PVS-Studio warning V556 for TortoiseGIT

static enum {
  ABORT, VERBATIM, WARN, WARN_STRIP, STRIP
} signed_tag_mode = ABORT;

static enum {
  ERROR, DROP, REWRITE
} tag_of_filtered_mode = ERROR;

static void handle_tag(const char *name, struct tag *tag)
{
  ....
  switch(tag_of_filtered_mode) {
  case ABORT:
  ....
}

This suspicious code was found in TortoiseGIT project by PVS-Studio static code analyzer.
Warning message is:
V556 The values of different enum types are compared: switch(ENUM_TYPE_A) { case ENUM_TYPE_B: ... }. fast-export.c 449

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/