Remove std::either

18 files changed, 114 insertions, 341 deletions

diff --git a/src/libextra/test.rs b/src/libextra/test.rs
index 3d6dfd612f2..63e19df9519 100644
--- a/src/libextra/test.rs
+++ b/src/libextra/test.rs
@@ -337,9 +337,14 @@ pub enum TestResult {
     TrBench(BenchSamples),
 }
 
+enum OutputLocation<T> {
+    Pretty(term::Terminal<T>),
+    Raw(T),
+}
+
 struct ConsoleTestState<T> {
     log_out: Option<File>,
-    out: Either<term::Terminal<T>, T>,
+    out: OutputLocation<T>,
     use_color: bool,
     total: uint,
     passed: uint,
@@ -358,8 +363,8 @@ impl<T: Writer> ConsoleTestState<T> {
             None => None
         };
         let out = match term::Terminal::new(io::stdout()) {
-            Err(_) => Right(io::stdout()),
-            Ok(t) => Left(t)
+            Err(_) => Raw(io::stdout()),
+            Ok(t) => Pretty(t)
         };
         ConsoleTestState {
             out: out,
@@ -416,7 +421,7 @@ impl<T: Writer> ConsoleTestState<T> {
                         word: &str,
                         color: term::color::Color) {
         match self.out {
-            Left(ref mut term) => {
+            Pretty(ref mut term) => {
                 if self.use_color {
                     term.fg(color);
                 }
@@ -425,14 +430,14 @@ impl<T: Writer> ConsoleTestState<T> {
                     term.reset();
                 }
             }
-            Right(ref mut stdout) => stdout.write(word.as_bytes())
+            Raw(ref mut stdout) => stdout.write(word.as_bytes())
         }
     }
 
     pub fn write_plain(&mut self, s: &str) {
         match self.out {
-            Left(ref mut term) => term.write(s.as_bytes()),
-            Right(ref mut stdout) => stdout.write(s.as_bytes())
+            Pretty(ref mut term) => term.write(s.as_bytes()),
+            Raw(ref mut stdout) => stdout.write(s.as_bytes())
         }
     }
 
@@ -683,7 +688,7 @@ fn should_sort_failures_before_printing_them() {
 
     let mut st = ConsoleTestState {
         log_out: None,
-        out: Right(MemWriter::new()),
+        out: Raw(MemWriter::new()),
         use_color: false,
         total: 0u,
         passed: 0u,
@@ -697,8 +702,8 @@ fn should_sort_failures_before_printing_them() {
 
     st.write_failures();
     let s = match st.out {
-        Right(ref m) => str::from_utf8(*m.inner_ref()),
-        Left(_) => unreachable!()
+        Raw(ref m) => str::from_utf8(*m.inner_ref()),
+        Pretty(_) => unreachable!()
     };
 
     let apos = s.find_str("a").unwrap();
diff --git a/src/librustc/middle/typeck/check/mod.rs b/src/librustc/middle/typeck/check/mod.rs
index 74575ba3517..4a884847e62 100644
--- a/src/librustc/middle/typeck/check/mod.rs
+++ b/src/librustc/middle/typeck/check/mod.rs
@@ -1705,9 +1705,12 @@ pub fn check_expr_with_unifier(fcx: @FnCtxt,
                 fn_inputs.map(|a| *a)
             } else {
                 let msg = format!(
-                    "this function takes at least {0, plural, =1{# parameter} \
-                    other{# parameters}} but {1, plural, =1{# parameter was} \
-                    other{# parameters were}} supplied", expected_arg_count, supplied_arg_count);
+                    "this function takes at least {} parameter{} \
+                     but {} parameter{} supplied",
+                     expected_arg_count,
+                     if expected_arg_count == 1 {""} else {"s"},
+                     supplied_arg_count,
+                     if supplied_arg_count == 1 {" was"} else {"s were"});
 
                 tcx.sess.span_err(sp, msg);
 
