diff --git a/src/liballoc/lib.rs b/src/liballoc/lib.rs
index a880ba5cfe4e..b92dfa9117e6 100644
--- a/src/liballoc/lib.rs
+++ b/src/liballoc/lib.rs
@@ -78,7 +78,6 @@
 #![feature(unsafe_no_drop_flag, filling_drop)]
 #![feature(core)]
 #![feature(unique)]
-#![feature(convert)]
 #![cfg_attr(test, feature(test, alloc, rustc_private))]
 #![cfg_attr(all(not(feature = "external_funcs"), not(feature = "external_crate")),
             feature(libc))]
diff --git a/src/libcollections/str.rs b/src/libcollections/str.rs
index 62a6df71e355..f8f2909291f3 100644
--- a/src/libcollections/str.rs
+++ b/src/libcollections/str.rs
@@ -12,10 +12,10 @@
 
 //! Unicode string manipulation (the `str` type).
 //!
-//! Rust's `str` type is one of the core primitive types of the language. `&str` is the borrowed
-//! string type. This type of string can only be created from other strings, unless it is a
-//! `&'static str` (see below). It is not possible to move out of borrowed strings because they are
-//! owned elsewhere.
+//! Rust's `str` type is one of the core primitive types of the language. `&str`
+//! is the borrowed string type. This type of string can only be created from
+//! other strings, unless it is a `&'static str` (see below). It is not possible
+//! to move out of borrowed strings because they are owned elsewhere.
 //!
 //! # Examples
 //!
@@ -25,8 +25,9 @@
 //! let s = "Hello, world.";
 //! ```
 //!
-//! This `&str` is a `&'static str`, which is the type of string literals. They're `'static`
-//! because literals are available for the entire lifetime of the program.
+//! This `&str` is a `&'static str`, which is the type of string literals.
+//! They're `'static` because literals are available for the entire lifetime of
+//! the program.
 //!
 //! You can get a non-`'static` `&str` by taking a slice of a `String`:
 //!
@@ -37,12 +38,13 @@
 //!
 //! # Representation
 //!
-//! Rust's string type, `str`, is a sequence of Unicode scalar values encoded as a stream of UTF-8
-//! bytes. All [strings](../../reference.html#literals) are guaranteed to be validly encoded UTF-8
-//! sequences. Additionally, strings are not null-terminated and can thus contain null bytes.
+//! Rust's string type, `str`, is a sequence of Unicode scalar values encoded as
+//! a stream of UTF-8 bytes. All [strings](../../reference.html#literals) are
+//! guaranteed to be validly encoded UTF-8 sequences. Additionally, strings are
+//! not null-terminated and can thus contain null bytes.
 //!
-//! The actual representation of `str`s have direct mappings to slices: `&str` is the same as
-//! `&[u8]`.
+//! The actual representation of `str`s have direct mappings to slices: `&str`
+//! is the same as `&[u8]`.
 
 #![doc(primitive = "str")]
 #![stable(feature = "rust1", since = "1.0.0")]
diff --git a/src/libcore/iter.rs b/src/libcore/iter.rs
index cf417d9d2d8b..2d69eeb9fa96 100644
--- a/src/libcore/iter.rs
+++ b/src/libcore/iter.rs
@@ -41,10 +41,11 @@
 //! }
 //!
 //! // Rough translation of the iteration without a `for` iterator.
+//! # let values = vec![1, 2, 3];
 //! let mut it = values.into_iter();
 //! loop {
 //!     match it.next() {
-//!         Some(&x) => {
+//!         Some(x) => {
 //!             println!("{}", x);
 //!         }
 //!         None => { break }
diff --git a/src/librbml/lib.rs b/src/librbml/lib.rs
index 878ef04942a4..3e91b9887706 100644
--- a/src/librbml/lib.rs
+++ b/src/librbml/lib.rs
@@ -123,7 +123,6 @@
        html_root_url = "http://doc.rust-lang.org/nightly/",
        html_playground_url = "http://play.rust-lang.org/")]
 
-#![feature(io)]
 #![feature(core)]
 #![feature(rustc_private)]
 #![feature(staged_api)]
diff --git a/src/librustc/middle/ty.rs b/src/librustc/middle/ty.rs
index 1090ba984ee6..161fae11ea6d 100644
--- a/src/librustc/middle/ty.rs
+++ b/src/librustc/middle/ty.rs
@@ -73,7 +73,6 @@ use std::cmp;
 use std::fmt;
 use std::hash::{Hash, SipHasher, Hasher};
 use std::mem;
-use std::num::ToPrimitive;
 use std::ops;
 use std::rc::Rc;
 use std::vec::IntoIter;
diff --git a/src/libstd/io/buffered.rs b/src/libstd/io/buffered.rs
index 479665c4728d..6fe35614a85b 100644
--- a/src/libstd/io/buffered.rs
+++ b/src/libstd/io/buffered.rs
@@ -503,34 +503,34 @@ mod tests {
 
