syntax_data: {"ast_node_type":"other","tokens":[{"end":54,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:             // invalidated by assignment to a variant.
context_before:             // Only invalidate variants and discriminant. Fields (for coroutines) are not
context_after:             if let Some(TrackElem::Variant(..) | TrackElem::Discriminant) = elem