warning: function pointers are not nullable, so checking them for null will always return false --> $DIR/ptr_null_checks.rs:14:8 | LL | if (fn_ptr as *mut ()).is_null() {} | ^------^^^^^^^^^^^^^^^^^^^^^^ | | | expression has type `fn() {main}` | = help: wrap the function pointer inside an `Option` and use `Option::is_none` to check for null pointer value = note: `#[warn(useless_ptr_null_checks)]` on by default warning: function pointers are not nullable, so checking them for null will always return false --> $DIR/ptr_null_checks.rs:16:8 | LL | if (fn_ptr as *const u8).is_null() {} | ^------^^^^^^^^^^^^^^^^^^^^^^^^ | | | expression has type `fn() {main}` | = help: wrap the function pointer inside an `Option` and use `Option::is_none` to check for null pointer value warning: function pointers are not nullable, so checking them for null will always return false --> $DIR/ptr_null_checks.rs:18:8 | LL | if (fn_ptr as *const ()) == std::ptr::null() {} | ^------^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | | | expression has type `fn() {main}` | = help: wrap the function pointer inside an `Option` and use `Option::is_none` to check for null pointer value warning: function pointers are not nullable, so checking them for null will always return false --> $DIR/ptr_null_checks.rs:20:8 | LL | if (fn_ptr as *mut ()) == std::ptr::null_mut() {} | ^------^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | | | expression has type `fn() {main}` | = help: wrap the function pointer inside an `Option` and use `Option::is_none` to check for null pointer value warning: function pointers are not nullable, so checking them for null will always return false --> $DIR/ptr_null_checks.rs:22:8 | LL | if (fn_ptr as *const ()) == (0 as *const ()) {} | ^------^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | | | expression has type `fn() {main}` | = help: wrap the function pointer inside an `Option` and use `Option::is_none` to check for null pointer value warning: function pointers are not nullable, so checking them for null will always return false --> $DIR/ptr_null_checks.rs:24:8 | LL | if <*const _>::is_null(fn_ptr as *const ()) {} | ^^^^^^^^^^^^^^^^^^^^------^^^^^^^^^^^^^^ | | | expression has type `fn() {main}` | = help: wrap the function pointer inside an `Option` and use `Option::is_none` to check for null pointer value warning: function pointers are not nullable, so checking them for null will always return false --> $DIR/ptr_null_checks.rs:26:8 | LL | if (fn_ptr as *mut fn() as *const fn() as *const ()).is_null() {} | ^------^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | | | expression has type `fn() {main}` | = help: wrap the function pointer inside an `Option` and use `Option::is_none` to check for null pointer value warning: function pointers are not nullable, so checking them for null will always return false --> $DIR/ptr_null_checks.rs:28:8 | LL | if (fn_ptr as *mut fn() as *const fn()).cast_mut().is_null() {} | ^------^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | | | expression has type `fn() {main}` | = help: wrap the function pointer inside an `Option` and use `Option::is_none` to check for null pointer value warning: function pointers are not nullable, so checking them for null will always return false --> $DIR/ptr_null_checks.rs:30:8 | LL | if ((fn_ptr as *mut fn()).cast() as *const fn()).cast_mut().is_null() {} | ^^------^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | | | expression has type `fn() {main}` | = help: wrap the function pointer inside an `Option` and use `Option::is_none` to check for null pointer value warning: function pointers are not nullable, so checking them for null will always return false --> $DIR/ptr_null_checks.rs:32:8 | LL | if (fn_ptr as fn() as *const ()).is_null() {} | ^--------------^^^^^^^^^^^^^^^^^^^^^^^^ | | | expression has type `fn()` | = help: wrap the function pointer inside an `Option` and use `Option::is_none` to check for null pointer value warning: function pointers are not nullable, so checking them for null will always return false --> $DIR/ptr_null_checks.rs:34:8 | LL | if (c_fn as *const fn()).is_null() {} | ^----^^^^^^^^^^^^^^^^^^^^^^^^^^ | | | expression