I just put the source code of exo-0.10.2 through
the static analyser cppcheck. It said

[exo-icon-bar.c:1164] -> [exo-icon-bar.c:1164]: (style) Same expression on both sides of '&&'.

Source code is

  if (G_LIKELY (item->width != -1 && item->width != -1))
    return;

Maybe 

  if (G_LIKELY (item->width != -1 && item->height != -1))
    return;

would be better code.