         let mut buf = [0, 0, 0];
         let nread = reader.read(&mut buf);
-        assert_eq!(Ok(3), nread);
+        assert_eq!(nread.unwrap(), 3);
         let b: &[_] = &[5, 6, 7];
         assert_eq!(buf, b);
 
         let mut buf = [0, 0];
         let nread = reader.read(&mut buf);
-        assert_eq!(Ok(2), nread);
+        assert_eq!(nread.unwrap(), 2);
         let b: &[_] = &[0, 1];
         assert_eq!(buf, b);
 
         let mut buf = [0];
         let nread = reader.read(&mut buf);
-        assert_eq!(Ok(1), nread);
+        assert_eq!(nread.unwrap(), 1);
         let b: &[_] = &[2];
         assert_eq!(buf, b);
 
         let mut buf = [0, 0, 0];
         let nread = reader.read(&mut buf);
-        assert_eq!(Ok(1), nread);
+        assert_eq!(nread.unwrap(), 1);
         let b: &[_] = &[3, 0, 0];
         assert_eq!(buf, b);
 
         let nread = reader.read(&mut buf);
-        assert_eq!(Ok(1), nread);
+        assert_eq!(nread.unwrap(), 1);
         let b: &[_] = &[4, 0, 0];
         assert_eq!(buf, b);
 
-        assert_eq!(reader.read(&mut buf), Ok(0));
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
     }
 
     #[test]
@@ -592,7 +592,7 @@ mod tests {
         }
 
         let mut stream = BufStream::new(S);
-        assert_eq!(stream.read(&mut [0; 10]), Ok(0));
+        assert_eq!(stream.read(&mut [0; 10]).unwrap(), 0);
         stream.write(&[0; 10]).unwrap();
         stream.flush().unwrap();
     }
@@ -658,10 +658,10 @@ mod tests {
         let in_buf: &[u8] = b"a\nb\nc";
         let reader = BufReader::with_capacity(2, in_buf);
         let mut it = reader.lines();
-        assert_eq!(it.next(), Some(Ok("a".to_string())));
-        assert_eq!(it.next(), Some(Ok("b".to_string())));
-        assert_eq!(it.next(), Some(Ok("c".to_string())));
-        assert_eq!(it.next(), None);
+        assert_eq!(it.next().unwrap().unwrap(), "a".to_string());
+        assert_eq!(it.next().unwrap().unwrap(), "b".to_string());
+        assert_eq!(it.next().unwrap().unwrap(), "c".to_string());
+        assert!(it.next().is_none());
     }
 
     #[test]
@@ -669,20 +669,20 @@ mod tests {
         let inner = ShortReader{lengths: vec![0, 1, 2, 0, 1, 0]};
         let mut reader = BufReader::new(inner);
         let mut buf = [0, 0];
-        assert_eq!(reader.read(&mut buf), Ok(0));
-        assert_eq!(reader.read(&mut buf), Ok(1));
-        assert_eq!(reader.read(&mut buf), Ok(2));
-        assert_eq!(reader.read(&mut buf), Ok(0));
-        assert_eq!(reader.read(&mut buf), Ok(1));
-        assert_eq!(reader.read(&mut buf), Ok(0));
-        assert_eq!(reader.read(&mut buf), Ok(0));
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.read(&mut buf).unwrap(), 2);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
     }
 
     #[test]
     fn read_char_buffered() {
         let buf = [195, 159];
         let reader = BufReader::with_capacity(1, &buf[..]);
-        assert_eq!(reader.chars().next(), Some(Ok('ß')));
+        assert_eq!(reader.chars().next().unwrap().unwrap(), 'ß');
     }
 
     #[test]
@@ -690,9 +690,9 @@ mod tests {
         let buf = [195, 159, b'a'];
         let reader = BufReader::with_capacity(1, &buf[..]);
         let mut it = reader.chars();
-        assert_eq!(it.next(), Some(Ok('ß')));
-        assert_eq!(it.next(), Some(Ok('a')));
-        assert_eq!(it.next(), None);
+        assert_eq!(it.next().unwrap().unwrap(), 'ß');
+        assert_eq!(it.next().unwrap().unwrap(), 'a');
+        assert!(it.next().is_none());
     }
 
