diff --git a/appkit.rs b/appkit.rs
index 3eae4dc..9ddb5f6 100644
--- a/appkit.rs
+++ b/appkit.rs
@@ -7,8 +7,8 @@ extern mod appkit {
 }
 
 fn NSApp() -> base::id {
-    let klass = str::as_c_str("NSApplication", |s| objc::objc_getClass(s));
-    let sel = str::as_c_str("sharedApplication", |s| objc::sel_registerName(s));
+    let klass = str::as_c_str(~"NSApplication", |s| objc::objc_getClass(s));
+    let sel = str::as_c_str(~"sharedApplication", |s| objc::sel_registerName(s));
     ret objc::objc_msgSend(klass, sel);
 }
 
diff --git a/foundation.rs b/foundation.rs
index 650d1a1..243e08f 100644
--- a/foundation.rs
+++ b/foundation.rs
@@ -10,12 +10,12 @@ enum NSAutoreleasePool {
 }
 
 fn NSAutoreleasePool() -> base::id {
-    let klass = str::as_c_str("NSAutoreleasePool", |s|
+    let klass = str::as_c_str(~"NSAutoreleasePool", |s|
         objc::objc_getClass(s)
     );
 
-    let alloc_sel = str::as_c_str("alloc", |s| objc::sel_registerName(s));
-    let init_sel = str::as_c_str("init", |s| objc::sel_registerName(s));
+    let alloc_sel = str::as_c_str(~"alloc", |s| objc::sel_registerName(s));
+    let init_sel = str::as_c_str(~"init", |s| objc::sel_registerName(s));
 
     let pool = objc::objc_msgSend(klass, alloc_sel);
     ret objc::objc_msgSend(pool, init_sel);