syntax_data: {"ast_node_type":"other","tokens":[{"end":94,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:                 // Mark this block as useful (even inside `unsafe fn`, where it is technically
context_before:             SafetyContext::UnsafeBlock { ref mut used, .. } => {
context_after:                 // redundant -- but we want to eventually enable `unsafe_op_in_unsafe_fn` by