Auto merge of #53085 - ljedrz:cleanup_syntax_structures, r=ljedrz

Move SmallVector and ThinVec out of libsyntax

- move `libsyntax::util::SmallVector` tests to `librustc_data_structures::small_vec`
- remove `libsyntax::util::SmallVector`
- move `libsyntax::util::thin_vec` to `librustc_data_structures::thin_vec`

Other than moving these data structures where they belong it allows modules using `SmallVector<T>` (`SmallVec<[T; 1]>`) to specify their own length (e.g. 8 or 32) independently from `libsyntax`.

19 files changed, 131 insertions, 268 deletions

diff --git a/src/libsyntax/ast.rs b/src/libsyntax/ast.rs
index b66946affad..e53f3ea9036 100644
--- a/src/libsyntax/ast.rs
+++ b/src/libsyntax/ast.rs
@@ -13,7 +13,6 @@
 pub use self::UnsafeSource::*;
 pub use self::GenericArgs::*;
 pub use symbol::{Ident, Symbol as Name};
-pub use util::ThinVec;
 pub use util::parser::ExprPrecedence;
 
 use syntax_pos::{Span, DUMMY_SP};
@@ -25,6 +24,7 @@ use ptr::P;
 use rustc_data_structures::indexed_vec;
 use rustc_data_structures::indexed_vec::Idx;
 use symbol::{Symbol, keywords};
+use ThinVec;
 use tokenstream::{ThinTokenStream, TokenStream};
 
 use serialize::{self, Encoder, Decoder};
diff --git a/src/libsyntax/attr/mod.rs b/src/libsyntax/attr/mod.rs
index b3b173db70b..879f555ba03 100644
--- a/src/libsyntax/attr/mod.rs
+++ b/src/libsyntax/attr/mod.rs
@@ -33,8 +33,8 @@ use parse::{self, ParseSess, PResult};
 use parse::token::{self, Token};
 use ptr::P;
 use symbol::Symbol;
+use ThinVec;
 use tokenstream::{TokenStream, TokenTree, Delimited};
-use util::ThinVec;
 use GLOBALS;
 
 use std::iter;
diff --git a/src/libsyntax/config.rs b/src/libsyntax/config.rs
index 33643789139..4fe78bf829a 100644
--- a/src/libsyntax/config.rs
+++ b/src/libsyntax/config.rs
@@ -15,9 +15,9 @@ use ast;
 use codemap::Spanned;
 use edition::Edition;
 use parse::{token, ParseSess};
+use OneVector;
 
 use ptr::P;
-use util::small_vector::SmallVector;
 
 /// A folder that strips out items that do not belong in the current configuration.
 pub struct StripUnconfigured<'a> {
@@ -319,22 +319,22 @@ impl<'a> fold::Folder for StripUnconfigured<'a> {
         Some(P(fold::noop_fold_expr(expr, self)))
     }
 
-    fn fold_stmt(&mut self, stmt: ast::Stmt) -> SmallVector<ast::Stmt> {
+    fn fold_stmt(&mut self, stmt: ast::Stmt) -> OneVector<ast::Stmt> {
         match self.configure_stmt(stmt) {
             Some(stmt) => fold::noop_fold_stmt(stmt, self),
-            None => return SmallVector::new(),
+            None => return OneVector::new(),
         }
     }
 
-    fn fold_item(&mut self, item: P<ast::Item>) -> SmallVector<P<ast::Item>> {
+    fn fold_item(&mut self, item: P<ast::Item>) -> OneVector<P<ast::Item>> {
         fold::noop_fold_item(configure!(self, item), self)
     }
 
-    fn fold_impl_item(&mut self, item: ast::ImplItem) -> SmallVector<ast::ImplItem> {
+    fn fold_impl_item(&mut self, item: ast::ImplItem) -> OneVector<ast::ImplItem> {
         fold::noop_fold_impl_item(configure!(self, item), self)
     }
 
-    fn fold_trait_item(&mut self, item: ast::TraitItem) -> SmallVector<ast::TraitItem> {
+    fn fold_trait_item(&mut self, item: ast::TraitItem) -> OneVector<ast::TraitItem> {
         fold::noop_fold_trait_item(configure!(self, item), self)
     }
 
diff --git a/src/libsyntax/diagnostics/plugin.rs b/src/libsyntax/diagnostics/plugin.rs
index 72ce2740190..6a5a2a5e500 100644
--- a/src/libsyntax/diagnostics/plugin.rs
+++ b/src/libsyntax/diagnostics/plugin.rs
@@ -19,9 +19,9 @@ use ext::base::{ExtCtxt, MacEager, MacResult};
 use ext::build::AstBuilder;
 use parse::token;
 use ptr::P;
+use OneVector;
 use symbol::{keywords, Symbol};
 use tokenstream::{TokenTree};
-use util::small_vector::SmallVector;
 
 use diagnostics::metadata::output_metadata;
 
@@ -131,7 +131,7 @@ pub fn expand_register_diagnostic<'cx>(ecx: &'cx mut ExtCtxt,
     let sym = Ident::with_empty_ctxt(Symbol::gensym(&format!(
         "__register_diagnostic_{}", code
     )));
-    MacEager::items(SmallVector::many(vec![
+    MacEager::items(OneVector::many(vec![
         ecx.item_mod(
             span,
             span,
@@ -214,7 +214,7 @@ pub fn expand_build_diagnostic_array<'cx>(ecx: &'cx mut ExtCtxt,
         ),
     );
 
-    MacEager::items(SmallVector::many(vec![
+    MacEager::items(OneVector::many(vec![
         P(ast::Item {
             ident: *name,
             attrs: Vec::new(),
diff --git a/src/libsyntax/ext/base.rs b/src/libsyntax/ext/base.rs
index de391ee4219..482d8c2cf98 100644
--- a/src/libsyntax/ext/base.rs
+++ b/src/libsyntax/ext/base.rs
@@ -22,8 +22,9 @@ use fold::{self, Folder};
 use parse::{self, parser, DirectoryOwnership};
 use parse::token;
 use ptr::P;
+use OneVector;
 use symbol::{keywords, Ident, Symbol};
-use util::small_vector::SmallVector;
+use ThinVec;
 
 use std::collections::HashMap;
 use std::iter;
@@ -315,7 +316,7 @@ impl<F> IdentMacroExpander for F
 // Use a macro because forwarding to a simple function has type system issues
 macro_rules! make_stmts_default {
     ($me:expr) => {
-        $me.make_expr().map(|e| SmallVector::one(ast::Stmt {
+        $me.make_expr().map(|e| OneVector::one(ast::Stmt {
             id: ast::DUMMY_NODE_ID,
             span: e.span,
             node: ast::StmtKind::Expr(e),
@@ -331,22 +332,22 @@ pub trait MacResult {
         None
     }
     /// Create zero or more items.
-    fn make_items(self: Box<Self>) -> Option<SmallVector<P<ast::Item>>> {
+    fn make_items(self: Box<Self>) -> Option<OneVector<P<ast::Item>>> {
         None
     }
 
