Move `syntax::util::interner` -> `syntax::symbol`, cleanup.

26 files changed, 487 insertions, 548 deletions

diff --git a/src/libsyntax/ast.rs b/src/libsyntax/ast.rs
index 45970a63ab4..a001985ded9 100644
--- a/src/libsyntax/ast.rs
+++ b/src/libsyntax/ast.rs
@@ -14,15 +14,16 @@ pub use self::TyParamBound::*;
 pub use self::UnsafeSource::*;
 pub use self::ViewPath_::*;
 pub use self::PathParameters::*;
+pub use symbol::Symbol as Name;
 pub use util::ThinVec;
 
 use syntax_pos::{mk_sp, Span, DUMMY_SP, ExpnId};
 use codemap::{respan, Spanned};
 use abi::Abi;
 use ext::hygiene::SyntaxContext;
-use parse::token::{self, keywords, InternedString};
 use print::pprust;
 use ptr::P;
+use symbol::{Symbol, keywords, InternedString};
 use tokenstream::{TokenTree};
 
 use std::collections::HashSet;
@@ -32,60 +33,24 @@ use std::u32;
 
 use serialize::{self, Encodable, Decodable, Encoder, Decoder};
 
-/// A name is a part of an identifier, representing a string or gensym. It's
-/// the result of interning.
-#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
-pub struct Name(pub u32);
-
 /// An identifier contains a Name (index into the interner
 /// table) and a SyntaxContext to track renaming and
 /// macro expansion per Flatt et al., "Macros That Work Together"
 #[derive(Clone, Copy, PartialEq, Eq, Hash)]
 pub struct Ident {
-    pub name: Name,
+    pub name: Symbol,
     pub ctxt: SyntaxContext
 }
 
-impl Name {
-    pub fn as_str(self) -> token::InternedString {
-        token::InternedString::new_from_name(self)
-    }
-}
-
-impl fmt::Debug for Name {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        write!(f, "{}({})", self, self.0)
-    }
-}
-
-impl fmt::Display for Name {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        fmt::Display::fmt(&self.as_str(), f)
-    }
-}
-
-impl Encodable for Name {
-    fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
-        s.emit_str(&self.as_str())
-    }
-}
-
-impl Decodable for Name {
-    fn decode<D: Decoder>(d: &mut D) -> Result<Name, D::Error> {
-        Ok(token::intern(&d.read_str()?))
-    }
-}
-
-impl<'a> ::std::cmp::PartialEq<&'a str> for Name {
-    fn eq(&self, other: &&str) -> bool {
-        *self.as_str() == **other
-    }
-}
-
 impl Ident {
     pub const fn with_empty_ctxt(name: Name) -> Ident {
         Ident { name: name, ctxt: SyntaxContext::empty() }
     }
+
+   /// Maps a string to an identifier with an empty syntax context.
+   pub fn from_str(s: &str) -> Ident {
+       Ident::with_empty_ctxt(Symbol::intern(s))
+   }
 }
 
 impl fmt::Debug for Ident {
diff --git a/src/libsyntax/attr.rs b/src/libsyntax/attr.rs
index cd93b8e96e4..4fce739efe2 100644
--- a/src/libsyntax/attr.rs
+++ b/src/libsyntax/attr.rs
@@ -23,9 +23,9 @@ use syntax_pos::{Span, BytePos, DUMMY_SP};
 use errors::Handler;
 use feature_gate::{Features, GatedCfg};
 use parse::lexer::comments::{doc_comment_style, strip_doc_comment_decoration};
-use parse::token::InternedString;
-use parse::{ParseSess, token};
+use parse::ParseSess;
 use ptr::P;
+use symbol::{self, Symbol, InternedString};
 use util::ThinVec;
 
 use std::cell::{RefCell, Cell};
@@ -278,8 +278,8 @@ impl Attribute {
         if self.is_sugared_doc {
             let comment = self.value_str().unwrap();
             let meta = mk_name_value_item_str(
-                token::intern("doc"),
-                token::intern_and_get_ident(&strip_doc_comment_decoration(
+                Symbol::intern("doc"),
+                symbol::intern_and_get_ident(&strip_doc_comment_decoration(
                         &comment)));
             if self.style == ast::AttrStyle::Outer {
                 f(&mk_attr_outer(self.id, meta))
@@ -392,7 +392,7 @@ pub fn mk_sugared_doc_attr(id: AttrId, text: InternedString, lo: BytePos, hi: By
         style: style,
         value: MetaItem {
             span: mk_sp(lo, hi),
-            name: token::intern("doc"),
+            name: Symbol::intern("doc"),
             node: MetaItemKind::NameValue(lit),
         },
         is_sugared_doc: true,
diff --git a/src/libsyntax/diagnostics/plugin.rs b/src/libsyntax/diagnostics/plugin.rs
index 81c8e0bdb82..aa81d7afcb3 100644
--- a/src/libsyntax/diagnostics/plugin.rs
+++ b/src/libsyntax/diagnostics/plugin.rs
@@ -19,6 +19,7 @@ use ext::base::{ExtCtxt, MacEager, MacResult};
 use ext::build::AstBuilder;
 use parse::token;
 use ptr::P;
+use symbol::Symbol;
 use tokenstream::{TokenTree};
 use util::small_vector::SmallVector;
 
@@ -141,7 +142,7 @@ pub fn expand_register_diagnostic<'cx>(ecx: &'cx mut ExtCtxt,
             ));
         }
     });
-    let sym = Ident::with_empty_ctxt(token::gensym(&format!(
+    let sym = Ident::with_empty_ctxt(Symbol::gensym(&format!(
         "__register_diagnostic_{}", code
     )));
     MacEager::items(SmallVector::many(vec![
diff --git a/src/libsyntax/ext/base.rs b/src/libsyntax/ext/base.rs
index 7f66b060052..0fd360ba2e4 100644
--- a/src/libsyntax/ext/base.rs
+++ b/src/libsyntax/ext/base.rs
@@ -20,8 +20,8 @@ use ext::hygiene::Mark;
 use fold::{self, Folder};
 use parse::{self, parser};
 use parse::token;
-use parse::token::{InternedString, str_to_ident};
 use ptr::P;
+use symbol::{Symbol, InternedString};
 use util::small_vector::SmallVector;
 
 use std::path::PathBuf;
@@ -735,7 +735,7 @@ impl<'a> ExtCtxt<'a> {
         self.ecfg.trace_mac = x
     }
     pub fn ident_of(&self, st: &str) -> ast::Ident {
-        str_to_ident(st)
+        ast::Ident::from_str(st)
     }
     pub fn std_path(&self, components: &[&str]) -> Vec<ast::Ident> {
         let mut v = Vec::new();
@@ -746,7 +746,7 @@ impl<'a> ExtCtxt<'a> {
         return v
     }
     pub fn name_of(&self, st: &str) -> ast::Name {
-        token::intern(st)
+        Symbol::intern(st)
     }
 }
 
diff --git a/src/libsyntax/ext/build.rs b/src/libsyntax/ext/build.rs
index f488e1cf95c..b96a4624508 100644
--- a/src/libsyntax/ext/build.rs
+++ b/src/libsyntax/ext/build.rs
@@ -14,8 +14,8 @@ use attr;
 use syntax_pos::{Span, DUMMY_SP, Pos};
 use codemap::{dummy_spanned, respan, Spanned};
 use ext::base::ExtCtxt;
-use parse::token::{self, keywords, InternedString};
 use ptr::P;
+use symbol::{intern_and_get_ident, keywords, InternedString};
 
 // Transitional reexports so qquote can find the paths it is looking for
 mod syntax {
@@ -787,8 +787,7 @@ impl<'a> AstBuilder for ExtCtxt<'a> {
 
     fn expr_fail(&self, span: Span, msg: InternedString) -> P<ast::Expr> {
         let loc = self.codemap().lookup_char_pos(span.lo);
-        let expr_file = self.expr_str(span,
-                                      token::intern_and_get_ident(&loc.file.name));
+        let expr_file = self.expr_str(span, intern_and_get_ident(&loc.file.name));
         let expr_line = self.expr_u32(span, loc.line as u32);
         let expr_file_line_tuple = self.expr_tuple(span, vec![expr_file, expr_line]);
         let expr_file_line_ptr = self.expr_addr_of(span, expr_file_line_tuple);
diff --git a/src/libsyntax/ext/expand.rs b/src/libsyntax/ext/expand.rs
index a2d42e14592..f033b3400d0 100644
--- a/src/libsyntax/ext/expand.rs
+++ b/src/libsyntax/ext/expand.rs
@@ -23,10 +23,11 @@ use fold;
 use fold::*;
 use parse::{ParseSess, PResult, lexer};
 use parse::parser::Parser;
-use parse::token::{self, keywords};
+use parse::token;
 use print::pprust;
 use ptr::P;
 use std_inject;
+use symbol::keywords;
 use tokenstream::{TokenTree, TokenStream};
 use util::small_vector::SmallVector;
 use visit::Visitor;
@@ -190,7 +191,7 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
     pub fn expand_crate(&mut self, mut krate: ast::Crate) -> ast::Crate {
         self.cx.crate_root = std_inject::injected_crate_name(&krate);
         let mut module = ModuleData {
-            mod_path: vec![token::str_to_ident(&self.cx.ecfg.crate_name)],
+            mod_path: vec![Ident::from_str(&self.cx.ecfg.crate_name)],
             directory: PathBuf::from(self.cx.codemap().span_to_filename(krate.span)),
         };
         module.directory.pop();
@@ -246,7 +247,7 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
                     self.cx.resolver.resolve_macro(scope, &mac.node.path, force)
                 }
                 InvocationKind::Attr { ref attr, .. } => {
-                    let ident = ast::Ident::with_empty_ctxt(attr.name());
+                    let ident = Ident::with_empty_ctxt(attr.name());
                     let path = ast::Path::from_ident(attr.span, ident);
                     self.cx.resolver.resolve_macro(scope, &path, force)
                 }
diff --git a/src/libsyntax/ext/placeholders.rs b/src/libsyntax/ext/placeholders.rs
index e323dd2f623..4fe57a8345e 100644
--- a/src/libsyntax/ext/placeholders.rs
+++ b/src/libsyntax/ext/placeholders.rs
@@ -13,8 +13,8 @@ use codemap::{DUMMY_SP, dummy_spanned};
 use ext::base::ExtCtxt;
 use ext::expand::{Expansion, ExpansionKind};
 use fold::*;
-use parse::token::{intern, keywords};
 use ptr::P;
+use symbol::{Symbol, keywords};
 use util::move_map::MoveMap;
 use util::small_vector::SmallVector;
 
