error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell`
  --> $DIR/reference_casting.rs:17:16
   |
LL |     let _num = &mut *(num as *const i32 as *mut i32);
   |                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>
   = note: `#[deny(invalid_reference_casting)]` on by default

error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell`
  --> $DIR/reference_casting.rs:19:16
   |
LL |     let _num = &mut *(num as *const i32).cast_mut();
   |                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>

error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell`
  --> $DIR/reference_casting.rs:21:16
   |
LL |     let _num = &mut *std::ptr::from_ref(num).cast_mut();
   |                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>

error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell`
  --> $DIR/reference_casting.rs:23:16
   |
LL |     let _num = &mut *std::ptr::from_ref({ num }).cast_mut();
   |                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>

error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell`
  --> $DIR/reference_casting.rs:25:16
   |
LL |     let _num = &mut *{ std::ptr::from_ref(num) }.cast_mut();
   |                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>

error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell`
  --> $DIR/reference_casting.rs:27:16
   |
LL |     let _num = &mut *(std::ptr::from_ref({ num }) as *mut i32);
   |                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>

error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell`
  --> $DIR/reference_casting.rs:29:16
   |
LL |     let _num = &mut *(num as *const i32).cast::<i32>().cast_mut();
   |                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>

error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell`
  --> $DIR/reference_casting.rs:31:16
   |
LL |     let _num = &mut *(num as *const i32).cast::<i32>().cast_mut().cast_const().cast_mut();
   |                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>

error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell`
  --> $DIR/reference_casting.rs:33:16
   |
LL |     let _num = &mut *(std::ptr::from_ref(static_u8()) as *mut i8);
   |                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>

error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell`
  --> $DIR/reference_casting.rs:35:16
   |
LL |     let _num = &mut *std::mem::transmute::<_, *mut i32>(num);
   |                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>

error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell`
  --> $DIR/reference_casting.rs:37:16
   |
LL |     let _num = &mut *(std::mem::transmute::<_, *mut i32>(num) as *mut i32);
   |                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>

error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell`
  --> $DIR/reference_casting.rs:39:16
   |
LL |       let _num = &mut *std::cell::UnsafeCell::raw_get(
   |  ________________^
LL | |
LL | |         num as *const i32 as *const std::cell::UnsafeCell<i32>
LL | |     );
   | |_____^
   |
   = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>

error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell`
  --> $DIR/reference_casting.rs:45:16
   |
LL |     let deferred = num as *const i32 as *mut i32;
   |                    ----------------------------- casting happened here
LL |     let _num = &mut *deferred;
   |                ^^^^^^^^^^^^^^
   |
   = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>

error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell`
  --> $DIR/reference_casting.rs:48:16
   |
LL |     let deferred = (std::ptr::from_ref(num) as *const i32 as *const i32).cast_mut() as *mut i32;
   |                    ---------------------------------------------------------------------------- casting happened here
LL |     let _num = &mut *deferred;
   |                ^^^^^^^^^^^^^^
   |
   = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>

error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell`
  --> $DIR/reference_casting.rs:51:16
   |
LL |     let deferred = (std::ptr::from_ref(num) as *const i32 as *const i32).cast_mut() as *mut i32;
   |                    ---------------------------------------------------------------------------- casting happened here
...
LL |     let _num = &mut *deferred_rebind;
   |                ^^^^^^^^^^^^^^^^^^^^^
   |
   = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>

error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell`
  --> $DIR/reference_casting.rs:53:16
   |
LL |     let _num = &mut *(num as *const _ as usize as *mut i32);
   |                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>

error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell`
  --> $DIR/reference_casting.rs:55:16
   |
LL |     let _num = &mut *(std::mem::transmute::<_, *mut _>(num as *const i32) as *mut i32);
   |                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>

error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell`
  --> $DIR/reference_casting.rs:62:16
   |
LL |     let num = NUM as *const i32 as *mut i32;
   |               ----------------------------- casting happened here
...
LL |     let _num = &mut *num;
   |                ^^^^^^^^^
   |
   = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>

error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell`
  --> $DIR/reference_casting.rs:66:16
   |
LL |     let _num = &mut *(cell as *const _ as *mut i32);
   |                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>
   = note: even for types with interior mutability, the only legal way to obtain a mutable pointer from a shared reference is through `UnsafeCell::get`

error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell`
  --> $DIR/reference_casting.rs:70:9
   |
LL |         &mut *((this as *const _) as *mut _)
   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>

error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell`
  --> $DIR/reference_casting.rs:75:18
   |
LL |         unsafe { &mut *std::cell::UnsafeCell::raw_get(x as *const _ as *const _) }
   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>

error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell`
  --> $DIR/reference_casting.rs:80:18
   |
LL |         unsafe { &mut *std::cell::UnsafeCell::raw_get(x as *const _ as *const _) }
   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>

error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell`
  --> $DIR/reference_casting.rs:90:5
   |
LL |     *(a as *const _ as *mut _) = String::from("Replaced");
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>