     /// Create zero or more impl items.
-    fn make_impl_items(self: Box<Self>) -> Option<SmallVector<ast::ImplItem>> {
+    fn make_impl_items(self: Box<Self>) -> Option<OneVector<ast::ImplItem>> {
         None
     }
 
     /// Create zero or more trait items.
-    fn make_trait_items(self: Box<Self>) -> Option<SmallVector<ast::TraitItem>> {
+    fn make_trait_items(self: Box<Self>) -> Option<OneVector<ast::TraitItem>> {
         None
     }
 
     /// Create zero or more items in an `extern {}` block
-    fn make_foreign_items(self: Box<Self>) -> Option<SmallVector<ast::ForeignItem>> { None }
+    fn make_foreign_items(self: Box<Self>) -> Option<OneVector<ast::ForeignItem>> { None }
 
     /// Create a pattern.
     fn make_pat(self: Box<Self>) -> Option<P<ast::Pat>> {
@@ -357,7 +358,7 @@ pub trait MacResult {
     ///
     /// By default this attempts to create an expression statement,
     /// returning None if that fails.
-    fn make_stmts(self: Box<Self>) -> Option<SmallVector<ast::Stmt>> {
+    fn make_stmts(self: Box<Self>) -> Option<OneVector<ast::Stmt>> {
         make_stmts_default!(self)
     }
 
@@ -393,11 +394,11 @@ macro_rules! make_MacEager {
 make_MacEager! {
     expr: P<ast::Expr>,
     pat: P<ast::Pat>,
-    items: SmallVector<P<ast::Item>>,
-    impl_items: SmallVector<ast::ImplItem>,
-    trait_items: SmallVector<ast::TraitItem>,
-    foreign_items: SmallVector<ast::ForeignItem>,
-    stmts: SmallVector<ast::Stmt>,
+    items: OneVector<P<ast::Item>>,
+    impl_items: OneVector<ast::ImplItem>,
+    trait_items: OneVector<ast::TraitItem>,
+    foreign_items: OneVector<ast::ForeignItem>,
+    stmts: OneVector<ast::Stmt>,
     ty: P<ast::Ty>,
 }
 
@@ -406,23 +407,23 @@ impl MacResult for MacEager {
         self.expr
     }
 
-    fn make_items(self: Box<Self>) -> Option<SmallVector<P<ast::Item>>> {
+    fn make_items(self: Box<Self>) -> Option<OneVector<P<ast::Item>>> {
         self.items
     }
 
-    fn make_impl_items(self: Box<Self>) -> Option<SmallVector<ast::ImplItem>> {
+    fn make_impl_items(self: Box<Self>) -> Option<OneVector<ast::ImplItem>> {
         self.impl_items
     }
 
-    fn make_trait_items(self: Box<Self>) -> Option<SmallVector<ast::TraitItem>> {
+    fn make_trait_items(self: Box<Self>) -> Option<OneVector<ast::TraitItem>> {
         self.trait_items
     }
 
-    fn make_foreign_items(self: Box<Self>) -> Option<SmallVector<ast::ForeignItem>> {
+    fn make_foreign_items(self: Box<Self>) -> Option<OneVector<ast::ForeignItem>> {
         self.foreign_items
     }
 
-    fn make_stmts(self: Box<Self>) -> Option<SmallVector<ast::Stmt>> {
+    fn make_stmts(self: Box<Self>) -> Option<OneVector<ast::Stmt>> {
         match self.stmts.as_ref().map_or(0, |s| s.len()) {
             0 => make_stmts_default!(self),
             _ => self.stmts,
@@ -482,7 +483,7 @@ impl DummyResult {
             id: ast::DUMMY_NODE_ID,
             node: ast::ExprKind::Lit(P(codemap::respan(sp, ast::LitKind::Bool(false)))),
             span: sp,
-            attrs: ast::ThinVec::new(),
+            attrs: ThinVec::new(),
         })
     }
 
@@ -513,41 +514,41 @@ impl MacResult for DummyResult {
         Some(P(DummyResult::raw_pat(self.span)))
     }
 
-    fn make_items(self: Box<DummyResult>) -> Option<SmallVector<P<ast::Item>>> {
+    fn make_items(self: Box<DummyResult>) -> Option<OneVector<P<ast::Item>>> {
         // this code needs a comment... why not always just return the Some() ?
         if self.expr_only {
             None
         } else {
-            Some(SmallVector::new())
+            Some(OneVector::new())
         }
     }
 
-    fn make_impl_items(self: Box<DummyResult>) -> Option<SmallVector<ast::ImplItem>> {
+    fn make_impl_items(self: Box<DummyResult>) -> Option<OneVector<ast::ImplItem>> {
         if self.expr_only {
             None
         } else {
-            Some(SmallVector::new())
+            Some(OneVector::new())
         }
     }
 
-    fn make_trait_items(self: Box<DummyResult>) -> Option<SmallVector<ast::TraitItem>> {
+    fn make_trait_items(self: Box<DummyResult>) -> Option<OneVector<ast::TraitItem>> {
         if self.expr_only {
             None
         } else {
-            Some(SmallVector::new())
+            Some(OneVector::new())
         }
     }
 
-    fn make_foreign_items(self: Box<Self>) -> Option<SmallVector<ast::ForeignItem>> {
+    fn make_foreign_items(self: Box<Self>) -> Option<OneVector<ast::ForeignItem>> {
         if self.expr_only {
             None
         } else {
-            Some(SmallVector::new())
+            Some(OneVector::new())
         }
     }
 
-    fn make_stmts(self: Box<DummyResult>) -> Option<SmallVector<ast::Stmt>> {
-        Some(SmallVector::one(ast::Stmt {
+    fn make_stmts(self: Box<DummyResult>) -> Option<OneVector<ast::Stmt>> {
+        Some(OneVector::one(ast::Stmt {
             id: ast::DUMMY_NODE_ID,
             node: ast::StmtKind::Expr(DummyResult::raw_expr(self.span)),
             span: self.span,
diff --git a/src/libsyntax/ext/build.rs b/src/libsyntax/ext/build.rs
index 61356507665..1a17aa3e8fb 100644
--- a/src/libsyntax/ext/build.rs
+++ b/src/libsyntax/ext/build.rs
@@ -16,6 +16,7 @@ use codemap::{dummy_spanned, respan, Spanned};
 use ext::base::ExtCtxt;
 use ptr::P;
 use symbol::{Symbol, keywords};
+use ThinVec;
 