     #[test]
diff --git a/src/libstd/io/cursor.rs b/src/libstd/io/cursor.rs
index a7b7f96c22b3..6433c29bb9d6 100644
--- a/src/libstd/io/cursor.rs
+++ b/src/libstd/io/cursor.rs
@@ -171,9 +171,9 @@ mod tests {
     #[test]
     fn test_vec_writer() {
         let mut writer = Vec::new();
-        assert_eq!(writer.write(&[0]), Ok(1));
-        assert_eq!(writer.write(&[1, 2, 3]), Ok(3));
-        assert_eq!(writer.write(&[4, 5, 6, 7]), Ok(4));
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
         let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7];
         assert_eq!(writer, b);
     }
@@ -181,9 +181,9 @@ mod tests {
     #[test]
     fn test_mem_writer() {
         let mut writer = Cursor::new(Vec::new());
-        assert_eq!(writer.write(&[0]), Ok(1));
-        assert_eq!(writer.write(&[1, 2, 3]), Ok(3));
-        assert_eq!(writer.write(&[4, 5, 6, 7]), Ok(4));
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
         let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7];
         assert_eq!(&writer.get_ref()[..], b);
     }
@@ -194,16 +194,16 @@ mod tests {
         {
             let mut writer = Cursor::new(&mut buf[..]);
             assert_eq!(writer.position(), 0);
-            assert_eq!(writer.write(&[0]), Ok(1));
+            assert_eq!(writer.write(&[0]).unwrap(), 1);
             assert_eq!(writer.position(), 1);
-            assert_eq!(writer.write(&[1, 2, 3]), Ok(3));
-            assert_eq!(writer.write(&[4, 5, 6, 7]), Ok(4));
+            assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+            assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
             assert_eq!(writer.position(), 8);
-            assert_eq!(writer.write(&[]), Ok(0));
+            assert_eq!(writer.write(&[]).unwrap(), 0);
             assert_eq!(writer.position(), 8);
 
-            assert_eq!(writer.write(&[8, 9]), Ok(1));
-            assert_eq!(writer.write(&[10]), Ok(0));
+            assert_eq!(writer.write(&[8, 9]).unwrap(), 1);
+            assert_eq!(writer.write(&[10]).unwrap(), 0);
         }
         let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8];
         assert_eq!(buf, b);
@@ -215,22 +215,22 @@ mod tests {
         {
             let mut writer = Cursor::new(&mut buf[..]);
             assert_eq!(writer.position(), 0);
-            assert_eq!(writer.write(&[1]), Ok(1));
+            assert_eq!(writer.write(&[1]).unwrap(), 1);
             assert_eq!(writer.position(), 1);
 
-            assert_eq!(writer.seek(SeekFrom::Start(2)), Ok(2));
+            assert_eq!(writer.seek(SeekFrom::Start(2)).unwrap(), 2);
             assert_eq!(writer.position(), 2);
-            assert_eq!(writer.write(&[2]), Ok(1));
+            assert_eq!(writer.write(&[2]).unwrap(), 1);
             assert_eq!(writer.position(), 3);
 
-            assert_eq!(writer.seek(SeekFrom::Current(-2)), Ok(1));
+            assert_eq!(writer.seek(SeekFrom::Current(-2)).unwrap(), 1);
             assert_eq!(writer.position(), 1);
-            assert_eq!(writer.write(&[3]), Ok(1));
+            assert_eq!(writer.write(&[3]).unwrap(), 1);
             assert_eq!(writer.position(), 2);
 
-            assert_eq!(writer.seek(SeekFrom::End(-1)), Ok(7));
+            assert_eq!(writer.seek(SeekFrom::End(-1)).unwrap(), 7);
             assert_eq!(writer.position(), 7);
-            assert_eq!(writer.write(&[4]), Ok(1));
+            assert_eq!(writer.write(&[4]).unwrap(), 1);
             assert_eq!(writer.position(), 8);
 
         }
@@ -242,31 +242,31 @@ mod tests {
     fn test_buf_writer_error() {
         let mut buf = [0 as u8; 2];
         let mut writer = Cursor::new(&mut buf[..]);
-        assert_eq!(writer.write(&[0]), Ok(1));
-        assert_eq!(writer.write(&[0, 0]), Ok(1));
-        assert_eq!(writer.write(&[0, 0]), Ok(0));
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
+        assert_eq!(writer.write(&[0, 0]).unwrap(), 1);
+        assert_eq!(writer.write(&[0, 0]).unwrap(), 0);
     }
 
     #[test]
     fn test_mem_reader() {
         let mut reader = Cursor::new(vec!(0, 1, 2, 3, 4, 5, 6, 7));
         let mut buf = [];
-        assert_eq!(reader.read(&mut buf), Ok(0));
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
         assert_eq!(reader.position(), 0);
         let mut buf = [0];
-        assert_eq!(reader.read(&mut buf), Ok(1));
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
         assert_eq!(reader.position(), 1);
         let b: &[_] = &[0];
         assert_eq!(buf, b);
         let mut buf = [0; 4];
-        assert_eq!(reader.read(&mut buf), Ok(4));
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
         assert_eq!(reader.position(), 5);
         let b: &[_] = &[1, 2, 3, 4];
         assert_eq!(buf, b);
-        assert_eq!(reader.read(&mut buf), Ok(3));
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
         let b: &[_] = &[5, 6, 7];
         assert_eq!(&buf[..3], b);
-        assert_eq!(reader.read(&mut buf), Ok(0));
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
     }
 
