syntax_data: {"ast_node_type":"variable","tokens":[{"end":52,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:         let b1 = layout::Tree::<Def, !, !>::byte(1);
context_before:         let b0 = layout::Tree::<Def, !, !>::byte(0);
context_after:         let b2 = layout::Tree::<Def, !, !>::byte(2);