 // Transitional re-exports so qquote can find the paths it is looking for
 mod syntax {
@@ -519,7 +520,7 @@ impl<'a> AstBuilder for ExtCtxt<'a> {
             init: Some(ex),
             id: ast::DUMMY_NODE_ID,
             span: sp,
-            attrs: ast::ThinVec::new(),
+            attrs: ThinVec::new(),
         });
         ast::Stmt {
             id: ast::DUMMY_NODE_ID,
@@ -547,7 +548,7 @@ impl<'a> AstBuilder for ExtCtxt<'a> {
             init: Some(ex),
             id: ast::DUMMY_NODE_ID,
             span: sp,
-            attrs: ast::ThinVec::new(),
+            attrs: ThinVec::new(),
         });
         ast::Stmt {
             id: ast::DUMMY_NODE_ID,
@@ -564,7 +565,7 @@ impl<'a> AstBuilder for ExtCtxt<'a> {
             init: None,
             id: ast::DUMMY_NODE_ID,
             span,
-            attrs: ast::ThinVec::new(),
+            attrs: ThinVec::new(),
         });
         ast::Stmt {
             id: ast::DUMMY_NODE_ID,
@@ -603,7 +604,7 @@ impl<'a> AstBuilder for ExtCtxt<'a> {
             id: ast::DUMMY_NODE_ID,
             node,
             span,
-            attrs: ast::ThinVec::new(),
+            attrs: ThinVec::new(),
         })
     }
 
@@ -678,7 +679,7 @@ impl<'a> AstBuilder for ExtCtxt<'a> {
             expr: e,
             span,
             is_shorthand: false,
-            attrs: ast::ThinVec::new(),
+            attrs: ThinVec::new(),
         }
     }
     fn expr_struct(&self, span: Span, path: ast::Path, fields: Vec<ast::Field>) -> P<ast::Expr> {
diff --git a/src/libsyntax/ext/expand.rs b/src/libsyntax/ext/expand.rs
index 12941a85669..f7ea781e021 100644
--- a/src/libsyntax/ext/expand.rs
+++ b/src/libsyntax/ext/expand.rs
@@ -26,12 +26,12 @@ use parse::{DirectoryOwnership, PResult, ParseSess};
 use parse::token::{self, Token};
 use parse::parser::Parser;
 use ptr::P;
+use OneVector;
 use symbol::Symbol;
 use symbol::keywords;
 use syntax_pos::{Span, DUMMY_SP, FileName};
 use syntax_pos::hygiene::ExpnFormat;
 use tokenstream::{TokenStream, TokenTree};
-use util::small_vector::SmallVector;
 use visit::{self, Visitor};
 
 use std::collections::HashMap;
@@ -131,7 +131,7 @@ macro_rules! ast_fragments {
                 self.expand_fragment(AstFragment::$Kind(ast)).$make_ast()
             })*)*
             $($(fn $fold_ast_elt(&mut self, ast_elt: <$AstTy as IntoIterator>::Item) -> $AstTy {
-                self.expand_fragment(AstFragment::$Kind(SmallVector::one(ast_elt))).$make_ast()
+                self.expand_fragment(AstFragment::$Kind(OneVector::one(ast_elt))).$make_ast()
             })*)*
         }
 
@@ -148,15 +148,15 @@ ast_fragments! {
     Expr(P<ast::Expr>) { "expression"; one fn fold_expr; fn visit_expr; fn make_expr; }
     Pat(P<ast::Pat>) { "pattern"; one fn fold_pat; fn visit_pat; fn make_pat; }
     Ty(P<ast::Ty>) { "type"; one fn fold_ty; fn visit_ty; fn make_ty; }
-    Stmts(SmallVector<ast::Stmt>) { "statement"; many fn fold_stmt; fn visit_stmt; fn make_stmts; }
-    Items(SmallVector<P<ast::Item>>) { "item"; many fn fold_item; fn visit_item; fn make_items; }
-    TraitItems(SmallVector<ast::TraitItem>) {
+    Stmts(OneVector<ast::Stmt>) { "statement"; many fn fold_stmt; fn visit_stmt; fn make_stmts; }
+    Items(OneVector<P<ast::Item>>) { "item"; many fn fold_item; fn visit_item; fn make_items; }
+    TraitItems(OneVector<ast::TraitItem>) {
         "trait item"; many fn fold_trait_item; fn visit_trait_item; fn make_trait_items;
     }
-    ImplItems(SmallVector<ast::ImplItem>) {
+    ImplItems(OneVector<ast::ImplItem>) {
         "impl item"; many fn fold_impl_item; fn visit_impl_item; fn make_impl_items;
     }
-    ForeignItems(SmallVector<ast::ForeignItem>) {
+    ForeignItems(OneVector<ast::ForeignItem>) {
         "foreign item"; many fn fold_foreign_item; fn visit_foreign_item; fn make_foreign_items;
     }
 }
@@ -279,7 +279,7 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
 
         let orig_mod_span = krate.module.inner;
 
-        let krate_item = AstFragment::Items(SmallVector::one(P(ast::Item {
+        let krate_item = AstFragment::Items(OneVector::one(P(ast::Item {
             attrs: krate.attrs,
             span: krate.span,
             node: ast::ItemKind::Mod(krate.module),
@@ -989,28 +989,28 @@ impl<'a> Parser<'a> {
                               -> PResult<'a, AstFragment> {
         Ok(match kind {
             AstFragmentKind::Items => {
-                let mut items = SmallVector::new();
+                let mut items = OneVector::new();
                 while let Some(item) = self.parse_item()? {
                     items.push(item);
                 }
                 AstFragment::Items(items)
             }
             AstFragmentKind::TraitItems => {
-                let mut items = SmallVector::new();
+                let mut items = OneVector::new();
                 while self.token != token::Eof {
                     items.push(self.parse_trait_item(&mut false)?);
                 }
                 AstFragment::TraitItems(items)
             }
             AstFragmentKind::ImplItems => {
-                let mut items = SmallVector::new();
+                let mut items = OneVector::new();
                 while self.token != token::Eof {
                     items.push(self.parse_impl_item(&mut false)?);
                 }
                 AstFragment::ImplItems(items)
             }
             AstFragmentKind::ForeignItems => {
-                let mut items = SmallVector::new();
+                let mut items = OneVector::new();
                 while self.token != token::Eof {
                     if let Some(item) = self.parse_foreign_item()? {
                         items.push(item);
@@ -1019,7 +1019,7 @@ impl<'a> Parser<'a> {
                 AstFragment::ForeignItems(items)
             }
             AstFragmentKind::Stmts => {
-                let mut stmts = SmallVector::new();
+                let mut stmts = OneVector::new();
                 while self.token != token::Eof &&
                       // won't make progress on a `}`
                       self.token != token::CloseDelim(token::Brace) {
@@ -1086,12 +1086,12 @@ impl<'a, 'b> InvocationCollector<'a, 'b> {
 
