vlib/v/checker/tests/assign_immutable_reference_struct_field_err.vv:13:29: notice: `parent` is immutable, cannot have a mutable reference to an immutable object
   11 |     }
   12 |     // taking a reference of `parent` and putting it under a `mut:` struct field
   13 |     mut child := Tree{parent: &parent}
      |                                ~~~~~~
   14 |
   15 |     // unwrap the reference of `parent`, but declare it as `mut`
