error[E0308]: mismatched types
  --> $DIR/ptr-null-mutability-suggestions.rs:9:24
   |
LL |     expecting_null_mut(ptr::null());
   |     ------------------ ^^^^^^^^^^^ types differ in mutability
   |     |
   |     arguments to this function are incorrect
   |
   = note: expected raw pointer `*mut u8`
              found raw pointer `*const _`
note: function defined here
  --> $DIR/ptr-null-mutability-suggestions.rs:6:4
   |
LL | fn expecting_null_mut(_: *mut u8) {}
   |    ^^^^^^^^^^^^^^^^^^ ----------
help: consider using `core::ptr::null_mut` instead
   |
LL -     expecting_null_mut(ptr::null());
LL +     expecting_null_mut(core::ptr::null_mut());
   |

error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0308`.