diff --git a/src/main.rs b/src/main.rs
index bb6a869..414a4b9 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -22,9 +22,8 @@ use recovery::{Guard, FrameInfo};
 mod tracerunner;
 use tracerunner::Runner;
 
-mod util;
-use util::ConvertingStack;
-
+mod traits;
+use traits::vec::ConvertingStack;
 
 pub struct Module {
     funcs: BTreeMap<String, Rc<Func>>,
diff --git a/src/tracerunner.rs b/src/tracerunner.rs
index 01d073e..c614b7a 100644
--- a/src/tracerunner.rs
+++ b/src/tracerunner.rs
@@ -4,7 +4,7 @@ use super::{TraceInstruction, Comp, Value, Interpreter, CallFrame, Func};
 use recovery::Guard;
 use kaktus::PushPop;
 
-use util::ConvertingStack;
+use traits::vec::ConvertingStack;
 
 
 pub struct Runner<'a, 'b: 'a> {
diff --git a/src/traits.rs b/src/traits.rs
new file mode 100644
index 0000000..b115885
--- /dev/null
+++ b/src/traits.rs
@@ -0,0 +1,31 @@
+
+pub mod vec {
+
+    pub trait ConvertingStack<T> {
+        fn pop_into<U>(&mut self) -> U where U: From<T>;
+
+        fn pop_2_into<U>(&mut self) -> (U, U) where U: From<T>;
+
+        fn push_from<U: Into<T>>(&mut self, val: U);
+
+    }
+
+    impl<T> ConvertingStack<T> for Vec<T> {
+        fn pop_into<U>(&mut self) -> U
+            where U: From<T>
+        {
+            self.pop().unwrap().into()
+        }
+
+        fn pop_2_into<U>(&mut self) -> (U, U)
+            where U: From<T>
+        {
+            (self.pop().unwrap().into(), self.pop().unwrap().into())
+        }
+
+        fn push_from<U: Into<T>>(&mut self, val: U) {
+            self.push(val.into());
+        }
+    }
+
+}
diff --git a/src/util.rs b/src/util.rs
deleted file mode 100644
index f1a843c..0000000
--- a/src/util.rs
+++ /dev/null
@@ -1,27 +0,0 @@
-
-
-pub trait ConvertingStack<T> {
-    fn pop_into<U>(&mut self) -> U where U: From<T>;
-
-    fn pop_2_into<U>(&mut self) -> (U, U) where U: From<T>;
-
-    fn push_from<U: Into<T>>(&mut self, val: U);
-}
-
-impl<T> ConvertingStack<T> for Vec<T> {
-    fn pop_into<U>(&mut self) -> U
-        where U: From<T>
-    {
-        self.pop().unwrap().into()
-    }
-
-    fn pop_2_into<U>(&mut self) -> (U, U)
-        where U: From<T>
-    {
-        (self.pop().unwrap().into(), self.pop().unwrap().into())
-    }
-
-    fn push_from<U: Into<T>>(&mut self, val: U) {
-        self.push(val.into());
-    }
-}