     /// Folds the item allowing tests to be expanded because they are still nameable.
     /// This should probably only be called with module items
-    fn fold_nameable(&mut self, item: P<ast::Item>) -> SmallVector<P<ast::Item>> {
+    fn fold_nameable(&mut self, item: P<ast::Item>) -> OneVector<P<ast::Item>> {
         fold::noop_fold_item(item, self)
     }
 
     /// Folds the item but doesn't allow tests to occur within it
-    fn fold_unnameable(&mut self, item: P<ast::Item>) -> SmallVector<P<ast::Item>> {
+    fn fold_unnameable(&mut self, item: P<ast::Item>) -> OneVector<P<ast::Item>> {
         let was_nameable = mem::replace(&mut self.tests_nameable, false);
         let items = fold::noop_fold_item(item, self);
         self.tests_nameable = was_nameable;
@@ -1254,10 +1254,10 @@ impl<'a, 'b> Folder for InvocationCollector<'a, 'b> {
         })
     }
 
-    fn fold_stmt(&mut self, stmt: ast::Stmt) -> SmallVector<ast::Stmt> {
+    fn fold_stmt(&mut self, stmt: ast::Stmt) -> OneVector<ast::Stmt> {
         let mut stmt = match self.cfg.configure_stmt(stmt) {
             Some(stmt) => stmt,
-            None => return SmallVector::new(),
+            None => return OneVector::new(),
         };
 
         // we'll expand attributes on expressions separately
@@ -1313,7 +1313,7 @@ impl<'a, 'b> Folder for InvocationCollector<'a, 'b> {
         result
     }
 
-    fn fold_item(&mut self, item: P<ast::Item>) -> SmallVector<P<ast::Item>> {
+    fn fold_item(&mut self, item: P<ast::Item>) -> OneVector<P<ast::Item>> {
         let item = configure!(self, item);
 
         let (attr, traits, mut item) = self.classify_item(item);
@@ -1422,7 +1422,7 @@ impl<'a, 'b> Folder for InvocationCollector<'a, 'b> {
                         ui
                     });
 
-                    SmallVector::many(
+                    OneVector::many(
                         self.fold_unnameable(item).into_iter()
                             .chain(self.fold_unnameable(use_item)))
                 } else {
@@ -1433,7 +1433,7 @@ impl<'a, 'b> Folder for InvocationCollector<'a, 'b> {
         }
     }
 
-    fn fold_trait_item(&mut self, item: ast::TraitItem) -> SmallVector<ast::TraitItem> {
+    fn fold_trait_item(&mut self, item: ast::TraitItem) -> OneVector<ast::TraitItem> {
         let item = configure!(self, item);
 
         let (attr, traits, item) = self.classify_item(item);
@@ -1453,7 +1453,7 @@ impl<'a, 'b> Folder for InvocationCollector<'a, 'b> {
         }
     }
 
-    fn fold_impl_item(&mut self, item: ast::ImplItem) -> SmallVector<ast::ImplItem> {
+    fn fold_impl_item(&mut self, item: ast::ImplItem) -> OneVector<ast::ImplItem> {
         let item = configure!(self, item);
 
         let (attr, traits, item) = self.classify_item(item);
@@ -1490,7 +1490,7 @@ impl<'a, 'b> Folder for InvocationCollector<'a, 'b> {
     }
 
     fn fold_foreign_item(&mut self,
-                         foreign_item: ast::ForeignItem) -> SmallVector<ast::ForeignItem> {
+                         foreign_item: ast::ForeignItem) -> OneVector<ast::ForeignItem> {
         let (attr, traits, foreign_item) = self.classify_item(foreign_item);
 
         if attr.is_some() || !traits.is_empty() {
diff --git a/src/libsyntax/ext/placeholders.rs b/src/libsyntax/ext/placeholders.rs
index 968cf508eda..1dc9bae8848 100644
--- a/src/libsyntax/ext/placeholders.rs
+++ b/src/libsyntax/ext/placeholders.rs
@@ -16,9 +16,10 @@ use ext::hygiene::Mark;
 use tokenstream::TokenStream;
 use fold::*;
 use ptr::P;
+use OneVector;
 use symbol::keywords;
+use ThinVec;
 use util::move_map::MoveMap;
-use util::small_vector::SmallVector;
 
 use std::collections::HashMap;
 
@@ -38,31 +39,31 @@ pub fn placeholder(kind: AstFragmentKind, id: ast::NodeId) -> AstFragment {
     let span = DUMMY_SP;
     let expr_placeholder = || P(ast::Expr {
         id, span,
-        attrs: ast::ThinVec::new(),
+        attrs: ThinVec::new(),
         node: ast::ExprKind::Mac(mac_placeholder()),
     });
 
     match kind {
         AstFragmentKind::Expr => AstFragment::Expr(expr_placeholder()),
         AstFragmentKind::OptExpr => AstFragment::OptExpr(Some(expr_placeholder())),
-        AstFragmentKind::Items => AstFragment::Items(SmallVector::one(P(ast::Item {
+        AstFragmentKind::Items => AstFragment::Items(OneVector::one(P(ast::Item {
             id, span, ident, vis, attrs,
             node: ast::ItemKind::Mac(mac_placeholder()),
             tokens: None,
         }))),
-        AstFragmentKind::TraitItems => AstFragment::TraitItems(SmallVector::one(ast::TraitItem {
+        AstFragmentKind::TraitItems => AstFragment::TraitItems(OneVector::one(ast::TraitItem {
             id, span, ident, attrs, generics,
             node: ast::TraitItemKind::Macro(mac_placeholder()),
             tokens: None,
         })),
-        AstFragmentKind::ImplItems => AstFragment::ImplItems(SmallVector::one(ast::ImplItem {
+        AstFragmentKind::ImplItems => AstFragment::ImplItems(OneVector::one(ast::ImplItem {
             id, span, ident, vis, attrs, generics,
             node: ast::ImplItemKind::Macro(mac_placeholder()),
             defaultness: ast::Defaultness::Final,
             tokens: None,
         })),
         AstFragmentKind::ForeignItems =>
-            AstFragment::ForeignItems(SmallVector::one(ast::ForeignItem {
+            AstFragment::ForeignItems(OneVector::one(ast::ForeignItem {
                 id, span, ident, vis, attrs,
                 node: ast::ForeignItemKind::Macro(mac_placeholder()),
             })),
@@ -72,8 +73,8 @@ pub fn placeholder(kind: AstFragmentKind, id: ast::NodeId) -> AstFragment {
         AstFragmentKind::Ty => AstFragment::Ty(P(ast::Ty {
             id, span, node: ast::TyKind::Mac(mac_placeholder()),
         })),
-        AstFragmentKind::Stmts => AstFragment::Stmts(SmallVector::one({
-            let mac = P((mac_placeholder(), ast::MacStmtStyle::Braces, ast::ThinVec::new()));
+        AstFragmentKind::Stmts => AstFragment::Stmts(OneVector::one({
+            let mac = P((mac_placeholder(), ast::MacStmtStyle::Braces, ThinVec::new()));
             ast::Stmt { id, span, node: ast::StmtKind::Mac(mac) }
         })),
     }
@@ -114,31 +115,31 @@ impl<'a, 'b> PlaceholderExpander<'a, 'b> {
 }
 