     #[test]
@@ -282,21 +282,21 @@ mod tests {
         let in_buf = vec![0, 1, 2, 3, 4, 5, 6, 7];
         let mut reader = &mut &in_buf[..];
         let mut buf = [];
-        assert_eq!(reader.read(&mut buf), Ok(0));
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
         let mut buf = [0];
-        assert_eq!(reader.read(&mut buf), Ok(1));
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
         assert_eq!(reader.len(), 7);
         let b: &[_] = &[0];
         assert_eq!(&buf[..], b);
         let mut buf = [0; 4];
-        assert_eq!(reader.read(&mut buf), Ok(4));
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
         assert_eq!(reader.len(), 3);
         let b: &[_] = &[1, 2, 3, 4];
         assert_eq!(&buf[..], b);
-        assert_eq!(reader.read(&mut buf), Ok(3));
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
         let b: &[_] = &[5, 6, 7];
         assert_eq!(&buf[..3], b);
-        assert_eq!(reader.read(&mut buf), Ok(0));
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
     }
 
     #[test]
@@ -304,33 +304,33 @@ mod tests {
         let in_buf = vec![0, 1, 2, 3, 4, 5, 6, 7];
         let mut reader = Cursor::new(&in_buf[..]);
         let mut buf = [];
-        assert_eq!(reader.read(&mut buf), Ok(0));
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
         assert_eq!(reader.position(), 0);
         let mut buf = [0];
-        assert_eq!(reader.read(&mut buf), Ok(1));
+        assert_eq!(reader.read(&mut buf).unwrap(), 1);
         assert_eq!(reader.position(), 1);
         let b: &[_] = &[0];
         assert_eq!(buf, b);
         let mut buf = [0; 4];
-        assert_eq!(reader.read(&mut buf), Ok(4));
+        assert_eq!(reader.read(&mut buf).unwrap(), 4);
         assert_eq!(reader.position(), 5);
         let b: &[_] = &[1, 2, 3, 4];
         assert_eq!(buf, b);
-        assert_eq!(reader.read(&mut buf), Ok(3));
+        assert_eq!(reader.read(&mut buf).unwrap(), 3);
         let b: &[_] = &[5, 6, 7];
         assert_eq!(&buf[..3], b);
-        assert_eq!(reader.read(&mut buf), Ok(0));
+        assert_eq!(reader.read(&mut buf).unwrap(), 0);
     }
 
     #[test]
     fn test_read_char() {
         let b = &b"Vi\xE1\xBB\x87t"[..];
         let mut c = Cursor::new(b).chars();
-        assert_eq!(c.next(), Some(Ok('V')));
-        assert_eq!(c.next(), Some(Ok('i')));
-        assert_eq!(c.next(), Some(Ok('ệ')));
-        assert_eq!(c.next(), Some(Ok('t')));
-        assert_eq!(c.next(), None);
+        assert_eq!(c.next().unwrap().unwrap(), 'V');
+        assert_eq!(c.next().unwrap().unwrap(), 'i');
+        assert_eq!(c.next().unwrap().unwrap(), 'ệ');
+        assert_eq!(c.next().unwrap().unwrap(), 't');
+        assert!(c.next().is_none());
     }
 
     #[test]
@@ -344,17 +344,17 @@ mod tests {
     fn seek_past_end() {
         let buf = [0xff];
         let mut r = Cursor::new(&buf[..]);
-        assert_eq!(r.seek(SeekFrom::Start(10)), Ok(10));
-        assert_eq!(r.read(&mut [0]), Ok(0));
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.read(&mut [0]).unwrap(), 0);
 
         let mut r = Cursor::new(vec!(10));
-        assert_eq!(r.seek(SeekFrom::Start(10)), Ok(10));
-        assert_eq!(r.read(&mut [0]), Ok(0));
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.read(&mut [0]).unwrap(), 0);
 
         let mut buf = [0];
         let mut r = Cursor::new(&mut buf[..]);
-        assert_eq!(r.seek(SeekFrom::Start(10)), Ok(10));
-        assert_eq!(r.write(&[3]), Ok(0));
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.write(&[3]).unwrap(), 0);
     }
 
     #[test]
@@ -375,32 +375,32 @@ mod tests {
     fn test_seekable_mem_writer() {
         let mut writer = Cursor::new(Vec::<u8>::new());
         assert_eq!(writer.position(), 0);
-        assert_eq!(writer.write(&[0]), Ok(1));
+        assert_eq!(writer.write(&[0]).unwrap(), 1);
         assert_eq!(writer.position(), 1);
-        assert_eq!(writer.write(&[1, 2, 3]), Ok(3));
-        assert_eq!(writer.write(&[4, 5, 6, 7]), Ok(4));
+        assert_eq!(writer.write(&[1, 2, 3]).unwrap(), 3);
+        assert_eq!(writer.write(&[4, 5, 6, 7]).unwrap(), 4);
         assert_eq!(writer.position(), 8);
         let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7];
         assert_eq!(&writer.get_ref()[..], b);
 
-        assert_eq!(writer.seek(SeekFrom::Start(0)), Ok(0));
+        assert_eq!(writer.seek(SeekFrom::Start(0)).unwrap(), 0);
         assert_eq!(writer.position(), 0);
-        assert_eq!(writer.write(&[3, 4]), Ok(2));
+        assert_eq!(writer.write(&[3, 4]).unwrap(), 2);
         let b: &[_] = &[3, 4, 2, 3, 4, 5, 6, 7];
         assert_eq!(&writer.get_ref()[..], b);
 
