syntax_data: {"ast_node_type":"other","tokens":[{"end":88,"kind":"keyword","start":0,"text":"Rvalue::BinaryOp(BinOp::Sub,"}]}
source_snippet:             Rvalue::BinaryOp(BinOp::Sub, Box::new((Operand::Copy(discr), start_const))),
context_before:             discr_diff,
context_after:         ))),