base.Fatalf("deferStructFnField is %q, not fn", name)
	}

	n := ir.NewDeclNameAt(src.NoXPos, ir.OTYPE, ir.Pkgs.Runtime.Lookup("_defer"))
	typ := types.NewNamed(n)
	n.SetType(typ)
	n.SetTypecheck(1)

	// build struct holding the above fields
	typ.SetUnderlying(types.NewStruct(fields))
	types.CalcStructSize(typ)

	deferType = typ
	return typ
}