diff --git a/src/compiletest/errors.rs b/src/compiletest/errors.rs
index b7df43aabdd20..16c6f7250306d 100644
--- a/src/compiletest/errors.rs
+++ b/src/compiletest/errors.rs
@@ -67,7 +67,7 @@ fn parse_expected(last_nonfollow_error: Option<uint>,
                   re: &Regex) -> Option<(WhichLine, ExpectedError)> {
     re.captures(line).and_then(|caps| {
         let adjusts = caps.name("adjusts").unwrap_or("").len();
-        let kind = caps.name("kind").unwrap_or("").to_ascii_lower();
+        let kind = caps.name("kind").unwrap_or("").to_ascii_lowercase();
         let msg = caps.name("msg").unwrap_or("").trim().to_string();
         let follow = caps.name("follow").unwrap_or("").len() > 0;
 
diff --git a/src/compiletest/runtest.rs b/src/compiletest/runtest.rs
index bf72250c4705a..1abcd8bd21407 100644
--- a/src/compiletest/runtest.rs
+++ b/src/compiletest/runtest.rs
@@ -21,6 +21,8 @@ use util::logv;
 #[cfg(target_os = "windows")]
 use util;
 
+#[cfg(target_os = "windows")]
+use std::ascii::AsciiExt;
 use std::io::File;
 use std::io::fs::PathExtensions;
 use std::io::fs;
@@ -985,22 +987,9 @@ fn check_expected_errors(expected_errors: Vec<errors::ExpectedError> ,
         format!("{}:{}:", testfile.display(), ee.line)
     }).collect::<Vec<String> >();
 
-    #[cfg(target_os = "windows")]
-    fn to_lower( s : &str ) -> String {
-        let i = s.chars();
-        let c : Vec<char> = i.map( |c| {
-            if c.is_ascii() {
-                c.to_ascii().to_lowercase().as_char()
-            } else {
-                c
-            }
-        } ).collect();
-        String::from_chars(c.as_slice())
-    }
-
     #[cfg(windows)]
     fn prefix_matches( line : &str, prefix : &str ) -> bool {
-        to_lower(line).as_slice().starts_with(to_lower(prefix).as_slice())
+        line.to_ascii_lowercase().starts_with(prefix.to_ascii_lowercase().as_slice())
     }
 
     #[cfg(unix)]
diff --git a/src/librustc/lint/mod.rs b/src/librustc/lint/mod.rs
index 009a1d444dc13..787e999eea9f1 100644
--- a/src/librustc/lint/mod.rs
+++ b/src/librustc/lint/mod.rs
@@ -68,7 +68,7 @@ pub struct Lint {
 impl Lint {
     /// Get the lint's name, with ASCII letters converted to lowercase.
     pub fn name_lower(&self) -> String {
-        self.name.to_ascii_lower()
+        self.name.to_ascii_lowercase()
     }
 }
 
diff --git a/src/librustdoc/html/markdown.rs b/src/librustdoc/html/markdown.rs
index f7984b8973cc6..af0bc65d3cf7f 100644
--- a/src/librustdoc/html/markdown.rs
+++ b/src/librustdoc/html/markdown.rs
@@ -235,7 +235,7 @@ pub fn render(w: &mut fmt::Formatter, s: &str, print_toc: bool) -> fmt::Result {
         };
 
         // Transform the contents of the header into a hyphenated string
-        let id = s.words().map(|s| s.to_ascii_lower())
+        let id = s.words().map(|s| s.to_ascii_lowercase())
             .collect::<Vec<String>>().connect("-");
 
         // This is a terrible hack working around how hoedown gives us rendered
diff --git a/src/libstd/ascii.rs b/src/libstd/ascii.rs
index 6c213555ce496..c3af95f15988d 100644
--- a/src/libstd/ascii.rs
+++ b/src/libstd/ascii.rs
@@ -16,500 +16,185 @@
 #![allow(deprecated)]
 
 use core::kinds::Sized;
-use fmt;
 use iter::IteratorExt;
-use mem;
 use ops::FnMut;
-use option::Option;
-use option::Option::{Some, None};
-use slice::{SliceExt, AsSlice};
-use str::{Str, StrExt};
-use string::{String, IntoString};
+use slice::SliceExt;
+use str::StrExt;
+use string::String;
 use vec::Vec;
 
