syntax_data: {"ast_node_type":"variable","tokens":[{"end":44,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:     let expn_data1 = ctxt.outer_expn_data();
context_before:     let enclosing_ctxt = enclosing_sp.ctxt();
context_after:     if !enclosing_ctxt.is_root()