diff --git a/src/codegen/mod.rs b/src/codegen/mod.rs
index 3f7c87e84d..8e04fd7c05 100755
--- a/src/codegen/mod.rs
+++ b/src/codegen/mod.rs
@@ -5,11 +5,11 @@ use aster;
 
 use ir::annotations::FieldAccessorKind;
 use ir::comp::{CompInfo, CompKind, Field, Method};
-use ir::context::BindgenContext;
+use ir::context::{BindgenContext, ItemId};
 use ir::enum_ty::{Enum, EnumVariant, EnumVariantValue};
 use ir::function::{Function, FunctionSig};
 use ir::int::IntKind;
-use ir::item::{Item, ItemCanonicalName, ItemCanonicalPath, ItemId};
+use ir::item::{Item, ItemCanonicalName, ItemCanonicalPath};
 use ir::item_kind::ItemKind;
 use ir::layout::Layout;
 use ir::module::Module;
@@ -1919,8 +1919,8 @@ pub fn codegen(context: &mut BindgenContext) -> Vec<P<ast::Item>> {
 
 mod utils {
     use aster;
-    use ir::context::BindgenContext;
-    use ir::item::{Item, ItemCanonicalPath, ItemId};
+    use ir::context::{BindgenContext, ItemId};
+    use ir::item::{Item, ItemCanonicalPath};
     use ir::ty::TypeKind;
     use std::mem;
     use super::ItemToRustTy;
diff --git a/src/ir/comp.rs b/src/ir/comp.rs
index 1d823d0a90..d19d12092b 100644
--- a/src/ir/comp.rs
+++ b/src/ir/comp.rs
@@ -5,8 +5,8 @@ use parse::{ClangItemParser, ParseError};
 use std::cell::Cell;
 use std::cmp;
 use super::annotations::Annotations;
-use super::context::BindgenContext;
-use super::item::{Item, ItemId};
+use super::context::{BindgenContext, ItemId};
+use super::item::Item;
 use super::layout::Layout;
 use super::ty::{RUST_DERIVE_IN_ARRAY_LIMIT, Type};
 use super::type_collector::{ItemSet, TypeCollector};
diff --git a/src/ir/context.rs b/src/ir/context.rs
index 8c84b328e6..857219780e 100644
--- a/src/ir/context.rs
+++ b/src/ir/context.rs
@@ -10,7 +10,7 @@ use std::collections::{HashMap, hash_map};
 use std::collections::btree_map::{self, BTreeMap};
 use std::fmt;
 use super::int::IntKind;
-use super::item::{Item, ItemCanonicalName, ItemId};
+use super::item::{Item, ItemCanonicalName};
 use super::item_kind::ItemKind;
 use super::module::Module;
 use super::ty::{FloatKind, Type, TypeKind};
@@ -19,6 +19,19 @@ use syntax::ast::Ident;
 use syntax::codemap::{DUMMY_SP, Span};
 use syntax::ext::base::ExtCtxt;
 
+/// A single identifier for an item.
+///
+/// TODO: Build stronger abstractions on top of this, like TypeId(ItemId)?
+#[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct ItemId(usize);
+
+impl ItemId {
+    /// Get a numeric representation of this id.
+    pub fn as_usize(&self) -> usize {
+        self.0
+    }
+}
+
 /// A key used to index a resolved type, so we only process it once.
 ///
 /// This is almost always a USR string (an unique identifier generated by
@@ -50,6 +63,9 @@ pub struct BindgenContext<'ctx> {
     /// output.
     items: BTreeMap<ItemId, Item>,
 
+    /// The next item id to use during this bindings regeneration.
+    next_item_id: ItemId,
+
     /// Clang USR to type map. This is needed to be able to associate types with
     /// item ids during parsing.
     types: HashMap<TypeKey, ItemId>,
@@ -122,11 +138,12 @@ impl<'ctx> BindgenContext<'ctx> {
                                           parse_options)
                 .expect("TranslationUnit::parse");
 
-        let root_module = Self::build_root_module();
+        let root_module = Self::build_root_module(ItemId(0));
         let mut me = BindgenContext {
             items: Default::default(),
             types: Default::default(),
             modules: Default::default(),
+            next_item_id: ItemId(1),
             root_module: root_module.id(),
             current_module: root_module.id(),
             currently_parsed_types: vec![],
@@ -422,9 +439,8 @@ impl<'ctx> BindgenContext<'ctx> {
         assert!(old_item.is_none(), "Inserted type twice?");
     }
 
-    fn build_root_module() -> Item {
+    fn build_root_module(id: ItemId) -> Item {
         let module = Module::new(Some("root".into()));
-        let id = ItemId::next();
         Item::new(id, None, None, id, ItemKind::Module(module))
     }
 