@@ -1722,10 +1725,12 @@ pub fn check_expr_with_unifier(fcx: @FnCtxt,
                                   the `for` keyword)"
             };
             let msg = format!(
-                "this function takes {0, plural, =1{# parameter} \
-                other{# parameters}} but {1, plural, =1{# parameter was} \
-                other{# parameters were}} supplied{2}",
-                expected_arg_count, supplied_arg_count, suffix);
+                "this function takes {} parameter{} \
+                 but {} parameter{} supplied{}",
+                 expected_arg_count, if expected_arg_count == 1 {""} else {"s"},
+                 supplied_arg_count,
+                 if supplied_arg_count == 1 {" was"} else {"s were"},
+                 suffix);
 
             tcx.sess.span_err(sp, msg);
 
diff --git a/src/libstd/either.rs b/src/libstd/either.rs
deleted file mode 100644
index d07006aa6de..00000000000
--- a/src/libstd/either.rs
+++ /dev/null
@@ -1,248 +0,0 @@
-// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution and at
-// http://rust-lang.org/COPYRIGHT.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-//! Representing values with two possibilities (`Either` type)
-
-#[allow(missing_doc)];
-
-use option::{Some, None};
-use clone::Clone;
-use container::Container;
-use cmp::Eq;
-use iter::{Iterator, FilterMap};
-use str::StrSlice;
-use vec;
-use vec::{OwnedVector, ImmutableVector};
-
-/// `Either` is a type that represents one of two alternatives
-#[deriving(Clone, Eq, IterBytes)]
-pub enum Either<L, R> {
-    Left(L),
-    Right(R)
-}
-
-impl<L, R> Either<L, R> {
-    /// Applies a function based on the given either value
-    ///
-    /// If `value` is `Left(L)` then `f_left` is applied to its contents, if
-    /// `value` is `Right(R)` then `f_right` is applied to its contents, and the
-    /// result is returned.
-    #[inline]
-    pub fn either<T>(&self, f_left: |&L| -> T, f_right: |&R| -> T) -> T {
-        match *self {
-            Left(ref l) => f_left(l),
-            Right(ref r) => f_right(r)
-        }
-    }
-
-    /// Flips between left and right of a given `Either`
-    #[inline]
-    pub fn flip(self) -> Either<R, L> {
-        match self {
-            Right(r) => Left(r),
-            Left(l) => Right(l)
-        }
-    }
-
-    /// Checks whether the given value is a `Left`
-    #[inline]
-    pub fn is_left(&self) -> bool {
-        match *self {
-            Left(_) => true,
-            _ => false
-        }
-    }
-
-    /// Checks whether the given value is a `Right`
-    #[inline]
-    pub fn is_right(&self) -> bool {
-        match *self {
-            Right(_) => true,
-            _ => false
-        }
-    }
-
-    /// Retrieves the value from a `Left`.
-    /// Fails with a specified reason if the `Either` is `Right`.
-    #[inline]
-    pub fn expect_left(self, reason: &str) -> L {
-        match self {
-            Left(x) => x,
-            Right(_) => fail!("{}", reason.to_owned())
-        }
-    }
-
-    /// Retrieves the value from a `Left`. Fails if the `Either` is `Right`.
-    #[inline]
-    pub fn unwrap_left(self) -> L {
-        self.expect_left("called Either::unwrap_left()` on `Right` value")
-    }
-
-    /// Retrieves the value from a `Right`.
-    /// Fails with a specified reason if the `Either` is `Left`.
-    #[inline]
-    pub fn expect_right(self, reason: &str) -> R {
-        match self {
-            Right(x) => x,
-            Left(_) => fail!("{}", reason.to_owned())
-        }
-    }
-
-    /// Retrieves the value from a `Right`. Fails if the `Either` is `Left`.
-    #[inline]
-    pub fn unwrap_right(self) -> R {
-        self.expect_right("called Either::unwrap_right()` on `Left` value")
-    }
-}
-
-/// An iterator yielding the `Left` values of its source
-pub type Lefts<L, R, Iter> = FilterMap<'static, Either<L, R>, L, Iter>;
-
-/// An iterator yielding the `Right` values of its source
-pub type Rights<L, R, Iter> = FilterMap<'static, Either<L, R>, R, Iter>;
-
-/// Extracts all the left values
-pub fn lefts<L, R, Iter: Iterator<Either<L, R>>>(eithers: Iter)
-    -> Lefts<L, R, Iter> {
-    eithers.filter_map(|elt| {
-        match elt {
-            Left(x) => Some(x),
-            _ => None,
-        }
-    })
-}
-
-/// Extracts all the right values
-pub fn rights<L, R, Iter: Iterator<Either<L, R>>>(eithers: Iter)
-    -> Rights<L, R, Iter> {
-    eithers.filter_map(|elt| {
-        match elt {
-            Right(x) => Some(x),
-            _ => None,
-        }
-    })
-}
-
-
-// FIXME: #8228 Replaceable by an external iterator?