-/// Datatype to hold one ascii character. It wraps a `u8`, with the highest bit always zero.
-#[deriving(Clone, Copy, PartialEq, PartialOrd, Ord, Eq, Hash)]
-pub struct Ascii { chr: u8 }
-
-impl Ascii {
-    /// Converts an ascii character into a `u8`.
-    #[inline]
-    #[unstable = "recently renamed"]
-    pub fn as_byte(&self) -> u8 {
-        self.chr
-    }
-
-    /// Deprecated: use `as_byte` instead.
-    #[deprecated = "use as_byte"]
-    pub fn to_byte(self) -> u8 {
-        self.as_byte()
-    }
-
-    /// Converts an ascii character into a `char`.
-    #[inline]
-    #[unstable = "recently renamed"]
-    pub fn as_char(&self) -> char {
-        self.chr as char
-    }
-
-    /// Deprecated: use `as_char` instead.
-    #[deprecated = "use as_char"]
-    pub fn to_char(self) -> char {
-        self.as_char()
-    }
-
-    /// Convert to lowercase.
-    #[inline]
-    #[stable]
-    pub fn to_lowercase(&self) -> Ascii {
-        Ascii{chr: ASCII_LOWER_MAP[self.chr as uint]}
-    }
-
-    /// Convert to uppercase.
-    #[inline]
-    #[stable]
-    pub fn to_uppercase(&self) -> Ascii {
-        Ascii{chr: ASCII_UPPER_MAP[self.chr as uint]}
-    }
-
-    /// Compares two ascii characters of equality, ignoring case.
-    #[inline]
-    #[deprecated = "normalize with to_lowercase"]
-    pub fn eq_ignore_case(self, other: Ascii) -> bool {
-        ASCII_LOWER_MAP[self.chr as uint] == ASCII_LOWER_MAP[other.chr as uint]
-    }
-
-    // the following methods are like ctype, and the implementation is inspired by musl
-
-    /// Check if the character is a letter (a-z, A-Z)
-    #[inline]
-    #[stable]
-    pub fn is_alphabetic(&self) -> bool {
-        (self.chr >= 0x41 && self.chr <= 0x5A) || (self.chr >= 0x61 && self.chr <= 0x7A)
-    }
-
-    /// Check if the character is a number (0-9)
-    #[inline]
-    #[unstable = "may be renamed"]
-    pub fn is_digit(&self) -> bool {
-        self.chr >= 0x30 && self.chr <= 0x39
-    }
-
-    /// Check if the character is a letter or number
-    #[inline]
-    #[stable]
-    pub fn is_alphanumeric(&self) -> bool {
-        self.is_alphabetic() || self.is_digit()
-    }
-
-    /// Check if the character is a space or horizontal tab
-    #[inline]
-    #[experimental = "likely to be removed"]
-    pub fn is_blank(&self) -> bool {
-        self.chr == b' ' || self.chr == b'\t'
-    }
-
-    /// Check if the character is a control character
-    #[inline]
-    #[stable]
-    pub fn is_control(&self) -> bool {
-        self.chr < 0x20 || self.chr == 0x7F
-    }
-
-    /// Checks if the character is printable (except space)
-    #[inline]
-    #[experimental = "unsure about naming, or whether this is needed"]
-    pub fn is_graph(&self) -> bool {
-        (self.chr - 0x21) < 0x5E
-    }
-
-    /// Checks if the character is printable (including space)
-    #[inline]
-    #[unstable = "unsure about naming"]
-    pub fn is_print(&self) -> bool {
-        (self.chr - 0x20) < 0x5F
-    }
-
-    /// Checks if the character is alphabetic and lowercase
-    #[inline]
-    #[stable]
-    pub fn is_lowercase(&self) -> bool {
-        (self.chr - b'a') < 26
-    }
-
-    /// Checks if the character is alphabetic and uppercase
-    #[inline]
-    #[stable]
-    pub fn is_uppercase(&self) -> bool {
-        (self.chr - b'A') < 26
-    }
-
-    /// Checks if the character is punctuation
-    #[inline]
-    #[stable]
-    pub fn is_punctuation(&self) -> bool {
-        self.is_graph() && !self.is_alphanumeric()
-    }
-
-    /// Checks if the character is a valid hex digit
-    #[inline]
-    #[stable]
-    pub fn is_hex(&self) -> bool {
-        self.is_digit() || ((self.chr | 32u8) - b'a') < 6
-    }
-}
+/// Extension methods for ASCII-subset only operations on owned strings
+#[experimental = "would prefer to do this in a more general way"]
+pub trait OwnedAsciiExt {
+    /// Convert the string to ASCII upper case:
+    /// ASCII letters 'a' to 'z' are mapped to 'A' to 'Z',
+    /// but non-ASCII letters are unchanged.
+    fn into_ascii_uppercase(self) -> Self;
 
-impl<'a> fmt::Show for Ascii {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        (self.chr as char).fmt(f)
-    }
+    /// Convert the string to ASCII lower case:
+    /// ASCII letters 'A' to 'Z' are mapped to 'a' to 'z',
+    /// but non-ASCII letters are unchanged.
+    fn into_ascii_lowercase(self) -> Self;
 }
 
-/// Trait for converting into an ascii type.
-#[experimental = "may be replaced by generic conversion traits"]
-pub trait AsciiCast<T> for Sized? {
-    /// Convert to an ascii type, panic on non-ASCII input.
-    #[inline]
-    fn to_ascii(&self) -> T {
-        assert!(self.is_ascii());
-        unsafe {self.to_ascii_nocheck()}
-    }
-
-    /// Convert to an ascii type, return None on non-ASCII input.
-    #[inline]
-    fn to_ascii_opt(&self) -> Option<T> {
-        if self.is_ascii() {
-            Some(unsafe { self.to_ascii_nocheck() })
-        } else {
-            None
-        }
-    }
-
-    /// Convert to an ascii type, not doing any range asserts
-    unsafe fn to_ascii_nocheck(&self) -> T;
-
-    /// Check if convertible to ascii
+/// Extension methods for ASCII-subset only operations on string slices
+#[experimental = "would prefer to do this in a more general way"]
+pub trait AsciiExt<T = Self> for Sized? {
+    /// Check if within the ASCII range.
     fn is_ascii(&self) -> bool;
-}
 
-#[experimental = "may be replaced by generic conversion traits"]
-impl<'a> AsciiCast<&'a[Ascii]> for [u8] {
-    #[inline]
-    unsafe fn to_ascii_nocheck(&self) -> &'a[Ascii] {
-        mem::transmute(self)
-    }
+    /// Makes a copy of the string in ASCII upper case:
+    /// ASCII letters 'a' to 'z' are mapped to 'A' to 'Z',
+    /// but non-ASCII letters are unchanged.
+    fn to_ascii_uppercase(&self) -> T;
 
-    #[inline]
-    fn is_ascii(&self) -> bool {
-        for b in self.iter() {
-            if !b.is_ascii() { return false; }
-        }
-        true
-    }
-}
+    /// Makes a copy of the string in ASCII lower case:
+    /// ASCII letters 'A' to 'Z' are mapped to 'a' to 'z',
+    /// but non-ASCII letters are unchanged.
+    fn to_ascii_lowercase(&self) -> T;
 
-#[experimental = "may be replaced by generic conversion traits"]
-impl<'a> AsciiCast<&'a [Ascii]> for str {
-    #[inline]
-    unsafe fn to_ascii_nocheck(&self) -> &'a [Ascii] {
-        mem::transmute(self)
-    }
+    /// Check that two strings are an ASCII case-insensitive match.
+    /// Same as `to_ascii_lowercase(a) == to_ascii_lower(b)`,
+    /// but without allocating and copying temporary strings.
+    fn eq_ignore_ascii_case(&self, other: &Self) -> bool;
+}
 
+#[experimental = "would prefer to do this in a more general way"]
+impl AsciiExt<String> for str {
     #[inline]
     fn is_ascii(&self) -> bool {
         self.bytes().all(|b| b.is_ascii())
     }
-}
-
-#[experimental = "may be replaced by generic conversion traits"]
-impl AsciiCast<Ascii> for u8 {
-    #[inline]
-    unsafe fn to_ascii_nocheck(&self) -> Ascii {
-        Ascii{ chr: *self }
-    }
 
