syntax_data: {"ast_node_type":"variable","tokens":[{"end":66,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:     let sizedness_trait_def_id = sizedness.require_lang_item(tcx);
context_before:     // that the type is sized and do not need to check it on the impl.
context_after:     let predicates = tcx.predicates_of(def.did()).predicates;