@@ -227,7 +227,7 @@ pub fn reconstructed_macro_rules(def: &ast::MacroDef) -> Expansion {
                     span: DUMMY_SP,
                     global: false,
                     segments: vec![ast::PathSegment {
-                        identifier: ast::Ident::with_empty_ctxt(intern("macro_rules")),
+                        identifier: ast::Ident::with_empty_ctxt(Symbol::intern("macro_rules")),
                         parameters: ast::PathParameters::none(),
                     }],
                 },
diff --git a/src/libsyntax/ext/proc_macro_shim.rs b/src/libsyntax/ext/proc_macro_shim.rs
index dc3a01f41bc..21ce89a6dd5 100644
--- a/src/libsyntax/ext/proc_macro_shim.rs
+++ b/src/libsyntax/ext/proc_macro_shim.rs
@@ -66,6 +66,7 @@ pub mod prelude {
     pub use ast::Ident;
     pub use codemap::{DUMMY_SP, Span};
     pub use ext::base::{ExtCtxt, MacResult};
-    pub use parse::token::{self, Token, DelimToken, keywords, str_to_ident};
+    pub use parse::token::{self, Token, DelimToken};
+    pub use symbol::keywords;
     pub use tokenstream::{TokenTree, TokenStream};
 }
diff --git a/src/libsyntax/ext/quote.rs b/src/libsyntax/ext/quote.rs
index fa38f21e9b3..0bd018603d2 100644
--- a/src/libsyntax/ext/quote.rs
+++ b/src/libsyntax/ext/quote.rs
@@ -33,6 +33,7 @@ pub mod rt {
     use parse::{self, token, classify};
     use ptr::P;
     use std::rc::Rc;
+    use symbol;
 
     use tokenstream::{self, TokenTree};
 
@@ -239,7 +240,7 @@ pub mod rt {
     impl ToTokens for str {
         fn to_tokens(&self, cx: &ExtCtxt) -> Vec<TokenTree> {
             let lit = ast::LitKind::Str(
-                token::intern_and_get_ident(self), ast::StrStyle::Cooked);
+                symbol::intern_and_get_ident(self), ast::StrStyle::Cooked);
             dummy_spanned(lit).to_tokens(cx)
         }
     }
@@ -527,12 +528,12 @@ pub fn expand_quote_matcher(cx: &mut ExtCtxt,
     base::MacEager::expr(expanded)
 }
 
-fn ids_ext(strs: Vec<String> ) -> Vec<ast::Ident> {
-    strs.iter().map(|str| str_to_ident(&(*str))).collect()
+fn ids_ext(strs: Vec<String>) -> Vec<ast::Ident> {
+    strs.iter().map(|s| ast::Ident::from_str(s)).collect()
 }
 
-fn id_ext(str: &str) -> ast::Ident {
-    str_to_ident(str)
+fn id_ext(s: &str) -> ast::Ident {
+    ast::Ident::from_str(s)
 }
 
 // Lift an ident to the expr that evaluates to that ident.
diff --git a/src/libsyntax/ext/source_util.rs b/src/libsyntax/ext/source_util.rs
index bda84cdaf39..7893ad839ea 100644
--- a/src/libsyntax/ext/source_util.rs
+++ b/src/libsyntax/ext/source_util.rs
@@ -17,6 +17,7 @@ use parse::token;
 use parse;
 use print::pprust;
 use ptr::P;
+use symbol;
 use tokenstream;
 use util::small_vector::SmallVector;
 
@@ -60,15 +61,14 @@ pub fn expand_file(cx: &mut ExtCtxt, sp: Span, tts: &[tokenstream::TokenTree])
 
     let topmost = cx.expansion_cause();
     let loc = cx.codemap().lookup_char_pos(topmost.lo);
-    let filename = token::intern_and_get_ident(&loc.file.name);
+    let filename = symbol::intern_and_get_ident(&loc.file.name);
     base::MacEager::expr(cx.expr_str(topmost, filename))
 }
 
 pub fn expand_stringify(cx: &mut ExtCtxt, sp: Span, tts: &[tokenstream::TokenTree])
                         -> Box<base::MacResult+'static> {
     let s = pprust::tts_to_string(tts);
-    base::MacEager::expr(cx.expr_str(sp,
-                                   token::intern_and_get_ident(&s[..])))
+    base::MacEager::expr(cx.expr_str(sp, symbol::intern_and_get_ident(&s)))
 }
 
 pub fn expand_mod(cx: &mut ExtCtxt, sp: Span, tts: &[tokenstream::TokenTree])
@@ -77,9 +77,7 @@ pub fn expand_mod(cx: &mut ExtCtxt, sp: Span, tts: &[tokenstream::TokenTree])
     let mod_path = &cx.current_expansion.module.mod_path;
     let string = mod_path.iter().map(|x| x.to_string()).collect::<Vec<String>>().join("::");
 
-    base::MacEager::expr(cx.expr_str(
-            sp,
-            token::intern_and_get_ident(&string[..])))
+    base::MacEager::expr(cx.expr_str(sp, symbol::intern_and_get_ident(&string)))
 }
 
 /// include! : parse the given file as an expr
@@ -144,7 +142,7 @@ pub fn expand_include_str(cx: &mut ExtCtxt, sp: Span, tts: &[tokenstream::TokenT
             // Add this input file to the code map to make it available as
             // dependency information
             let filename = format!("{}", file.display());
-            let interned = token::intern_and_get_ident(&src[..]);
+            let interned = symbol::intern_and_get_ident(&src);
             cx.codemap().new_filemap_and_lines(&filename, None, &src);
 
             base::MacEager::expr(cx.expr_str(sp, interned))
diff --git a/src/libsyntax/ext/tt/macro_rules.rs b/src/libsyntax/ext/tt/macro_rules.rs
index 552d4de9617..4c37a0a71e2 100644
--- a/src/libsyntax/ext/tt/macro_rules.rs
+++ b/src/libsyntax/ext/tt/macro_rules.rs
@@ -20,9 +20,10 @@ use ext::tt::macro_parser::{parse, parse_failure_msg};
 use parse::ParseSess;
 use parse::lexer::new_tt_reader;
 use parse::parser::{Parser, Restrictions};
-use parse::token::{self, gensym_ident, NtTT, Token};
+use parse::token::{self, NtTT, Token};
 use parse::token::Token::*;
 use print;
+use symbol::Symbol;
 use tokenstream::{self, TokenTree};
 
 use std::collections::{HashMap};
@@ -187,16 +188,16 @@ impl IdentMacroExpander for MacroRulesExpander {
 
 /// Converts a `macro_rules!` invocation into a syntax extension.
 pub fn compile(sess: &ParseSess, def: &ast::MacroDef) -> SyntaxExtension {
-    let lhs_nm =  gensym_ident("lhs");
-    let rhs_nm =  gensym_ident("rhs");
+    let lhs_nm = ast::Ident::with_empty_ctxt(Symbol::gensym("lhs"));
+    let rhs_nm = ast::Ident::with_empty_ctxt(Symbol::gensym("rhs"));
 
     // The pattern that macro_rules matches.
     // The grammar for macro_rules! is:
     // $( $lhs:tt => $rhs:tt );+
     // ...quasiquoting this would be nice.
     // These spans won't matter, anyways
-    let match_lhs_tok = MatchNt(lhs_nm, token::str_to_ident("tt"));
-    let match_rhs_tok = MatchNt(rhs_nm, token::str_to_ident("tt"));
+    let match_lhs_tok = MatchNt(lhs_nm, ast::Ident::from_str("tt"));
+    let match_rhs_tok = MatchNt(rhs_nm, ast::Ident::from_str("tt"));
     let argument_gram = vec![
         TokenTree::Sequence(DUMMY_SP, Rc::new(tokenstream::SequenceRepetition {
             tts: vec![
diff --git a/src/libsyntax/feature_gate.rs b/src/libsyntax/feature_gate.rs
index 19f5e860b27..0f94018997c 100644
--- a/src/libsyntax/feature_gate.rs
+++ b/src/libsyntax/feature_gate.rs
@@ -33,7 +33,7 @@ use syntax_pos::Span;
 use errors::{DiagnosticBuilder, Handler};
 use visit::{self, FnKind, Visitor};
 use parse::ParseSess;
-use parse::token::InternedString;
+use symbol::InternedString;
 
 use std::ascii::AsciiExt;
 use std::env;
diff --git a/src/libsyntax/fold.rs b/src/libsyntax/fold.rs
index b6c87155d6b..44ce8668c54 100644
--- a/src/libsyntax/fold.rs
+++ b/src/libsyntax/fold.rs
@@ -22,8 +22,9 @@ use ast::*;
 use ast;
 use syntax_pos::Span;
 use codemap::{Spanned, respan};
-use parse::token::{self, keywords};
+use parse::token;
 use ptr::P;
+use symbol::keywords;
 use tokenstream::*;
 use util::small_vector::SmallVector;
 use util::move_map::MoveMap;
diff --git a/src/libsyntax/lib.rs b/src/libsyntax/lib.rs
index 34280812421..15b93a4864b 100644
--- a/src/libsyntax/lib.rs
+++ b/src/libsyntax/lib.rs
@@ -83,7 +83,6 @@ pub mod diagnostics {
 pub mod diagnostic_list;
 
