diff --git a/src/parser/nom_context.rs b/src/parser/nom_context.rs
index 624027d..8c98875 100644
--- a/src/parser/nom_context.rs
+++ b/src/parser/nom_context.rs
@@ -7,9 +7,11 @@ use nom::error::VerboseError;
 use nom::IResult;
 use nom::Parser;
 
+type ContextReference<T> = Option<Rc<ContextLayer<T>>>;
+
 pub struct ContextLayer<T> {
     data: T,
-    parent: Option<Rc<ContextLayer<T>>>,
+    parent: ContextReference<T>,
 }
 
 impl<T> ContextLayer<T> {
@@ -21,8 +23,6 @@ impl<T> ContextLayer<T> {
     }
 }
 
-type ContextReference<T> = Option<Rc<ContextLayer<T>>>;
-
 pub struct TestContext<T> {
     head: ContextReference<T>,
 }