nac3core/src/codegen/concrete_type.rs

@@ -148,8 +148,9 @@ impl ConcreteTypeStore {
                         .borrow()
                         .iter()
                         .filter_map(|(name, ty)| {
-                            // filter out functions as they can have type vars and
+                            // here we should not have type vars, but some partial instantiated
-                            // will not affect codegen
+                            // class methods can still have uninstantiated type vars, so
+                            // filter out all the methods, as this will not affect codegen
                             if let TypeEnum::TFunc( .. ) = &*unifier.get_ty(ty.0) {
                                 None
                             } else {

nac3core/src/typecheck/typedef/mod.rs

@@ -725,8 +725,9 @@ impl Unifier {
             if let TypeEnum::TVar { id, range, .. } =
                 self.unification_table.probe_value(*v).as_ref()
             {
-                // need to do this for partial instantiated function
+                // for class methods that contain type vars not in class declaration,
-                // (in class methods that contains type vars not in class)
+                // as long as there exits one uninstantiated type var, the function is not instantiated,
+                // and need to do substitution on those type vars
                 if k == id {
                     instantiated = false;
                     vars.push((*k, range.clone()));