 pub mod util {
-    pub mod interner;
     pub mod lev_distance;
     pub mod node_count;
     pub mod parser;
@@ -118,6 +117,7 @@ pub mod ptr;
 pub mod show_span;
 pub mod std_inject;
 pub mod str;
+pub mod symbol;
 pub mod test;
 pub mod tokenstream;
 pub mod visit;
diff --git a/src/libsyntax/parse/lexer/mod.rs b/src/libsyntax/parse/lexer/mod.rs
index cf48c445c80..7048be1478b 100644
--- a/src/libsyntax/parse/lexer/mod.rs
+++ b/src/libsyntax/parse/lexer/mod.rs
@@ -8,13 +8,14 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-use ast;
+use ast::{self, Ident};
 use syntax_pos::{self, BytePos, CharPos, Pos, Span};
 use codemap::CodeMap;
 use errors::{FatalError, Handler, DiagnosticBuilder};
 use ext::tt::transcribe::tt_next_token;
-use parse::token::{self, keywords, str_to_ident};
+use parse::token;
 use str::char_at;
+use symbol::{Symbol, keywords};
 use rustc_unicode::property::Pattern_White_Space;
 
 use std::borrow::Cow;
@@ -350,13 +351,13 @@ impl<'a> StringReader<'a> {
     /// single-byte delimiter).
     pub fn name_from(&self, start: BytePos) -> ast::Name {
         debug!("taking an ident from {:?} to {:?}", start, self.pos);
-        self.with_str_from(start, token::intern)
+        self.with_str_from(start, Symbol::intern)
     }
 
     /// As name_from, with an explicit endpoint.
     pub fn name_from_to(&self, start: BytePos, end: BytePos) -> ast::Name {
         debug!("taking an ident from {:?} to {:?}", start, end);
-        self.with_str_from_to(start, end, token::intern)
+        self.with_str_from_to(start, end, Symbol::intern)
     }
 
     /// Calls `f` with a string slice of the source text spanning from `start`
@@ -492,7 +493,7 @@ impl<'a> StringReader<'a> {
             if string == "_" {
                 None
             } else {
-                Some(token::intern(string))
+                Some(Symbol::intern(string))
             }
         })
     }
@@ -540,7 +541,7 @@ impl<'a> StringReader<'a> {
                         self.with_str_from(start_bpos, |string| {
                             // comments with only more "/"s are not doc comments
                             let tok = if is_doc_comment(string) {
-                                token::DocComment(token::intern(string))
+                                token::DocComment(Symbol::intern(string))
                             } else {
                                 token::Comment
                             };
@@ -669,7 +670,7 @@ impl<'a> StringReader<'a> {
                 } else {
                     string.into()
                 };
-                token::DocComment(token::intern(&string[..]))
+                token::DocComment(Symbol::intern(&string[..]))
             } else {
                 token::Comment
             };
@@ -758,7 +759,7 @@ impl<'a> StringReader<'a> {
             self.err_span_(start_bpos,
                            self.pos,
                            "no valid digits found for number");
-            return token::Integer(token::intern("0"));
+            return token::Integer(Symbol::intern("0"));
         }
 
         // might be a float, but don't be greedy if this is actually an
@@ -1097,7 +1098,7 @@ impl<'a> StringReader<'a> {
                     token::Underscore
                 } else {
                     // FIXME: perform NFKC normalization here. (Issue #2253)
-                    token::Ident(str_to_ident(string))
+                    token::Ident(Ident::from_str(string))
                 }
             }));
         }
@@ -1277,13 +1278,13 @@ impl<'a> StringReader<'a> {
                     // expansion purposes. See #12512 for the gory details of why
                     // this is necessary.
                     let ident = self.with_str_from(start, |lifetime_name| {
-                        str_to_ident(&format!("'{}", lifetime_name))
+                        Ident::from_str(&format!("'{}", lifetime_name))
                     });
 
                     // Conjure up a "keyword checking ident" to make sure that
                     // the lifetime name is not a keyword.
                     let keyword_checking_ident = self.with_str_from(start, |lifetime_name| {
-                        str_to_ident(lifetime_name)
+                        Ident::from_str(lifetime_name)
                     });
                     let keyword_checking_token = &token::Ident(keyword_checking_ident);
                     let last_bpos = self.pos;
@@ -1310,7 +1311,7 @@ impl<'a> StringReader<'a> {
                 let id = if valid {
                     self.name_from(start)
                 } else {
-                    token::intern("0")
+                    Symbol::intern("0")
                 };
                 self.bump(); // advance ch past token
                 let suffix = self.scan_optional_raw_name();
@@ -1352,7 +1353,7 @@ impl<'a> StringReader<'a> {
                 let id = if valid {
                     self.name_from(start_bpos + BytePos(1))
                 } else {
-                    token::intern("??")
+                    Symbol::intern("??")
                 };
                 self.bump();
                 let suffix = self.scan_optional_raw_name();
@@ -1424,7 +1425,7 @@ impl<'a> StringReader<'a> {
                 let id = if valid {
                     self.name_from_to(content_start_bpos, content_end_bpos)
                 } else {
-                    token::intern("??")
+                    Symbol::intern("??")
                 };
                 let suffix = self.scan_optional_raw_name();
                 return Ok(token::Literal(token::StrRaw(id, hash_count), suffix));
@@ -1551,7 +1552,7 @@ impl<'a> StringReader<'a> {
         let id = if valid {
             self.name_from(start)
         } else {
-            token::intern("?")
+            Symbol::intern("?")
         };
         self.bump(); // advance ch past token
         return token::Byte(id);
@@ -1584,7 +1585,7 @@ impl<'a> StringReader<'a> {
         let id = if valid {
             self.name_from(start)
         } else {
-            token::intern("??")
+            Symbol::intern("??")
         };
         self.bump();
         return token::ByteStr(id);
@@ -1700,11 +1701,11 @@ fn ident_continue(c: Option<char>) -> bool {
 mod tests {
     use super::*;
 
+    use ast::Ident;
     use syntax_pos::{BytePos, Span, NO_EXPANSION};
     use codemap::CodeMap;
     use errors;
     use parse::token;
-    use parse::token::str_to_ident;
     use std::io;
     use std::rc::Rc;
 
@@ -1732,7 +1733,7 @@ mod tests {
                                       &sh,
                                       "/* my source file */ fn main() { println!(\"zebra\"); }\n"
                                           .to_string());
-        let id = str_to_ident("fn");
+        let id = Ident::from_str("fn");
         assert_eq!(string_reader.next_token().tok, token::Comment);
         assert_eq!(string_reader.next_token().tok, token::Whitespace);
         let tok1 = string_reader.next_token();
@@ -1813,7 +1814,7 @@ mod tests {
         let cm = Rc::new(CodeMap::new());
         let sh = mk_sh(cm.clone());
         assert_eq!(setup(&cm, &sh, "'a'".to_string()).next_token().tok,
-                   token::Literal(token::Char(token::intern("a")), None));
+                   token::Literal(token::Char(Symbol::intern("a")), None));
     }
 
     #[test]
@@ -1821,7 +1822,7 @@ mod tests {
         let cm = Rc::new(CodeMap::new());
         let sh = mk_sh(cm.clone());
         assert_eq!(setup(&cm, &sh, "' '".to_string()).next_token().tok,
-                   token::Literal(token::Char(token::intern(" ")), None));
+                   token::Literal(token::Char(Symbol::intern(" ")), None));
     }
 
     #[test]
@@ -1829,7 +1830,7 @@ mod tests {
         let cm = Rc::new(CodeMap::new());
         let sh = mk_sh(cm.clone());
         assert_eq!(setup(&cm, &sh, "'\\n'".to_string()).next_token().tok,
-                   token::Literal(token::Char(token::intern("\\n")), None));
+                   token::Literal(token::Char(Symbol::intern("\\n")), None));
     }
 
     #[test]
@@ -1847,7 +1848,7 @@ mod tests {
         assert_eq!(setup(&cm, &sh, "r###\"\"#a\\b\x00c\"\"###".to_string())
                        .next_token()
                        .tok,
-                   token::Literal(token::StrRaw(token::intern("\"#a\\b\x00c\""), 3), None));
+                   token::Literal(token::StrRaw(Symol::intern("\"#a\\b\x00c\""), 3), None));
     }
 
     #[test]
@@ -1857,11 +1858,11 @@ mod tests {
         macro_rules! test {
             ($input: expr, $tok_type: ident, $tok_contents: expr) => {{
                 assert_eq!(setup(&cm, &sh, format!("{}suffix", $input)).next_token().tok,
-                           token::Literal(token::$tok_type(token::intern($tok_contents)),
-                                          Some(token::intern("suffix"))));
+                           token::Literal(token::$tok_type(Symbol::intern($tok_contents)),
+                                          Some(Symbol::intern("suffix"))));
                 // with a whitespace separator:
                 assert_eq!(setup(&cm, &sh, format!("{} suffix", $input)).next_token().tok,
-                           token::Literal(token::$tok_type(token::intern($tok_contents)),
+                           token::Literal(token::$tok_type(Symbol::intern($tok_contents)),
                                           None));
             }}
         }
@@ -1877,14 +1878,14 @@ mod tests {
         test!("1.0e10", Float, "1.0e10");
 
         assert_eq!(setup(&cm, &sh, "2us".to_string()).next_token().tok,
-                   token::Literal(token::Integer(token::intern("2")),
-                                  Some(token::intern("us"))));
+                   token::Literal(token::Integer(Symbol::intern("2")),
+                                  Some(Symbol::intern("us"))));
         assert_eq!(setup(&cm, &sh, "r###\"raw\"###suffix".to_string()).next_token().tok,
-                   token::Literal(token::StrRaw(token::intern("raw"), 3),
-                                  Some(token::intern("suffix"))));
+                   token::Literal(token::StrRaw(Symbol::intern("raw"), 3),
+                                  Some(Symbol::intern("suffix"))));
         assert_eq!(setup(&cm, &sh, "br###\"raw\"###suffix".to_string()).next_token().tok,
-                   token::Literal(token::ByteStrRaw(token::intern("raw"), 3),
-                                  Some(token::intern("suffix"))));
+                   token::Literal(token::ByteStrRaw(Symbol::intern("raw"), 3),
+                                  Some(Symbol::intern("suffix"))));
     }
 
