Rollup merge of rust-lang#113657 - Urgau:expand-incorrect_fn_null_check-lint, r=cjgillot

Expand, rename and improve `incorrect_fn_null_checks` lint

This PR,

 - firstly, expand the lint by now linting on references
 - secondly, it renames the lint `incorrect_fn_null_checks` -> `useless_ptr_null_checks`
 - and thirdly it improves the lint by catching `ptr::from_mut`, `ptr::from_ref`, as well as `<*mut _>::cast` and `<*const _>::cast_mut`

Fixes rust-lang#113601
cc ```@est31```

Author: matthiaskrgr

clippy_lints/src/renamed_lints.rs

@@ -43,7 +43,7 @@ pub static RENAMED_LINTS: &[(&str, &str)] = &[
     ("clippy::for_loops_over_fallibles", "for_loops_over_fallibles"),
     ("clippy::forget_copy", "forgetting_copy_types"),
     ("clippy::forget_ref", "forgetting_references"),
-    ("clippy::fn_null_check", "incorrect_fn_null_checks"),
+    ("clippy::fn_null_check", "useless_ptr_null_checks"),
     ("clippy::into_iter_on_array", "array_into_iter"),
     ("clippy::invalid_atomic_ordering", "invalid_atomic_ordering"),
     ("clippy::invalid_ref", "invalid_value"),

tests/ui/rename.fixed

@@ -38,7 +38,7 @@
 #![allow(for_loops_over_fallibles)]
 #![allow(forgetting_copy_types)]
 #![allow(forgetting_references)]
-#![allow(incorrect_fn_null_checks)]
+#![allow(useless_ptr_null_checks)]
 #![allow(array_into_iter)]
 #![allow(invalid_atomic_ordering)]
 #![allow(invalid_value)]
@@ -92,7 +92,7 @@
 #![warn(for_loops_over_fallibles)]
 #![warn(forgetting_copy_types)]
 #![warn(forgetting_references)]
-#![warn(incorrect_fn_null_checks)]
+#![warn(useless_ptr_null_checks)]
 #![warn(array_into_iter)]
 #![warn(invalid_atomic_ordering)]
 #![warn(invalid_value)]

tests/ui/rename.rs

@@ -38,7 +38,7 @@
 #![allow(for_loops_over_fallibles)]
 #![allow(forgetting_copy_types)]
 #![allow(forgetting_references)]
-#![allow(incorrect_fn_null_checks)]
+#![allow(useless_ptr_null_checks)]
 #![allow(array_into_iter)]
 #![allow(invalid_atomic_ordering)]
 #![allow(invalid_value)]

tests/ui/rename.stderr

@@ -246,11 +246,11 @@ error: lint `clippy::forget_ref` has been renamed to `forgetting_references`
 LL | #![warn(clippy::forget_ref)]
    |         ^^^^^^^^^^^^^^^^^^ help: use the new name: `forgetting_references`
 
-error: lint `clippy::fn_null_check` has been renamed to `incorrect_fn_null_checks`
+error: lint `clippy::fn_null_check` has been renamed to `useless_ptr_null_checks`
   --> $DIR/rename.rs:95:9
    |
 LL | #![warn(clippy::fn_null_check)]
-   |         ^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `incorrect_fn_null_checks`
+   |         ^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `useless_ptr_null_checks`
 
 error: lint `clippy::into_iter_on_array` has been renamed to `array_into_iter`
   --> $DIR/rename.rs:96:9