-        assert_eq!(writer.seek(SeekFrom::Current(1)), Ok(3));
-        assert_eq!(writer.write(&[0, 1]), Ok(2));
+        assert_eq!(writer.seek(SeekFrom::Current(1)).unwrap(), 3);
+        assert_eq!(writer.write(&[0, 1]).unwrap(), 2);
         let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 7];
         assert_eq!(&writer.get_ref()[..], b);
 
-        assert_eq!(writer.seek(SeekFrom::End(-1)), Ok(7));
-        assert_eq!(writer.write(&[1, 2]), Ok(2));
+        assert_eq!(writer.seek(SeekFrom::End(-1)).unwrap(), 7);
+        assert_eq!(writer.write(&[1, 2]).unwrap(), 2);
         let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 1, 2];
         assert_eq!(&writer.get_ref()[..], b);
 
-        assert_eq!(writer.seek(SeekFrom::End(1)), Ok(10));
-        assert_eq!(writer.write(&[1]), Ok(1));
+        assert_eq!(writer.seek(SeekFrom::End(1)).unwrap(), 10);
+        assert_eq!(writer.write(&[1]).unwrap(), 1);
         let b: &[_] = &[3, 4, 2, 0, 1, 5, 6, 1, 2, 0, 1];
         assert_eq!(&writer.get_ref()[..], b);
     }
@@ -408,8 +408,8 @@ mod tests {
     #[test]
     fn vec_seek_past_end() {
         let mut r = Cursor::new(Vec::new());
-        assert_eq!(r.seek(SeekFrom::Start(10)), Ok(10));
-        assert_eq!(r.write(&[3]), Ok(1));
+        assert_eq!(r.seek(SeekFrom::Start(10)).unwrap(), 10);
+        assert_eq!(r.write(&[3]).unwrap(), 1);
     }
 
     #[test]
diff --git a/src/libstd/io/mod.rs b/src/libstd/io/mod.rs
index d72abe8c69bf..a014d6e68ffb 100644
--- a/src/libstd/io/mod.rs
+++ b/src/libstd/io/mod.rs
@@ -920,18 +920,18 @@ mod tests {
     fn read_until() {
         let mut buf = Cursor::new(&b"12"[..]);
         let mut v = Vec::new();
-        assert_eq!(buf.read_until(b'3', &mut v), Ok(2));
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 2);
         assert_eq!(v, b"12");
 
         let mut buf = Cursor::new(&b"1233"[..]);
         let mut v = Vec::new();
-        assert_eq!(buf.read_until(b'3', &mut v), Ok(3));
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 3);
         assert_eq!(v, b"123");
         v.truncate(0);
-        assert_eq!(buf.read_until(b'3', &mut v), Ok(1));
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 1);
         assert_eq!(v, b"3");
         v.truncate(0);
-        assert_eq!(buf.read_until(b'3', &mut v), Ok(0));
+        assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 0);
         assert_eq!(v, []);
     }
 
@@ -939,32 +939,32 @@ mod tests {
     fn split() {
         let buf = Cursor::new(&b"12"[..]);
         let mut s = buf.split(b'3');
-        assert_eq!(s.next(), Some(Ok(vec![b'1', b'2'])));
-        assert_eq!(s.next(), None);
+        assert_eq!(s.next().unwrap().unwrap(), vec![b'1', b'2']);
+        assert!(s.next().is_none());
 
         let buf = Cursor::new(&b"1233"[..]);
         let mut s = buf.split(b'3');
-        assert_eq!(s.next(), Some(Ok(vec![b'1', b'2'])));
-        assert_eq!(s.next(), Some(Ok(vec![])));
-        assert_eq!(s.next(), None);
+        assert_eq!(s.next().unwrap().unwrap(), vec![b'1', b'2']);
+        assert_eq!(s.next().unwrap().unwrap(), vec![]);
+        assert!(s.next().is_none());
     }
 
     #[test]
     fn read_line() {
         let mut buf = Cursor::new(&b"12"[..]);
         let mut v = String::new();
-        assert_eq!(buf.read_line(&mut v), Ok(2));
+        assert_eq!(buf.read_line(&mut v).unwrap(), 2);
         assert_eq!(v, "12");
 
         let mut buf = Cursor::new(&b"12\n\n"[..]);
         let mut v = String::new();
-        assert_eq!(buf.read_line(&mut v), Ok(3));
+        assert_eq!(buf.read_line(&mut v).unwrap(), 3);
         assert_eq!(v, "12\n");
         v.truncate(0);
-        assert_eq!(buf.read_line(&mut v), Ok(1));
+        assert_eq!(buf.read_line(&mut v).unwrap(), 1);
         assert_eq!(v, "\n");
         v.truncate(0);
-        assert_eq!(buf.read_line(&mut v), Ok(0));
+        assert_eq!(buf.read_line(&mut v).unwrap(), 0);
         assert_eq!(v, "");
     }
 
