syntax_data: {"ast_node_type":"other","tokens":[{"end":36,"kind":"keyword","start":0,"text":"callee_body:"}]}
source_snippet:         callee_body: &'b Body<'tcx>,
context_before:         instance: Option<ty::Instance<'tcx>>,
context_after:     ) -> CostChecker<'b, 'tcx> {