-/// Extracts from a vector of either all the left values and right values
-///
-/// Returns a structure containing a vector of left values and a vector of
-/// right values.
-pub fn partition<L, R>(eithers: ~[Either<L, R>]) -> (~[L], ~[R]) {
-    let n_lefts = eithers.iter().count(|elt| elt.is_left());
-    let mut lefts = vec::with_capacity(n_lefts);
-    let mut rights = vec::with_capacity(eithers.len() - n_lefts);
-    for elt in eithers.move_iter() {
-        match elt {
-            Left(l) => lefts.push(l),
-            Right(r) => rights.push(r)
-        }
-    }
-    return (lefts, rights);
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn test_either_left() {
-        let val = Left(10);
-        fn f_left(x: &int) -> bool { *x == 10 }
-        fn f_right(_x: &uint) -> bool { false }
-        assert!(val.either(f_left, f_right));
-    }
-
-    #[test]
-    fn test_either_right() {
-        let val = Right(10u);
-        fn f_left(_x: &int) -> bool { false }
-        fn f_right(x: &uint) -> bool { *x == 10u }
-        assert!(val.either(f_left, f_right));
-    }
-
-    #[test]
-    fn test_lefts() {
-        let input = ~[Left(10), Right(11), Left(12), Right(13), Left(14)];
-        let result = lefts(input.move_iter()).to_owned_vec();
-        assert_eq!(result, ~[10, 12, 14]);
-    }
-
-    #[test]
-    fn test_lefts_none() {
-        let input: ~[Either<int, int>] = ~[Right(10), Right(10)];
-        let result = lefts(input.move_iter()).to_owned_vec();
-        assert_eq!(result.len(), 0u);
-    }
-
-    #[test]
-    fn test_lefts_empty() {
-        let input: ~[Either<int, int>] = ~[];
-        let result = lefts(input.move_iter()).to_owned_vec();
-        assert_eq!(result.len(), 0u);
-    }
-
-    #[test]
-    fn test_rights() {
-        let input = ~[Left(10), Right(11), Left(12), Right(13), Left(14)];
-        let result = rights(input.move_iter()).to_owned_vec();
-        assert_eq!(result, ~[11, 13]);
-    }
-
-    #[test]
-    fn test_rights_none() {
-        let input: ~[Either<int, int>] = ~[Left(10), Left(10)];
-        let result = rights(input.move_iter()).to_owned_vec();
-        assert_eq!(result.len(), 0u);
-    }
-
-    #[test]
-    fn test_rights_empty() {
-        let input: ~[Either<int, int>] = ~[];
-        let result = rights(input.move_iter()).to_owned_vec();
-        assert_eq!(result.len(), 0u);
-    }
-
-    #[test]
-    fn test_partition() {
-        let input = ~[Left(10), Right(11), Left(12), Right(13), Left(14)];
-        let (lefts, rights) = partition(input);
-        assert_eq!(lefts[0], 10);
-        assert_eq!(lefts[1], 12);
-        assert_eq!(lefts[2], 14);
-        assert_eq!(rights[0], 11);
-        assert_eq!(rights[1], 13);
-    }
-
-    #[test]
-    fn test_partition_no_lefts() {
-        let input: ~[Either<int, int>] = ~[Right(10), Right(11)];
-        let (lefts, rights) = partition(input);
-        assert_eq!(lefts.len(), 0u);
-        assert_eq!(rights.len(), 2u);
-    }
-
-    #[test]
-    fn test_partition_no_rights() {
-        let input: ~[Either<int, int>] = ~[Left(10), Left(11)];
-        let (lefts, rights) = partition(input);
-        assert_eq!(lefts.len(), 2u);
-        assert_eq!(rights.len(), 0u);
-    }
-
-    #[test]
-    fn test_partition_empty() {
-        let input: ~[Either<int, int>] = ~[];
-        let (lefts, rights) = partition(input);
-        assert_eq!(lefts.len(), 0u);
-        assert_eq!(rights.len(), 0u);
-    }
-}
diff --git a/src/libstd/fmt/mod.rs b/src/libstd/fmt/mod.rs
index cd9c0f5d2b7..53eaf17c7f8 100644
--- a/src/libstd/fmt/mod.rs
+++ b/src/libstd/fmt/mod.rs
@@ -757,7 +757,7 @@ impl<'a> Formatter<'a> {
                 // offsetted value
                 for s in selectors.iter() {
                     match s.selector {
-                        Right(val) if value == val => {
+                        rt::Literal(val) if value == val => {
                             return self.runplural(value, s.result);
                         }
                         _ => {}
@@ -769,17 +769,17 @@ impl<'a> Formatter<'a> {
                 let value = value - match offset { Some(i) => i, None => 0 };
                 for s in selectors.iter() {
                     let run = match s.selector {
-                        Left(parse::Zero) => value == 0,
-                        Left(parse::One) => value == 1,
-                        Left(parse::Two) => value == 2,
+                        rt::Keyword(parse::Zero) => value == 0,
+                        rt::Keyword(parse::One) => value == 1,
+                        rt::Keyword(parse::Two) => value == 2,
 