     #[test]
@@ -1904,7 +1905,7 @@ mod tests {
             _ => panic!("expected a comment!"),
         }
         assert_eq!(lexer.next_token().tok,
-                   token::Literal(token::Char(token::intern("a")), None));
+                   token::Literal(token::Char(Symbol::intern("a")), None));
     }
 
     #[test]
@@ -1917,6 +1918,6 @@ mod tests {
         assert_eq!(comment.sp, ::syntax_pos::mk_sp(BytePos(0), BytePos(7)));
         assert_eq!(lexer.next_token().tok, token::Whitespace);
         assert_eq!(lexer.next_token().tok,
-                   token::DocComment(token::intern("/// test")));
+                   token::DocComment(Symbol::intern("/// test")));
     }
 }
diff --git a/src/libsyntax/parse/mod.rs b/src/libsyntax/parse/mod.rs
index 19e8b711ba4..a44f78b3c3a 100644
--- a/src/libsyntax/parse/mod.rs
+++ b/src/libsyntax/parse/mod.rs
@@ -16,9 +16,9 @@ use syntax_pos::{self, Span, FileMap};
 use errors::{Handler, ColorConfig, DiagnosticBuilder};
 use feature_gate::UnstableFeatures;
 use parse::parser::Parser;
-use parse::token::InternedString;
 use ptr::P;
 use str::char_at;
+use symbol::{self, InternedString};
 use tokenstream;
 
 use std::cell::RefCell;
@@ -372,7 +372,7 @@ fn looks_like_width_suffix(first_chars: &[char], s: &str) -> bool {
         s[1..].chars().all(|c| '0' <= c && c <= '9')
 }
 
-fn filtered_float_lit(data: token::InternedString, suffix: Option<&str>,
+fn filtered_float_lit(data: InternedString, suffix: Option<&str>,
                       sd: &Handler, sp: Span) -> ast::LitKind {
     debug!("filtered_float_lit: {}, {:?}", data, suffix);
     match suffix.as_ref().map(|s| &**s) {
@@ -400,7 +400,7 @@ pub fn float_lit(s: &str, suffix: Option<InternedString>,
     debug!("float_lit: {:?}, {:?}", s, suffix);
     // FIXME #2252: bounds checking float literals is deferred until trans
     let s = s.chars().filter(|&c| c != '_').collect::<String>();
-    let data = token::intern_and_get_ident(&s);
+    let data = symbol::intern_and_get_ident(&s);
     filtered_float_lit(data, suffix.as_ref().map(|s| &**s), sd, sp)
 }
 
@@ -530,7 +530,7 @@ pub fn integer_lit(s: &str,
                 2 => sd.span_err(sp, "binary float literal is not supported"),
                 _ => ()
             }
-            let ident = token::intern_and_get_ident(&s);
+            let ident = symbol::intern_and_get_ident(&s);
             return filtered_float_lit(ident, Some(&suf), sd, sp)
         }
     }
diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index 98ce00c7d38..13c701795a8 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -48,13 +48,14 @@ use parse::classify;
 use parse::common::SeqSep;
 use parse::lexer::{Reader, TokenAndSpan};
 use parse::obsolete::ObsoleteSyntax;
-use parse::token::{self, intern, keywords, MatchNt, SubstNt, InternedString};
+use parse::token::{self, MatchNt, SubstNt};
 use parse::{new_sub_parser_from_file, ParseSess};
 use util::parser::{AssocOp, Fixity};
 use print::pprust;
 use ptr::P;
 use parse::PResult;
 use tokenstream::{self, Delimited, SequenceRepetition, TokenTree};
+use symbol::{self, Symbol, keywords, InternedString};
 use util::ThinVec;
 
 use std::collections::HashSet;
@@ -1537,13 +1538,13 @@ impl<'a> Parser<'a> {
 
                     token::Str_(s) => {
                         (true,
-                         LitKind::Str(token::intern_and_get_ident(&parse::str_lit(&s.as_str())),
+                         LitKind::Str(symbol::intern_and_get_ident(&parse::str_lit(&s.as_str())),
                                       ast::StrStyle::Cooked))
                     }
                     token::StrRaw(s, n) => {
                         (true,
                          LitKind::Str(
-                            token::intern_and_get_ident(&parse::raw_str_lit(&s.as_str())),
+                            symbol::intern_and_get_ident(&parse::raw_str_lit(&s.as_str())),
                             ast::StrStyle::Raw(n)))
                     }
                     token::ByteStr(i) =>
@@ -2627,7 +2628,7 @@ impl<'a> Parser<'a> {
                                       })));
                 } else if self.token.is_keyword(keywords::Crate) {
                     let ident = match self.token {
-                        token::Ident(id) => ast::Ident { name: token::intern("$crate"), ..id },
+                        token::Ident(id) => ast::Ident { name: Symbol::intern("$crate"), ..id },
                         _ => unreachable!(),
                     };
                     self.bump();
@@ -4835,7 +4836,7 @@ impl<'a> Parser<'a> {
             Visibility::Inherited => (),
             _ => {
                 let is_macro_rules: bool = match self.token {
-                    token::Ident(sid) => sid.name == intern("macro_rules"),
+                    token::Ident(sid) => sid.name == Symbol::intern("macro_rules"),
                     _ => false,
                 };
                 if is_macro_rules {
diff --git a/src/libsyntax/parse/token.rs b/src/libsyntax/parse/token.rs
index 4aaa028ef75..8ac39dd462e 100644
--- a/src/libsyntax/parse/token.rs
+++ b/src/libsyntax/parse/token.rs
@@ -16,13 +16,10 @@ pub use self::Token::*;
 
 use ast::{self};
 use ptr::P;
-use util::interner::Interner;
+use symbol::keywords;
 use tokenstream;
 
-use serialize::{Decodable, Decoder, Encodable, Encoder};
-use std::cell::RefCell;
 use std::fmt;
-use std::ops::Deref;
 use std::rc::Rc;
 