@@ -702,6 +718,13 @@ impl<'ctx> BindgenContext<'ctx> {
         with_id
     }
 
+    /// Returns the next item id to be used for an item.
+    pub fn next_item_id(&mut self) -> ItemId {
+        let ret = self.next_item_id;
+        self.next_item_id = ItemId(self.next_item_id.0 + 1);
+        ret
+    }
+
     fn build_builtin_ty(&mut self,
                         ty: &clang::Type,
                         _declaration: Cursor)
@@ -747,7 +770,7 @@ impl<'ctx> BindgenContext<'ctx> {
         let is_const = ty.is_const();
         let layout = ty.fallible_layout().ok();
         let ty = Type::new(Some(spelling), layout, type_kind, is_const);
-        let id = ItemId::next();
+        let id = self.next_item_id();
         let item =
             Item::new(id, None, None, self.root_module, ItemKind::Type(ty));
         self.add_builtin_item(item);
@@ -841,11 +864,11 @@ impl<'ctx> BindgenContext<'ctx> {
         use clangll::*;
         assert!(cursor.kind() == CXCursor_Namespace, "Be a nice person");
         let cursor = cursor.canonical();
-        let module_id = match self.modules.get(&cursor) {
-            Some(id) => return *id,
-            None => ItemId::next(),
-        };
+        if let Some(id) = self.modules.get(&cursor) {
+            return *id;
+        }
 
+        let module_id = self.next_item_id();
         let module_name = self.translation_unit
             .tokens(&cursor)
             .and_then(|tokens| {
diff --git a/src/ir/enum_ty.rs b/src/ir/enum_ty.rs
index 8efd9e3be1..6085833d18 100644
--- a/src/ir/enum_ty.rs
+++ b/src/ir/enum_ty.rs
@@ -2,8 +2,8 @@
 
 use clang;
 use parse::{ClangItemParser, ParseError};
-use super::context::BindgenContext;
-use super::item::{Item, ItemId};
+use super::context::{BindgenContext, ItemId};
+use super::item::Item;
 use super::ty::TypeKind;
 
 /// A C/C++ enumeration.
diff --git a/src/ir/function.rs b/src/ir/function.rs
index e45dcbe817..eacb6c0ea8 100644
--- a/src/ir/function.rs
+++ b/src/ir/function.rs
@@ -3,8 +3,8 @@
 use clang;
 use clangll::Enum_CXCallingConv;
 use parse::{ClangItemParser, ClangSubItemParser, ParseError, ParseResult};
-use super::context::BindgenContext;
-use super::item::{Item, ItemId};
+use super::context::{BindgenContext, ItemId};
+use super::item::Item;
 use super::ty::TypeKind;
 use super::type_collector::{ItemSet, TypeCollector};
 use syntax::abi;
diff --git a/src/ir/item.rs b/src/ir/item.rs
index 17d249b560..1f05f92f39 100644
--- a/src/ir/item.rs
+++ b/src/ir/item.rs
@@ -4,9 +4,8 @@ use clang;
 use parse::{ClangItemParser, ClangSubItemParser, ParseError, ParseResult};
 use regex::Regex;
 use std::cell::{Cell, RefCell};
-use std::sync::atomic::{ATOMIC_USIZE_INIT, AtomicUsize, Ordering};
 use super::annotations::Annotations;
-use super::context::BindgenContext;
+use super::context::{BindgenContext, ItemId};
 use super::function::Function;
 use super::item_kind::ItemKind;
 use super::module::Module;
@@ -78,21 +77,6 @@ impl<'a, 'b> Iterator for ItemAncestorsIter<'a, 'b>
     }
 }
 
-/// A single identifier for an item.
-///
-/// TODO: Build stronger abstractions on top of this, like TypeId(ItemId)?
-#[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
-pub struct ItemId(usize);
-
-impl ItemId {
-    /// Allocate the next `ItemId`.
-    pub fn next() -> Self {
-        static NEXT_ITEM_ID: AtomicUsize = ATOMIC_USIZE_INIT;
-        let next_id = NEXT_ITEM_ID.fetch_add(1, Ordering::Relaxed);
-        ItemId(next_id)
-    }
-}
-
 // Pure convenience
 impl ItemCanonicalName for ItemId {
     fn canonical_name(&self, ctx: &BindgenContext) -> String {
@@ -667,7 +651,7 @@ impl Item {
         // Note that this `id_` prefix prevents (really unlikely) collisions
         // between the global id and the local id of an item with the same
         // parent.
-        format!("id_{}", self.id().0)
+        format!("id_{}", self.id().as_usize())
     }
 
     fn make_exposed_name(&self,
@@ -747,7 +731,7 @@ impl ClangItemParser for Item {
         }
 
         let ty = Type::new(None, None, kind, is_const);
-        let id = ItemId::next();
+        let id = ctx.next_item_id();
         let module = ctx.root_module();
         ctx.add_item(Item::new(id, None, None, module, ItemKind::Type(ty)),
                      None,
@@ -779,7 +763,7 @@ impl ClangItemParser for Item {
             ($what:ident) => {
                 match $what::parse(cursor, ctx) {
                     Ok(ParseResult::New(item, declaration)) => {
-                        let id = ItemId::next();
+                        let id = ctx.next_item_id();
 
