clippy: fix ptr_as_ptr lint

https://rust-lang.github.io/rust-clippy/master/index.html#ptr_as_ptr

Cargo.toml

@@ -668,7 +668,6 @@ doc_markdown = "allow"
 unused_self = "allow"
 enum_glob_use = "allow"
 ptr_cast_constness = "allow"
-ptr_as_ptr = "allow"
 needless_raw_string_hashes = "allow"
 unreadable_literal = "allow"
 unnested_or_patterns = "allow"

fuzz/uufuzz/src/lib.rs

@@ -193,13 +193,8 @@ fn read_from_fd(fd: RawFd) -> String {
     let mut captured_output = Vec::new();
     let mut read_buffer = [0; 1024];
     loop {
-        let bytes_read = unsafe {
-            libc::read(
-                fd,
-                read_buffer.as_mut_ptr() as *mut libc::c_void,
-                read_buffer.len(),
-            )
-        };
+        let bytes_read =
+            unsafe { libc::read(fd, read_buffer.as_mut_ptr().cast(), read_buffer.len()) };
 
         if bytes_read == -1 {
             eprintln!("Failed to read from the pipe");

src/uu/chroot/src/chroot.rs

@@ -439,7 +439,7 @@ fn enter_chroot(root: &Path, skip_chdir: bool) -> UResult<()> {
                 .map_err(|e| ChrootError::CannotEnter("root".to_string(), e.into()))?
                 .as_bytes_with_nul()
                 .as_ptr()
-                .cast::<libc::c_char>(),
+                .cast(),
         )
     };
 

src/uucore/src/lib/features/fsext.rs

@@ -881,7 +881,7 @@ impl FsMeta for StatFs {
     fn fsid(&self) -> u64 {
         // Use type inference to determine the type of f_fsid
         // (libc::__fsid_t on Android, libc::fsid_t on other platforms)
-        let f_fsid: &[u32; 2] = unsafe { &*(&raw const self.f_fsid as *const [u32; 2]) };
+        let f_fsid: &[u32; 2] = unsafe { &*(&raw const self.f_fsid).cast() };
         ((u64::from(f_fsid[0])) << 32) | u64::from(f_fsid[1])
     }
     #[cfg(not(any(

src/uucore/src/lib/features/systemd_logind.rs

@@ -71,11 +71,11 @@ mod login {
                 let session_cstr = unsafe { CStr::from_ptr(session_ptr) };
                 sessions.push(session_cstr.to_string_lossy().into_owned());
 
-                unsafe { libc::free(session_ptr as *mut libc::c_void) };
+                unsafe { libc::free(session_ptr.cast()) };
                 i += 1;
             }
 
-            unsafe { libc::free(sessions_ptr as *mut libc::c_void) };
+            unsafe { libc::free(sessions_ptr.cast()) };
         }
 
         Ok(sessions)
@@ -135,7 +135,7 @@ mod login {
         let tty_cstr = unsafe { CStr::from_ptr(tty_ptr) };
         let tty_string = tty_cstr.to_string_lossy().into_owned();
 
-        unsafe { libc::free(tty_ptr as *mut libc::c_void) };
+        unsafe { libc::free(tty_ptr.cast()) };
 
         Ok(Some(tty_string))
     }
@@ -164,7 +164,7 @@ mod login {
         let host_cstr = unsafe { CStr::from_ptr(host_ptr) };
         let host_string = host_cstr.to_string_lossy().into_owned();
 
-        unsafe { libc::free(host_ptr as *mut libc::c_void) };
+        unsafe { libc::free(host_ptr.cast()) };
 
         Ok(Some(host_string))
     }
@@ -193,7 +193,7 @@ mod login {
         let display_cstr = unsafe { CStr::from_ptr(display_ptr) };
         let display_string = display_cstr.to_string_lossy().into_owned();
 
-        unsafe { libc::free(display_ptr as *mut libc::c_void) };
+        unsafe { libc::free(display_ptr.cast()) };
 
         Ok(Some(display_string))
     }
@@ -221,7 +221,7 @@ mod login {
         let type_cstr = unsafe { CStr::from_ptr(type_ptr) };
         let type_string = type_cstr.to_string_lossy().into_owned();
 
-        unsafe { libc::free(type_ptr as *mut libc::c_void) };
+        unsafe { libc::free(type_ptr.cast()) };
 
         Ok(Some(type_string))
     }
@@ -249,7 +249,7 @@ mod login {
         let seat_cstr = unsafe { CStr::from_ptr(seat_ptr) };
         let seat_string = seat_cstr.to_string_lossy().into_owned();
 
-        unsafe { libc::free(seat_ptr as *mut libc::c_void) };
+        unsafe { libc::free(seat_ptr.cast()) };
 
         Ok(Some(seat_string))
     }
@@ -376,7 +376,7 @@ pub fn read_login_records() -> UResult<Vec<SystemdLoginRecord>> {
             let ret = libc::getpwuid_r(
                 uid,
                 passwd.as_mut_ptr(),
-                buf.as_mut_ptr() as *mut libc::c_char,
+                buf.as_mut_ptr().cast(),
                 buf.len(),
                 &raw mut result,
             );