@@ -972,26 +972,26 @@ mod tests {
     fn lines() {
         let buf = Cursor::new(&b"12"[..]);
         let mut s = buf.lines();
-        assert_eq!(s.next(), Some(Ok("12".to_string())));
-        assert_eq!(s.next(), None);
+        assert_eq!(s.next().unwrap().unwrap(), "12".to_string());
+        assert!(s.next().is_none());
 
         let buf = Cursor::new(&b"12\n\n"[..]);
         let mut s = buf.lines();
-        assert_eq!(s.next(), Some(Ok("12".to_string())));
-        assert_eq!(s.next(), Some(Ok(String::new())));
-        assert_eq!(s.next(), None);
+        assert_eq!(s.next().unwrap().unwrap(), "12".to_string());
+        assert_eq!(s.next().unwrap().unwrap(), "".to_string());
+        assert!(s.next().is_none());
     }
 
     #[test]
     fn read_to_end() {
         let mut c = Cursor::new(&b""[..]);
         let mut v = Vec::new();
-        assert_eq!(c.read_to_end(&mut v), Ok(0));
+        assert_eq!(c.read_to_end(&mut v).unwrap(), 0);
         assert_eq!(v, []);
 
         let mut c = Cursor::new(&b"1"[..]);
         let mut v = Vec::new();
-        assert_eq!(c.read_to_end(&mut v), Ok(1));
+        assert_eq!(c.read_to_end(&mut v).unwrap(), 1);
         assert_eq!(v, b"1");
     }
 
@@ -999,12 +999,12 @@ mod tests {
     fn read_to_string() {
         let mut c = Cursor::new(&b""[..]);
         let mut v = String::new();
-        assert_eq!(c.read_to_string(&mut v), Ok(0));
+        assert_eq!(c.read_to_string(&mut v).unwrap(), 0);
         assert_eq!(v, "");
 
         let mut c = Cursor::new(&b"1"[..]);
         let mut v = String::new();
-        assert_eq!(c.read_to_string(&mut v), Ok(1));
+        assert_eq!(c.read_to_string(&mut v).unwrap(), 1);
         assert_eq!(v, "1");
 
         let mut c = Cursor::new(&b"\xff"[..]);
@@ -1018,11 +1018,11 @@ mod tests {
 
         impl Read for R {
             fn read(&mut self, _: &mut [u8]) -> io::Result<usize> {
-                Err(io::Error::new(io::ErrorKind::Other, "", None))
+                Err(io::Error::new(io::ErrorKind::Other, ""))
             }
         }
 
         let mut buf = [0; 1];
-        assert_eq!(Ok(0), R.take(0).read(&mut buf));
+        assert_eq!(0, R.take(0).read(&mut buf).unwrap());
     }
 }
diff --git a/src/libstd/io/util.rs b/src/libstd/io/util.rs
index 20426025257c..c82f9515e8d5 100644
--- a/src/libstd/io/util.rs
+++ b/src/libstd/io/util.rs
@@ -111,33 +111,33 @@ mod test {
     #[test]
     fn sink_sinks() {
         let mut s = sink();
-        assert_eq!(s.write(&[]), Ok(0));
-        assert_eq!(s.write(&[0]), Ok(1));
-        assert_eq!(s.write(&[0; 1024]), Ok(1024));
-        assert_eq!(s.by_ref().write(&[0; 1024]), Ok(1024));
+        assert_eq!(s.write(&[]).unwrap(), 0);
+        assert_eq!(s.write(&[0]).unwrap(), 1);
+        assert_eq!(s.write(&[0; 1024]).unwrap(), 1024);
+        assert_eq!(s.by_ref().write(&[0; 1024]).unwrap(), 1024);
     }
 
     #[test]
     fn empty_reads() {
         let mut e = empty();
-        assert_eq!(e.read(&mut []), Ok(0));
-        assert_eq!(e.read(&mut [0]), Ok(0));
-        assert_eq!(e.read(&mut [0; 1024]), Ok(0));
-        assert_eq!(e.by_ref().read(&mut [0; 1024]), Ok(0));
+        assert_eq!(e.read(&mut []).unwrap(), 0);
+        assert_eq!(e.read(&mut [0]).unwrap(), 0);
+        assert_eq!(e.read(&mut [0; 1024]).unwrap(), 0);
+        assert_eq!(e.by_ref().read(&mut [0; 1024]).unwrap(), 0);
     }
 
     #[test]
     fn repeat_repeats() {
         let mut r = repeat(4);
         let mut b = [0; 1024];
-        assert_eq!(r.read(&mut b), Ok(1024));
+        assert_eq!(r.read(&mut b).unwrap(), 1024);
         assert!(b.iter().all(|b| *b == 4));
     }
 
     #[test]
     fn take_some_bytes() {
         assert_eq!(repeat(4).take(100).bytes().count(), 100);
-        assert_eq!(repeat(4).take(100).bytes().next(), Some(Ok(4)));
+        assert_eq!(repeat(4).take(100).bytes().next().unwrap().unwrap(), 4);
         assert_eq!(repeat(1).take(10).chain(repeat(2).take(10)).bytes().count(), 20);
     }
 