                         // XXX: Few/Many should have a user-specified boundary
                         //      One possible option would be in the function
                         //      pointer of the 'arg: Argument' struct.
-                        Left(parse::Few) => value < 8,
-                        Left(parse::Many) => value >= 8,
+                        rt::Keyword(parse::Few) => value < 8,
+                        rt::Keyword(parse::Many) => value >= 8,
 
-                        Right(..) => false
+                        rt::Literal(..) => false
                     };
                     if run {
                         return self.runplural(value, s.result);
diff --git a/src/libstd/fmt/parse.rs b/src/libstd/fmt/parse.rs
index e9f7af181a7..0ac1aac2380 100644
--- a/src/libstd/fmt/parse.rs
+++ b/src/libstd/fmt/parse.rs
@@ -122,12 +122,21 @@ pub enum Method<'a> {
     Select(~[SelectArm<'a>], ~[Piece<'a>]),
 }
 
+/// A selector for what pluralization a plural method should take
+#[deriving(Eq, IterBytes)]
+pub enum PluralSelector {
+    /// One of the plural keywords should be used
+    Keyword(PluralKeyword),
+    /// A literal pluralization should be used
+    Literal(uint),
+}
+
 /// Structure representing one "arm" of the `plural` function.
 #[deriving(Eq)]
 pub struct PluralArm<'a> {
     /// A selector can either be specified by a keyword or with an integer
     /// literal.
-    selector: Either<PluralKeyword, uint>,
+    selector: PluralSelector,
     /// Array of pieces which are the format of this arm
     result: ~[Piece<'a>],
 }
@@ -504,29 +513,29 @@ impl<'a> Parser<'a> {
             let mut isother = false;
             let selector = if self.wsconsume('=') {
                 match self.integer() {
-                    Some(i) => Right(i),
+                    Some(i) => Literal(i),
                     None => {
                         self.err("plural `=` selectors must be followed by an \
                                   integer");
-                        Right(0)
+                        Literal(0)
                     }
                 }
             } else {
                 let word = self.word();
                 match word {
-                    "other" => { isother = true; Left(Zero) }
-                    "zero"  => Left(Zero),
-                    "one"   => Left(One),
-                    "two"   => Left(Two),
-                    "few"   => Left(Few),
-                    "many"  => Left(Many),
+                    "other" => { isother = true; Keyword(Zero) }
+                    "zero"  => Keyword(Zero),
+                    "one"   => Keyword(One),
+                    "two"   => Keyword(Two),
+                    "few"   => Keyword(Few),
+                    "many"  => Keyword(Many),
                     word    => {
                         self.err(format!("unexpected plural selector `{}`",
                                          word));
                         if word == "" {
                             break
                         } else {
-                            Left(Zero)
+                            Keyword(Zero)
                         }
                     }
                 }
@@ -955,9 +964,9 @@ mod tests {
             position: ArgumentNext,
             format: fmtdflt(),
             method: Some(~Plural(Some(1), ~[
-                PluralArm{ selector: Right(2), result: ~[String("2")] },
-                PluralArm{ selector: Right(3), result: ~[String("3")] },
-                PluralArm{ selector: Left(Many), result: ~[String("yes")] }
+                PluralArm{ selector: Literal(2), result: ~[String("2")] },
+                PluralArm{ selector: Literal(3), result: ~[String("3")] },
+                PluralArm{ selector: Keyword(Many), result: ~[String("yes")] }
             ], ~[String("haha")]))
         })]);
     }
diff --git a/src/libstd/fmt/rt.rs b/src/libstd/fmt/rt.rs
index c139a2f5734..89895f30585 100644
--- a/src/libstd/fmt/rt.rs
+++ b/src/libstd/fmt/rt.rs
@@ -17,7 +17,6 @@
 #[allow(missing_doc)];
 #[doc(hidden)];
 