     #[inline]
-    fn is_ascii(&self) -> bool {
-        *self & 128 == 0u8
+    fn to_ascii_uppercase(&self) -> String {
+        // Vec<u8>::to_ascii_uppercase() preserves the UTF-8 invariant.
+        unsafe { String::from_utf8_unchecked(self.as_bytes().to_ascii_uppercase()) }
     }
-}
 
-#[experimental = "may be replaced by generic conversion traits"]
-impl AsciiCast<Ascii> for char {
     #[inline]
-    unsafe fn to_ascii_nocheck(&self) -> Ascii {
-        Ascii{ chr: *self as u8 }
+    fn to_ascii_lowercase(&self) -> String {
+        // Vec<u8>::to_ascii_lowercase() preserves the UTF-8 invariant.
+        unsafe { String::from_utf8_unchecked(self.as_bytes().to_ascii_lowercase()) }
     }
 
     #[inline]
-    fn is_ascii(&self) -> bool {
-        *self as u32 - ('\x7F' as u32 & *self as u32) == 0
+    fn eq_ignore_ascii_case(&self, other: &str) -> bool {
+        self.as_bytes().eq_ignore_ascii_case(other.as_bytes())
     }
 }
 
-/// Trait for copyless casting to an ascii vector.
-#[experimental = "may be replaced by generic conversion traits"]
-pub trait OwnedAsciiCast {
-    /// Check if convertible to ascii
-    fn is_ascii(&self) -> bool;
-
-    /// Take ownership and cast to an ascii vector.
-    /// # Panics
-    ///
-    /// Panic on non-ASCII input.
+#[experimental = "would prefer to do this in a more general way"]
+impl OwnedAsciiExt for String {
     #[inline]
-    fn into_ascii(self) -> Vec<Ascii> {
-        assert!(self.is_ascii());
-        unsafe {self.into_ascii_nocheck()}
+    fn into_ascii_uppercase(self) -> String {
+        // Vec<u8>::into_ascii_uppercase() preserves the UTF-8 invariant.
+        unsafe { String::from_utf8_unchecked(self.into_bytes().into_ascii_uppercase()) }
     }
 
-    /// Take ownership and cast to an ascii vector. Return None on non-ASCII input.
     #[inline]
-    fn into_ascii_opt(self) -> Option<Vec<Ascii>> {
-        if self.is_ascii() {
-            Some(unsafe { self.into_ascii_nocheck() })
-        } else {
-            None
-        }
+    fn into_ascii_lowercase(self) -> String {
+        // Vec<u8>::into_ascii_lowercase() preserves the UTF-8 invariant.
+        unsafe { String::from_utf8_unchecked(self.into_bytes().into_ascii_lowercase()) }
     }
-
-    /// Take ownership and cast to an ascii vector.
-    /// Does not perform validation checks.
-    unsafe fn into_ascii_nocheck(self) -> Vec<Ascii>;
 }
 
-#[experimental = "may be replaced by generic conversion traits"]
-impl OwnedAsciiCast for String {
+#[experimental = "would prefer to do this in a more general way"]
+impl AsciiExt<Vec<u8>> for [u8] {
     #[inline]
     fn is_ascii(&self) -> bool {
-        self.as_slice().is_ascii()
+        self.iter().all(|b| b.is_ascii())
     }
 
     #[inline]
-    unsafe fn into_ascii_nocheck(self) -> Vec<Ascii> {
-        self.into_bytes().into_ascii_nocheck()
+    fn to_ascii_uppercase(&self) -> Vec<u8> {
+        self.iter().map(|b| b.to_ascii_uppercase()).collect()
     }
-}
 
-#[experimental = "may be replaced by generic conversion traits"]
-impl OwnedAsciiCast for Vec<u8> {
     #[inline]
-    fn is_ascii(&self) -> bool {
-        self.as_slice().is_ascii()
+    fn to_ascii_lowercase(&self) -> Vec<u8> {
+        self.iter().map(|b| b.to_ascii_lowercase()).collect()
     }
 
     #[inline]
-    unsafe fn into_ascii_nocheck(self) -> Vec<Ascii> {
-        let v = Vec::from_raw_parts(self.as_ptr() as *mut Ascii,
-                                    self.len(),
-                                    self.capacity());
-
-        // We forget `self` to avoid freeing it at the end of the scope
-        // Otherwise, the returned `Vec` would point to freed memory
-        mem::forget(self);
-        v
+    fn eq_ignore_ascii_case(&self, other: &[u8]) -> bool {
+        self.len() == other.len() &&
+        self.iter().zip(other.iter()).all(|(a, b)| {
+            a.eq_ignore_ascii_case(b)
+        })
     }
 }
 
-/// Trait for converting an ascii type to a string. Needed to convert
-/// `&[Ascii]` to `&str`.
-#[experimental = "may be replaced by generic conversion traits"]
-pub trait AsciiStr for Sized? {
-    /// Convert to a string.
-    fn as_str_ascii<'a>(&'a self) -> &'a str;
-
-    /// Deprecated: use `to_lowercase`
-    #[deprecated="renamed `to_lowercase`"]
-    fn to_lower(&self) -> Vec<Ascii>;
-
-    /// Convert to vector representing a lower cased ascii string.
-    #[deprecated = "use iterators instead"]
-    fn to_lowercase(&self) -> Vec<Ascii>;
-
-    /// Deprecated: use `to_uppercase`
-    #[deprecated="renamed `to_uppercase`"]
-    fn to_upper(&self) -> Vec<Ascii>;
-
-    /// Convert to vector representing a upper cased ascii string.
-    #[deprecated = "use iterators instead"]
-    fn to_uppercase(&self) -> Vec<Ascii>;
-
-    /// Compares two Ascii strings ignoring case.
-    #[deprecated = "use iterators instead"]
-    fn eq_ignore_case(&self, other: &[Ascii]) -> bool;
-}
-
-#[experimental = "may be replaced by generic conversion traits"]
-impl AsciiStr for [Ascii] {
-    #[inline]
-    fn as_str_ascii<'a>(&'a self) -> &'a str {
-        unsafe { mem::transmute(self) }
-    }
-
-    #[inline]
-    fn to_lower(&self) -> Vec<Ascii> {
-      self.to_lowercase()
-    }
-
-    #[inline]
-    fn to_lowercase(&self) -> Vec<Ascii> {
-        self.iter().map(|a| a.to_lowercase()).collect()
-    }
-
-    #[inline]
-    fn to_upper(&self) -> Vec<Ascii> {
-      self.to_uppercase()
-    }
-
-    #[inline]
-    fn to_uppercase(&self) -> Vec<Ascii> {
-        self.iter().map(|a| a.to_uppercase()).collect()
-    }
-
+#[experimental = "would prefer to do this in a more general way"]
+impl OwnedAsciiExt for Vec<u8> {
     #[inline]
-    fn eq_ignore_case(&self, other: &[Ascii]) -> bool {
-        self.iter().zip(other.iter()).all(|(&a, &b)| a.eq_ignore_case(b))
+    fn into_ascii_uppercase(mut self) -> Vec<u8> {
+        for byte in self.iter_mut() {
+            *byte = byte.to_ascii_uppercase();
+        }
+        self
     }
-}
 
