:81:27
+  --> $DIR/transmute.rs:41:27
    |
 LL |         let _: Vec<i32> = my_transmute(my_vec());
    |                           ^^^^^^^^^^^^^^^^^^^^^^
 
 error: transmute from an integer to a pointer
-  --> $DIR/transmute.rs:83:31
+  --> $DIR/transmute.rs:43:31
    |
 LL |         let _: *const usize = std::mem::transmute(5_isize);
    |                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `5_isize as *const usize`
 
 error: transmute from an integer to a pointer
-  --> $DIR/transmute.rs:87:31
+  --> $DIR/transmute.rs:47:31
    |
 LL |         let _: *const usize = std::mem::transmute(1 + 1usize);
    |                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `(1 + 1usize) as *const usize`
 
 error: transmute from a type (`*const Usize`) to the type that it points to (`Usize`)
-  --> $DIR/transmute.rs:102:24
+  --> $DIR/transmute.rs:62:24
    |
 LL |         let _: Usize = core::intrinsics::transmute(int_const_ptr);
    |                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: `-D clippy::crosspointer-transmute` implied by `-D warnings`
 
 error: transmute from a type (`*mut Usize`) to the type that it points to (`Usize`)
-  --> $DIR/transmute.rs:104:24
+  --> $DIR/transmute.rs:64:24
    |
 LL |         let _: Usize = core::intrinsics::transmute(int_mut_ptr);
    |                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: transmute from a type (`Usize`) to a pointer to that type (`*const Usize`)
-  --> $DIR/transmute.rs:106:31
+  --> $DIR/transmute.rs:66:31
    |
 LL |         let _: *const Usize = core::intrinsics::transmute(my_int());
    |                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: transmute from a type (`Usize`) to a pointer to that type (`*mut Usize`)
-  --> $DIR/transmute.rs:108:29
+  --> $DIR/transmute.rs:68:29
    |
 LL |         let _: *mut Usize = core::intrinsics::transmute(my_int());
    |                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: transmute from a `u32` to a `char`
-  --> $DIR/transmute.rs:114:28
+  --> $DIR/transmute.rs:74:28
    |
 LL |     let _: char = unsafe { std::mem::transmute(0_u32) };
    |                            ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `std::char::from_u32(0_u32).unwrap()`
    |
    = note: `-D clippy::transmute-int-to-char` implied by `-D warnings`
 
 error: transmute from a `i32` to a `char`
-  --> $DIR/transmute.rs:115:28
+  --> $DIR/transmute.rs:75:28
    |
 LL |     let _: char = unsafe { std::mem::transmute(0_i32) };
    |                            ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `std::char::from_u32(0_i32 as u32).unwrap()`
 
 error: transmute from a `u8` to a `bool`
-  --> $DIR/transmute.rs:120:28
+  --> $DIR/transmute.rs:80:28
    |
 LL |     let _: bool = unsafe { std::mem::transmute(0_u8) };
    |                            ^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `0_u8 != 0`
    |
    = note: `-D clippy::transmute-int-to-bool` implied by `-D warnings`
 
 error: transmute from a `u32` to a `f32`
-  --> $DIR/transmute.rs:125:27
+  --> $DIR/transmute.rs:85:27
    |
 LL |     let _: f32 = unsafe { std::mem::transmute(0_u32) };
    |                           ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `f32::from_bits(0_u32)`
    |
    = note: `-D clippy::transmute-int-to-float` implied by `-D warnings`
 
 error: transmute from a `i32` to a `f32`
-  --> $DIR/transmute.rs:126:27
+  --> $DIR/transmute.rs:86:27
    |
 LL |     let _: f32 = unsafe { std::mem::transmute(0_i32) };
    |                           ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `f32::from_bits(0_i32 as u32)`
 
 error: transmute from a `&[u8]` to a `&str`
-  --> $DIR/transmute.rs:130:28
+  --> $DIR/transmute.rs:90:28
    |
 LL |     let _: &str = unsafe { std::mem::transmute(b) };
    |                            ^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `std::str::from_utf8(b).unwrap()`
    |
    = note: `-D clippy::transmute-bytes-to-str` implied by `-D warnings`
 
 error: transmute from a `&mut [u8]` to a `&mut str`
-  --> $DIR/transmute.rs:131:32
+  --> $DIR/transmute.rs:91:32
    |
 LL |     let _: &mut str = unsafe { std::mem::transmute(mb) };
    |                                ^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `std::str::from_utf8_mut(mb).unwrap()`
 
-error: transmute from a pointer to a pointer
-  --> $DIR/transmute.rs:163:29
-   |
-LL |         let _: *const f32 = std::mem::transmute(ptr);
-   |                             ^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `ptr as *const f32`
-   |
-   = note: `-D clippy::transmute-ptr-to-ptr` implied by `-D warnings`
-
-error: transmute from a pointer to a pointer
-  --> $DIR/transmute.rs:164:27
-   |
-LL |         let _: *mut f32 = std::mem::transmute(mut_ptr);
-   |                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `mut_ptr as *mut f32`
-
-error: transmute from a reference to a reference
-  --> $DIR/transmute.rs:166:23
-   |
-LL |         let _: &f32 = std::mem::transmute(&1u32);
-   |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `&*(&1u32 as *const u32 as *const f32)`
-
-error: transmute from a reference to a reference
-  --> $DIR/transmute.rs:167:23
-   |
-LL |         let _: &f64 = std::mem::transmute(&1f32);
-   |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `&*(&1f32 as *const f32 as *const f64)`
-
-error: transmute from a reference to a reference
-  --> $DIR/transmute.rs:170:27
-   |
-LL |         let _: &mut f32 = std::mem::transmute(&mut 1u32);
-   |                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `&mut *(&mut 1u32 as *mut u32 as *mut f32)`
-
-error: transmute from a reference to a reference
-  --> $DIR/transmute.rs:171:37
-   |
-LL |         let _: &GenericParam<f32> = std::mem::transmute(&GenericParam { t: 1u32 });
-   |                                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `&*(&GenericParam { t: 1u32 } as *const GenericParam<u32> as *const GenericParam<f32>)`
-
-error: aborting due to 38 previous errors
+error: aborting due to 22 previous errors