It seems (based on the NEWS file and on output from R CMD check) that we may no longer use SET_VECTOR_ELT on STRSXPs. So I guess that section 5.14 of R-extensions needs to be updated, the current phrasing is "By default a certain amount of misuse is allowed where the internal representation is the same: for example LOGICAL can be used on a INTSXP and SET_VECTOR_ELT on a STRSXP" which indicates that it is allowed to do so. I also suggest to change the error message in line 2648-2649 of src/ main/memory.c from SET_VECTOR_ELT() can only be applied to a 'list', not a '%s' to SET_VECTOR_ELT() / SET_ELEMENT() can only be applied to a 'list', not a '%s' I guess I ought to have remembered that the two macros are synonymous, but I didn't and it took me a while to realize this when I tried to fix some code written by another person (who preferred to use SET_ELEMENT). Kasper