Fix get_attr_lazy

I had misunderstood/misused the ? suffix operator for the Option type.

Signed-off-by: Alek Ratzloff <alekratz@gmail.com>

src/obj.rs

@@ -256,6 +256,7 @@ pub trait Obj: Debug + Display + Any + Trace {
 
         let mut type_inst = self.type_inst();
         loop {
+            let vtable_entry =
                 with_obj_downcast_mut(type_inst.clone(), |type_inst: &mut TypeInst| {
                     type_inst.vtable.get(name).cloned()
                 })
@@ -269,7 +270,10 @@ pub trait Obj: Debug + Display + Any + Trace {
                     };
                     self.set_attr(name, ptr.clone());
                     ptr
-            })?;
+                });
+            if vtable_entry.is_some() {
+                return vtable_entry;
+            }
             let type_inst_copy = type_inst.borrow().type_inst();
             if type_inst.borrow().equals(&*type_inst_copy.borrow()) {
                 return None;
@@ -1158,6 +1162,7 @@ fn test_obj_equals() {
     assert!(obj2.borrow().equals(&*obj1.borrow()));
 }
 
+#[test]
 fn test_obj_vtable() {
     let mut builtins = HashMap::new();
     init_types(&mut builtins);