syntax_data: {"ast_node_type":"other","tokens":[{"end":101,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:                 // supported at all, so this is sound to do, but once we want to support them, you'll
context_before:                 // FIXME: implement higher kinded lifetime bounds on nested opaque types. They are not
context_after:                 // start seeing the error below.