syntax_data: {"ast_node_type":"other","tokens":[{"end":47,"kind":"keyword","start":0,"text":"v21:"}]}
source_snippet:         v21: vreg = ["v21"] % reserved_v20to31,
context_before:         v20: vreg = ["v20"] % reserved_v20to31,
context_after:         v22: vreg = ["v22"] % reserved_v20to31,