syntax_data: {"ast_node_type":"other","tokens":[{"end":14,"kind":"keyword","start":0,"text":"),"}]}
source_snippet:             ),
context_before:                 "to get the signature of a closure, use `args.as_closure().sig()` not `fn_sig()`",
context_after:             _ => panic!("Ty::fn_sig() called on non-fn type: {:?}", self),