Auto merge of #23682 - tamird:DRY-is-empty, r=alexcrichton

r? @alexcrichton 

4 files changed, 13 insertions, 13 deletions

diff --git a/src/libcore/char.rs b/src/libcore/char.rs
index ba9748eea71..740fa3eb19e 100644
--- a/src/libcore/char.rs
+++ b/src/libcore/char.rs
@@ -227,7 +227,7 @@ impl CharExt for char {
 #[inline]
 pub fn encode_utf8_raw(code: u32, dst: &mut [u8]) -> Option<usize> {
     // Marked #[inline] to allow llvm optimizing it away
-    if code < MAX_ONE_B && dst.len() >= 1 {
+    if code < MAX_ONE_B && !dst.is_empty() {
         dst[0] = code as u8;
         Some(1)
     } else if code < MAX_TWO_B && dst.len() >= 2 {
@@ -258,7 +258,7 @@ pub fn encode_utf8_raw(code: u32, dst: &mut [u8]) -> Option<usize> {
 #[inline]
 pub fn encode_utf16_raw(mut ch: u32, dst: &mut [u16]) -> Option<usize> {
     // Marked #[inline] to allow llvm optimizing it away
-    if (ch & 0xFFFF) == ch  && dst.len() >= 1 {
+    if (ch & 0xFFFF) == ch && !dst.is_empty() {
         // The BMP falls through (assuming non-surrogate, as it should)
         dst[0] = ch as u16;
         Some(1)
diff --git a/src/libcore/slice.rs b/src/libcore/slice.rs
index 0e6acf0160d..4b1742a4348 100644
--- a/src/libcore/slice.rs
+++ b/src/libcore/slice.rs
@@ -204,7 +204,7 @@ impl<T> SliceExt for [T] {
 
     #[inline]
     fn first(&self) -> Option<&T> {
-        if self.len() == 0 { None } else { Some(&self[0]) }
+        if self.is_empty() { None } else { Some(&self[0]) }
     }
 
     #[inline]
@@ -217,7 +217,7 @@ impl<T> SliceExt for [T] {
 
     #[inline]
     fn last(&self) -> Option<&T> {
-        if self.len() == 0 { None } else { Some(&self[self.len() - 1]) }
+        if self.is_empty() { None } else { Some(&self[self.len() - 1]) }
     }
 
     #[inline]
@@ -296,7 +296,7 @@ impl<T> SliceExt for [T] {
 
     #[inline]
     fn first_mut(&mut self) -> Option<&mut T> {
-        if self.len() == 0 { None } else { Some(&mut self[0]) }
+        if self.is_empty() { None } else { Some(&mut self[0]) }
     }
 
     #[inline]
@@ -1306,7 +1306,7 @@ impl<'a, T> Iterator for Chunks<'a, T> {
 
     #[inline]
     fn next(&mut self) -> Option<&'a [T]> {
-        if self.v.len() == 0 {
+        if self.v.is_empty() {
             None
         } else {
             let chunksz = cmp::min(self.v.len(), self.size);
@@ -1318,7 +1318,7 @@ impl<'a, T> Iterator for Chunks<'a, T> {
 
     #[inline]
     fn size_hint(&self) -> (usize, Option<usize>) {
-        if self.v.len() == 0 {
+        if self.v.is_empty() {
             (0, Some(0))
         } else {
             let n = self.v.len() / self.size;
@@ -1333,7 +1333,7 @@ impl<'a, T> Iterator for Chunks<'a, T> {
 impl<'a, T> DoubleEndedIterator for Chunks<'a, T> {
     #[inline]
     fn next_back(&mut self) -> Option<&'a [T]> {
-        if self.v.len() == 0 {
+        if self.v.is_empty() {
             None
         } else {
             let remainder = self.v.len() % self.size;
@@ -1384,7 +1384,7 @@ impl<'a, T> Iterator for ChunksMut<'a, T> {
 
     #[inline]
     fn next(&mut self) -> Option<&'a mut [T]> {
-        if self.v.len() == 0 {
+        if self.v.is_empty() {
             None
         } else {
             let sz = cmp::min(self.v.len(), self.chunk_size);
@@ -1397,7 +1397,7 @@ impl<'a, T> Iterator for ChunksMut<'a, T> {
 
     #[inline]
     fn size_hint(&self) -> (usize, Option<usize>) {
-        if self.v.len() == 0 {
+        if self.v.is_empty() {
             (0, Some(0))
         } else {
             let n = self.v.len() / self.chunk_size;
@@ -1412,7 +1412,7 @@ impl<'a, T> Iterator for ChunksMut<'a, T> {
 impl<'a, T> DoubleEndedIterator for ChunksMut<'a, T> {
     #[inline]
     fn next_back(&mut self) -> Option<&'a mut [T]> {
-        if self.v.len() == 0 {
+        if self.v.is_empty() {
             None
         } else {
             let remainder = self.v.len() % self.chunk_size;
diff --git a/src/libcore/str/mod.rs b/src/libcore/str/mod.rs
index fc623f21167..2d6ef39361e 100644
--- a/src/libcore/str/mod.rs
+++ b/src/libcore/str/mod.rs
@@ -1119,7 +1119,7 @@ enum OldSearcher {
 impl OldSearcher {
     #[allow(dead_code)]
     fn new(haystack: &[u8], needle: &[u8]) -> OldSearcher {
-        if needle.len() == 0 {
+        if needle.is_empty() {
             // Handle specially
             unimplemented!()
         // FIXME: Tune this.
diff --git a/src/libcore/str/pattern.rs b/src/libcore/str/pattern.rs
index 62b693dcbe6..9a96612195c 100644
--- a/src/libcore/str/pattern.rs
+++ b/src/libcore/str/pattern.rs
@@ -457,7 +457,7 @@ fn str_search_step<F, G>(mut m: &mut StrSearcher,
 {
     if m.state.done() {
         SearchStep::Done
-    } else if m.needle.len() == 0 && m.start <= m.end {
+    } else if m.needle.is_empty() && m.start <= m.end {
         // Case for needle == ""
         if let State::Reject(a, b) = m.state.take() {
             SearchStep::Reject(a, b)