diff --git a/src/chroot/chroot.rs b/src/chroot/chroot.rs
index daa6795ec..c0467dd32 100644
--- a/src/chroot/chroot.rs
+++ b/src/chroot/chroot.rs
@@ -96,7 +96,7 @@ pub fn uumain(args: Vec<String>) -> isize {
 
     unsafe {
         let executable = CString::from_slice(command[0].as_bytes()).as_bytes_with_nul().as_ptr();
-        let mut command_parts: Vec<*const i8> = command.iter().map(|x| CString::from_slice(x.as_bytes()).as_bytes_with_nul().as_ptr()).collect();
+        let mut command_parts: Vec<*const u8> = command.iter().map(|x| CString::from_slice(x.as_bytes()).as_bytes_with_nul().as_ptr()).collect();
         command_parts.push(std::ptr::null());
         execvp(executable as *const libc::c_char, command_parts.as_ptr() as *mut *const libc::c_char) as isize
     }
diff --git a/src/common/c_types.rs b/src/common/c_types.rs
index 50fcb287e..a84142ff8 100644
--- a/src/common/c_types.rs
+++ b/src/common/c_types.rs
@@ -134,7 +134,7 @@ pub fn get_pw_from_args(free: &Vec<String>) -> Option<c_passwd> {
         } else {
             let pw_pointer = unsafe {
                 let cstr = CString::from_slice(username.as_bytes());
-                getpwnam(cstr.as_bytes_with_nul().as_ptr())
+                getpwnam(cstr.as_bytes_with_nul().as_ptr() as *const i8)
             };
             if !pw_pointer.is_null() {
                 Some(unsafe { read(pw_pointer) })
@@ -199,7 +199,7 @@ unsafe fn get_group_list_internal(name: *const c_char, gid: gid_t, groups: *mut
     }
 }
 
-pub fn get_groups() -> Result<Vec<gid_t>, usize> {
+pub fn get_groups() -> Result<Vec<gid_t>, i32> {
     let ngroups = unsafe { getgroups(0, null_mut()) };
     if ngroups == -1 {
         return Err(os::errno());
diff --git a/src/echo/echo.rs b/src/echo/echo.rs
index f44862011..df90b432a 100644
--- a/src/echo/echo.rs
+++ b/src/echo/echo.rs
@@ -31,7 +31,7 @@ struct EchoOptions {
 }
 
 #[inline(always)]
-fn to_char(bytes: &Vec<u8>, base: usize) -> char {
+fn to_char(bytes: &Vec<u8>, base: u32) -> char {
     from_str_radix::<usize>(from_utf8(bytes.as_slice()).unwrap(), base).unwrap() as u8 as char
 }
 
@@ -52,10 +52,10 @@ fn isodigit(c: u8) -> bool {
     }
 }
 
-fn convert_str(string: &[u8], index: usize, base: usize) -> (char, usize) {
+fn convert_str(string: &[u8], index: usize, base: u32) -> (char, usize) {
     let (max_digits, is_legal_digit) : (usize, fn(u8) -> bool) = match base {
-        8us => (3, isodigit),
-        16us => (2, isxdigit),
+        8 => (3, isodigit),
+        16 => (2, isxdigit),
         _ => panic!(),
     };
 
@@ -202,7 +202,7 @@ pub fn uumain(args: Vec<String>) -> isize {
                                 't' => print!("\t"),
                                 'v' => print!("\x0B"),
                                 'x' => {
-                                    let (c, num_char_used) = convert_str(string.as_bytes(), index + 1, 16us);
+                                    let (c, num_char_used) = convert_str(string.as_bytes(), index + 1, 16);
                                     if num_char_used == 0 {
                                         print!("\\x");
                                     } else {
@@ -213,7 +213,7 @@ pub fn uumain(args: Vec<String>) -> isize {
                                     }
                                 },
                                 '0' => {
-                                    let (c, num_char_used) = convert_str(string.as_bytes(), index + 1, 8us);
+                                    let (c, num_char_used) = convert_str(string.as_bytes(), index + 1, 8);
                                     if num_char_used == 0 {
                                         print!("\0");
                                     } else {
@@ -224,7 +224,7 @@ pub fn uumain(args: Vec<String>) -> isize {
                                     }
                                 }
                                 _ => {
-                                    let (esc_c, num_char_used) = convert_str(string.as_bytes(), index, 8us);
+                                    let (esc_c, num_char_used) = convert_str(string.as_bytes(), index, 8);
                                     if num_char_used == 0 {
                                         print!("\\{}", c);
                                     } else {
diff --git a/src/split/split.rs b/src/split/split.rs
index 696410b7c..c92170e2a 100644
--- a/src/split/split.rs
+++ b/src/split/split.rs
@@ -243,7 +243,7 @@ fn num_prefix(i: usize, width: usize) -> String {
         let div = Int::pow(10 as usize, w);
         let r = n / div;
         n -= r * div;
-        c.push(char::from_digit(r, 10).unwrap());
+        c.push(char::from_digit(r as u32, 10).unwrap());
     }
     c
 }