40 columns                              |
>>> empty set
var s = <int>  { };
<<<
var s = <int>{};
>>> exactly 40 characters
var s = {first, second, third, forth__};
<<<
var s = {first, second, third, forth__};
>>>
var s = {first, second, third, fourth, fifth, sixth};
<<<
var s = {
  first,
  second,
  third,
  fourth,
  fifth,
  sixth
};
>>> splits outer sets even if they fit
var s = {a, {b, c}, d, {},
    e, {f, {g, h} }  };
<<<
var s = {
  a,
  {b, c},
  d,
  {},
  e,
  {
    f,
    {g, h}
  }
};
>>> split indirect outer
var s = {a, function({b, inner})};
<<<
var s = {
  a,
  function({b, inner})
};
>>> empty literal does not force outer split
var s = {a, <int>{}, b, [], c, () {}};
<<<
var s = {a, <int>{}, b, [], c, () {}};
>>> nested split set
var s = {first, 1, second, {third, fourth}, fifth, 5, nested, {sixth, seventh, eighth, nine,
    tenth, eleventh}};
<<<
var s = {
  first,
  1,
  second,
  {third, fourth},
  fifth,
  5,
  nested,
  {
    sixth,
    seventh,
    eighth,
    nine,
    tenth,
    eleventh
  }
};
>>> force multi-line because of contained block
var s = {first, 1, fn, () {"fn";},third,fourth};
<<<
var s = {
  first,
  1,
  fn,
  () {
    "fn";
  },
  third,
  fourth
};
>>> containing comments
var s = {first, one /* bang */, second, two};
<<<
var s = {
  first,
  one /* bang */,
  second,
  two
};
>>> const
var set = const {"foo", "bar", "fuz", null};
<<<
var set = const {
  "foo",
  "bar",
  "fuz",
  null
};
>>> trailing comma forces split
var set = {"foo", "bar" , };
<<<
var set = {
  "foo",
  "bar",
};
>>> trailing comma multiline
var set = {"foo", "bar", "fuzzy", null , };
<<<
var set = {
  "foo",
  "bar",
  "fuzzy",
  null,
};
>>> preserve newlines in sets containing a line comment
var set = {
  // yeah
  a,b,c,d,
  e,f,g,h
};
<<<
var set = {
  // yeah
  a, b, c, d,
  e, f, g, h
};
>>> wrap between elements even when newlines are preserved
var set = {
  // yes
  first, "value", second, "value", third, "value",

  fourth, "value", fifth, "value", sixth, "value", seventh, "value"
};
<<<
var set = {
  // yes
  first, "value", second, "value",
  third, "value",

  fourth, "value", fifth, "value",
  sixth, "value", seventh, "value"
};
>>> ignore line comment after the "}"
var set = {
  a,b,c,
  d
} // comment
;
<<<
var set = {a, b, c, d} // comment
    ;
>>> preserves one blank line between elements
var set = {


  element,


  // comment
  element,


  element


};
<<<
var set = {
  element,

  // comment
  element,

  element
};
>>> spread cascade
var set = {1, ...thing..cascade()..another(), 4};
<<<
var set = {
  1,
  ...thing
    ..cascade()
    ..another(),
  4
};
>>> spread lambda
var set = {1, ...() { body; }, 4};
<<<
var set = {
  1,
  ...() {
    body;
  },
  4
};
>>> spread immediately invoked lambda
var set = {1, ...() sync* { yield thing; }(), 4};
<<<
var set = {
  1,
  ...() sync* {
    yield thing;
  }(),
  4
};