syntax_data: {"ast_node_type":"other","tokens":[{"end":56,"kind":"keyword","start":0,"text":"tcx.type_of(impl_def_id).instantiate_identity(),"}]}
source_snippet:         tcx.type_of(impl_def_id).instantiate_identity(),
context_before:     let tail = tcx.struct_tail_raw(
context_after:         |ty| {