error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell`
  --> $DIR/reference_casting.rs:92:5
   |
LL |     *(a as *const _ as *mut String) += " world";
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>

error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell`
  --> $DIR/reference_casting.rs:94:5
   |
LL |     *std::ptr::from_ref(num).cast_mut() += 1;
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>

error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell`
  --> $DIR/reference_casting.rs:96:5
   |
LL |     *std::ptr::from_ref({ num }).cast_mut() += 1;
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>

error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell`
  --> $DIR/reference_casting.rs:98:5
   |
LL |     *{ std::ptr::from_ref(num) }.cast_mut() += 1;
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>

error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell`
  --> $DIR/reference_casting.rs:100:5
   |
LL |     *(std::ptr::from_ref({ num }) as *mut i32) += 1;
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>

error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell`
  --> $DIR/reference_casting.rs:102:5
   |
LL |     *std::mem::transmute::<_, *mut i32>(num) += 1;
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>

error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell`
  --> $DIR/reference_casting.rs:104:5
   |
LL |     *(std::mem::transmute::<_, *mut i32>(num) as *mut i32) += 1;
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>

error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell`
  --> $DIR/reference_casting.rs:106:5
   |
LL | /     std::ptr::write(
LL | |
LL | |         std::mem::transmute::<*const i32, *mut i32>(num),
LL | |         -1i32,
LL | |     );
   | |_____^
   |
   = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>

error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell`
  --> $DIR/reference_casting.rs:111:5
   |
LL |     *((&std::cell::UnsafeCell::new(0)) as *const _ as *mut i32) = 5;
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>
   = note: even for types with interior mutability, the only legal way to obtain a mutable pointer from a shared reference is through `UnsafeCell::get`

error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell`
  --> $DIR/reference_casting.rs:115:5
   |
LL |     let value = num as *const i32 as *mut i32;
   |                 ----------------------------- casting happened here
LL |     *value = 1;
   |     ^^^^^^^^^^
   |
   = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>

error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell`
  --> $DIR/reference_casting.rs:119:5
   |
LL |     let value = value as *mut i32;
   |                 ----------------- casting happened here
LL |     *value = 1;
   |     ^^^^^^^^^^
   |
   = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>

error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell`
  --> $DIR/reference_casting.rs:122:5
   |
LL |     let value = num as *const i32 as *mut i32;
   |                 ----------------------------- casting happened here
LL |     *value = 1;
   |     ^^^^^^^^^^
   |
   = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>

error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell`
  --> $DIR/reference_casting.rs:125:5
   |
LL |     let value = num as *const i32 as *mut i32;
   |                 ----------------------------- casting happened here
...
LL |     *value_rebind = 1;
   |     ^^^^^^^^^^^^^^^^^
   |
   = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>

error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell`
  --> $DIR/reference_casting.rs:127:5
   |
LL |     *(num as *const i32).cast::<i32>().cast_mut() = 2;
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>

error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell`
  --> $DIR/reference_casting.rs:129:5
   |
LL |     *(num as *const _ as usize as *mut i32) = 2;
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>

error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell`
  --> $DIR/reference_casting.rs:131:5
   |
LL |     let value = num as *const i32 as *mut i32;
   |                 ----------------------------- casting happened here
...
LL |     std::ptr::write(value, 2);
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>

error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell`
  --> $DIR/reference_casting.rs:133:5
   |
LL |     let value = num as *const i32 as *mut i32;
   |                 ----------------------------- casting happened here
...
LL |     std::ptr::write_unaligned(value, 2);
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>

error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell`
  --> $DIR/reference_casting.rs:135:5
   |
LL |     let value = num as *const i32 as *mut i32;
   |                 ----------------------------- casting happened here
...
LL |     std::ptr::write_volatile(value, 2);
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>

error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell`
  --> $DIR/reference_casting.rs:139:9
   |
LL |         *(this as *const _ as *mut _) = a;
   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>

error: casting references to a bigger memory layout than the backing allocation is undefined behavior, even if the reference is unused
  --> $DIR/reference_casting.rs:161:20
   |
LL |         let num = &mut 3i32;
   |                        ---- backing allocation comes from here
LL |
LL |         let _num = &*(num as *const i32 as *const i64);
   |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: casting from `i32` (4 bytes) to `i64` (8 bytes)

error: casting references to a bigger memory layout than the backing allocation is undefined behavior, even if the reference is unused
  --> $DIR/reference_casting.rs:163:20
   |
LL |         let num = &mut 3i32;
   |                        ---- backing allocation comes from here
...
LL |         let _num = &mut *(num as *mut i32 as *mut i64);
   |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: casting from `i32` (4 bytes) to `i64` (8 bytes)

error: casting references to a bigger memory layout than the backing allocation is undefined behavior, even if the reference is unused
  --> $DIR/reference_casting.rs:165:20
   |
LL |         let num = &mut 3i32;
   |                        ---- backing allocation comes from here
...
LL |         let _num = &mut *(num as *mut i32 as *mut I64);
   |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: casting from `i32` (4 bytes) to `I64` (16 bytes)