 impl<'a, 'b> Folder for PlaceholderExpander<'a, 'b> {
-    fn fold_item(&mut self, item: P<ast::Item>) -> SmallVector<P<ast::Item>> {
+    fn fold_item(&mut self, item: P<ast::Item>) -> OneVector<P<ast::Item>> {
         match item.node {
             ast::ItemKind::Mac(_) => return self.remove(item.id).make_items(),
-            ast::ItemKind::MacroDef(_) => return SmallVector::one(item),
+            ast::ItemKind::MacroDef(_) => return OneVector::one(item),
             _ => {}
         }
 
         noop_fold_item(item, self)
     }
 
-    fn fold_trait_item(&mut self, item: ast::TraitItem) -> SmallVector<ast::TraitItem> {
+    fn fold_trait_item(&mut self, item: ast::TraitItem) -> OneVector<ast::TraitItem> {
         match item.node {
             ast::TraitItemKind::Macro(_) => self.remove(item.id).make_trait_items(),
             _ => noop_fold_trait_item(item, self),
         }
     }
 
-    fn fold_impl_item(&mut self, item: ast::ImplItem) -> SmallVector<ast::ImplItem> {
+    fn fold_impl_item(&mut self, item: ast::ImplItem) -> OneVector<ast::ImplItem> {
         match item.node {
             ast::ImplItemKind::Macro(_) => self.remove(item.id).make_impl_items(),
             _ => noop_fold_impl_item(item, self),
         }
     }
 
-    fn fold_foreign_item(&mut self, item: ast::ForeignItem) -> SmallVector<ast::ForeignItem> {
+    fn fold_foreign_item(&mut self, item: ast::ForeignItem) -> OneVector<ast::ForeignItem> {
         match item.node {
             ast::ForeignItemKind::Macro(_) => self.remove(item.id).make_foreign_items(),
             _ => noop_fold_foreign_item(item, self),
@@ -159,7 +160,7 @@ impl<'a, 'b> Folder for PlaceholderExpander<'a, 'b> {
         }
     }
 
-    fn fold_stmt(&mut self, stmt: ast::Stmt) -> SmallVector<ast::Stmt> {
+    fn fold_stmt(&mut self, stmt: ast::Stmt) -> OneVector<ast::Stmt> {
         let (style, mut stmts) = match stmt.node {
             ast::StmtKind::Mac(mac) => (mac.1, self.remove(stmt.id).make_stmts()),
             _ => return noop_fold_stmt(stmt, self),
diff --git a/src/libsyntax/ext/quote.rs b/src/libsyntax/ext/quote.rs
index 1ace4d4a880..bc891700fc1 100644
--- a/src/libsyntax/ext/quote.rs
+++ b/src/libsyntax/ext/quote.rs
@@ -34,6 +34,7 @@ pub mod rt {
     use parse::token::{self, Token};
     use ptr::P;
     use symbol::Symbol;
+    use ThinVec;
 
     use tokenstream::{self, TokenTree, TokenStream};
 
@@ -274,7 +275,7 @@ pub mod rt {
                 id: ast::DUMMY_NODE_ID,
                 node: ast::ExprKind::Lit(P(self.clone())),
                 span: DUMMY_SP,
-                attrs: ast::ThinVec::new(),
+                attrs: ThinVec::new(),
             }).to_tokens(cx)
         }
     }
@@ -305,7 +306,7 @@ pub mod rt {
                         id: ast::DUMMY_NODE_ID,
                         node: ast::ExprKind::Lit(P(dummy_spanned(lit))),
                         span: DUMMY_SP,
-                        attrs: ast::ThinVec::new(),
+                        attrs: ThinVec::new(),
                     });
                     if *self >= 0 {
                         return lit.to_tokens(cx);
@@ -314,7 +315,7 @@ pub mod rt {
                         id: ast::DUMMY_NODE_ID,
                         node: ast::ExprKind::Unary(ast::UnOp::Neg, lit),
                         span: DUMMY_SP,
-                        attrs: ast::ThinVec::new(),
+                        attrs: ThinVec::new(),
                     }).to_tokens(cx)
                 }
             }
diff --git a/src/libsyntax/ext/source_util.rs b/src/libsyntax/ext/source_util.rs
index 0c36c072a03..9b7e0fe1ae5 100644
--- a/src/libsyntax/ext/source_util.rs
+++ b/src/libsyntax/ext/source_util.rs
@@ -17,9 +17,9 @@ use parse::{token, DirectoryOwnership};
 use parse;
 use print::pprust;
 use ptr::P;
+use OneVector;
 use symbol::Symbol;
 use tokenstream;
-use util::small_vector::SmallVector;
 
 use std::fs::File;
 use std::io::prelude::*;
@@ -111,8 +111,8 @@ pub fn expand_include<'cx>(cx: &'cx mut ExtCtxt, sp: Span, tts: &[tokenstream::T
             Some(panictry!(self.p.parse_expr()))
         }
         fn make_items(mut self: Box<ExpandResult<'a>>)
-                      -> Option<SmallVector<P<ast::Item>>> {
-            let mut ret = SmallVector::new();
+                      -> Option<OneVector<P<ast::Item>>> {
+            let mut ret = OneVector::new();
             while self.p.token != token::Eof {
                 match panictry!(self.p.parse_item()) {
                     Some(item) => ret.push(item),
diff --git a/src/libsyntax/ext/tt/macro_parser.rs b/src/libsyntax/ext/tt/macro_parser.rs
index 3046525b714..82f88d1d864 100644
--- a/src/libsyntax/ext/tt/macro_parser.rs
+++ b/src/libsyntax/ext/tt/macro_parser.rs
@@ -92,9 +92,9 @@ use parse::{Directory, ParseSess};
 use parse::parser::{Parser, PathStyle};
 use parse::token::{self, DocComment, Nonterminal, Token};
 use print::pprust;
+use OneVector;
 use symbol::keywords;
 use tokenstream::TokenStream;
-use util::small_vector::SmallVector;
 
