syntax_data: {"ast_node_type":"other","tokens":[{"end":50,"kind":"keyword","start":0,"text":"Cast"}]}
source_snippet:     Cast { pad_i32: bool, cast: Box<CastTarget> },
context_before:     /// `pad_i32` indicates if a `Reg::i32()` dummy argument is emitted before the real argument.
context_after:     /// Pass the argument indirectly via a hidden pointer.