-use either::Either;
 use fmt::parse;
 use option::Option;
 
@@ -55,8 +54,13 @@ pub enum Method<'a> {
     Select(&'a [SelectArm<'a>], &'a [Piece<'a>]),
 }
 
+pub enum PluralSelector {
+    Keyword(parse::PluralKeyword),
+    Literal(uint),
+}
+
 pub struct PluralArm<'a> {
-    selector: Either<parse::PluralKeyword, uint>,
+    selector: PluralSelector,
     result: &'a [Piece<'a>],
 }
 
diff --git a/src/libstd/lib.rs b/src/libstd/lib.rs
index 442c7f3f856..6126b73e28f 100644
--- a/src/libstd/lib.rs
+++ b/src/libstd/lib.rs
@@ -148,7 +148,6 @@ pub mod any;
 
 pub mod option;
 pub mod result;
-pub mod either;
 pub mod hashmap;
 pub mod cell;
 pub mod trie;
diff --git a/src/libstd/prelude.rs b/src/libstd/prelude.rs
index 3c81ff661bc..e1478de9485 100644
--- a/src/libstd/prelude.rs
+++ b/src/libstd/prelude.rs
@@ -29,7 +29,6 @@ Rust's prelude has three main parts:
 */
 
 // Reexported core operators
-pub use either::{Either, Left, Right};
 pub use kinds::{Freeze, Pod, Send, Sized};
 pub use ops::{Add, Sub, Mul, Div, Rem, Neg, Not};
 pub use ops::{BitAnd, BitOr, BitXor};
diff --git a/src/libstd/util.rs b/src/libstd/util.rs
index d12d61ed46c..6c0424b50e1 100644
--- a/src/libstd/util.rs
+++ b/src/libstd/util.rs
@@ -82,7 +82,6 @@ mod tests {
     use clone::Clone;
     use ops::Drop;
     use option::{None, Some};
-    use either::{Either, Left, Right};
     use mem::size_of;
 
     #[test]
@@ -112,15 +111,6 @@ mod tests {
     }
 
     #[test]
-    fn test_uninhabited() {
-        let could_only_be_coin : Either <Void, ()> = Right (());
-        match could_only_be_coin {
-            Right (coin) => coin,
-            Left (is_void) => is_void.uninhabited ()
-        }
-    }
-
-    #[test]
     fn test_noncopyable() {
         assert_eq!(size_of::<NonCopyable>(), 0);
 
diff --git a/src/libsyntax/ext/format.rs b/src/libsyntax/ext/format.rs
index 3bfab7da9b4..3f1775ba75b 100644
--- a/src/libsyntax/ext/format.rs
+++ b/src/libsyntax/ext/format.rs
@@ -28,6 +28,11 @@ enum ArgumentType {
     String,
 }
 
+enum Position {
+    Exact(uint),
+    Named(@str),
+}
+
 struct Context<'a> {
     ecx: &'a mut ExtCtxt,
     fmtsp: Span,
@@ -148,10 +153,10 @@ impl<'a> Context<'a> {
                         if self.check_positional_ok() {
                             self.next_arg += 1;
                         }
-                        Left(i)
+                        Exact(i)
                     }
-                    parse::ArgumentIs(i) => Left(i),
-                    parse::ArgumentNamed(s) => Right(s.to_managed()),
+                    parse::ArgumentIs(i) => Exact(i),
+                    parse::ArgumentNamed(s) => Named(s.to_managed()),
                 };
 
