3 files changed, 23 insertions, 55 deletions
diff --git a/src/libstd/sync/mutex.rs b/src/libstd/sync/mutex.rs
index 846a97b547d..f1d264b38a0 100644
--- a/src/libstd/sync/mutex.rs
+++ b/src/libstd/sync/mutex.rs
@@ -536,16 +536,15 @@ mod tests {
         assert_eq!(*lock, 2);
     }
 
-    // FIXME(#25351) needs deeply nested coercions of DST structs.
-    // #[test]
-    // fn test_mutex_unsized() {
-    //     let mutex: &Mutex<[i32]> = &Mutex::new([1, 2, 3]);
-    //     {
-    //         let b = &mut *mutex.lock().unwrap();
-    //         b[0] = 4;
-    //         b[2] = 5;
-    //     }
-    //     let comp: &[i32] = &[4, 2, 5];
-    //     assert_eq!(&*mutex.lock().unwrap(), comp);
-    // }
+    #[test]
+    fn test_mutex_unsized() {
+        let mutex: &Mutex<[i32]> = &Mutex::new([1, 2, 3]);
+        {
+            let b = &mut *mutex.lock().unwrap();
+            b[0] = 4;
+            b[2] = 5;
+        }
+        let comp: &[i32] = &[4, 2, 5];
+        assert_eq!(&*mutex.lock().unwrap(), comp);
+    }
 }
diff --git a/src/libstd/sync/rwlock.rs b/src/libstd/sync/rwlock.rs
index 7210328fad8..04ad4708246 100644
--- a/src/libstd/sync/rwlock.rs
+++ b/src/libstd/sync/rwlock.rs
@@ -578,18 +578,17 @@ mod tests {
         assert_eq!(*lock, 2);
     }
 
-    // FIXME(#25351) needs deeply nested coercions of DST structs.
-    // #[test]
-    // fn test_rwlock_unsized() {
-    //     let rw: &RwLock<[i32]> = &RwLock::new([1, 2, 3]);
-    //     {
-    //         let b = &mut *rw.write().unwrap();
-    //         b[0] = 4;
-    //         b[2] = 5;
-    //     }
-    //     let comp: &[i32] = &[4, 2, 5];
-    //     assert_eq!(&*rw.read().unwrap(), comp);
-    // }
+    #[test]
+    fn test_rwlock_unsized() {
+        let rw: &RwLock<[i32]> = &RwLock::new([1, 2, 3]);
+        {
+            let b = &mut *rw.write().unwrap();
+            b[0] = 4;
+            b[2] = 5;
+        }
+        let comp: &[i32] = &[4, 2, 5];
+        assert_eq!(&*rw.read().unwrap(), comp);
+    }
 
     #[test]
     fn test_rwlock_try_write() {
diff --git a/src/libstd/sys/common/wtf8.rs b/src/libstd/sys/common/wtf8.rs
index 633e7d78a9a..10f77d0207c 100644
--- a/src/libstd/sys/common/wtf8.rs
+++ b/src/libstd/sys/common/wtf8.rs
@@ -31,7 +31,6 @@ use core::str::next_code_point;
 use ascii::*;
 use borrow::Cow;
 use char;
-use cmp;
 use fmt;
 use hash::{Hash, Hasher};
 use iter::FromIterator;
@@ -375,6 +374,7 @@ impl Extend<CodePoint> for Wtf8Buf {
 ///
 /// Similar to `&str`, but can additionally contain surrogate code points
 /// if they’re not in a surrogate pair.
+#[derive(Eq, Ord, PartialEq, PartialOrd)]
 pub struct Wtf8 {
     bytes: [u8]
 }
@@ -383,36 +383,6 @@ impl AsInner<[u8]> for Wtf8 {
     fn as_inner(&self) -> &[u8] { &self.bytes }
 }
 
-// FIXME: https://github.com/rust-lang/rust/issues/18805
-impl PartialEq for Wtf8 {
-    fn eq(&self, other: &Wtf8) -> bool { self.bytes.eq(&other.bytes) }
-}
-
-// FIXME: https://github.com/rust-lang/rust/issues/18805
-impl Eq for Wtf8 {}
-
-// FIXME: https://github.com/rust-lang/rust/issues/18738
-impl PartialOrd for Wtf8 {
-    #[inline]
-    fn partial_cmp(&self, other: &Wtf8) -> Option<cmp::Ordering> {
-        self.bytes.partial_cmp(&other.bytes)
-    }
-    #[inline]
-    fn lt(&self, other: &Wtf8) -> bool { self.bytes.lt(&other.bytes) }
-    #[inline]
-    fn le(&self, other: &Wtf8) -> bool { self.bytes.le(&other.bytes) }
-    #[inline]
-    fn gt(&self, other: &Wtf8) -> bool { self.bytes.gt(&other.bytes) }
-    #[inline]
-    fn ge(&self, other: &Wtf8) -> bool { self.bytes.ge(&other.bytes) }
-}
-
-// FIXME: https://github.com/rust-lang/rust/issues/18738
-impl Ord for Wtf8 {
-    #[inline]
-    fn cmp(&self, other: &Wtf8) -> cmp::Ordering { self.bytes.cmp(&other.bytes) }
-}
-
 /// Format the slice with double quotes,
 /// and surrogates as `\u` followed by four hexadecimal digits.
 /// Example: `"a\u{D800}"` for a slice with code points [U+0061, U+D800]