diff --git a/schala-lang/language/src/typechecking.rs b/schala-lang/language/src/typechecking.rs
index 49ba798..08803a8 100644
--- a/schala-lang/language/src/typechecking.rs
+++ b/schala-lang/language/src/typechecking.rs
@@ -208,7 +208,15 @@ impl<'a> TypeContext<'a> {
     }
   }
 
-  fn decl(&mut self, _decl: &Declaration) -> InferResult<Type> {
+  fn decl(&mut self, decl: &Declaration) -> InferResult<Type> {
+    use self::Declaration::*;
+    match decl {
+      Binding { name, expr, .. } => {
+        let ty = self.expr(expr)?;
+        self.variable_map.insert(name.clone(), ty);
+      },
+      _ => (),
+    }
     Ok(ty!(Unit))
   }