Add Free enum variant to the symbol scope to be able to distuingish between true local and free variables.

bytecode/src/bytecode.rs

@@ -59,10 +59,19 @@ bitflags! {
 pub type Label = usize;
 
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+/// An indication where the name must be accessed.
 pub enum NameScope {
+    /// The name will be in the local scope.
     Local,
+
+    /// The name will be located in scope surrounding the current scope.
     NonLocal,
+
+    /// The name will be in global scope.
     Global,
+
+    /// The name will be located in any scope between the current scope and the top scope.
+    Free,
 }
 
 /// Transforms a value prior to formatting it.