syntax_data: {"ast_node_type":"other","tokens":[{"end":44,"kind":"keyword","start":0,"text":"self.comma_sep(tys.iter())?;"}]}
source_snippet:                 self.comma_sep(tys.iter())?;
context_before:                 write!(self, "(")?;
context_after:                 if tys.len() == 1 {