syntax_data: {"ast_node_type":"other","tokens":[{"end":43,"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(