syntax_data: {"ast_node_type":"other","tokens":[{"end":94,"kind":"keyword","start":0,"text":"[self_ty].into_iter().chain(sig.inputs()[0].tuple_fields()).collect(),"}]}
source_snippet:                         [self_ty].into_iter().chain(sig.inputs()[0].tuple_fields()).collect(),
context_before:                     (
context_after:                         sig.output(),