 use std::mem;
 use std::ops::{Deref, DerefMut};
@@ -440,10 +440,10 @@ fn token_name_eq(t1: &Token, t2: &Token) -> bool {
 /// A `ParseResult`. Note that matches are kept track of through the items generated.
 fn inner_parse_loop<'a>(
     sess: &ParseSess,
-    cur_items: &mut SmallVector<MatcherPosHandle<'a>>,
+    cur_items: &mut OneVector<MatcherPosHandle<'a>>,
     next_items: &mut Vec<MatcherPosHandle<'a>>,
-    eof_items: &mut SmallVector<MatcherPosHandle<'a>>,
-    bb_items: &mut SmallVector<MatcherPosHandle<'a>>,
+    eof_items: &mut OneVector<MatcherPosHandle<'a>>,
+    bb_items: &mut OneVector<MatcherPosHandle<'a>>,
     token: &Token,
     span: syntax_pos::Span,
 ) -> ParseResult<()> {
@@ -644,15 +644,15 @@ pub fn parse(
     // This MatcherPos instance is allocated on the stack. All others -- and
     // there are frequently *no* others! -- are allocated on the heap.
     let mut initial = initial_matcher_pos(ms, parser.span.lo());
-    let mut cur_items = SmallVector::one(MatcherPosHandle::Ref(&mut initial));
+    let mut cur_items = OneVector::one(MatcherPosHandle::Ref(&mut initial));
     let mut next_items = Vec::new();
 
     loop {
         // Matcher positions black-box parsed by parser.rs (`parser`)
-        let mut bb_items = SmallVector::new();
+        let mut bb_items = OneVector::new();
 
         // Matcher positions that would be valid if the macro invocation was over now
-        let mut eof_items = SmallVector::new();
+        let mut eof_items = OneVector::new();
         assert!(next_items.is_empty());
 
         // Process `cur_items` until either we have finished the input or we need to get some
diff --git a/src/libsyntax/ext/tt/transcribe.rs b/src/libsyntax/ext/tt/transcribe.rs
index 1cdb6b0e5c9..d451227e77c 100644
--- a/src/libsyntax/ext/tt/transcribe.rs
+++ b/src/libsyntax/ext/tt/transcribe.rs
@@ -15,9 +15,9 @@ use ext::tt::macro_parser::{NamedMatch, MatchedSeq, MatchedNonterminal};
 use ext::tt::quoted;
 use fold::noop_fold_tt;
 use parse::token::{self, Token, NtTT};
+use OneVector;
 use syntax_pos::{Span, DUMMY_SP};
 use tokenstream::{TokenStream, TokenTree, Delimited};
-use util::small_vector::SmallVector;
 
 use std::rc::Rc;
 use rustc_data_structures::sync::Lrc;
@@ -70,7 +70,7 @@ pub fn transcribe(cx: &ExtCtxt,
                   interp: Option<HashMap<Ident, Rc<NamedMatch>>>,
                   src: Vec<quoted::TokenTree>)
                   -> TokenStream {
-    let mut stack = SmallVector::one(Frame::new(src));
+    let mut stack = OneVector::one(Frame::new(src));
     let interpolations = interp.unwrap_or_else(HashMap::new); /* just a convenience */
     let mut repeats = Vec::new();
     let mut result: Vec<TokenStream> = Vec::new();
diff --git a/src/libsyntax/fold.rs b/src/libsyntax/fold.rs
index 9d5982c1e28..3209939d9b1 100644
--- a/src/libsyntax/fold.rs
+++ b/src/libsyntax/fold.rs
@@ -24,9 +24,10 @@ use syntax_pos::Span;
 use codemap::{Spanned, respan};
 use parse::token::{self, Token};
 use ptr::P;
+use OneVector;
 use symbol::keywords;
+use ThinVec;
 use tokenstream::*;
-use util::small_vector::SmallVector;
 use util::move_map::MoveMap;
 
 use rustc_data_structures::sync::Lrc;
@@ -60,7 +61,7 @@ pub trait Folder : Sized {
         noop_fold_use_tree(use_tree, self)
     }
 
-    fn fold_foreign_item(&mut self, ni: ForeignItem) -> SmallVector<ForeignItem> {
+    fn fold_foreign_item(&mut self, ni: ForeignItem) -> OneVector<ForeignItem> {
         noop_fold_foreign_item(ni, self)
     }
 
@@ -68,7 +69,7 @@ pub trait Folder : Sized {
         noop_fold_foreign_item_simple(ni, self)
     }
 
-    fn fold_item(&mut self, i: P<Item>) -> SmallVector<P<Item>> {
+    fn fold_item(&mut self, i: P<Item>) -> OneVector<P<Item>> {
         noop_fold_item(i, self)
     }
 
@@ -88,11 +89,11 @@ pub trait Folder : Sized {
         noop_fold_item_kind(i, self)
     }
 
-    fn fold_trait_item(&mut self, i: TraitItem) -> SmallVector<TraitItem> {
+    fn fold_trait_item(&mut self, i: TraitItem) -> OneVector<TraitItem> {
         noop_fold_trait_item(i, self)
     }
 
-    fn fold_impl_item(&mut self, i: ImplItem) -> SmallVector<ImplItem> {
+    fn fold_impl_item(&mut self, i: ImplItem) -> OneVector<ImplItem> {
         noop_fold_impl_item(i, self)
     }
 
@@ -108,7 +109,7 @@ pub trait Folder : Sized {
         noop_fold_block(b, self)
     }
 
-    fn fold_stmt(&mut self, s: Stmt) -> SmallVector<Stmt> {
+    fn fold_stmt(&mut self, s: Stmt) -> OneVector<Stmt> {
         noop_fold_stmt(s, self)
     }
 
@@ -960,8 +961,8 @@ pub fn noop_fold_item_kind<T: Folder>(i: ItemKind, folder: &mut T) -> ItemKind {
 }
 
 pub fn noop_fold_trait_item<T: Folder>(i: TraitItem, folder: &mut T)
-                                       -> SmallVector<TraitItem> {
-    SmallVector::one(TraitItem {
+                                       -> OneVector<TraitItem> {
+    OneVector::one(TraitItem {
         id: folder.new_id(i.id),
         ident: folder.fold_ident(i.ident),
         attrs: fold_attrs(i.attrs, folder),
@@ -989,8 +990,8 @@ pub fn noop_fold_trait_item<T: Folder>(i: TraitItem, folder: &mut T)
 }
 
 pub fn noop_fold_impl_item<T: Folder>(i: ImplItem, folder: &mut T)
-                                      -> SmallVector<ImplItem> {
-    SmallVector::one(ImplItem {
+                                      -> OneVector<ImplItem> {
+    OneVector::one(ImplItem {
         id: folder.new_id(i.id),
         vis: folder.fold_vis(i.vis),
         ident: folder.fold_ident(i.ident),
@@ -1065,8 +1066,8 @@ pub fn noop_fold_crate<T: Folder>(Crate {module, attrs, span}: Crate,
 }
 