@@ -146,7 +146,7 @@ mod test {
         let mut buf = [0; 10];
         {
             let mut ptr: &mut [u8] = &mut buf;
-            assert_eq!(repeat(4).tee(&mut ptr).take(5).read(&mut [0; 10]), Ok(5));
+            assert_eq!(repeat(4).tee(&mut ptr).take(5).read(&mut [0; 10]).unwrap(), 5);
         }
         assert_eq!(buf, [4, 4, 4, 4, 4, 0, 0, 0, 0, 0]);
     }
@@ -160,7 +160,7 @@ mod test {
             let mut ptr2: &mut [u8] = &mut buf2;
 
             assert_eq!((&mut ptr1).broadcast(&mut ptr2)
-                                  .write(&[1, 2, 3]), Ok(3));
+                                  .write(&[1, 2, 3]).unwrap(), 3);
         }
         assert_eq!(buf1, buf2);
         assert_eq!(buf1, [1, 2, 3, 0, 0, 0, 0, 0, 0, 0]);
diff --git a/src/libstd/net/addr.rs b/src/libstd/net/addr.rs
index eb6cb4416063..c45230e91ba9 100644
--- a/src/libstd/net/addr.rs
+++ b/src/libstd/net/addr.rs
@@ -697,8 +697,11 @@ mod tests {
               false, false, false, true,  false, false, false, Some(Global));
     }
 
-    fn tsa<A: ToSocketAddrs>(a: A) -> io::Result<Vec<SocketAddr>> {
-        Ok(try!(a.to_socket_addrs()).collect())
+    fn tsa<A: ToSocketAddrs>(a: A) -> Result<Vec<SocketAddr>, String> {
+        match a.to_socket_addrs() {
+            Ok(a) => Ok(a.collect()),
+            Err(e) => Err(e.to_string()),
+        }
     }
 
     #[test]
diff --git a/src/libstd/net/tcp.rs b/src/libstd/net/tcp.rs
index a1a27f28fd95..04d1013af1fa 100644
--- a/src/libstd/net/tcp.rs
+++ b/src/libstd/net/tcp.rs
@@ -521,7 +521,7 @@ mod tests {
 
             let mut c = t!(TcpStream::connect(&addr));
             let mut b = [0; 10];
-            assert_eq!(c.read(&mut b), Ok(1));
+            assert_eq!(c.read(&mut b).unwrap(), 1);
             t!(c.write(&[1]));
             rx.recv().unwrap();
         })
@@ -566,7 +566,7 @@ mod tests {
             let _t = thread::spawn(move|| {
                 let mut s = t!(TcpStream::connect(&addr));
                 let mut buf = [0, 0];
-                assert_eq!(s.read(&mut buf), Ok(1));
+                assert_eq!(s.read(&mut buf).unwrap(), 1);
                 assert_eq!(buf[0], 1);
                 t!(s.write(&[2]));
             });
@@ -584,7 +584,7 @@ mod tests {
             });
             tx1.send(()).unwrap();
             let mut buf = [0, 0];
-            assert_eq!(s1.read(&mut buf), Ok(1));
+            assert_eq!(s1.read(&mut buf).unwrap(), 1);
             rx2.recv().unwrap();
         })
     }
@@ -657,7 +657,7 @@ mod tests {
             let _t = thread::spawn(move|| {
                 let mut c = t!(a.accept()).0;
                 let mut b = [0];
-                assert_eq!(c.read(&mut b), Ok(0));
+                assert_eq!(c.read(&mut b).unwrap(), 0);
                 t!(c.write(&[1]));
             });
 
@@ -688,16 +688,16 @@ mod tests {
             t!(s.shutdown(Shutdown::Write));
             assert!(s.write(&[0]).is_err());
             t!(s.shutdown(Shutdown::Read));
-            assert_eq!(s.read(&mut b), Ok(0));
+            assert_eq!(s.read(&mut b).unwrap(), 0);
 
             // closing should affect previous handles
             assert!(s2.write(&[0]).is_err());
-            assert_eq!(s2.read(&mut b), Ok(0));
+            assert_eq!(s2.read(&mut b).unwrap(), 0);
 
             // closing should affect new handles
             let mut s3 = t!(s.try_clone());
             assert!(s3.write(&[0]).is_err());
-            assert_eq!(s3.read(&mut b), Ok(0));
+            assert_eq!(s3.read(&mut b).unwrap(), 0);
 