                 // and finally the method being applied
@@ -176,14 +181,14 @@ impl<'a> Context<'a> {
         match c {
             parse::CountImplied | parse::CountIs(..) => {}
             parse::CountIsParam(i) => {
-                self.verify_arg_type(Left(i), Unsigned);
+                self.verify_arg_type(Exact(i), Unsigned);
             }
             parse::CountIsName(s) => {
-                self.verify_arg_type(Right(s.to_managed()), Unsigned);
+                self.verify_arg_type(Named(s.to_managed()), Unsigned);
             }
             parse::CountIsNextParam => {
                 if self.check_positional_ok() {
-                    self.verify_arg_type(Left(self.next_arg), Unsigned);
+                    self.verify_arg_type(Exact(self.next_arg), Unsigned);
                     self.next_arg += 1;
                 }
             }
@@ -200,7 +205,7 @@ impl<'a> Context<'a> {
         }
     }
 
-    fn verify_method(&mut self, pos: Either<uint, @str>, m: &parse::Method) {
+    fn verify_method(&mut self, pos: Position, m: &parse::Method) {
         self.nest_level += 1;
         match *m {
             parse::Plural(_, ref arms, ref default) => {
@@ -209,12 +214,12 @@ impl<'a> Context<'a> {
                 for arm in arms.iter() {
                     if !seen_cases.insert(arm.selector) {
                         match arm.selector {
-                            Left(name) => {
+                            parse::Keyword(name) => {
                                 self.ecx.span_err(self.fmtsp,
                                                   format!("duplicate selector \
                                                            `{:?}`", name));
                             }
-                            Right(idx) => {
+                            parse::Literal(idx) => {
                                 self.ecx.span_err(self.fmtsp,
                                                   format!("duplicate selector \
                                                            `={}`", idx));
@@ -245,9 +250,9 @@ impl<'a> Context<'a> {
         self.nest_level -= 1;
     }
 
-    fn verify_arg_type(&mut self, arg: Either<uint, @str>, ty: ArgumentType) {
+    fn verify_arg_type(&mut self, arg: Position, ty: ArgumentType) {
         match arg {
-            Left(arg) => {
+            Exact(arg) => {
                 if arg < 0 || self.args.len() <= arg {
                     let msg = format!("invalid reference to argument `{}` (there \
                                     are {} arguments)", arg, self.args.len());
@@ -260,7 +265,7 @@ impl<'a> Context<'a> {
                 }
             }
 
-            Right(name) => {
+            Named(name) => {
                 let span = match self.names.find(&name) {
                     Some(e) => e.span,
                     None => {
@@ -434,18 +439,16 @@ impl<'a> Context<'a> {
                             self.trans_piece(p)
                         }).collect();
                         let (lr, selarg) = match arm.selector {
-                            Left(t) => {
+                            parse::Keyword(t) => {
                                 let p = ctpath(format!("{:?}", t));
                                 let p = self.ecx.path_global(sp, p);
-                                (self.ecx.ident_of("Left"),
-                                 self.ecx.expr_path(p))
+                                (rtpath("Keyword"), self.ecx.expr_path(p))
                             }
-                            Right(i) => {
-                                (self.ecx.ident_of("Right"),
-                                 self.ecx.expr_uint(sp, i))
+                            parse::Literal(i) => {
+                                (rtpath("Literal"), self.ecx.expr_uint(sp, i))
                             }
                         };
-                        let selector = self.ecx.expr_call_ident(sp,
+                        let selector = self.ecx.expr_call_global(sp,
                                 lr, ~[selarg]);
                         self.ecx.expr_struct(sp, p, ~[
                             self.ecx.field_imm(sp,
@@ -617,7 +620,7 @@ impl<'a> Context<'a> {
             let name = self.ecx.ident_of(format!("__arg{}", i));
             let e = self.ecx.expr_addr_of(e.span, e);
             lets.push(self.ecx.stmt_let(e.span, false, name, e));
-            locals.push(self.format_arg(e.span, Left(i),
+            locals.push(self.format_arg(e.span, Exact(i),
                                         self.ecx.expr_ident(e.span, name)));
         }
         for (&name, &e) in self.names.iter() {
@@ -627,7 +630,7 @@ impl<'a> Context<'a> {
             let e = self.ecx.expr_addr_of(e.span, e);
             lets.push(self.ecx.stmt_let(e.span, false, lname, e));
             names[*self.name_positions.get(&name)] =
-                Some(self.format_arg(e.span, Right(name),
+                Some(self.format_arg(e.span, Named(name),
                                      self.ecx.expr_ident(e.span, lname)));
         }
 
