PVS-Studio warning V595 for MongoDB

static void freeCompletions(linenoiseCompletions *lc) {
  size_t i;
  for (i = 0; i < lc->len; i++)
    free(lc->cvec[i]);
  if (lc->cvec != NULL)
    free(lc->cvec);
}

This suspicious code was found in MongoDB project by PVS-Studio static code analyzer.
Warning message is:
V595 The 'lc->cvec' pointer was utilized before it was verified against nullptr. Check lines: 447, 448. linenoise.cpp 447

PVS-Studio is a static analyzer for detecting bugs in the source code of applications written in C, C++, C++11, C++/CX. Site: http://www.viva64.com/en/pvs-studio/