-impl IntoString for Vec<Ascii> {
     #[inline]
-    fn into_string(self) -> String {
-        unsafe { String::from_utf8_unchecked(self.into_bytes()) }
-    }
-}
-
-/// Trait to convert to an owned byte vector by consuming self
-#[experimental = "may be replaced by generic conversion traits"]
-pub trait IntoBytes {
-    /// Converts to an owned byte vector by consuming self
-    fn into_bytes(self) -> Vec<u8>;
-}
-
-#[experimental = "may be replaced by generic conversion traits"]
-impl IntoBytes for Vec<Ascii> {
-    fn into_bytes(self) -> Vec<u8> {
-        unsafe {
-            let v = Vec::from_raw_parts(self.as_ptr() as *mut u8,
-                                        self.len(),
-                                        self.capacity());
-
-            // We forget `self` to avoid freeing it at the end of the scope
-            // Otherwise, the returned `Vec` would point to freed memory
-            mem::forget(self);
-            v
+    fn into_ascii_lowercase(mut self) -> Vec<u8> {
+        for byte in self.iter_mut() {
+            *byte = byte.to_ascii_lowercase();
         }
+        self
     }
 }
 
-
-/// Extension methods for ASCII-subset only operations on owned strings
 #[experimental = "would prefer to do this in a more general way"]
-pub trait OwnedAsciiExt {
-    /// Convert the string to ASCII upper case:
-    /// ASCII letters 'a' to 'z' are mapped to 'A' to 'Z',
-    /// but non-ASCII letters are unchanged.
-    fn into_ascii_upper(self) -> Self;
-
-    /// Convert the string to ASCII lower case:
-    /// ASCII letters 'A' to 'Z' are mapped to 'a' to 'z',
-    /// but non-ASCII letters are unchanged.
-    fn into_ascii_lower(self) -> Self;
-}
-
-/// Extension methods for ASCII-subset only operations on string slices
-#[experimental = "would prefer to do this in a more general way"]
-pub trait AsciiExt<T> for Sized? {
-    /// Makes a copy of the string in ASCII upper case:
-    /// ASCII letters 'a' to 'z' are mapped to 'A' to 'Z',
-    /// but non-ASCII letters are unchanged.
-    fn to_ascii_upper(&self) -> T;
-
-    /// Makes a copy of the string in ASCII lower case:
-    /// ASCII letters 'A' to 'Z' are mapped to 'a' to 'z',
-    /// but non-ASCII letters are unchanged.
-    fn to_ascii_lower(&self) -> T;
-
-    /// Check that two strings are an ASCII case-insensitive match.
-    /// Same as `to_ascii_lower(a) == to_ascii_lower(b)`,
-    /// but without allocating and copying temporary strings.
-    fn eq_ignore_ascii_case(&self, other: &Self) -> bool;
-}
-
-#[experimental = "would prefer to do this in a more general way"]
-impl AsciiExt<String> for str {
-    #[inline]
-    fn to_ascii_upper(&self) -> String {
-        // Vec<u8>::to_ascii_upper() preserves the UTF-8 invariant.
-        unsafe { String::from_utf8_unchecked(self.as_bytes().to_ascii_upper()) }
-    }
-
+impl AsciiExt for u8 {
     #[inline]
-    fn to_ascii_lower(&self) -> String {
-        // Vec<u8>::to_ascii_lower() preserves the UTF-8 invariant.
-        unsafe { String::from_utf8_unchecked(self.as_bytes().to_ascii_lower()) }
+    fn is_ascii(&self) -> bool {
+        *self & 128 == 0u8
     }
 
     #[inline]
-    fn eq_ignore_ascii_case(&self, other: &str) -> bool {
-        self.as_bytes().eq_ignore_ascii_case(other.as_bytes())
+    fn to_ascii_uppercase(&self) -> u8 {
+        ASCII_UPPERCASE_MAP[*self as uint]
     }
-}
 
-#[experimental = "would prefer to do this in a more general way"]
-impl OwnedAsciiExt for String {
     #[inline]
-    fn into_ascii_upper(self) -> String {
-        // Vec<u8>::into_ascii_upper() preserves the UTF-8 invariant.
-        unsafe { String::from_utf8_unchecked(self.into_bytes().into_ascii_upper()) }
+    fn to_ascii_lowercase(&self) -> u8 {
+        ASCII_LOWERCASE_MAP[*self as uint]
     }
 
     #[inline]
-    fn into_ascii_lower(self) -> String {
-        // Vec<u8>::into_ascii_lower() preserves the UTF-8 invariant.
-        unsafe { String::from_utf8_unchecked(self.into_bytes().into_ascii_lower()) }
+    fn eq_ignore_ascii_case(&self, other: &u8) -> bool {
+        self.to_ascii_lowercase() == other.to_ascii_lowercase()
     }
 }
 
