diff --git a/src/bits.rs b/src/bits.rs
index b798f35..13ee3b6 100644
--- a/src/bits.rs
+++ b/src/bits.rs
@@ -457,7 +457,7 @@ impl Bits {
     #[unstable]
     pub fn push_byte_data(&mut self, data: &[u8]) -> QrResult<()> {
         try!(self.push_header(Mode::Byte, data.len()));
-        for b in data.iter() {
+        for b in data {
             self.push_number(8, *b as u16);
         }
         Ok(())
@@ -754,7 +754,7 @@ mod finish_tests {
 
 impl Bits {
     /// Push a segmented data to the bits, and then terminate it.
-    pub fn push_segments<I>(&mut self, data: &[u8], mut segments_iter: I) -> QrResult<()>
+    pub fn push_segments<I>(&mut self, data: &[u8], segments_iter: I) -> QrResult<()>
         where I: Iterator<Item=Segment>
     {
         for segment in segments_iter {
@@ -823,8 +823,8 @@ mod encode_tests {
 /// This method will not consider any Micro QR code versions.
 pub fn encode_auto(data: &[u8], ec_level: EcLevel) -> QrResult<Bits> {
     let segments = Parser::new(data).collect::<Vec<Segment>>();
-    for version in [Version::Normal(9), Version::Normal(26), Version::Normal(40)].iter() {
-        let opt_segments = Optimizer::new(segments.iter().map(|s| *s), *version).collect::<Vec<Segment>>();
+    for version in &[Version::Normal(9), Version::Normal(26), Version::Normal(40)] {
+        let opt_segments = Optimizer::new(segments.iter().map(|s| *s), *version).collect::<Vec<_>>();
         let total_len = total_encoded_len(&*opt_segments, *version);
         let data_capacity = version.fetch(ec_level, &DATA_LENGTHS).unwrap();
         if total_len <= data_capacity {
diff --git a/src/canvas.rs b/src/canvas.rs
index 47bcd3e..8700f63 100644
--- a/src/canvas.rs
+++ b/src/canvas.rs
@@ -111,9 +111,9 @@ impl Canvas {
     fn to_debug_str(&self) -> String {
         let width = self.width;
         let mut res = String::with_capacity((width * (width + 1)) as usize);
-        for y in (0 .. width) {
+        for y in 0 .. width {
             res.push('\n');
-            for x in (0 .. width) {
+            for x in 0 .. width {
                 res.push(match self.get(x, y) {
                     Module::Empty => '?',
                     Module::Light => '.',
@@ -626,7 +626,7 @@ impl Canvas {
                            coords: &[(i16, i16)]) {
         let zero: N = Int::zero();
         let mut mask: N = !(!zero >> 1);
-        for &(x, y) in coords.iter() {
+        for &(x, y) in coords {
             let color = if (mask & number) == zero { off_color } else { on_color };
             self.put(x, y, color);
             mask = mask >> 1;
@@ -1428,8 +1428,8 @@ impl Canvas {
     /// patterns.
     pub fn apply_mask(&mut self, pattern: MaskPattern) {
         let mask_fn = get_mask_function(pattern);
-        for x in (0 .. self.width) {
-            for y in (0 .. self.width) {
+        for x in 0 .. self.width {
+            for y in 0 .. self.width {
                 let module = self.get_mut(x, y);
                 *module = module.mask(mask_fn(x, y));
             }
@@ -1587,15 +1587,15 @@ impl Canvas {
     fn compute_adjacent_penalty_score(&self, is_horizontal: bool) -> u16 {
         let mut total_score = 0;
 
-        for i in (0 .. self.width) {
+        for i in 0 .. self.width {
             let map_fn = |&:j| if is_horizontal {
                 self.get(j, i)
             } else {
                 self.get(i, j)
             };
 
-            let mut colors = (0 .. self.width).map(map_fn)
-                                              .chain(Some(Module::Empty).into_iter());
+            let colors = (0 .. self.width).map(map_fn)
+                                          .chain(Some(Module::Empty).into_iter());
             let mut last_color = Module::Empty;
             let mut consecutive_len = 1u16;
 
@@ -1623,8 +1623,8 @@ impl Canvas {
     fn compute_block_penalty_score(&self) -> u16 {
         let mut total_score = 0;
 
-        for i in (0 .. self.width-1) {
-            for j in (0 .. self.width-1) {
+        for i in 0 .. self.width-1 {
+            for j in 0 .. self.width-1 {
                 let this = self.get(i, j);
                 let right = self.get(i+1, j);
                 let bottom = self.get(i, j+1);
@@ -1651,8 +1651,8 @@ impl Canvas {
 
         let mut total_score = 0;
 
-        for i in (0 .. self.width) {
-            for j in (0 .. self.width-6) {
+        for i in 0 .. self.width {
+            for j in 0 .. self.width-6 {
                 // TODO a ref to a closure should be enough?
                 let get: Box<Fn(i16) -> Module> = if is_horizontal {
                     Box::new(|&: k: i16| self.get(k, i))
diff --git a/src/ec.rs b/src/ec.rs
index 3cf5234..68fe4eb 100644
--- a/src/ec.rs
+++ b/src/ec.rs
@@ -24,7 +24,7 @@ pub fn create_error_correction_code(data: &[u8], ec_code_size: usize) -> Vec<u8>
     let data_len = data.len();
     let log_den = GENERATOR_POLYNOMIALS[ec_code_size];
 
-    for i in (0 .. data_len) {
+    for i in 0 .. data_len {
         let lead_coeff = res[i] as usize;
         if lead_coeff == 0 {
             continue;
@@ -76,8 +76,8 @@ mod ec_tests {
 fn interleave<T: Copy, V: Deref<Target=[T]>>(blocks: &Vec<V>) -> Vec<T> {
     let last_block_len = blocks.last().unwrap().len();
     let mut res = Vec::with_capacity(last_block_len * blocks.len());
-    for i in (0 .. last_block_len) {
-        for t in blocks.iter() {
+    for i in 0 .. last_block_len {
+        for t in blocks {
             if i < t.len() {
                 res.push(t[i]);
             }
diff --git a/src/lib.rs b/src/lib.rs
index 7b4e8e9..5e45610 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -8,8 +8,8 @@
 //!     match code {
 //!         Err(err) => panic!("Failed to encode the QR code: {:?}", err),
 //!         Ok(code) => {
-//!             for y in (0 .. code.width()) {
-//!                 for x in (0 .. code.width()) {
+//!             for y in 0 .. code.width() {
+//!                 for x in 0 .. code.width() {
 //!                     let color = if code[(x, y)] { "black" } else { "white" };
 //!                     // render color at position (x, y)
 //!                 }
@@ -164,9 +164,9 @@ impl QrCode {
         let width = self.width;
         let mut k = 0;
         let mut res = String::with_capacity(width * (width + 1));
-        for _ in (0 .. width) {
+        for _ in 0 .. width {
             res.push('\n');
-            for _ in (0 .. width) {
+            for _ in 0 .. width {
                 res.push(if self.content[k] { on_char } else { off_char });
                 k += 1;
             }