syntax_data: {"ast_node_type":"other","tokens":[{"end":90,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:                     // For `&pin mut $place` where `$place` is not `Unpin`, move the place
context_before:                     let mut arg = self.mirror_expr(arg_expr);
context_after:                     // `$place` to ensure it will not be used afterwards.