error: casting references to a bigger memory layout than the backing allocation is undefined behavior, even if the reference is unused
  --> $DIR/reference_casting.rs:167:9
   |
LL |         let num = &mut 3i32;
   |                        ---- backing allocation comes from here
...
LL |         std::ptr::write(num as *mut i32 as *mut i64, 2);
   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: casting from `i32` (4 bytes) to `i64` (8 bytes)

error: casting references to a bigger memory layout than the backing allocation is undefined behavior, even if the reference is unused
  --> $DIR/reference_casting.rs:176:20
   |
LL |         let num = &mut [0i32; 3];
   |                        --------- backing allocation comes from here
LL |
LL |         let _num = &mut *(num as *mut _ as *mut [i64; 2]);
   |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: casting from `[i32; 3]` (12 bytes) to `[i64; 2]` (16 bytes)

error: casting references to a bigger memory layout than the backing allocation is undefined behavior, even if the reference is unused
  --> $DIR/reference_casting.rs:178:9
   |
LL |         let num = &mut [0i32; 3];
   |                        --------- backing allocation comes from here
...
LL |         std::ptr::write_unaligned(num as *mut _ as *mut [i32; 4], [0, 0, 1, 1]);
   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: casting from `[i32; 3]` (12 bytes) to `[i32; 4]` (16 bytes)

error: casting references to a bigger memory layout than the backing allocation is undefined behavior, even if the reference is unused
  --> $DIR/reference_casting.rs:188:20
   |
LL |         let num = &mut [0i32; 3] as &mut [i32];
   |                        --------- backing allocation comes from here
LL |
LL |         let _num = &mut *(num as *mut _ as *mut i128);
   |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: casting from `[i32; 3]` (12 bytes) to `i128` (16 bytes)

error: casting references to a bigger memory layout than the backing allocation is undefined behavior, even if the reference is unused
  --> $DIR/reference_casting.rs:190:20
   |
LL |         let num = &mut [0i32; 3] as &mut [i32];
   |                        --------- backing allocation comes from here
...
LL |         let _num = &mut *(num as *mut _ as *mut [i64; 4]);
   |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: casting from `[i32; 3]` (12 bytes) to `[i64; 4]` (32 bytes)

error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell`
  --> $DIR/reference_casting.rs:200:20
   |
LL |         let _num = &mut *(&mat3 as *const _ as *mut [[i64; 3]; 3]);
   |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>

error: casting references to a bigger memory layout than the backing allocation is undefined behavior, even if the reference is unused
  --> $DIR/reference_casting.rs:200:20
   |
LL |         let _num = &mut *(&mat3 as *const _ as *mut [[i64; 3]; 3]);
   |                    ^^^^^^^^----^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |                            |
   |                            backing allocation comes from here
   |
   = note: casting from `Mat3<i32>` (36 bytes) to `[[i64; 3]; 3]` (72 bytes)

error: casting references to a bigger memory layout than the backing allocation is undefined behavior, even if the reference is unused
  --> $DIR/reference_casting.rs:203:20
   |
LL |         let _num = &*(&mat3 as *const _ as *mut [[i64; 3]; 3]);
   |                    ^^^^----^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |                        |
   |                        backing allocation comes from here
   |
   = note: casting from `Mat3<i32>` (36 bytes) to `[[i64; 3]; 3]` (72 bytes)

error: casting references to a bigger memory layout than the backing allocation is undefined behavior, even if the reference is unused
  --> $DIR/reference_casting.rs:212:37
   |
LL |         let w: *mut [u16; 2] = &mut l as *mut [u8; 2] as *mut _;
   |                                --------------------------------
   |                                |    |
   |                                |    backing allocation comes from here
   |                                casting happened here
LL |         let w: *mut [u16] = unsafe {&mut *w};
   |                                     ^^^^^^^
   |
   = note: casting from `[u8; 2]` (2 bytes) to `[u16; 2]` (4 bytes)

error: casting references to a bigger memory layout than the backing allocation is undefined behavior, even if the reference is unused
  --> $DIR/reference_casting.rs:220:20
   |
LL |         let _num = &*(&num as *const i32 as *const i64);
   |                    ^^^^---^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |                        |
   |                        backing allocation comes from here
   |
   = note: casting from `[i32; 1]` (4 bytes) to `i64` (8 bytes)

error: casting references to a bigger memory layout than the backing allocation is undefined behavior, even if the reference is unused
  --> $DIR/reference_casting.rs:222:20
   |
LL |         let _num = &*(&foo() as *const i32 as *const i64);
   |                    ^^^^-----^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |                        |
   |                        backing allocation comes from here
   |
   = note: casting from `[i32; 1]` (4 bytes) to `i64` (8 bytes)

error: casting references to a bigger memory layout than the backing allocation is undefined behavior, even if the reference is unused
  --> $DIR/reference_casting.rs:238:20
   |
LL |         let _num = &*(&num as *const i32 as *const i64);
   |                    ^^^^---^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |                        |
   |                        backing allocation comes from here
   |
   = note: casting from `i32` (4 bytes) to `i64` (8 bytes)

error: aborting due to 57 previous errors