 #[derive(Clone, RustcEncodable, RustcDecodable, PartialEq, Eq, Hash, Debug, Copy)]
@@ -335,266 +332,3 @@ impl fmt::Debug for Nonterminal {
         }
     }
 }
-
-// In this macro, there is the requirement that the name (the number) must be monotonically
-// increasing by one in the special identifiers, starting at 0; the same holds for the keywords,
-// except starting from the next number instead of zero.
-macro_rules! declare_keywords {(
-    $( ($index: expr, $konst: ident, $string: expr) )*
-) => {
-    pub mod keywords {
-        use ast;
-        #[derive(Clone, Copy, PartialEq, Eq)]
-        pub struct Keyword {
-            ident: ast::Ident,
-        }
-        impl Keyword {
-            #[inline] pub fn ident(self) -> ast::Ident { self.ident }
-            #[inline] pub fn name(self) -> ast::Name { self.ident.name }
-        }
-        $(
-            #[allow(non_upper_case_globals)]
-            pub const $konst: Keyword = Keyword {
-                ident: ast::Ident::with_empty_ctxt(ast::Name($index))
-            };
-        )*
-    }
-
-    fn mk_fresh_ident_interner() -> IdentInterner {
-        Interner::prefill(&[$($string,)*])
-    }
-}}
-
-// NB: leaving holes in the ident table is bad! a different ident will get
-// interned with the id from the hole, but it will be between the min and max
-// of the reserved words, and thus tagged as "reserved".
-// After modifying this list adjust `is_strict_keyword`/`is_reserved_keyword`,
-// this should be rarely necessary though if the keywords are kept in alphabetic order.
-declare_keywords! {
-    // Invalid identifier
-    (0,  Invalid,        "")
-
-    // Strict keywords used in the language.
-    (1,  As,             "as")
-    (2,  Box,            "box")
-    (3,  Break,          "break")
-    (4,  Const,          "const")
-    (5,  Continue,       "continue")
-    (6,  Crate,          "crate")
-    (7,  Else,           "else")
-    (8,  Enum,           "enum")
-    (9,  Extern,         "extern")
-    (10, False,          "false")
-    (11, Fn,             "fn")
-    (12, For,            "for")
-    (13, If,             "if")
-    (14, Impl,           "impl")
-    (15, In,             "in")
-    (16, Let,            "let")
-    (17, Loop,           "loop")
-    (18, Match,          "match")
-    (19, Mod,            "mod")
-    (20, Move,           "move")
-    (21, Mut,            "mut")
-    (22, Pub,            "pub")
-    (23, Ref,            "ref")
-    (24, Return,         "return")
-    (25, SelfValue,      "self")
-    (26, SelfType,       "Self")
-    (27, Static,         "static")
-    (28, Struct,         "struct")
-    (29, Super,          "super")
-    (30, Trait,          "trait")
-    (31, True,           "true")
-    (32, Type,           "type")
-    (33, Unsafe,         "unsafe")
-    (34, Use,            "use")
-    (35, Where,          "where")
-    (36, While,          "while")
-
-    // Keywords reserved for future use.
-    (37, Abstract,       "abstract")
-    (38, Alignof,        "alignof")
-    (39, Become,         "become")
-    (40, Do,             "do")
-    (41, Final,          "final")
-    (42, Macro,          "macro")
-    (43, Offsetof,       "offsetof")
-    (44, Override,       "override")
-    (45, Priv,           "priv")
-    (46, Proc,           "proc")
-    (47, Pure,           "pure")
-    (48, Sizeof,         "sizeof")
-    (49, Typeof,         "typeof")
-    (50, Unsized,        "unsized")
-    (51, Virtual,        "virtual")
-    (52, Yield,          "yield")
-
-    // Weak keywords, have special meaning only in specific contexts.
-    (53, Default,        "default")
-    (54, StaticLifetime, "'static")
-    (55, Union,          "union")
-}
-
-// looks like we can get rid of this completely...
-pub type IdentInterner = Interner;
-
-// if an interner exists in TLS, return it. Otherwise, prepare a
-// fresh one.
-// FIXME(eddyb) #8726 This should probably use a thread-local reference.
-pub fn with_ident_interner<T, F: FnOnce(&mut IdentInterner) -> T>(f: F) -> T {
-    thread_local!(static KEY: RefCell<IdentInterner> = {
-        RefCell::new(mk_fresh_ident_interner())
-    });
-    KEY.with(|interner| f(&mut *interner.borrow_mut()))
-}
-
-/// Reset the ident interner to its initial state.
-pub fn reset_ident_interner() {
-    with_ident_interner(|interner| *interner = mk_fresh_ident_interner());
-}
-
-/// Represents a string stored in the thread-local interner. Because the
-/// interner lives for the life of the thread, this can be safely treated as an
-/// immortal string, as long as it never crosses between threads.
-///
-/// FIXME(pcwalton): You must be careful about what you do in the destructors
-/// of objects stored in TLS, because they may run after the interner is
-/// destroyed. In particular, they must not access string contents. This can
-/// be fixed in the future by just leaking all strings until thread death
-/// somehow.
-#[derive(Clone, PartialEq, Hash, PartialOrd, Eq, Ord)]
-pub struct InternedString {
-    string: Rc<str>,
-}
-
-impl InternedString {
-    #[inline]
-    pub fn new(string: &'static str) -> InternedString {
-        InternedString {
-            string: Rc::__from_str(string),
-        }
-    }
-
-    #[inline]
-    pub fn new_from_name(name: ast::Name) -> InternedString {
-        with_ident_interner(|interner| InternedString { string: interner.get(name) })
-    }
-}
-
-impl Deref for InternedString {
-    type Target = str;
-
-    fn deref(&self) -> &str { &self.string }
-}
-
-impl fmt::Debug for InternedString {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        fmt::Debug::fmt(&self.string, f)
-    }
-}
-
-impl fmt::Display for InternedString {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        fmt::Display::fmt(&self.string, f)
-    }
-}
-
-impl<'a> PartialEq<&'a str> for InternedString {
-    #[inline(always)]
-    fn eq(&self, other: & &'a str) -> bool {
-        PartialEq::eq(&self.string[..], *other)
-    }
-    #[inline(always)]
-    fn ne(&self, other: & &'a str) -> bool {
-        PartialEq::ne(&self.string[..], *other)
-    }
-}
-
-impl<'a> PartialEq<InternedString> for &'a str {
-    #[inline(always)]
-    fn eq(&self, other: &InternedString) -> bool {
-        PartialEq::eq(*self, &other.string[..])
-    }
-    #[inline(always)]
-    fn ne(&self, other: &InternedString) -> bool {
-        PartialEq::ne(*self, &other.string[..])
-    }
-}
-
-impl PartialEq<str> for InternedString {
-    #[inline(always)]
-    fn eq(&self, other: &str) -> bool {
-        PartialEq::eq(&self.string[..], other)
-    }
-    #[inline(always)]
-    fn ne(&self, other: &str) -> bool {
-        PartialEq::ne(&self.string[..], other)
-    }
-}
-
-impl PartialEq<InternedString> for str {
-    #[inline(always)]
-    fn eq(&self, other: &InternedString) -> bool {
-        PartialEq::eq(self, &other.string[..])
-    }
-    #[inline(always)]
-    fn ne(&self, other: &InternedString) -> bool {
-        PartialEq::ne(self, &other.string[..])
-    }
-}
-
-impl Decodable for InternedString {
-    fn decode<D: Decoder>(d: &mut D) -> Result<InternedString, D::Error> {
-        Ok(intern(&d.read_str()?).as_str())
-    }
-}
-
-impl Encodable for InternedString {
-    fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
-        s.emit_str(&self.string)
-    }
-}
-
-/// Interns and returns the string contents of an identifier, using the
-/// thread-local interner.
-#[inline]
-pub fn intern_and_get_ident(s: &str) -> InternedString {
-    intern(s).as_str()
-}
-
-/// Maps a string to its interned representation.
-#[inline]
-pub fn intern(s: &str) -> ast::Name {
-    with_ident_interner(|interner| interner.intern(s))
-}
-
-/// gensym's a new usize, using the current interner.
-#[inline]
-pub fn gensym(s: &str) -> ast::Name {
-    with_ident_interner(|interner| interner.gensym(s))
-}
-
-/// Maps a string to an identifier with an empty syntax context.
-#[inline]
-pub fn str_to_ident(s: &str) -> ast::Ident {
-    ast::Ident::with_empty_ctxt(intern(s))
-}
-
-/// Maps a string to a gensym'ed identifier.
-#[inline]
-pub fn gensym_ident(s: &str) -> ast::Ident {
-    ast::Ident::with_empty_ctxt(gensym(s))
-}
-
-// create a fresh name that maps to the same string as the old one.
-// note that this guarantees that str_ptr_eq(ident_to_string(src),interner_get(fresh_name(src)));
-// that is, that the new name and the old one are connected to ptr_eq strings.
-pub fn fresh_name(src: ast::Ident) -> ast::Name {
-    with_ident_interner(|interner| interner.gensym_copy(src.name))
-    // following: debug version. Could work in final except that it's incompatible with
-    // good error messages and uses of struct names in ambiguous could-be-binding
-    // locations. Also definitely destroys the guarantee given above about ptr_eq.
-    /*let num = rand::thread_rng().gen_uint_range(0,0xffff);
-    gensym(format!("{}_{}",ident_to_string(src),num))*/
-}
diff --git a/src/libsyntax/print/pprust.rs b/src/libsyntax/print/pprust.rs
index da766d17672..52ff17d1c12 100644
--- a/src/libsyntax/print/pprust.rs
+++ b/src/libsyntax/print/pprust.rs
@@ -19,7 +19,7 @@ use attr;
 use codemap::{self, CodeMap};
 use syntax_pos::{self, BytePos};
 use errors;
-use parse::token::{self, keywords, BinOpToken, Token};
+use parse::token::{self, BinOpToken, Token};
 use parse::lexer::comments;
 use parse;
 use print::pp::{self, break_offset, word, space, zerobreak, hardbreak};
@@ -27,6 +27,7 @@ use print::pp::{Breaks, eof};
 use print::pp::Breaks::{Consistent, Inconsistent};
 use ptr::P;
 use std_inject;
+use symbol::{Symbol, keywords};
 use tokenstream::{self, TokenTree};
 
 use std::ascii;
@@ -119,13 +120,13 @@ pub fn print_crate<'a>(cm: &'a CodeMap,
         // of the feature gate, so we fake them up here.
 
         // #![feature(prelude_import)]
-        let prelude_import_meta = attr::mk_list_word_item(token::intern("prelude_import"));
-        let list = attr::mk_list_item(token::intern("feature"), vec![prelude_import_meta]);
+        let prelude_import_meta = attr::mk_list_word_item(Symbol::intern("prelude_import"));
+        let list = attr::mk_list_item(Symbol::intern("feature"), vec![prelude_import_meta]);
         let fake_attr = attr::mk_attr_inner(attr::mk_attr_id(), list);
         try!(s.print_attribute(&fake_attr));
 
         // #![no_std]
-        let no_std_meta = attr::mk_word_item(token::intern("no_std"));
+        let no_std_meta = attr::mk_word_item(Symbol::intern("no_std"));
         let fake_attr = attr::mk_attr_inner(attr::mk_attr_id(), no_std_meta);
         try!(s.print_attribute(&fake_attr));
     }
diff --git a/src/libsyntax/std_inject.rs b/src/libsyntax/std_inject.rs
index 166d95911b9..6a291ad9c40 100644
--- a/src/libsyntax/std_inject.rs
+++ b/src/libsyntax/std_inject.rs
@@ -10,10 +10,10 @@
 
 use ast;
 use attr;
+use symbol::{Symbol, keywords};
 use syntax_pos::{DUMMY_SP, Span};
 use codemap::{self, ExpnInfo, NameAndSpan, MacroAttribute};
-use parse::token::{intern, keywords};
-use parse::{token, ParseSess};
+use parse::ParseSess;
 use ptr::P;
 
 /// Craft a span that will be ignored by the stability lint's
@@ -23,7 +23,7 @@ fn ignored_span(sess: &ParseSess, sp: Span) -> Span {
     let info = ExpnInfo {
         call_site: DUMMY_SP,
         callee: NameAndSpan {
-            format: MacroAttribute(intern("std_inject")),
+            format: MacroAttribute(Symbol::intern("std_inject")),
             span: None,
             allow_internal_unstable: true,
         }
@@ -53,14 +53,14 @@ pub fn maybe_inject_crates_ref(sess: &ParseSess,
         None => return krate,
     };
 
