1 files changed, 10 insertions, 12 deletions
diff --git a/src/libstd/sys/common/wtf8.rs b/src/libstd/sys/common/wtf8.rs
index 702a34633dc..2e092d5f770 100644
--- a/src/libstd/sys/common/wtf8.rs
+++ b/src/libstd/sys/common/wtf8.rs
@@ -243,7 +243,7 @@ impl Wtf8Buf {
     /// Append a UTF-8 slice at the end of the string.
     #[inline]
     pub fn push_str(&mut self, other: &str) {
-        self.bytes.push_all(other.as_bytes())
+        self.bytes.extend_from_slice(other.as_bytes())
     }
 
     /// Append a WTF-8 slice at the end of the string.
@@ -262,9 +262,9 @@ impl Wtf8Buf {
                 // 4 bytes for the supplementary code point
                 self.bytes.reserve(4 + other_without_trail_surrogate.len());
                 self.push_char(decode_surrogate_pair(lead, trail));
-                self.bytes.push_all(other_without_trail_surrogate);
+                self.bytes.extend_from_slice(other_without_trail_surrogate);
             }
-            _ => self.bytes.push_all(&other.bytes)
+            _ => self.bytes.extend_from_slice(&other.bytes)
         }
     }
 
@@ -331,10 +331,8 @@ impl Wtf8Buf {
             match self.next_surrogate(pos) {
                 Some((surrogate_pos, _)) => {
                     pos = surrogate_pos + 3;
-                    slice::bytes::copy_memory(
-                        UTF8_REPLACEMENT_CHARACTER,
-                        &mut self.bytes[surrogate_pos .. pos],
-                    );
+                    self.bytes[surrogate_pos..pos]
+                        .clone_from_slice(UTF8_REPLACEMENT_CHARACTER);
                 },
                 None => return unsafe { String::from_utf8_unchecked(self.bytes) }
             }
@@ -493,18 +491,18 @@ impl Wtf8 {
         };
         let wtf8_bytes = &self.bytes;
         let mut utf8_bytes = Vec::with_capacity(self.len());
-        utf8_bytes.push_all(&wtf8_bytes[..surrogate_pos]);
-        utf8_bytes.push_all(UTF8_REPLACEMENT_CHARACTER);
+        utf8_bytes.extend_from_slice(&wtf8_bytes[..surrogate_pos]);
+        utf8_bytes.extend_from_slice(UTF8_REPLACEMENT_CHARACTER);
         let mut pos = surrogate_pos + 3;
         loop {
             match self.next_surrogate(pos) {
                 Some((surrogate_pos, _)) => {
-                    utf8_bytes.push_all(&wtf8_bytes[pos .. surrogate_pos]);
-                    utf8_bytes.push_all(UTF8_REPLACEMENT_CHARACTER);
+                    utf8_bytes.extend_from_slice(&wtf8_bytes[pos .. surrogate_pos]);
+                    utf8_bytes.extend_from_slice(UTF8_REPLACEMENT_CHARACTER);
                     pos = surrogate_pos + 3;
                 },
                 None => {
-                    utf8_bytes.push_all(&wtf8_bytes[pos..]);
+                    utf8_bytes.extend_from_slice(&wtf8_bytes[pos..]);
                     return Cow::Owned(unsafe { String::from_utf8_unchecked(utf8_bytes) })
                 }
             }