 #[experimental = "would prefer to do this in a more general way"]
-impl AsciiExt<Vec<u8>> for [u8] {
-    #[inline]
-    fn to_ascii_upper(&self) -> Vec<u8> {
-        self.iter().map(|&byte| ASCII_UPPER_MAP[byte as uint]).collect()
-    }
-
+impl AsciiExt for char {
     #[inline]
-    fn to_ascii_lower(&self) -> Vec<u8> {
-        self.iter().map(|&byte| ASCII_LOWER_MAP[byte as uint]).collect()
+    fn is_ascii(&self) -> bool {
+        *self as u32 <= 0x7F
     }
 
     #[inline]
-    fn eq_ignore_ascii_case(&self, other: &[u8]) -> bool {
-        self.len() == other.len() &&
-            self.iter().zip(other.iter()).all(
-            |(byte_self, byte_other)| {
-                ASCII_LOWER_MAP[*byte_self as uint] ==
-                    ASCII_LOWER_MAP[*byte_other as uint]
-            })
+    fn to_ascii_uppercase(&self) -> char {
+        if self.is_ascii() {
+            (*self as u8).to_ascii_uppercase() as char
+        } else {
+            *self
+        }
     }
-}
 
-#[experimental = "would prefer to do this in a more general way"]
-impl OwnedAsciiExt for Vec<u8> {
     #[inline]
-    fn into_ascii_upper(mut self) -> Vec<u8> {
-        for byte in self.iter_mut() {
-            *byte = ASCII_UPPER_MAP[*byte as uint];
+    fn to_ascii_lowercase(&self) -> char {
+        if self.is_ascii() {
+            (*self as u8).to_ascii_lowercase() as char
+        } else {
+            *self
         }
-        self
     }
 
     #[inline]
-    fn into_ascii_lower(mut self) -> Vec<u8> {
-        for byte in self.iter_mut() {
-            *byte = ASCII_LOWER_MAP[*byte as uint];
-        }
-        self
+    fn eq_ignore_ascii_case(&self, other: &char) -> bool {
+        self.to_ascii_lowercase() == other.to_ascii_lowercase()
     }
 }
 
@@ -549,7 +234,7 @@ pub fn escape_default<F>(c: u8, mut f: F) where
     }
 }
 
-static ASCII_LOWER_MAP: [u8, ..256] = [
+static ASCII_LOWERCASE_MAP: [u8, ..256] = [
     0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
     0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
     0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
@@ -588,7 +273,7 @@ static ASCII_LOWER_MAP: [u8, ..256] = [
     0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff,
 ];
 
-static ASCII_UPPER_MAP: [u8, ..256] = [
+static ASCII_UPPERCASE_MAP: [u8, ..256] = [
     0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
     0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
     0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
@@ -634,65 +319,14 @@ mod tests {
     use super::*;
     use char::from_u32;
 
-    macro_rules! v2ascii {
-        ( [$($e:expr),*]) => (&[$(Ascii{chr:$e}),*]);
-        (&[$($e:expr),*]) => (&[$(Ascii{chr:$e}),*]);
-    }
-
-    macro_rules! vec2ascii {
-        ($($e:expr),*) => ([$(Ascii{chr:$e}),*].to_vec());
-    }
-
     #[test]
     fn test_ascii() {
-        assert_eq!(65u8.to_ascii().to_byte(), 65u8);
-        assert_eq!(65u8.to_ascii().to_char(), 'A');
-        assert_eq!('A'.to_ascii().to_char(), 'A');
-        assert_eq!('A'.to_ascii().to_byte(), 65u8);
-
-        assert_eq!('A'.to_ascii().to_lowercase().to_char(), 'a');
-        assert_eq!('Z'.to_ascii().to_lowercase().to_char(), 'z');
-        assert_eq!('a'.to_ascii().to_uppercase().to_char(), 'A');
-        assert_eq!('z'.to_ascii().to_uppercase().to_char(), 'Z');
-
-        assert_eq!('@'.to_ascii().to_lowercase().to_char(), '@');
-        assert_eq!('['.to_ascii().to_lowercase().to_char(), '[');
-        assert_eq!('`'.to_ascii().to_uppercase().to_char(), '`');
-        assert_eq!('{'.to_ascii().to_uppercase().to_char(), '{');
-
-        assert!('0'.to_ascii().is_digit());
-        assert!('9'.to_ascii().is_digit());
-        assert!(!'/'.to_ascii().is_digit());
-        assert!(!':'.to_ascii().is_digit());
-
-        assert!((0x1fu8).to_ascii().is_control());
-        assert!(!' '.to_ascii().is_control());
-        assert!((0x7fu8).to_ascii().is_control());
-
         assert!("banana".chars().all(|c| c.is_ascii()));
         assert!(!"ประเทศไทย中华Việt Nam".chars().all(|c| c.is_ascii()));
     }
 
     #[test]
     fn test_ascii_vec() {
-        let test = &[40u8, 32u8, 59u8];
-        let b: &[_] = v2ascii!([40, 32, 59]);
-        assert_eq!(test.to_ascii(), b);
-        assert_eq!("( ;".to_ascii(), b);
-        let v = vec![40u8, 32u8, 59u8];
-        assert_eq!(v.to_ascii(), b);
-        assert_eq!("( ;".to_string().to_ascii(), b);
-
-        assert_eq!("abCDef&?#".to_ascii().to_lowercase().into_string(), "abcdef&?#");
-        assert_eq!("abCDef&?#".to_ascii().to_uppercase().into_string(), "ABCDEF&?#");
-
-        assert_eq!("".to_ascii().to_lowercase().into_string(), "");
-        assert_eq!("YMCA".to_ascii().to_lowercase().into_string(), "ymca");
-        let mixed = "abcDEFxyz:.;".to_ascii();
-        assert_eq!(mixed.to_uppercase().into_string(), "ABCDEFXYZ:.;");
-
-        assert!("aBcDeF&?#".to_ascii().eq_ignore_case("AbCdEf&?#".to_ascii()));
-
         assert!("".is_ascii());
         assert!("a".is_ascii());
         assert!(!"\u{2009}".is_ascii());
@@ -700,139 +334,64 @@ mod tests {
     }
 