 // fold one item into possibly many items
-pub fn noop_fold_item<T: Folder>(i: P<Item>, folder: &mut T) -> SmallVector<P<Item>> {
-    SmallVector::one(i.map(|i| folder.fold_item_simple(i)))
+pub fn noop_fold_item<T: Folder>(i: P<Item>, folder: &mut T) -> OneVector<P<Item>> {
+    OneVector::one(i.map(|i| folder.fold_item_simple(i)))
 }
 
 // fold one item into exactly one item
@@ -1087,8 +1088,8 @@ pub fn noop_fold_item_simple<T: Folder>(Item {id, ident, attrs, node, vis, span,
 }
 
 pub fn noop_fold_foreign_item<T: Folder>(ni: ForeignItem, folder: &mut T)
--> SmallVector<ForeignItem> {
-    SmallVector::one(folder.fold_foreign_item_simple(ni))
+-> OneVector<ForeignItem> {
+    OneVector::one(folder.fold_foreign_item_simple(ni))
 }
 
 pub fn noop_fold_foreign_item_simple<T: Folder>(ni: ForeignItem, folder: &mut T) -> ForeignItem {
@@ -1366,7 +1367,7 @@ pub fn noop_fold_exprs<T: Folder>(es: Vec<P<Expr>>, folder: &mut T) -> Vec<P<Exp
     es.move_flat_map(|e| folder.fold_opt_expr(e))
 }
 
-pub fn noop_fold_stmt<T: Folder>(Stmt {node, span, id}: Stmt, folder: &mut T) -> SmallVector<Stmt> {
+pub fn noop_fold_stmt<T: Folder>(Stmt {node, span, id}: Stmt, folder: &mut T) -> OneVector<Stmt> {
     let id = folder.new_id(id);
     let span = folder.new_span(span);
     noop_fold_stmt_kind(node, folder).into_iter().map(|node| {
@@ -1374,9 +1375,9 @@ pub fn noop_fold_stmt<T: Folder>(Stmt {node, span, id}: Stmt, folder: &mut T) ->
     }).collect()
 }
 
-pub fn noop_fold_stmt_kind<T: Folder>(node: StmtKind, folder: &mut T) -> SmallVector<StmtKind> {
+pub fn noop_fold_stmt_kind<T: Folder>(node: StmtKind, folder: &mut T) -> OneVector<StmtKind> {
     match node {
-        StmtKind::Local(local) => SmallVector::one(StmtKind::Local(folder.fold_local(local))),
+        StmtKind::Local(local) => OneVector::one(StmtKind::Local(folder.fold_local(local))),
         StmtKind::Item(item) => folder.fold_item(item).into_iter().map(StmtKind::Item).collect(),
         StmtKind::Expr(expr) => {
             folder.fold_opt_expr(expr).into_iter().map(StmtKind::Expr).collect()
@@ -1384,7 +1385,7 @@ pub fn noop_fold_stmt_kind<T: Folder>(node: StmtKind, folder: &mut T) -> SmallVe
         StmtKind::Semi(expr) => {
             folder.fold_opt_expr(expr).into_iter().map(StmtKind::Semi).collect()
         }
-        StmtKind::Mac(mac) => SmallVector::one(StmtKind::Mac(mac.map(|(mac, semi, attrs)| {
+        StmtKind::Mac(mac) => OneVector::one(StmtKind::Mac(mac.map(|(mac, semi, attrs)| {
             (folder.fold_mac(mac), semi, fold_attrs(attrs.into(), folder).into())
         }))),
     }
diff --git a/src/libsyntax/lib.rs b/src/libsyntax/lib.rs
index 12ce478fe1d..c48ad0a802c 100644
--- a/src/libsyntax/lib.rs
+++ b/src/libsyntax/lib.rs
@@ -45,6 +45,8 @@ extern crate serialize as rustc_serialize; // used by deriving
 
 use rustc_data_structures::sync::Lock;
 use rustc_data_structures::bitvec::BitVector;
+pub use rustc_data_structures::small_vec::OneVector;
+pub use rustc_data_structures::thin_vec::ThinVec;
 use ast::AttrId;
 
 // A variant of 'try!' that panics on an Err. This is used as a crutch on the
@@ -124,12 +126,8 @@ pub mod util {
     pub mod parser;
     #[cfg(test)]
     pub mod parser_testing;
-    pub mod small_vector;
     pub mod move_map;
 
-    mod thin_vec;
-    pub use self::thin_vec::ThinVec;
-
     mod rc_slice;
     pub use self::rc_slice::RcSlice;
 }
diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index 746e03d771a..0e45cacaf38 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -53,9 +53,9 @@ use util::parser::{AssocOp, Fixity};
 use print::pprust;
 use ptr::P;
 use parse::PResult;
+use ThinVec;
 use tokenstream::{self, Delimited, ThinTokenStream, TokenTree, TokenStream};
 use symbol::{Symbol, keywords};
-use util::ThinVec;
 
 use std::borrow::Cow;
 use std::cmp;
diff --git a/src/libsyntax/test.rs b/src/libsyntax/test.rs
index 62dd00387d3..1cbaf3cc312 100644
--- a/src/libsyntax/test.rs
+++ b/src/libsyntax/test.rs
@@ -38,8 +38,9 @@ use parse::{token, ParseSess};
 use print::pprust;
 use ast::{self, Ident};
 use ptr::P;
+use OneVector;
 use symbol::{self, Symbol, keywords};
-use util::small_vector::SmallVector;
+use ThinVec;
 
 enum ShouldPanic {
     No,
@@ -115,7 +116,7 @@ impl<'a> fold::Folder for TestHarnessGenerator<'a> {
         folded
     }
 
-    fn fold_item(&mut self, i: P<ast::Item>) -> SmallVector<P<ast::Item>> {
+    fn fold_item(&mut self, i: P<ast::Item>) -> OneVector<P<ast::Item>> {
         let ident = i.ident;
         if ident.name != keywords::Invalid.name() {
             self.cx.path.push(ident);
@@ -182,7 +183,7 @@ impl<'a> fold::Folder for TestHarnessGenerator<'a> {
         if ident.name != keywords::Invalid.name() {
             self.cx.path.pop();
         }
-        SmallVector::one(P(item))
+        OneVector::one(P(item))
     }
 
     fn fold_mac(&mut self, mac: ast::Mac) -> ast::Mac { mac }
@@ -194,7 +195,7 @@ struct EntryPointCleaner {
 }
 
 impl fold::Folder for EntryPointCleaner {
-    fn fold_item(&mut self, i: P<ast::Item>) -> SmallVector<P<ast::Item>> {
+    fn fold_item(&mut self, i: P<ast::Item>) -> OneVector<P<ast::Item>> {
         self.depth += 1;
         let folded = fold::noop_fold_item(i, self).expect_one("noop did something");
         self.depth -= 1;
@@ -234,7 +235,7 @@ impl fold::Folder for EntryPointCleaner {
             EntryPointType::OtherMain => folded,
         };
 