-    let crate_name = token::intern(&alt_std_name.unwrap_or(name.to_string()));
+    let crate_name = Symbol::intern(&alt_std_name.unwrap_or(name.to_string()));
 
     krate.module.items.insert(0, P(ast::Item {
         attrs: vec![attr::mk_attr_outer(attr::mk_attr_id(),
-                                        attr::mk_word_item(token::intern("macro_use")))],
+                                        attr::mk_word_item(Symbol::intern("macro_use")))],
         vis: ast::Visibility::Inherited,
         node: ast::ItemKind::ExternCrate(Some(crate_name)),
-        ident: token::str_to_ident(name),
+        ident: ast::Ident::from_str(name),
         id: ast::DUMMY_NODE_ID,
         span: DUMMY_SP,
     }));
@@ -70,7 +70,7 @@ pub fn maybe_inject_crates_ref(sess: &ParseSess,
         attrs: vec![ast::Attribute {
             style: ast::AttrStyle::Outer,
             value: ast::MetaItem {
-                name: token::intern("prelude_import"),
+                name: Symbol::intern("prelude_import"),
                 node: ast::MetaItemKind::Word,
                 span: span,
             },
@@ -82,7 +82,7 @@ pub fn maybe_inject_crates_ref(sess: &ParseSess,
         node: ast::ItemKind::Use(P(codemap::dummy_spanned(ast::ViewPathGlob(ast::Path {
             global: false,
             segments: vec![name, "prelude", "v1"].into_iter().map(|name| ast::PathSegment {
-                identifier: token::str_to_ident(name),
+                identifier: ast::Ident::from_str(name),
                 parameters: ast::PathParameters::none(),
             }).collect(),
             span: span,
diff --git a/src/libsyntax/symbol.rs b/src/libsyntax/symbol.rs
new file mode 100644
index 00000000000..9620b8412b4
--- /dev/null
+++ b/src/libsyntax/symbol.rs
@@ -0,0 +1,339 @@
+// Copyright 2016 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.
+
+//! An "interner" is a data structure that associates values with usize tags and
+//! allows bidirectional lookup; i.e. given a value, one can easily find the
+//! type, and vice versa.
+
+use serialize::{Decodable, Decoder, Encodable, Encoder};
+use std::cell::RefCell;
+use std::collections::HashMap;
+use std::fmt;
+use std::rc::Rc;
+
+/// A symbol is an interned or gensymed string.
+#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct Symbol(u32);
+
+impl Symbol {
+    /// Maps a string to its interned representation.
+    pub fn intern(string: &str) -> Self {
+        with_interner(|interner| interner.intern(string))
+    }
+
+    /// gensym's a new usize, using the current interner.
+    pub fn gensym(string: &str) -> Self {
+        with_interner(|interner| interner.gensym(string))
+    }
+
+    pub fn as_str(self) -> InternedString {
+        with_interner(|interner| InternedString { string: interner.get(self) })
+    }
+
+    pub fn as_u32(self) -> u32 {
+        self.0
+    }
+}
+
+impl fmt::Debug for Symbol {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "{}({})", self, self.0)
+    }
+}
+
+impl fmt::Display for Symbol {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        fmt::Display::fmt(&self.as_str(), f)
+    }
+}
+
+impl Encodable for Symbol {
+    fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
+        s.emit_str(&self.as_str())
+    }
+}
+
+impl Decodable for Symbol {
+    fn decode<D: Decoder>(d: &mut D) -> Result<Symbol, D::Error> {
+        Ok(Symbol::intern(&d.read_str()?))
+    }
+}
+
+impl<'a> PartialEq<&'a str> for Symbol {
+    fn eq(&self, other: &&str) -> bool {
+        *self.as_str() == **other
+    }
+}
+
+#[derive(Default)]
+pub struct Interner {
+    names: HashMap<Rc<str>, Symbol>,
+    strings: Vec<Rc<str>>,
+}
+
+impl Interner {
+    pub fn new() -> Self {
+        Interner::default()
+    }
+
+    fn prefill(init: &[&str]) -> Self {
+        let mut this = Interner::new();
+        for &string in init {
+            this.intern(string);
+        }
+        this
+    }
+
+    pub fn intern(&mut self, string: &str) -> Symbol {
+        if let Some(&name) = self.names.get(string) {
+            return name;
+        }
+
+        let name = Symbol(self.strings.len() as u32);
+        let string = Rc::__from_str(string);
+        self.strings.push(string.clone());
+        self.names.insert(string, name);
+        name
+    }
+
+    fn gensym(&mut self, string: &str) -> Symbol {
+        let gensym = Symbol(self.strings.len() as u32);
+        // leave out of `names` to avoid colliding
+        self.strings.push(Rc::__from_str(string));
+        gensym
+    }
+
+    pub fn get(&self, name: Symbol) -> Rc<str> {
+        self.strings[name.0 as usize].clone()
+    }
+}
+
+// In this macro, there is the requirement that the name (the number) must be monotonically
+// increasing by one in the special identifiers, starting at 0; the same holds for the keywords,
+// except starting from the next number instead of zero.
+macro_rules! declare_keywords {(
+    $( ($index: expr, $konst: ident, $string: expr) )*
+) => {
+    pub mod keywords {
+        use ast;
+        #[derive(Clone, Copy, PartialEq, Eq)]
+        pub struct Keyword {
+            ident: ast::Ident,
+        }
+        impl Keyword {
+            #[inline] pub fn ident(self) -> ast::Ident { self.ident }
+            #[inline] pub fn name(self) -> ast::Name { self.ident.name }
+        }
+        $(
+            #[allow(non_upper_case_globals)]
+            pub const $konst: Keyword = Keyword {
+                ident: ast::Ident::with_empty_ctxt(ast::Name($index))
+            };
+        )*
+    }
+
+    impl Interner {
+        fn fresh() -> Self {
+            Interner::prefill(&[$($string,)*])
+        }
+    }
+}}
+
+// NB: leaving holes in the ident table is bad! a different ident will get
+// interned with the id from the hole, but it will be between the min and max
+// of the reserved words, and thus tagged as "reserved".
+// After modifying this list adjust `is_strict_keyword`/`is_reserved_keyword`,
+// this should be rarely necessary though if the keywords are kept in alphabetic order.
+declare_keywords! {
+    // Invalid identifier
+    (0,  Invalid,        "")
+
+    // Strict keywords used in the language.
+    (1,  As,             "as")
+    (2,  Box,            "box")
+    (3,  Break,          "break")
+    (4,  Const,          "const")
+    (5,  Continue,       "continue")
+    (6,  Crate,          "crate")
+    (7,  Else,           "else")
+    (8,  Enum,           "enum")
+    (9,  Extern,         "extern")
+    (10, False,          "false")
+    (11, Fn,             "fn")
+    (12, For,            "for")
+    (13, If,             "if")
+    (14, Impl,           "impl")
+    (15, In,             "in")
+    (16, Let,            "let")
+    (17, Loop,           "loop")
+    (18, Match,          "match")
+    (19, Mod,            "mod")
+    (20, Move,           "move")
+    (21, Mut,            "mut")
+    (22, Pub,            "pub")
+    (23, Ref,            "ref")
+    (24, Return,         "return")
+    (25, SelfValue,      "self")
+    (26, SelfType,       "Self")
+    (27, Static,         "static")
+    (28, Struct,         "struct")
+    (29, Super,          "super")
+    (30, Trait,          "trait")
+    (31, True,           "true")
+    (32, Type,           "type")
+    (33, Unsafe,         "unsafe")
+    (34, Use,            "use")
+    (35, Where,          "where")
+    (36, While,          "while")
+
+    // Keywords reserved for future use.
+    (37, Abstract,       "abstract")
+    (38, Alignof,        "alignof")
+    (39, Become,         "become")
+    (40, Do,             "do")
+    (41, Final,          "final")
+    (42, Macro,          "macro")
+    (43, Offsetof,       "offsetof")
+    (44, Override,       "override")
+    (45, Priv,           "priv")
+    (46, Proc,           "proc")
+    (47, Pure,           "pure")
+    (48, Sizeof,         "sizeof")
+    (49, Typeof,         "typeof")
+    (50, Unsized,        "unsized")
+    (51, Virtual,        "virtual")
+    (52, Yield,          "yield")
+
+    // Weak keywords, have special meaning only in specific contexts.
+    (53, Default,        "default")
+    (54, StaticLifetime, "'static")
+    (55, Union,          "union")
+}
+
+// If an interner exists in TLS, return it. Otherwise, prepare a fresh one.
+fn with_interner<T, F: FnOnce(&mut Interner) -> T>(f: F) -> T {
+    thread_local!(static INTERNER: RefCell<Interner> = {
+        RefCell::new(Interner::fresh())
+    });
+    INTERNER.with(|interner| f(&mut *interner.borrow_mut()))
+}
+
+/// Reset the ident interner to its initial state.
+pub fn reset_interner() {
+    with_interner(|interner| *interner = Interner::fresh());
+}
+
+/// Represents a string stored in the thread-local interner. Because the
+/// interner lives for the life of the thread, this can be safely treated as an
+/// immortal string, as long as it never crosses between threads.
+///
+/// FIXME(pcwalton): You must be careful about what you do in the destructors
+/// of objects stored in TLS, because they may run after the interner is
+/// destroyed. In particular, they must not access string contents. This can
+/// be fixed in the future by just leaking all strings until thread death
+/// somehow.
+#[derive(Clone, PartialEq, Hash, PartialOrd, Eq, Ord)]
+pub struct InternedString {
+    string: Rc<str>,
+}
+
+impl InternedString {
+    pub fn new(string: &'static str) -> InternedString {
+        InternedString {
+            string: Rc::__from_str(string),
+        }
+    }
+}
+
+impl ::std::ops::Deref for InternedString {
+    type Target = str;
+    fn deref(&self) -> &str { &self.string }
+}
+
+impl fmt::Debug for InternedString {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        fmt::Debug::fmt(&self.string, f)
+    }
+}
+
+impl fmt::Display for InternedString {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        fmt::Display::fmt(&self.string, f)
+    }
+}
+
+impl<'a> PartialEq<&'a str> for InternedString {
+    fn eq(&self, other: & &'a str) -> bool {
+        PartialEq::eq(&self.string[..], *other)
+    }
+}
+
+impl<'a> PartialEq<InternedString> for &'a str {
+    fn eq(&self, other: &InternedString) -> bool {
+        PartialEq::eq(*self, &other.string[..])
+    }
+}
+
+impl PartialEq<str> for InternedString {
+    fn eq(&self, other: &str) -> bool {
+        PartialEq::eq(&self.string[..], other)
+    }
+}
+
+impl PartialEq<InternedString> for str {
+    fn eq(&self, other: &InternedString) -> bool {
+        PartialEq::eq(self, &other.string[..])
+    }
+}
+
+impl Decodable for InternedString {
+    fn decode<D: Decoder>(d: &mut D) -> Result<InternedString, D::Error> {
+        Ok(Symbol::intern(&d.read_str()?).as_str())
+    }
+}
+
+impl Encodable for InternedString {
+    fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
+        s.emit_str(&self.string)
+    }
+}
+
+/// Interns and returns the string contents of an identifier, using the
+/// thread-local interner.
+#[inline]
+pub fn intern_and_get_ident(s: &str) -> InternedString {
+    Symbol::intern(s).as_str()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use ast::Name;
+
+    #[test]
+    fn interner_tests() {
+        let mut i: Interner = Interner::new();
+        // first one is zero:
+        assert_eq!(i.intern("dog"), Name(0));
+        // re-use gets the same entry:
+        assert_eq!(i.intern ("dog"), Name(0));
+        // different string gets a different #:
+        assert_eq!(i.intern("cat"), Name(1));
+        assert_eq!(i.intern("cat"), Name(1));
+        // dog is still at zero
+        assert_eq!(i.intern("dog"), Name(0));
+        // gensym gets 3
+        assert_eq!(i.gensym("zebra"), Name(2));
+        // gensym of same string gets new number :
+        assert_eq!(i.gensym("zebra"), Name(3));
+        // gensym of *existing* string gets new number:
+        assert_eq!(i.gensym("dog"), Name(4));
+    }
+}
diff --git a/src/libsyntax/test.rs b/src/libsyntax/test.rs
index 194bd4a9085..271de16e7ac 100644
--- a/src/libsyntax/test.rs
+++ b/src/libsyntax/test.rs
@@ -34,11 +34,11 @@ use ext::expand::ExpansionConfig;
 use fold::Folder;
 use util::move_map::MoveMap;
 use fold;
-use parse::token::{intern, keywords, InternedString};
 use parse::{token, ParseSess};
 use print::pprust;
-use ast;
+use ast::{self, Ident};
 use ptr::P;
+use symbol::{self, Symbol, keywords, InternedString};
 use util::small_vector::SmallVector;
 
