why is lint saying this `unsafe` is unnecessary? There is a deref of a *ptr ...

gistfile1.txt

/Users/fklock/Dev/Mozilla/rust.git/src/libstd/pipes.rs:106:21: 106:69 warning: unnecessary `unsafe` block [-W unused-unsafe (default)]
/Users/fklock/Dev/Mozilla/rust.git/src/libstd/pipes.rs:106     { $x:expr } => ( unsafe { let y = *ptr::to_unsafe_ptr(&($x)); y } )
                                                                                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/Users/fklock/Dev/Mozilla/rust.git/src/libstd/pipes.rs:105:0: 107:1 note: in expansion of move_it!
/Users/fklock/Dev/Mozilla/rust.git/src/libstd/pipes.rs:321:24: 321:46 note: expansion site
/Users/fklock/Dev/Mozilla/rust.git/src/libstd/os.rs:962:12: 968:13 warning: unnecessary `unsafe` block [-W unused-unsafe (default)]
/Users/fklock/Dev/Mozilla/rust.git/src/libstd/os.rs:962             unsafe {
/Users/fklock/Dev/Mozilla/rust.git/src/libstd/os.rs:963                 if do str::as_c_str(to.to_str()) |to_buf| {
/Users/fklock/Dev/Mozilla/rust.git/src/libstd/os.rs:964                     libc::chmod(to_buf, from_mode as mode_t)
/Users/fklock/Dev/Mozilla/rust.git/src/libstd/os.rs:965                 } != 0 {
/Users/fklock/Dev/Mozilla/rust.git/src/libstd/os.rs:966                     return false; // should be a condition...
/Users/fklock/Dev/Mozilla/rust.git/src/libstd/os.rs:967                 }
                                                        ...