                         ctx.add_item(Item::new(id, comment, annotations,
                                                relevant_parent_id,
@@ -855,7 +839,8 @@ impl ClangItemParser for Item {
                       parent_id: Option<ItemId>,
                       ctx: &mut BindgenContext)
                       -> ItemId {
-        Self::from_ty_or_ref_with_id(ItemId::next(),
+        let id = ctx.next_item_id();
+        Self::from_ty_or_ref_with_id(id,
                                      ty,
                                      location,
                                      parent_id,
@@ -925,7 +910,8 @@ impl ClangItemParser for Item {
                parent_id: Option<ItemId>,
                ctx: &mut BindgenContext)
                -> Result<ItemId, ParseError> {
-        Self::from_ty_with_id(ItemId::next(), ty, location, parent_id, ctx)
+        let id = ctx.next_item_id();
+        Self::from_ty_with_id(id, ty, location, parent_id, ctx)
     }
 
     /// This is one of the trickiest methods you'll find (probably along with
@@ -1109,7 +1095,8 @@ impl ClangItemParser for Item {
                      -> ItemId
         where S: Into<String>,
     {
-        Self::named_type_with_id(ItemId::next(), name, default, parent_id, ctx)
+        let id = ctx.next_item_id();
+        Self::named_type_with_id(id, name, default, parent_id, ctx)
     }
 }
 
diff --git a/src/ir/module.rs b/src/ir/module.rs
index 42175b920e..c5d8cfa79e 100644
--- a/src/ir/module.rs
+++ b/src/ir/module.rs
@@ -3,8 +3,7 @@
 use clang;
 use parse::{ClangSubItemParser, ParseError, ParseResult};
 use parse_one;
-use super::context::BindgenContext;
-use super::item::ItemId;
+use super::context::{BindgenContext, ItemId};
 
 /// A module, as in, a C++ namespace.
 #[derive(Clone, Debug)]
diff --git a/src/ir/ty.rs b/src/ir/ty.rs
index ba69296b25..34af2db502 100644
--- a/src/ir/ty.rs
+++ b/src/ir/ty.rs
@@ -3,11 +3,11 @@
 use clang::{self, Cursor};
 use parse::{ClangItemParser, ParseError, ParseResult};
 use super::comp::CompInfo;
-use super::context::BindgenContext;
+use super::context::{BindgenContext, ItemId};
 use super::enum_ty::Enum;
 use super::function::FunctionSig;
 use super::int::IntKind;
-use super::item::{Item, ItemId};
+use super::item::Item;
 use super::layout::Layout;
 use super::type_collector::{ItemSet, TypeCollector};
 
diff --git a/src/ir/type_collector.rs b/src/ir/type_collector.rs
index a829b165ba..0f10152d4a 100644
--- a/src/ir/type_collector.rs
+++ b/src/ir/type_collector.rs
@@ -1,8 +1,7 @@
 //! Collecting type items.
 
 use std::collections::BTreeSet;
-use super::context::BindgenContext;
-use super::item::ItemId;
+use super::context::{BindgenContext, ItemId};
 
 /// A set of items.
 pub type ItemSet = BTreeSet<ItemId>;
diff --git a/src/ir/var.rs b/src/ir/var.rs
index 1c7b20280e..d0c4d9cacd 100644
--- a/src/ir/var.rs
+++ b/src/ir/var.rs
@@ -4,10 +4,10 @@ use cexpr;
 use clang;
 use parse::{ClangItemParser, ClangSubItemParser, ParseError, ParseResult};
 use std::num::Wrapping;
-use super::context::BindgenContext;
+use super::context::{BindgenContext, ItemId};
 use super::function::cursor_mangling;
 use super::int::IntKind;
-use super::item::{Item, ItemId};
+use super::item::Item;
 use super::ty::TypeKind;
 
 /// A `Var` is our intermediate representation of a variable.
diff --git a/src/lib.rs b/src/lib.rs
index db87eb228d..b56cb468e9 100755
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -78,8 +78,8 @@ mod codegen {
     include!(concat!(env!("OUT_DIR"), "/codegen.rs"));
 }
 
-use ir::context::BindgenContext;
-use ir::item::{Item, ItemId};
+use ir::context::{BindgenContext, ItemId};
+use ir::item::Item;
 use parse::{ClangItemParser, ParseError};
 use regex_set::RegexSet;
 
diff --git a/src/parse.rs b/src/parse.rs
index 98cf6b13e8..28e6575945 100644
--- a/src/parse.rs
+++ b/src/parse.rs
@@ -1,8 +1,7 @@
 //! Common traits and types related to parsing our IR from Clang cursors.
 
 use clang;
-use ir::context::BindgenContext;
-use ir::item::ItemId;
+use ir::context::{BindgenContext, ItemId};
 use ir::ty::TypeKind;
 
 /// Not so much an error in the traditional sense, but a control flow message