error: Comparing with null is better expressed by the .is_null() method
  --> $DIR/cmp_null.rs:11:8
   |
11 |     if p == ptr::null() {
   |        ^^^^^^^^^^^^^^^^
   |
   = note: `-D cmp-null` implied by `-D warnings`

error: Comparing with null is better expressed by the .is_null() method
  --> $DIR/cmp_null.rs:16:8
   |
16 |     if m == ptr::null_mut() {
   |        ^^^^^^^^^^^^^^^^^^^^