foo {
  minus-before-minus: - 1 - 2;
  minus-after-minus:  1 - - 2;
  plus-before-minus:  + 1 - 2;
  plus-after-minus:   1 - + 2;
  not-before-plus:    not 1 + 2;
  not-after-plus:     1 + not 2;

  minus-after-comma:  (1, - 2);
  plus-after-comma:   (1, + 2);
  slash-after-comma:  (1, / 2);
  not-after-comma:    (1, not 2);
}