40 columns                              |
>>> logic
if (o case 1   ||  2   &&  3  ) {}
<<<
if (o case 1 || 2 && 3) {}
>>> logic as subpattern
if (o case 1   &&  (  2   ||  3   )  ) {}
<<<
if (o case 1 && (2 || 3)) {}
>>> relational
switch (obj) {
  case   ==   other:
  case   !=   other:
  case   <   other:
  case   <=   other:
  case   >   other:
  case   >=   other:
    body;
}
<<<
switch (obj) {
  case == other:
  case != other:
  case < other:
  case <= other:
  case > other:
  case >= other:
    body;
}
>>> relational as subpattern
if (o case  >  1  &&  <   2 && (  ==   3 )) {}
<<<
if (o case > 1 && < 2 && (== 3)) {}
>>> cast
if (o case   1   as   List < int > ?  ) {}
<<<
if (o case 1 as List<int>?) {}
>>> null-check
if (o case pattern  ?  ) {}
<<<
if (o case pattern?) {}
>>> null-assert
if (o case pattern  !  ) {}
<<<
if (o case pattern!) {}
>>> simple constants
switch (obj) {
case  true  :
case  false  :
case  null  :
case  123  :
case  12.34  :
case  -  123  :
case  -  12.34  :
case  'string'  :
case  's$tr${  ing  }'  :
case  #symbol  :
  ok;
}
<<<
switch (obj) {
  case true:
  case false:
  case null:
  case 123:
  case 12.34:
  case -123:
  case -12.34:
  case 'string':
  case 's$tr${ing}':
  case #symbol:
    ok;
}
>>> identifiers
switch (obj) {
case  _  :
case  name  :
case  qualified  .  name  :
case  prefixed  .  qualified  .  name  :
  ok;
}
<<<
switch (obj) {
  case _:
  case name:
  case qualified.name:
  case prefixed.qualified.name:
    ok;
}
>>> variables
switch (obj) {
case  int  ?  _  :
case  List < String >  name  :
case  var  name  :
case  final  name  :
case  final  (  int  ,  String  )  name  :
  ok;
}
<<<
switch (obj) {
  case int? _:
  case List<String> name:
  case var name:
  case final name:
  case final (int, String) name:
    ok;
}
>>> list
switch (obj) {
case  [  ]  :
case  <  int  >  [  ]  :
case  [  _  ]  :
case  [  _  ,  ]  :
case  [  _  ,  _  ]  :
case  [  ...  ]  :
case  [  ...  _  ]  :
case  [  _  ,  ...  ]  :
case  [  ...  ,  _  ]  :
case  [  ...  ,  ]  :
  ok;
}
<<<
switch (obj) {
  case []:
  case <int>[]:
  case [_]:
  case [
      _,
    ]:
  case [_, _]:
  case [...]:
  case [..._]:
  case [_, ...]:
  case [..., _]:
  case [
      ...,
    ]:
    ok;
}
>>> map
switch (obj) {
case  {  }  :
case  <  int  ,  String  >  {  }  :
case  {  k  :  _  }  :
case  {  k  :  _  ,  }  :
case  {  k  :  1  ,  m  :  2  }  :
case  {  ...  }  :
case  {  k  :  _  ,  ...  }  :
  ok;
}
<<<
switch (obj) {
  case {}:
  case <int, String>{}:
  case {k: _}:
  case {
      k: _,
    }:
  case {k: 1, m: 2}:
  case {...}:
  case {k: _, ...}:
    ok;
}
>>> record
switch (obj) {
  case  (  )  :
  case  (  value  ,  )  :
  case  (  first  ,  second  ,  third  )  :
  case  (  first  :  1  ,  2  ,  third  :  3  )  :
  case  (  :  var  x  ,  :  var  y  )  :
    ok;
}
<<<
switch (obj) {
  case ():
  case (value,):
  case (first, second, third):
  case (first: 1, 2, third: 3):
  case (:var x, :var y):
    ok;
}
>>> object
switch (obj) {
case  Foo  (  )  :
case  Foo  (  getter  :  pattern  )  :
case  Foo  (  getter  :  pattern  ,  )  :
case  Foo  (  a  :  1  ,  b  :  2  ,  c  :  3  )  :
case  Foo  (  :  var  x  ,  :  var  y  )  :
case  Foo  <  int  ,  String  >  (  :  var  x  ,  :  var  y  )  :
ok;
}
<<<
switch (obj) {
  case Foo():
  case Foo(getter: pattern):
  case Foo(
      getter: pattern,
    ):
  case Foo(a: 1, b: 2, c: 3):
  case Foo(:var x, :var y):
  case Foo<int, String>(:var x, :var y):
    ok;
}
>>> object
switch (obj) {
case  Foo  (  )  :
case  Foo  (  getter  :  pattern  )  :
case  Foo  (  getter  :  pattern  ,  )  :
case  Foo  (  a  :  1  ,  b  :  2  ,  c  :  3  )  :
case  Foo  (  :  var  x  ,  :  var  y  )  :
case  Foo  <  int  ,  String  >  (  :  var  x  ,  :  var  y  )  :
ok;
}
<<<
switch (obj) {
  case Foo():
  case Foo(getter: pattern):
  case Foo(
      getter: pattern,
    ):
  case Foo(a: 1, b: 2, c: 3):
  case Foo(:var x, :var y):
  case Foo<int, String>(:var x, :var y):
    ok;
}
>>> constant collections
switch (obj) {
case  const  [  ]  :
case  const  <  int  >  [  ]  :
case  const  [  1  ,  2  ]  :
case  const  {  }  :
case  const  <  int  >  {  }  :
case  const  {  1  ,  2  }  :
case  const  <  int  ,  String  >  {  }  :
case  const  {  1  :  's'  ,  2  :  't'  }  :
  ok;
}
<<<
switch (obj) {
  case const []:
  case const <int>[]:
  case const [1, 2]:
  case const {}:
  case const <int>{}:
  case const {1, 2}:
  case const <int, String>{}:
  case const {1: 's', 2: 't'}:
    ok;
}
>>> constant constructor
switch (obj) {
case  const  Foo  (  )  :
case  const  Foo  (  field  ,  another  )  :
case  const  Foo  (  field  :  value  )  :
case  const  Foo  (  field  :  value  ,  )  :
case  const  Foo  <  int  ,  String  >  (  field  )  :
ok;
}
<<<
switch (obj) {
  case const Foo():
  case const Foo(field, another):
  case const Foo(field: value):
  case const Foo(
      field: value,
    ):
  case const Foo<int, String>(field):
    ok;
}
>>> parenthesized constant expression
switch (obj) {
case  const  (  1  )  :
case  const  (  -  foo  *  bar  )  :
ok;
}
<<<
switch (obj) {
  case const (1):
  case const (-foo * bar):
    ok;
}