     #[test]
-    fn test_ascii_vec_ng() {
-        assert_eq!("abCDef&?#".to_ascii().to_lowercase().into_string(), "abcdef&?#");
-        assert_eq!("abCDef&?#".to_ascii().to_uppercase().into_string(), "ABCDEF&?#");
-        assert_eq!("".to_ascii().to_lowercase().into_string(), "");
-        assert_eq!("YMCA".to_ascii().to_lowercase().into_string(), "ymca");
-        let mixed = "abcDEFxyz:.;".to_ascii();
-        assert_eq!(mixed.to_uppercase().into_string(), "ABCDEFXYZ:.;");
-    }
-
-    #[test]
-    fn test_owned_ascii_vec() {
-        assert_eq!(("( ;".to_string()).into_ascii(), vec2ascii![40, 32, 59]);
-        assert_eq!((vec![40u8, 32u8, 59u8]).into_ascii(), vec2ascii![40, 32, 59]);
-    }
-
-    #[test]
-    fn test_ascii_as_str() {
-        let v = v2ascii!([40, 32, 59]);
-        assert_eq!(v.as_str_ascii(), "( ;");
-    }
-
-    #[test]
-    fn test_ascii_into_string() {
-        assert_eq!(vec2ascii![40, 32, 59].into_string(), "( ;");
-        assert_eq!(vec2ascii!(40, 32, 59).into_string(), "( ;");
-    }
-
-    #[test]
-    fn test_ascii_to_bytes() {
-        assert_eq!(vec2ascii![40, 32, 59].into_bytes(), vec![40u8, 32u8, 59u8]);
-    }
-
-    #[test] #[should_fail]
-    fn test_ascii_vec_panic_u8_slice()  { (&[127u8, 128u8, 255u8]).to_ascii(); }
-
-    #[test] #[should_fail]
-    fn test_ascii_vec_panic_str_slice() { "zoä华".to_ascii(); }
-
-    #[test] #[should_fail]
-    fn test_ascii_panic_u8_slice() { 255u8.to_ascii(); }
-
-    #[test] #[should_fail]
-    fn test_ascii_panic_char_slice() { 'λ'.to_ascii(); }
-
-    #[test]
-    fn test_opt() {
-        assert_eq!(65u8.to_ascii_opt(), Some(Ascii { chr: 65u8 }));
-        assert_eq!(255u8.to_ascii_opt(), None);
-
-        assert_eq!('A'.to_ascii_opt(), Some(Ascii { chr: 65u8 }));
-        assert_eq!('λ'.to_ascii_opt(), None);
-
-        assert_eq!("zoä华".to_ascii_opt(), None);
-
-        let test1 = &[127u8, 128u8, 255u8];
-        assert_eq!((test1).to_ascii_opt(), None);
-
-        let v = [40u8, 32u8, 59u8];
-        let v2: &[_] = v2ascii!(&[40, 32, 59]);
-        assert_eq!(v.to_ascii_opt(), Some(v2));
-        let v = [127u8, 128u8, 255u8];
-        assert_eq!(v.to_ascii_opt(), None);
-
-        let v = "( ;";
-        assert_eq!(v.to_ascii_opt(), Some(v2));
-        assert_eq!("zoä华".to_ascii_opt(), None);
-
-        assert_eq!((vec![40u8, 32u8, 59u8]).into_ascii_opt(), Some(vec2ascii![40, 32, 59]));
-        assert_eq!((vec![127u8, 128u8, 255u8]).into_ascii_opt(), None);
-
-        assert_eq!(("( ;".to_string()).into_ascii_opt(), Some(vec2ascii![40, 32, 59]));
-        assert_eq!(("zoä华".to_string()).into_ascii_opt(), None);
-    }
-
-    #[test]
-    fn test_to_ascii_upper() {
-        assert_eq!("url()URL()uRl()ürl".to_ascii_upper(), "URL()URL()URL()üRL");
-        assert_eq!("hıKß".to_ascii_upper(), "HıKß");
+    fn test_to_ascii_uppercase() {
+        assert_eq!("url()URL()uRl()ürl".to_ascii_uppercase(), "URL()URL()URL()üRL");
+        assert_eq!("hıKß".to_ascii_uppercase(), "HıKß");
 
         let mut i = 0;
         while i <= 500 {
             let upper = if 'a' as u32 <= i && i <= 'z' as u32 { i + 'A' as u32 - 'a' as u32 }
                         else { i };
-            assert_eq!((from_u32(i).unwrap()).to_string().to_ascii_upper(),
+            assert_eq!((from_u32(i).unwrap()).to_string().to_ascii_uppercase(),
                        (from_u32(upper).unwrap()).to_string());
             i += 1;
         }
     }
 
     #[test]
-    fn test_to_ascii_lower() {
-        assert_eq!("url()URL()uRl()Ürl".to_ascii_lower(), "url()url()url()Ürl");
+    fn test_to_ascii_lowercase() {
+        assert_eq!("url()URL()uRl()Ürl".to_ascii_lowercase(), "url()url()url()Ürl");
         // Dotted capital I, Kelvin sign, Sharp S.
-        assert_eq!("HİKß".to_ascii_lower(), "hİKß");
+        assert_eq!("HİKß".to_ascii_lowercase(), "hİKß");
 
         let mut i = 0;
         while i <= 500 {
             let lower = if 'A' as u32 <= i && i <= 'Z' as u32 { i + 'a' as u32 - 'A' as u32 }
                         else { i };
-            assert_eq!((from_u32(i).unwrap()).to_string().to_ascii_lower(),
+            assert_eq!((from_u32(i).unwrap()).to_string().to_ascii_lowercase(),
                        (from_u32(lower).unwrap()).to_string());
             i += 1;
         }
     }
 
     #[test]
-    fn test_into_ascii_upper() {
-        assert_eq!(("url()URL()uRl()ürl".to_string()).into_ascii_upper(),
+    fn test_into_ascii_uppercase() {
+        assert_eq!(("url()URL()uRl()ürl".to_string()).into_ascii_uppercase(),
                    "URL()URL()URL()üRL".to_string());
-        assert_eq!(("hıKß".to_string()).into_ascii_upper(), "HıKß");
+        assert_eq!(("hıKß".to_string()).into_ascii_uppercase(), "HıKß");
 
         let mut i = 0;
         while i <= 500 {
             let upper = if 'a' as u32 <= i && i <= 'z' as u32 { i + 'A' as u32 - 'a' as u32 }
                         else { i };
-            assert_eq!((from_u32(i).unwrap()).to_string().into_ascii_upper(),
+            assert_eq!((from_u32(i).unwrap()).to_string().into_ascii_uppercase(),
                        (from_u32(upper).unwrap()).to_string());
             i += 1;
         }
     }
 