             // make sure these don't die
             let _ = s2.shutdown(Shutdown::Read);
diff --git a/src/libstd/net/udp.rs b/src/libstd/net/udp.rs
index 14b5c974b677..7b14e4dbea67 100644
--- a/src/libstd/net/udp.rs
+++ b/src/libstd/net/udp.rs
@@ -212,7 +212,7 @@ mod tests {
 
             let _t = thread::spawn(move|| {
                 let mut buf = [0, 0];
-                assert_eq!(sock2.recv_from(&mut buf), Ok((1, addr1)));
+                assert_eq!(sock2.recv_from(&mut buf).unwrap(), (1, addr1));
                 assert_eq!(buf[0], 1);
                 t!(sock2.send_to(&[2], &addr1));
             });
@@ -228,7 +228,7 @@ mod tests {
             });
             tx1.send(()).unwrap();
             let mut buf = [0, 0];
-            assert_eq!(sock1.recv_from(&mut buf), Ok((1, addr2)));
+            assert_eq!(sock1.recv_from(&mut buf).unwrap(), (1, addr2));
             rx2.recv().unwrap();
         })
     }
diff --git a/src/libstd/process.rs b/src/libstd/process.rs
index ca25cadb9dc6..c2d43ba2a059 100644
--- a/src/libstd/process.rs
+++ b/src/libstd/process.rs
@@ -576,7 +576,7 @@ mod tests {
         assert!(p.is_ok());
         let mut p = p.unwrap();
         assert!(p.wait().unwrap().code() == Some(1));
-        drop(p.wait().clone());
+        drop(p.wait());
     }
 
     #[cfg(all(unix, not(target_os="android")))]
diff --git a/src/libstd/sys/unix/fs2.rs b/src/libstd/sys/unix/fs2.rs
index 314d694f66aa..c0426af051be 100644
--- a/src/libstd/sys/unix/fs2.rs
+++ b/src/libstd/sys/unix/fs2.rs
@@ -277,7 +277,7 @@ impl File {
 
 fn cstr(path: &Path) -> io::Result<CString> {
     path.as_os_str().to_cstring().ok_or(
-        io::Error::new(io::ErrorKind::InvalidInput, "path contained a null", None))
+        io::Error::new(io::ErrorKind::InvalidInput, "path contained a null"))
 }
 
 impl FromInner<c_int> for File {
diff --git a/src/libstd/sys/windows/c.rs b/src/libstd/sys/windows/c.rs
index b930e35c0641..e74de595f975 100644
--- a/src/libstd/sys/windows/c.rs
+++ b/src/libstd/sys/windows/c.rs
@@ -433,7 +433,7 @@ extern "system" {
                             TokenHandle: *mut libc::HANDLE) -> libc::BOOL;
     pub fn GetCurrentProcess() -> libc::HANDLE;
     pub fn GetStdHandle(which: libc::DWORD) -> libc::HANDLE;
-    pub fn ExitProcess(uExitCode: libc::UINT) -> !;
+    pub fn ExitProcess(uExitCode: libc::c_uint) -> !;
 }
 
 #[link(name = "userenv")]
diff --git a/src/libstd/sys/windows/os.rs b/src/libstd/sys/windows/os.rs
index f98c39cfad01..d5843a2f9987 100644
--- a/src/libstd/sys/windows/os.rs
+++ b/src/libstd/sys/windows/os.rs
@@ -382,5 +382,5 @@ pub fn home_dir() -> Option<PathBuf> {
 }
 
 pub fn exit(code: i32) -> ! {
-    unsafe { libc::ExitProcess(code as libc::UINT) }
+    unsafe { c::ExitProcess(code as libc::c_uint) }
 }
diff --git a/src/libstd/sys/windows/stdio.rs b/src/libstd/sys/windows/stdio.rs
index d1bff0e135dd..91f6f328ff6e 100644
--- a/src/libstd/sys/windows/stdio.rs
+++ b/src/libstd/sys/windows/stdio.rs
@@ -41,7 +41,7 @@ fn get(handle: libc::DWORD) -> io::Result<Output> {
         Err(io::Error::last_os_error())
     } else if handle.is_null() {
         Err(io::Error::new(io::ErrorKind::Other,
-                           "no stdio handle available for this process", None))
+                           "no stdio handle available for this process"))
     } else {
         let ret = NoClose::new(handle);
         let mut out = 0;
@@ -160,6 +160,5 @@ impl Drop for NoClose {
 }
 
 fn invalid_encoding() -> io::Error {
-    io::Error::new(io::ErrorKind::InvalidInput, "text was not valid unicode",
-                   None)
+    io::Error::new(io::ErrorKind::InvalidInput, "text was not valid unicode")
 }
diff --git a/src/test/run-pass/issue-22577.rs b/src/test/run-pass/issue-22577.rs
index a47c844e1994..2c4141b0bd37 100644
--- a/src/test/run-pass/issue-22577.rs
+++ b/src/test/run-pass/issue-22577.rs
@@ -15,13 +15,14 @@
 use std::{fs, net};
 
 fn assert_both<T: Send + Sync>() {}
+fn assert_send<T: Send>() {}
 
 fn main() {
     assert_both::<fs::File>();
     assert_both::<fs::Metadata>();
     assert_both::<fs::ReadDir>();
     assert_both::<fs::DirEntry>();
-    assert_both::<fs::WalkDir>();
+    assert_send::<fs::WalkDir>();
     assert_both::<fs::OpenOptions>();
     assert_both::<fs::Permissions>();