more check

git-svn-id: https://svn.r-project.org/R/trunk@63357 00db46b3-68df-0310-9c12-caf00c1e9a41
tweak

git-svn-id: https://svn.r-project.org/R/trunk@63358 00db46b3-68df-0310-9c12-caf00c1e9a41
tweak

git-svn-id: https://svn.r-project.org/R/trunk@63359 00db46b3-68df-0310-9c12-caf00c1e9a41