-        SmallVector::one(folded)
+        OneVector::one(folded)
     }
 
     fn fold_mac(&mut self, mac: ast::Mac) -> ast::Mac { mac }
@@ -675,10 +676,10 @@ fn mk_test_descs(cx: &TestCtxt) -> P<ast::Expr> {
                     mk_test_desc_and_fn_rec(cx, test)
                 }).collect()),
                 span: DUMMY_SP,
-                attrs: ast::ThinVec::new(),
+                attrs: ThinVec::new(),
             })),
         span: DUMMY_SP,
-        attrs: ast::ThinVec::new(),
+        attrs: ThinVec::new(),
     })
 }
 
diff --git a/src/libsyntax/util/move_map.rs b/src/libsyntax/util/move_map.rs
index 8cc37afa354..eb2c5a2458c 100644
--- a/src/libsyntax/util/move_map.rs
+++ b/src/libsyntax/util/move_map.rs
@@ -9,8 +9,7 @@
 // except according to those terms.
 
 use std::ptr;
-
-use util::small_vector::SmallVector;
+use OneVector;
 
 pub trait MoveMap<T>: Sized {
     fn move_map<F>(self, mut f: F) -> Self where F: FnMut(T) -> T {
@@ -78,7 +77,7 @@ impl<T> MoveMap<T> for ::ptr::P<[T]> {
     }
 }
 
-impl<T> MoveMap<T> for SmallVector<T> {
+impl<T> MoveMap<T> for OneVector<T> {
     fn move_flat_map<F, I>(mut self, mut f: F) -> Self
         where F: FnMut(T) -> I,
               I: IntoIterator<Item=T>
diff --git a/src/libsyntax/util/small_vector.rs b/src/libsyntax/util/small_vector.rs
deleted file mode 100644
index 31e675836fc..00000000000
--- a/src/libsyntax/util/small_vector.rs
+++ /dev/null
@@ -1,81 +0,0 @@
-// Copyright 2013-2014 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.
-
-use rustc_data_structures::small_vec::SmallVec;
-
-pub type SmallVector<T> = SmallVec<[T; 1]>;
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn test_len() {
-        let v: SmallVector<isize> = SmallVector::new();
-        assert_eq!(0, v.len());
-
-        assert_eq!(1, SmallVector::one(1).len());
-        assert_eq!(5, SmallVector::many(vec![1, 2, 3, 4, 5]).len());
-    }
-
-    #[test]
-    fn test_push_get() {
-        let mut v = SmallVector::new();
-        v.push(1);
-        assert_eq!(1, v.len());
-        assert_eq!(1, v[0]);
-        v.push(2);
-        assert_eq!(2, v.len());
-        assert_eq!(2, v[1]);
-        v.push(3);
-        assert_eq!(3, v.len());
-        assert_eq!(3, v[2]);
-    }
-
-    #[test]
-    fn test_from_iter() {
-        let v: SmallVector<isize> = (vec![1, 2, 3]).into_iter().collect();
-        assert_eq!(3, v.len());
-        assert_eq!(1, v[0]);
-        assert_eq!(2, v[1]);
-        assert_eq!(3, v[2]);
-    }
-
-    #[test]
-    fn test_move_iter() {
-        let v = SmallVector::new();
-        let v: Vec<isize> = v.into_iter().collect();
-        assert_eq!(v, Vec::new());
-
-        let v = SmallVector::one(1);
-        assert_eq!(v.into_iter().collect::<Vec<_>>(), [1]);
-
-        let v = SmallVector::many(vec![1, 2, 3]);
-        assert_eq!(v.into_iter().collect::<Vec<_>>(), [1, 2, 3]);
-    }
-
-    #[test]
-    #[should_panic]
-    fn test_expect_one_zero() {
-        let _: isize = SmallVector::new().expect_one("");
-    }
-
-    #[test]
-    #[should_panic]
-    fn test_expect_one_many() {
-        SmallVector::many(vec![1, 2]).expect_one("");
-    }
-
-    #[test]
-    fn test_expect_one_one() {
-        assert_eq!(1, SmallVector::one(1).expect_one(""));
-        assert_eq!(1, SmallVector::many(vec![1]).expect_one(""));
-    }
-}
diff --git a/src/libsyntax/util/thin_vec.rs b/src/libsyntax/util/thin_vec.rs
deleted file mode 100644
index 546686b46b8..00000000000
--- a/src/libsyntax/util/thin_vec.rs
+++ /dev/null
@@ -1,59 +0,0 @@
-// 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.
-
-/// A vector type optimized for cases where this size is usually 0 (c.f. `SmallVector`).
-/// The `Option<Box<..>>` wrapping allows us to represent a zero sized vector with `None`,
-/// which uses only a single (null) pointer.
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
-pub struct ThinVec<T>(Option<Box<Vec<T>>>);
-
-impl<T> ThinVec<T> {
-    pub fn new() -> Self {
-        ThinVec(None)
-    }
-}
-
-impl<T> From<Vec<T>> for ThinVec<T> {
-    fn from(vec: Vec<T>) -> Self {
-        if vec.is_empty() {
-            ThinVec(None)
-        } else {
-            ThinVec(Some(Box::new(vec)))
-        }
-    }
-}
-
-impl<T> Into<Vec<T>> for ThinVec<T> {
-    fn into(self) -> Vec<T> {
-        match self {
-            ThinVec(None) => Vec::new(),
-            ThinVec(Some(vec)) => *vec,
-        }
-    }
-}
-
-impl<T> ::std::ops::Deref for ThinVec<T> {
-    type Target = [T];
-    fn deref(&self) -> &[T] {
-        match *self {
-            ThinVec(None) => &[],
-            ThinVec(Some(ref vec)) => vec,
-        }
-    }
-}
-
-impl<T> Extend<T> for ThinVec<T> {
-    fn extend<I: IntoIterator<Item = T>>(&mut self, iter: I) {
-        match *self {
-            ThinVec(Some(ref mut vec)) => vec.extend(iter),
-            ThinVec(None) => *self = iter.into_iter().collect::<Vec<_>>().into(),
-        }
-    }
-}