     #[test]
-    fn test_into_ascii_lower() {
-        assert_eq!(("url()URL()uRl()Ürl".to_string()).into_ascii_lower(),
+    fn test_into_ascii_lowercase() {
+        assert_eq!(("url()URL()uRl()Ürl".to_string()).into_ascii_lowercase(),
                    "url()url()url()Ürl");
         // Dotted capital I, Kelvin sign, Sharp S.
-        assert_eq!(("HİKß".to_string()).into_ascii_lower(), "hİKß");
+        assert_eq!(("HİKß".to_string()).into_ascii_lowercase(), "hİKß");
 
         let mut i = 0;
         while i <= 500 {
             let lower = if 'A' as u32 <= i && i <= 'Z' as u32 { i + 'a' as u32 - 'A' as u32 }
                         else { i };
-            assert_eq!((from_u32(i).unwrap()).to_string().into_ascii_lower(),
+            assert_eq!((from_u32(i).unwrap()).to_string().into_ascii_lowercase(),
                        (from_u32(lower).unwrap()).to_string());
             i += 1;
         }
@@ -858,16 +417,4 @@ mod tests {
             i += 1;
         }
     }
-
-    #[test]
-    fn test_to_string() {
-        let s = Ascii{ chr: b't' }.to_string();
-        assert_eq!(s, "t");
-    }
-
-    #[test]
-    fn test_show() {
-        let c = Ascii { chr: b't' };
-        assert_eq!(format!("{}", c), "t");
-    }
 }
diff --git a/src/libstd/path/windows.rs b/src/libstd/path/windows.rs
index 7d10188c437e2..83eddbc5da8d7 100644
--- a/src/libstd/path/windows.rs
+++ b/src/libstd/path/windows.rs
@@ -14,7 +14,7 @@
 
 use self::PathPrefix::*;
 
-use ascii::AsciiCast;
+use ascii::AsciiExt;
 use c_str::{CString, ToCStr};
 use clone::Clone;
 use cmp::{PartialEq, Eq, PartialOrd, Ord, Ordering};
@@ -237,10 +237,10 @@ impl GenericPathUnsafe for Path {
             let repr = me.repr[];
             match me.prefix {
                 Some(DiskPrefix) => {
-                    repr.as_bytes()[0] == path.as_bytes()[0].to_ascii().to_uppercase().as_byte()
+                    repr.as_bytes()[0] == path.as_bytes()[0].to_ascii_uppercase()
                 }
                 Some(VerbatimDiskPrefix) => {
-                    repr.as_bytes()[4] == path.as_bytes()[0].to_ascii().to_uppercase().as_byte()
+                    repr.as_bytes()[4] == path.as_bytes()[0].to_ascii_uppercase()
                 }
                 _ => false
             }
@@ -673,17 +673,17 @@ impl Path {
         match (self.prefix, other.prefix) {
             (Some(DiskPrefix), Some(VerbatimDiskPrefix)) => {
                 self.is_absolute() &&
-                    s_repr.as_bytes()[0].to_ascii().to_lowercase() ==
-                        o_repr.as_bytes()[4].to_ascii().to_lowercase()
+                    s_repr.as_bytes()[0].to_ascii_lowercase() ==
+                        o_repr.as_bytes()[4].to_ascii_lowercase()
             }
             (Some(VerbatimDiskPrefix), Some(DiskPrefix)) => {
                 other.is_absolute() &&
-                    s_repr.as_bytes()[4].to_ascii().to_lowercase() ==
-                        o_repr.as_bytes()[0].to_ascii().to_lowercase()
+                    s_repr.as_bytes()[4].to_ascii_lowercase() ==
+                        o_repr.as_bytes()[0].to_ascii_lowercase()
             }
             (Some(VerbatimDiskPrefix), Some(VerbatimDiskPrefix)) => {
-                s_repr.as_bytes()[4].to_ascii().to_lowercase() ==
-                    o_repr.as_bytes()[4].to_ascii().to_lowercase()
+                s_repr.as_bytes()[4].to_ascii_lowercase() ==
+                    o_repr.as_bytes()[4].to_ascii_lowercase()
             }
             (Some(UNCPrefix(_,_)), Some(VerbatimUNCPrefix(_,_))) => {
                 s_repr[2..self.prefix_len()] == o_repr[8..other.prefix_len()]
@@ -750,7 +750,7 @@ impl Path {
                                 let mut s = String::from_str(s[0..len]);
                                 unsafe {
                                     let v = s.as_mut_vec();
-                                    v[0] = (*v)[0].to_ascii().to_uppercase().as_byte();
+                                    v[0] = (*v)[0].to_ascii_uppercase();
                                 }
                                 if is_abs {
                                     // normalize C:/ to C:\
@@ -765,7 +765,7 @@ impl Path {
                                 let mut s = String::from_str(s[0..len]);
                                 unsafe {
                                     let v = s.as_mut_vec();
-                                    v[4] = (*v)[4].to_ascii().to_uppercase().as_byte();
+                                    v[4] = (*v)[4].to_ascii_uppercase();
                                 }
                                 Some(s)
                             }
@@ -786,14 +786,12 @@ impl Path {
                         let mut s = String::with_capacity(n);
                         match prefix {
                             Some(DiskPrefix) => {
-                                s.push(prefix_.as_bytes()[0].to_ascii()
-                                                   .to_uppercase().as_char());
+                                s.push(prefix_.as_bytes()[0].to_ascii_uppercase() as char);
                                 s.push(':');
                             }
                             Some(VerbatimDiskPrefix) => {
                                 s.push_str(prefix_[0..4]);
-                                s.push(prefix_.as_bytes()[4].to_ascii()
-                                                   .to_uppercase().as_char());
+                                s.push(prefix_.as_bytes()[4].to_ascii_uppercase() as char);
                                 s.push_str(prefix_[5..]);
                             }
                             Some(UNCPrefix(a,b)) => {
diff --git a/src/libstd/prelude.rs b/src/libstd/prelude.rs
index 49b888d17f47f..d1540f98a2355 100644
--- a/src/libstd/prelude.rs
+++ b/src/libstd/prelude.rs
@@ -56,8 +56,6 @@
 
