{"ast_node_type":"function","tokens":[{"end":85,"kind":"keyword","start":0,"text":"pub(crate)"}]}
pub(crate) fn span_err<T: Into<String>>(span: impl MultiSpan, msg: T) -> Diagnostic {
#[must_use]
    Diagnostic::spanned(span, Level::Error, format!("derive(Diagnostic): {}", msg.into()))