@@ -662,11 +665,11 @@ impl<'a> Context<'a> {
                                            Some(result)))
     }
 
-    fn format_arg(&self, sp: Span, argno: Either<uint, @str>,
+    fn format_arg(&self, sp: Span, argno: Position,
                   arg: @ast::Expr) -> @ast::Expr {
         let ty = match argno {
-            Left(i) => self.arg_types[i].unwrap(),
-            Right(s) => *self.name_types.get(&s)
+            Exact(i) => self.arg_types[i].unwrap(),
+            Named(s) => *self.name_types.get(&s)
         };
 
         let fmt_trait = match ty {
diff --git a/src/libsyntax/parse/lexer.rs b/src/libsyntax/parse/lexer.rs
index d48c1d9d8d7..7c187ac5dcf 100644
--- a/src/libsyntax/parse/lexer.rs
+++ b/src/libsyntax/parse/lexer.rs
@@ -19,7 +19,6 @@ use parse::token::{str_to_ident};
 
 use std::cast::transmute;
 use std::char;
-use std::either;
 use std::num::from_str_radix;
 use std::util;
 
@@ -475,34 +474,35 @@ fn scan_number(c: char, rdr: @mut StringReader) -> token::Token {
     c = rdr.curr;
     nextch(rdr);
     if c == 'u' || c == 'i' {
+        enum Result { Signed(ast::int_ty), Unsigned(ast::uint_ty) }
         let signed = c == 'i';
         let mut tp = {
-            if signed { either::Left(ast::ty_i) }
-            else { either::Right(ast::ty_u) }
+            if signed { Signed(ast::ty_i) }
+            else { Unsigned(ast::ty_u) }
         };
         bump(rdr);
         c = rdr.curr;
         if c == '8' {
             bump(rdr);
-            tp = if signed { either::Left(ast::ty_i8) }
-                      else { either::Right(ast::ty_u8) };
+            tp = if signed { Signed(ast::ty_i8) }
+                      else { Unsigned(ast::ty_u8) };
         }
         n = nextch(rdr);
         if c == '1' && n == '6' {
             bump(rdr);
             bump(rdr);
-            tp = if signed { either::Left(ast::ty_i16) }
-                      else { either::Right(ast::ty_u16) };
+            tp = if signed { Signed(ast::ty_i16) }
+                      else { Unsigned(ast::ty_u16) };
         } else if c == '3' && n == '2' {
             bump(rdr);
             bump(rdr);
-            tp = if signed { either::Left(ast::ty_i32) }
-                      else { either::Right(ast::ty_u32) };
+            tp = if signed { Signed(ast::ty_i32) }
+                      else { Unsigned(ast::ty_u32) };
         } else if c == '6' && n == '4' {
             bump(rdr);
             bump(rdr);
-            tp = if signed { either::Left(ast::ty_i64) }
-                      else { either::Right(ast::ty_u64) };
+            tp = if signed { Signed(ast::ty_i64) }
+                      else { Unsigned(ast::ty_u64) };
         }
         if num_str.len() == 0u {
             fatal_span(rdr, start_bpos, rdr.last_pos,
@@ -515,8 +515,8 @@ fn scan_number(c: char, rdr: @mut StringReader) -> token::Token {
         };
 
         match tp {
-          either::Left(t) => return token::LIT_INT(parsed as i64, t),
-          either::Right(t) => return token::LIT_UINT(parsed, t)
+          Signed(t) => return token::LIT_INT(parsed as i64, t),
+          Unsigned(t) => return token::LIT_UINT(parsed, t)
         }
     }
     let mut is_float = false;
diff --git a/src/test/compile-fail/borrowck-autoref-3261.rs b/src/test/compile-fail/borrowck-autoref-3261.rs
index 5c7e328969b..1bd791ad5e0 100644
--- a/src/test/compile-fail/borrowck-autoref-3261.rs
+++ b/src/test/compile-fail/borrowck-autoref-3261.rs
@@ -8,6 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+enum Either<T, U> { Left(T), Right(U) }
+
 struct X(Either<(uint,uint),extern fn()>);
 
