More optimization

• Some fixes and optimization.

juno_scheduler/src/pm.rs

@@ -1339,7 +1339,10 @@ fn interp_expr(
                     }
                 }
                 Value::Record { fields } => match fields.get(field) {
-                    None => Err(SchedulerError::UndefinedField(field.clone())),
+                    None => Err(SchedulerError::UndefinedField(format!(
+                        "{} not in {:?}",
+                        field, fields
+                    ))),
                     Some(v) => Ok((v.clone(), changed)),
                 },
             }