syntax_data: {"ast_node_type":"other","tokens":[{"end":57,"kind":"keyword","start":0,"text":".expect(\"failed"}]}
source_snippet:         .expect("failed to build vtable representation");
context_before:         .layout_of(ty::TypingEnv::fully_monomorphized().as_query_input(ty))
context_after:     assert!(layout.is_sized(), "can't create a vtable for an unsized type");