diff --git a/benches/context_new.rs b/benches/context_new.rs
index 4eec654..6ac9f51 100644
--- a/benches/context_new.rs
+++ b/benches/context_new.rs
@@ -3,7 +3,7 @@ extern crate test;
 extern crate lwkt;
 use lwkt::{Context, StackSource};
 
-static mut ctx_slot: *mut Context = 0 as *mut Context;
+static mut ctx_slot: *mut Context<lwkt::os::Stack> = 0 as *mut Context<_>;
 
 #[bench]
 fn context_new(b: &mut test::Bencher) {
diff --git a/benches/swap.rs b/benches/swap.rs
index b6eb363..7d3c4ea 100644
--- a/benches/swap.rs
+++ b/benches/swap.rs
@@ -3,7 +3,7 @@ extern crate test;
 extern crate lwkt;
 use lwkt::{Context, StackSource};
 
-static mut ctx_slot: *mut Context = 0 as *mut Context;
+static mut ctx_slot: *mut Context<lwkt::os::Stack> = 0 as *mut Context<_>;
 
 #[bench]
 fn swap(b: &mut test::Bencher) {
diff --git a/examples/basic.rs b/examples/basic.rs
index a421f13..435cbdd 100644
--- a/examples/basic.rs
+++ b/examples/basic.rs
@@ -3,7 +3,7 @@ extern crate lwkt;
 use lwkt::{Context, StackSource};
 
 #[thread_local]
-static mut ctx_slot: *mut Context = 0 as *mut Context;
+static mut ctx_slot: *mut Context<lwkt::os::Stack> = 0 as *mut Context<_>;
 
 fn main() {
   unsafe {
diff --git a/src/context.rs b/src/context.rs
index 8ffcb30..d322ba8 100644
--- a/src/context.rs
+++ b/src/context.rs
@@ -1,15 +1,16 @@
 use core::prelude::*;
 use arch::Registers;
-use os;
+use stack;
 
-pub struct Context {
+pub struct Context<Stack: stack::Stack> {
   regs: Registers,
-  _stack: os::Stack
+  _stack: Stack
 }
 
-impl Context {
+impl<Stack> Context<Stack> where Stack: stack::Stack {
   #[inline]
-  pub unsafe fn new<F>(mut stack: os::Stack, f: F) -> Context where F: FnOnce() + Send + 'static {
+  pub unsafe fn new<F>(mut stack: Stack, f: F) -> Context<Stack>
+    where F: FnOnce() + Send + 'static {
     let regs = Registers::new(&mut stack, f);
     Context {
       regs: regs,