message: Add some warnings
diff: @@ -47,9 +47,9 @@ pub fn trans_mono_item<'a, 'tcx: 'a>(cx: &mut CodegenCx<'a, 'tcx, CurrentBackend
  cx.module.define_function(func_id, context).unwrap();
  context.clear();
  }
  - _ => {}
  + inst => cx.tcx.sess.warn(&format!("Unimplemented instance {:?}", inst)),
  }
  - _ => {}
  + mono_item => cx.tcx.sess.warn(&format!("Unimplemented mono item {:?}", mono_item)),
  }
  }
  