================================================================================
struct with field default values
================================================================================

struct Player {
    name: string = "unknown",
    score: int = 42,
}
--------------------------------------------------------------------------------

(sourcefile
  (struct_definition
    (user_type_identifier)
    (struct_block
      (struct_field_definition
        (simple_identifier)
        (type
          (builtin_type_identifier))
        (expression
          (value
            (string_value))))
      (struct_field_definition
        (simple_identifier)
        (type
          (builtin_type_identifier))
        (expression
          (value
            (int_value)))))))
