/// Return the error code string for a `{{ rust_path }}` variant.
#[allow(dead_code)]
fn {{ code_fn_name }}(e: &{{ rust_path }}) -> &'static str {
#[allow(unreachable_patterns)]
match e {
{%- for pattern, code in variants %}
{{ pattern }} => "{{ code }}",
{%- endfor %}
_ => "{{ default_code }}",
}
}