 // Reexported types and traits
 
-#[doc(no_inline)] pub use ascii::{Ascii, AsciiCast, OwnedAsciiCast, AsciiStr};
-#[doc(no_inline)] pub use ascii::IntoBytes;
 #[doc(no_inline)] pub use borrow::IntoCow;
 #[doc(no_inline)] pub use c_str::ToCStr;
 #[doc(no_inline)] pub use char::{Char, UnicodeChar};
diff --git a/src/libsyntax/ext/bytes.rs b/src/libsyntax/ext/bytes.rs
index 2d1d13f16d06d..2844c0b523e5d 100644
--- a/src/libsyntax/ext/bytes.rs
+++ b/src/libsyntax/ext/bytes.rs
@@ -15,6 +15,7 @@ use codemap::Span;
 use ext::base::*;
 use ext::base;
 use ext::build::AstBuilder;
+use std::ascii::AsciiExt;
 
 
 pub fn expand_syntax_ext<'cx>(cx: &'cx mut ExtCtxt,
diff --git a/src/libsyntax/feature_gate.rs b/src/libsyntax/feature_gate.rs
index d53a4b0e8d1c1..28f7a78ddd08a 100644
--- a/src/libsyntax/feature_gate.rs
+++ b/src/libsyntax/feature_gate.rs
@@ -31,6 +31,8 @@ use visit::Visitor;
 use parse::token;
 
 use std::slice;
+use std::ascii::AsciiExt;
+
 
 // if you change this list without updating src/doc/reference.md, @cmr will be sad
 static KNOWN_FEATURES: &'static [(&'static str, Status)] = &[
diff --git a/src/libterm/terminfo/parm.rs b/src/libterm/terminfo/parm.rs
index 4ecbc54c59089..bac2452524e3e 100644
--- a/src/libterm/terminfo/parm.rs
+++ b/src/libterm/terminfo/parm.rs
@@ -14,6 +14,7 @@ pub use self::Param::*;
 use self::States::*;
 use self::FormatState::*;
 use self::FormatOp::*;
+use std::ascii::OwnedAsciiExt;
 use std::mem::replace;
 
 #[deriving(Copy, PartialEq)]
@@ -530,10 +531,7 @@ fn format(val: Param, op: FormatOp, flags: Flags) -> Result<Vec<u8> ,String> {
                     }
                 }
                 FormatHEX => {
-                    s = s.to_ascii()
-                         .iter()
-                         .map(|b| b.to_uppercase().as_byte())
-                         .collect();
+                    s = s.into_ascii_uppercase();
                     if flags.alternate {
                         let s_ = replace(&mut s, vec!(b'0', b'X'));
                         s.extend(s_.into_iter());
diff --git a/src/test/bench/shootout-k-nucleotide-pipes.rs b/src/test/bench/shootout-k-nucleotide-pipes.rs
index 8c11c3673d527..71b8a08e52665 100644
--- a/src/test/bench/shootout-k-nucleotide-pipes.rs
+++ b/src/test/bench/shootout-k-nucleotide-pipes.rs
@@ -17,6 +17,7 @@
 
 extern crate collections;
 
+use std::ascii::{AsciiExt, OwnedAsciiExt};
 use std::collections::HashMap;
 use std::mem::replace;
 use std::num::Float;
@@ -64,10 +65,8 @@ fn sort_and_fmt(mm: &HashMap<Vec<u8> , uint>, total: uint) -> String {
    let mut buffer = String::new();
    for &(ref k, v) in pairs_sorted.iter() {
        buffer.push_str(format!("{} {:0.3}\n",
-                               k.as_slice()
-                               .to_ascii()
-                               .to_uppercase()
-                               .into_string(), v).as_slice());
+                               k.to_ascii_uppercase(),
+                               v).as_slice());
    }
 
    return buffer
@@ -75,7 +74,7 @@ fn sort_and_fmt(mm: &HashMap<Vec<u8> , uint>, total: uint) -> String {
 
 // given a map, search for the frequency of a pattern
 fn find(mm: &HashMap<Vec<u8> , uint>, key: String) -> uint {
-   let key = key.into_ascii().as_slice().to_lowercase().into_string();
+   let key = key.into_ascii_lowercase();
    match mm.get(key.as_bytes()) {
       option::Option::None      => { return 0u; }
       option::Option::Some(&num) => { return num; }
diff --git a/src/test/bench/shootout-k-nucleotide.rs b/src/test/bench/shootout-k-nucleotide.rs
index 6aa6b02857fbe..a0ef392ed3af2 100644
--- a/src/test/bench/shootout-k-nucleotide.rs
+++ b/src/test/bench/shootout-k-nucleotide.rs
@@ -42,6 +42,7 @@
 
 #![feature(slicing_syntax)]
 
+use std::ascii::OwnedAsciiExt;
 use std::string::String;
 use std::slice;
 use std::sync::{Arc, Future};
@@ -286,10 +287,7 @@ fn get_sequence<R: Buffer>(r: &mut R, key: &str) -> Vec<u8> {
     {
         res.push_all(l.as_slice().trim().as_bytes());
     }
-    for b in res.iter_mut() {
-        *b = b.to_ascii().to_uppercase().to_byte();
-    }
-    res
+    res.into_ascii_uppercase()
 }
 
 fn main() {
diff --git a/src/test/run-pass/issue-10683.rs b/src/test/run-pass/issue-10683.rs
index df4342bfeb57e..26ee65fa565e2 100644
--- a/src/test/run-pass/issue-10683.rs
+++ b/src/test/run-pass/issue-10683.rs
@@ -13,7 +13,7 @@ use std::ascii::AsciiExt;
 static NAME: &'static str = "hello world";
 
 fn main() {
-    match NAME.to_ascii_lower().as_slice() {
+    match NAME.to_ascii_lowercase().as_slice() {
         "foo" => {}
         _ => {}
     }