Many columns + rename = memory errors

I was encountering crashes when trying to rename columns of a view containing about 200 columns. I reduced the problem to the following code:

 package require ratcl
 view [view 17 iota] def {} | to v
 view $v rename {0 blah -1 blah1} | meta | dump 1500

I don't get a crash, but if I run it under valgrind on linux, I see the following errors:

 ==2122== Invalid read of size 1
 ==2122==    at 0x80500E3: (within /home/sfw/tcl/linux/bin/tclkit)
 ==2122==  Address 0x48DF1A2 is 0 bytes after a block of size 34 alloc'd
 ==2122==    at 0x40056BF: calloc (vg_replace_malloc.c:279)
 ==2122==    by 0x804FD17: (within /home/sfw/tcl/linux/bin/tclkit)
 ==2122==
 ==2122== Invalid read of size 1
 ==2122==    at 0x804F440: (within /home/sfw/tcl/linux/bin/tclkit)
 ==2122==    by 0xFFFFFFFE: ???
 ==2122==  Address 0x48DF1A2 is 0 bytes after a block of size 34 alloc'd
 ==2122==    at 0x40056BF: calloc (vg_replace_malloc.c:279)
 ==2122==    by 0x804FD17: (within /home/sfw/tcl/linux/bin/tclkit)