40 columns                              |
>>>
typedef void A();
<<<
typedef A = void Function();
>>>
typedef void A(String name);
<<<
typedef A = void Function(String name);
>>>
typedef bool A(int count);
<<<
typedef A = bool Function(int count);
>>>
typedef void A<T>();
<<<
typedef A<T> = void Function();
>>>
typedef void A<T>(T x);
<<<
typedef A<T> = void Function(T x);
>>>
typedef void A<T>(x);
<<<
typedef A<T> = void Function(dynamic x);
>>>
typedef V A<K, V>();
<<<
typedef A<K, V> = V Function();
>>>
typedef V A<K, V>(K key);
<<<
typedef A<K, V> = V Function(K key);
>>>
typedef K A<K, V>(V value);
<<<
typedef A<K, V> = K Function(V value);
>>>
typedef F<T> = void Function(T);
<<<
typedef F<T> = void Function(T);
>>>
@meta typedef void X(y);
<<<
@meta
typedef X = void Function(dynamic y);
>>> split type parameters
typedef G = T Function<TypeOne, TypeTwo, TypeThree>();
<<<
typedef G = T Function<TypeOne, TypeTwo,
    TypeThree>();
>>> split all type parameters
typedef G = T Function<TypeOne, TypeTwo, TypeThree, TypeFour, TypeFive, TypeSix>();
<<<
typedef G = T Function<
    TypeOne,
    TypeTwo,
    TypeThree,
    TypeFour,
    TypeFive,
    TypeSix>();
>>> split type and value parameters
typedef G = T Function<TypeOne, TypeTwo, TypeThree>(TypeOne one, TypeTwo two, TypeThree three);
<<<
typedef G = T Function<TypeOne, TypeTwo,
        TypeThree>(TypeOne one,
    TypeTwo two, TypeThree three);
>>> generic typedef parameters on one line
typedef Foo<T, S> = Function();
<<<
typedef Foo<T, S> = Function();
>>> generic typedef parameters that split
typedef LongfunctionType<First, