t / t4034 / matlab / poston commit peel_onion: disambiguate to favor tree-ish when we know we want a tree-ish (ed1ca60)
   1(0) (-0e10) 'y';
   2[x] {x} x.y;
   3~x;
   4x*y x.*y x/y x./y x^y x.^y x.\y x.';
   5x+y x-y;
   6x&y x&&y x|y x||y;
   7x<y x<=y x>y x>=y;
   8x==y x~=y;
   9x,y;