syntax_data: {"ast_node_type":"other","tokens":[{"end":47,"kind":"keyword","start":0,"text":"span:"}]}
source_snippet:                         span: source_info.span,
context_before:                     Rvalue::Use(Operand::Constant(Box::new(ConstOperand {
context_after:                         const_: Const::Unevaluated(