syntax_data: {"ast_node_type":"other","tokens":[{"end":32,"kind":"keyword","start":0,"text":"diag.arg(\"ty\","}]}
source_snippet:         diag.arg("ty", self.ty);
context_before:     fn add_to_diag<G: EmissionGuarantee>(self, diag: &mut Diag<'_, G>) {
context_after:         let mut spans = MultiSpan::from(self.adt_def_span);