vlib/v/checker/tests/assign_immutable_reference_struct_field_err.vv:14:12: error: `parent` is immutable, cannot have a mutable reference to an immutable object
   12 |     // taking a reference of `parent` and putting it under a `mut:` struct field
   13 |     mut child := Tree{
   14 |         parent: &parent
      |                  ~~~~~~
   15 |     }
   16 |