pub fn push_about<P: Poison>(
errors: &mut Errors,
ast: &Ast,
about: P,
diagnostic: Diagnostic,
)Expand description
Records a diagnostic unless about is a node the parser already poisoned.
A free function rather than a method, because the sink is in rucc-diag and what makes a
node poisoned is a fact about this tree. Errors::push_unless is the half that does not
need to know that.