syntax_data: {"ast_node_type":"other","tokens":[{"end":76,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:             // if that was possible, so there's no reason to try again here.
context_before:             // NOTE(eddyb) `layout_of` query should've normalized these away,
context_after:             let err = if ty.has_param() {