 impl X {
diff --git a/src/test/compile-fail/borrowck-loan-local-as-both-mut-and-imm.rs b/src/test/compile-fail/borrowck-loan-local-as-both-mut-and-imm.rs
index e2136c82313..300efbbc4fa 100644
--- a/src/test/compile-fail/borrowck-loan-local-as-both-mut-and-imm.rs
+++ b/src/test/compile-fail/borrowck-loan-local-as-both-mut-and-imm.rs
@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-use std::either::{Either, Left, Right};
+enum Either<T, U> { Left(T), Right(U) }
 
     fn f(x: &mut Either<int,f64>, y: &Either<int,f64>) -> int {
         match *y {
diff --git a/src/test/compile-fail/issue-5358-1.rs b/src/test/compile-fail/issue-5358-1.rs
index a3d25e7d2ad..326d2e1c852 100644
--- a/src/test/compile-fail/issue-5358-1.rs
+++ b/src/test/compile-fail/issue-5358-1.rs
@@ -8,11 +8,12 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+enum Either<T, U> { Left(T), Right(U) }
 struct S(Either<uint, uint>);
 
 fn main() {
     match S(Left(5)) {
-        Right(_) => {}  //~ ERROR mismatched types: expected `S` but found `std::either::Either
+        Right(_) => {}  //~ ERROR mismatched types: expected `S` but found `Either
         _ => {}
     }
 }
diff --git a/src/test/compile-fail/issue-5358.rs b/src/test/compile-fail/issue-5358.rs
index 8d4f4633466..b9540fe2cf0 100644
--- a/src/test/compile-fail/issue-5358.rs
+++ b/src/test/compile-fail/issue-5358.rs
@@ -8,10 +8,11 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+enum Either<T, U> { Left(T), Right(U) }
 struct S(Either<uint, uint>);
 
 fn main() {
     match *S(Left(5)) {
-      S(_) => {}  //~ ERROR mismatched types: expected `std::either::Either<uint,uint>` but found a structure pattern
+      S(_) => {}  //~ ERROR mismatched types: expected `Either<uint,uint>` but found a structure pattern
     }
 }
diff --git a/src/test/compile-fail/lint-unused-imports.rs b/src/test/compile-fail/lint-unused-imports.rs
index e248184d5e2..c7565fa0169 100644
--- a/src/test/compile-fail/lint-unused-imports.rs
+++ b/src/test/compile-fail/lint-unused-imports.rs
@@ -14,8 +14,6 @@
 
 use cal = bar::c::cc;
 
-use std::either::Right;        //~ ERROR unused import
-
 use std::util::*;              // shouldn't get errors for not using
                                 // everything imported
 
diff --git a/src/test/run-pass/issue-6117.rs b/src/test/run-pass/issue-6117.rs
index 6b68e3c9ed7..400486b2f22 100644
--- a/src/test/run-pass/issue-6117.rs
+++ b/src/test/run-pass/issue-6117.rs
@@ -10,6 +10,8 @@
 
 #[feature(managed_boxes)];
 
+enum Either<T, U> { Left(T), Right(U) }
+
 pub fn main() {
     match Left(@17) {
         Right(()) => {}
diff --git a/src/test/run-pass/small-enums-with-fields.rs b/src/test/run-pass/small-enums-with-fields.rs
index c4f4b5e4e37..06b536b8391 100644
--- a/src/test/run-pass/small-enums-with-fields.rs
+++ b/src/test/run-pass/small-enums-with-fields.rs
@@ -12,6 +12,9 @@
 
 use std::mem::size_of;
 
+#[deriving(Eq)]
+enum Either<T, U> { Left(T), Right(U) }
+
 macro_rules! check {
     ($t:ty, $sz:expr, $($e:expr, $s:expr),*) => {{
         assert_eq!(size_of::<$t>(), $sz);