has type `extern "C" fn() {c_fn}` | = help: wrap the function pointer inside an `Option` and use `Option::is_none` to check for null pointer value warning: references are not nullable, so checking them for null will always return false --> $DIR/ptr_null_checks.rs:38:8 | LL | if (&mut 8 as *mut i32).is_null() {} | ^------^^^^^^^^^^^^^^^^^^^^^^^ | | | expression has type `&mut i32` warning: returned pointer of `from_mut` call is never null, so checking it for null will always return false --> $DIR/ptr_null_checks.rs:40:8 | LL | if ptr::from_mut(&mut 8).is_null() {} | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ warning: references are not nullable, so checking them for null will always return false --> $DIR/ptr_null_checks.rs:42:8 | LL | if (&8 as *const i32).is_null() {} | ^--^^^^^^^^^^^^^^^^^^^^^^^^^ | | | expression has type `&i32` warning: returned pointer of `from_ref` call is never null, so checking it for null will always return false --> $DIR/ptr_null_checks.rs:44:8 | LL | if ptr::from_ref(&8).is_null() {} | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ warning: returned pointer of `from_ref` call is never null, so checking it for null will always return false --> $DIR/ptr_null_checks.rs:46:8 | LL | if ptr::from_ref(&8).cast_mut().is_null() {} | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ warning: returned pointer of `from_ref` call is never null, so checking it for null will always return false --> $DIR/ptr_null_checks.rs:48:8 | LL | if (ptr::from_ref(&8).cast_mut() as *mut i32).is_null() {} | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ warning: references are not nullable, so checking them for null will always return false --> $DIR/ptr_null_checks.rs:50:8 | LL | if (&8 as *const i32) == std::ptr::null() {} | ^--^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | | | expression has type `&i32` warning: references are not nullable, so checking them for null will always return false --> $DIR/ptr_null_checks.rs:53:8 | LL | if (ref_num as *const i32) == std::ptr::null() {} | ^-------^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | | | expression has type `&i32` warning: references are not nullable, so checking them for null will always return false --> $DIR/ptr_null_checks.rs:55:8 | LL | if (b"\0" as *const u8).is_null() {} | ^-----^^^^^^^^^^^^^^^^^^^^^^^^ | | | expression has type `&[u8; 1]` warning: references are not nullable, so checking them for null will always return false --> $DIR/ptr_null_checks.rs:57:8 | LL | if ("aa" as *const str).is_null() {} | ^----^^^^^^^^^^^^^^^^^^^^^^^^^ | | | expression has type `&str` warning: references are not nullable, so checking them for null will always return false --> $DIR/ptr_null_checks.rs:59:8 | LL | if (&[1, 2] as *const i32).is_null() {} | ^-------^^^^^^^^^^^^^^^^^^^^^^^^^ | | | expression has type `&[i32; 2]` warning: references are not nullable, so checking them for null will always return false --> $DIR/ptr_null_checks.rs:61:8 | LL | if (&mut [1, 2] as *mut i32) == std::ptr::null_mut() {} | ^-----------^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | | | expression has type `&mut [i32; 2]` warning: references are not nullable, so checking them for null will always return false --> $DIR/ptr_null_checks.rs:63:8 | LL | if (static_i32() as *const i32).is_null() {} | ^------------^^^^^^^^^^^^^^^^^^^^^^^^^ | | | expression has type `&i32` warning: references are not nullable, so checking them for null will always return false --> $DIR/ptr_null_checks.rs:65:8 | LL | if (&*{ static_i32() } as *const i32).is_null() {} | ^------------------^^^^^^^^^^^^^^^^^^^^^^^^^ | | | expression has type `&i32` warning: returned pointer of `as_ptr` call is never null, so checking it for null will always return false --> $DIR/ptr_null_checks.rs:69:8 | LL | if ptr::NonNull::new(&mut 8).unwrap().as_ptr().is_null() {} | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ warning: returned pointer of `as_ptr` call is never null, so checking it for null will always return false --> $DIR/ptr_null_checks.rs:71:8 | LL | if ptr::NonNull::::dangling().as_ptr().is_null() {} | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ warning: 27 warnings emitted