 enum ShouldPanic {
@@ -48,7 +48,7 @@ enum ShouldPanic {
 
 struct Test {
     span: Span,
-    path: Vec<ast::Ident> ,
+    path: Vec<Ident> ,
     bench: bool,
     ignore: bool,
     should_panic: ShouldPanic
@@ -57,14 +57,14 @@ struct Test {
 struct TestCtxt<'a> {
     sess: &'a ParseSess,
     span_diagnostic: &'a errors::Handler,
-    path: Vec<ast::Ident>,
+    path: Vec<Ident>,
     ext_cx: ExtCtxt<'a>,
     testfns: Vec<Test>,
     reexport_test_harness_main: Option<InternedString>,
     is_test_crate: bool,
 
     // top-level re-export submodule, filled out after folding is finished
-    toplevel_reexport: Option<ast::Ident>,
+    toplevel_reexport: Option<Ident>,
 }
 
 // Traverse the crate, collecting all the test functions, eliding any
@@ -91,10 +91,10 @@ pub fn modify_for_testing(sess: &ParseSess,
 
 struct TestHarnessGenerator<'a> {
     cx: TestCtxt<'a>,
-    tests: Vec<ast::Ident>,
+    tests: Vec<Ident>,
 
     // submodule name, gensym'd identifier for re-exports
-    tested_submods: Vec<(ast::Ident, ast::Ident)>,
+    tested_submods: Vec<(Ident, Ident)>,
 }
 
 impl<'a> fold::Folder for TestHarnessGenerator<'a> {
@@ -191,8 +191,8 @@ impl fold::Folder for EntryPointCleaner {
             EntryPointType::MainAttr |
             EntryPointType::Start =>
                 folded.map(|ast::Item {id, ident, attrs, node, vis, span}| {
-                    let allow_str = token::intern("allow");
-                    let dead_code_str = token::intern("dead_code");
+                    let allow_str = Symbol::intern("allow");
+                    let dead_code_str = Symbol::intern("dead_code");
                     let word_vec = vec![attr::mk_list_word_item(dead_code_str)];
                     let allow_dead_code_item = attr::mk_list_item(allow_str, word_vec);
                     let allow_dead_code = attr::mk_attr_outer(attr::mk_attr_id(),
@@ -222,15 +222,18 @@ impl fold::Folder for EntryPointCleaner {
     fn fold_mac(&mut self, mac: ast::Mac) -> ast::Mac { mac }
 }
 
-fn mk_reexport_mod(cx: &mut TestCtxt, parent: ast::NodeId, tests: Vec<ast::Ident>,
-                   tested_submods: Vec<(ast::Ident, ast::Ident)>) -> (P<ast::Item>, ast::Ident) {
-    let super_ = token::str_to_ident("super");
+fn mk_reexport_mod(cx: &mut TestCtxt,
+                   parent: ast::NodeId,
+                   tests: Vec<Ident>,
+                   tested_submods: Vec<(Ident, Ident)>)
+                   -> (P<ast::Item>, Ident) {
+    let super_ = Ident::from_str("super");
 
     // Generate imports with `#[allow(private_in_public)]` to work around issue #36768.
     let allow_private_in_public = cx.ext_cx.attribute(DUMMY_SP, cx.ext_cx.meta_list(
         DUMMY_SP,
-        token::intern("allow"),
-        vec![cx.ext_cx.meta_list_item_word(DUMMY_SP, token::intern("private_in_public"))],
+        Symbol::intern("allow"),
+        vec![cx.ext_cx.meta_list_item_word(DUMMY_SP, Symbol::intern("private_in_public"))],
     ));
     let items = tests.into_iter().map(|r| {
         cx.ext_cx.item_use_simple(DUMMY_SP, ast::Visibility::Public,
@@ -247,7 +250,7 @@ fn mk_reexport_mod(cx: &mut TestCtxt, parent: ast::NodeId, tests: Vec<ast::Ident
         items: items,
     };
 
-    let sym = token::gensym_ident("__test_reexports");
+    let sym = Ident::with_empty_ctxt(Symbol::gensym("__test_reexports"));
     let parent = if parent == ast::DUMMY_NODE_ID { ast::CRATE_NODE_ID } else { parent };
     cx.ext_cx.current_expansion.mark = cx.ext_cx.resolver.get_module_scope(parent);
     let it = cx.ext_cx.monotonic_expander().fold_item(P(ast::Item {
@@ -286,7 +289,7 @@ fn generate_test_harness(sess: &ParseSess,
     cx.ext_cx.bt_push(ExpnInfo {
         call_site: DUMMY_SP,
         callee: NameAndSpan {
-            format: MacroAttribute(intern("test")),
+            format: MacroAttribute(Symbol::intern("test")),
             span: None,
             allow_internal_unstable: false,
         }
@@ -306,7 +309,7 @@ fn ignored_span(cx: &TestCtxt, sp: Span) -> Span {
     let info = ExpnInfo {
         call_site: DUMMY_SP,
         callee: NameAndSpan {
-            format: MacroAttribute(intern("test")),
+            format: MacroAttribute(Symbol::intern("test")),
             span: None,
             allow_internal_unstable: true,
         }
@@ -456,7 +459,7 @@ mod __test {
 */
 
 fn mk_std(cx: &TestCtxt) -> P<ast::Item> {
-    let id_test = token::str_to_ident("test");
+    let id_test = Ident::from_str("test");
     let (vi, vis, ident) = if cx.is_test_crate {
         (ast::ItemKind::Use(
             P(nospan(ast::ViewPathSimple(id_test,
@@ -487,16 +490,17 @@ fn mk_main(cx: &mut TestCtxt) -> P<ast::Item> {
     let ecx = &cx.ext_cx;
 
     // test::test_main_static
-    let test_main_path = ecx.path(sp, vec![token::str_to_ident("test"),
-                                           token::str_to_ident("test_main_static")]);
+    let test_main_path =
+        ecx.path(sp, vec![Ident::from_str("test"), Ident::from_str("test_main_static")]);
+
     // test::test_main_static(...)
     let test_main_path_expr = ecx.expr_path(test_main_path);
-    let tests_ident_expr = ecx.expr_ident(sp, token::str_to_ident("TESTS"));
+    let tests_ident_expr = ecx.expr_ident(sp, Ident::from_str("TESTS"));
     let call_test_main = ecx.expr_call(sp, test_main_path_expr,
                                        vec![tests_ident_expr]);
     let call_test_main = ecx.stmt_expr(call_test_main);
     // #![main]
-    let main_meta = ecx.meta_word(sp, token::intern("main"));
+    let main_meta = ecx.meta_word(sp, Symbol::intern("main"));
     let main_attr = ecx.attribute(sp, main_meta);
     // pub fn main() { ... }
     let main_ret_ty = ecx.ty(sp, ast::TyKind::Tup(vec![]));
@@ -506,7 +510,7 @@ fn mk_main(cx: &mut TestCtxt) -> P<ast::Item> {
                            dummy_spanned(ast::Constness::NotConst),
                            ::abi::Abi::Rust, ast::Generics::default(), main_body);
     let main = P(ast::Item {
-        ident: token::str_to_ident("main"),
+        ident: Ident::from_str("main"),
         attrs: vec![main_attr],
         id: ast::DUMMY_NODE_ID,
         node: main,
@@ -533,7 +537,7 @@ fn mk_test_module(cx: &mut TestCtxt) -> (P<ast::Item>, Option<P<ast::Item>>) {
         items: vec![import, mainfn, tests],
     };
     let item_ = ast::ItemKind::Mod(testmod);
-    let mod_ident = token::gensym_ident("__test");
+    let mod_ident = Ident::with_empty_ctxt(Symbol::gensym("__test"));
 
