treat error case separately

git-svn-id: https://svn.r-project.org/R/trunk@62654 00db46b3-68df-0310-9c12-caf00c1e9a41
arrayInd() and which() now use names(dimnames()) when available

git-svn-id: https://svn.r-project.org/R/trunk@62656 00db46b3-68df-0310-9c12-caf00c1e9a41
fix typo and trailing whitespace


git-svn-id: https://svn.r-project.org/R/trunk@62657 00db46b3-68df-0310-9c12-caf00c1e9a41