syntax_data: {"ast_node_type":"other","tokens":[{"end":79,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:                 // like `x @ subpat` we must establish any bindings in `subpat`
context_before:                 // In order to please the borrow checker, when lowering a pattern
context_after:                 // before establishing the binding for `x`.