     let mut expander = cx.ext_cx.monotonic_expander();
     let item = expander.fold_item(P(ast::Item {
@@ -546,11 +550,11 @@ fn mk_test_module(cx: &mut TestCtxt) -> (P<ast::Item>, Option<P<ast::Item>>) {
     })).pop().unwrap();
     let reexport = cx.reexport_test_harness_main.as_ref().map(|s| {
         // building `use <ident> = __test::main`
-        let reexport_ident = token::str_to_ident(&s);
+        let reexport_ident = Ident::from_str(&s);
 
         let use_path =
             nospan(ast::ViewPathSimple(reexport_ident,
-                                       path_node(vec![mod_ident, token::str_to_ident("main")])));
+                                       path_node(vec![mod_ident, Ident::from_str("main")])));
 
         expander.fold_item(P(ast::Item {
             id: ast::DUMMY_NODE_ID,
@@ -571,7 +575,7 @@ fn nospan<T>(t: T) -> codemap::Spanned<T> {
     codemap::Spanned { node: t, span: DUMMY_SP }
 }
 
-fn path_node(ids: Vec<ast::Ident> ) -> ast::Path {
+fn path_node(ids: Vec<Ident>) -> ast::Path {
     ast::Path {
         span: DUMMY_SP,
         global: false,
@@ -582,7 +586,7 @@ fn path_node(ids: Vec<ast::Ident> ) -> ast::Path {
     }
 }
 
-fn path_name_i(idents: &[ast::Ident]) -> String {
+fn path_name_i(idents: &[Ident]) -> String {
     // FIXME: Bad copies (#2543 -- same for everything else that says "bad")
     idents.iter().map(|i| i.to_string()).collect::<Vec<String>>().join("::")
 }
@@ -660,7 +664,7 @@ fn mk_test_desc_and_fn_rec(cx: &TestCtxt, test: &Test) -> P<ast::Expr> {
 
     // path to the #[test] function: "foo::bar::baz"
     let path_string = path_name_i(&path[..]);
-    let name_expr = ecx.expr_str(span, token::intern_and_get_ident(&path_string[..]));
+    let name_expr = ecx.expr_str(span, symbol::intern_and_get_ident(&path_string[..]));
 
     // self::test::StaticTestName($name_expr)
     let name_expr = ecx.expr_call(span,
diff --git a/src/libsyntax/tokenstream.rs b/src/libsyntax/tokenstream.rs
index 9ef6c07e489..7ca4650a3ae 100644
--- a/src/libsyntax/tokenstream.rs
+++ b/src/libsyntax/tokenstream.rs
@@ -34,6 +34,7 @@ use parse::lexer;
 use parse;
 use parse::token::{self, Token, Lit, Nonterminal};
 use print::pprust;
+use symbol::{self, Symbol};
 
 use std::fmt;
 use std::iter::*;
@@ -173,10 +174,10 @@ impl TokenTree {
                 TokenTree::Delimited(sp, Rc::new(Delimited {
                     delim: token::Bracket,
                     open_span: sp,
-                    tts: vec![TokenTree::Token(sp, token::Ident(token::str_to_ident("doc"))),
+                    tts: vec![TokenTree::Token(sp, token::Ident(ast::Ident::from_str("doc"))),
                               TokenTree::Token(sp, token::Eq),
                               TokenTree::Token(sp, token::Literal(
-                                  token::StrRaw(token::intern(&stripped), num_of_hashes), None))],
+                                  token::StrRaw(Symbol::intern(&stripped), num_of_hashes), None))],
                     close_span: sp,
                 }))
             }
@@ -295,7 +296,7 @@ impl TokenTree {
     pub fn maybe_str(&self) -> Option<ast::Lit> {
         match *self {
             TokenTree::Token(sp, Token::Literal(Lit::Str_(s), _)) => {
-                let l = LitKind::Str(token::intern_and_get_ident(&parse::str_lit(&s.as_str())),
+                let l = LitKind::Str(symbol::intern_and_get_ident(&parse::str_lit(&s.as_str())),
                                      ast::StrStyle::Cooked);
                 Some(Spanned {
                     node: l,
@@ -303,7 +304,7 @@ impl TokenTree {
                 })
             }
             TokenTree::Token(sp, Token::Literal(Lit::StrRaw(s, n), _)) => {
-                let l = LitKind::Str(token::intern_and_get_ident(&parse::raw_str_lit(&s.as_str())),
+                let l = LitKind::Str(symbol::intern_and_get_ident(&parse::raw_str_lit(&s.as_str())),
                                      ast::StrStyle::Raw(n));
                 Some(Spanned {
                     node: l,
diff --git a/src/libsyntax/util/interner.rs b/src/libsyntax/util/interner.rs
deleted file mode 100644
index f56c6cedcd1..00000000000
--- a/src/libsyntax/util/interner.rs
+++ /dev/null
@@ -1,111 +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.
-
-//! An "interner" is a data structure that associates values with usize tags and
-//! allows bidirectional lookup; i.e. given a value, one can easily find the
-//! type, and vice versa.
-
-use ast::Name;
-
-use std::collections::HashMap;
-use std::rc::Rc;
-
-#[derive(Default)]
-pub struct Interner {
-    names: HashMap<Rc<str>, Name>,
-    strings: Vec<Rc<str>>,
-}
-
-/// When traits can extend traits, we should extend index<Name,T> to get []
-impl Interner {
-    pub fn new() -> Self {
-        Interner::default()
-    }
-
-    pub fn prefill(init: &[&str]) -> Self {
-        let mut this = Interner::new();
-        for &string in init {
-            this.intern(string);
-        }
-        this
-    }
-
-    pub fn intern(&mut self, string: &str) -> Name {
-        if let Some(&name) = self.names.get(string) {
-            return name;
-        }
-
-        let name = Name(self.strings.len() as u32);
-        let string = Rc::__from_str(string);
-        self.strings.push(string.clone());
-        self.names.insert(string, name);
-        name
-    }
-
-    pub fn gensym(&mut self, string: &str) -> Name {
-        let gensym = Name(self.strings.len() as u32);
-        // leave out of `names` to avoid colliding
-        self.strings.push(Rc::__from_str(string));
-        gensym
-    }
-
-    /// Create a gensym with the same name as an existing entry.
-    pub fn gensym_copy(&mut self, name: Name) -> Name {
-        let gensym = Name(self.strings.len() as u32);
-        // leave out of `names` to avoid colliding
-        let string = self.strings[name.0 as usize].clone();
-        self.strings.push(string);
-        gensym
-    }
-
-    pub fn get(&self, name: Name) -> Rc<str> {
-        self.strings[name.0 as usize].clone()
-    }
-
-    pub fn find(&self, string: &str) -> Option<Name> {
-        self.names.get(string).cloned()
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use ast::Name;
-
-    #[test]
-    fn interner_tests() {
-        let mut i: Interner = Interner::new();
-        // first one is zero:
-        assert_eq!(i.intern("dog"), Name(0));
-        // re-use gets the same entry:
-        assert_eq!(i.intern ("dog"), Name(0));
-        // different string gets a different #:
-        assert_eq!(i.intern("cat"), Name(1));
-        assert_eq!(i.intern("cat"), Name(1));
-        // dog is still at zero
-        assert_eq!(i.intern("dog"), Name(0));
-        // gensym gets 3
-        assert_eq!(i.gensym("zebra"), Name(2));
-        // gensym of same string gets new number :
-        assert_eq!(i.gensym("zebra"), Name(3));
-        // gensym of *existing* string gets new number:
-        assert_eq!(i.gensym("dog"), Name(4));
-        // gensym tests again with gensym_copy:
-        assert_eq!(i.gensym_copy(Name(2)), Name(5));
-        assert_eq!(&*i.get(Name(5)), "zebra");
-        assert_eq!(i.gensym_copy(Name(2)), Name(6));
-        assert_eq!(&*i.get(Name(6)), "zebra");
-        assert_eq!(&*i.get(Name(0)), "dog");
-        assert_eq!(&*i.get(Name(1)), "cat");
-        assert_eq!(&*i.get(Name(2)), "zebra");
-        assert_eq!(&*i.get(Name(3)), "zebra");
-        assert_eq!(&*i.get(Name(4)), "dog");
-    }
-}
diff --git a/src/libsyntax/util/lev_distance.rs b/src/libsyntax/util/lev_distance.rs
index e0796c34e57..0d6df2cfcb6 100644
--- a/src/libsyntax/util/lev_distance.rs
+++ b/src/libsyntax/util/lev_distance.rs
@@ -10,7 +10,7 @@
 
 use ast::Name;
 use std::cmp;
-use parse::token::InternedString;
+use symbol::InternedString;
 
 /// To find the Levenshtein distance between two strings
 pub fn lev_distance(a: &str, b: &str) -> usize {
diff --git a/src/libsyntax/util/parser.rs b/src/libsyntax/util/parser.rs
index df4eb1c9ed7..ce24fe1eb61 100644
--- a/src/libsyntax/util/parser.rs
+++ b/src/libsyntax/util/parser.rs
@@ -7,7 +7,8 @@
 // <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.
-use parse::token::{Token, BinOpToken, keywords};
+use parse::token::{Token, BinOpToken};
+use symbol::keywords;
 use ast::BinOpKind;
 
 /// Associative operator with precedence.