syntax_data: {"ast_node_type":"other","tokens":[{"end":7,"kind":"keyword","start":0,"text":"///"}]}
source_snippet:     ///
context_before:     /// Pass the argument after casting it. See the `CastTarget` docs for details.
context_after:     /// `pad_i32` indicates if a `Reg::i32()` dummy argument is emitted before the real argument.