syntax_data: {"ast_node_type":"other","tokens":[{"end":79,"kind":"keyword","start":0,"text":"tcx.require_lang_item(LangItem::ExchangeMalloc,"}]}
source_snippet:                     tcx.require_lang_item(LangItem::ExchangeMalloc, expr_span),
context_before:                     tcx,
context_after:                     [],