syntax_data: {"ast_node_type":"variable","tokens":[{"end":78,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:                 let constant = self.tcx.at(expr.span).lit_to_const(lit_input);
context_before:                 let lit_input = LitToConstInput { lit: lit.node, ty: ct_ty, neg: *negated };
context_after:                 self.const_to_pat(constant, ct_ty, expr.hir_id, lit.span).kind