syntax_data: {"ast_node_type":"other","tokens":[{"end":51,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:                 // Also, must not be `extern` type.
context_before:                 assert!(arg.layout.is_unsized() && !on_stack);
context_after:                 let tail = tcx.struct_tail_for_codegen(arg.layout.ty, cx.typing_env);