syntax_data: {"ast_node_type":"variable","tokens":[{"end":81,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:         let unit = arg.layout.homogeneous_aggregate(cx).unwrap().unit().unwrap();
context_before:         // At this point we know this must be a primitive of sorts.
context_after:         assert_eq!(unit.size, arg.layout.size);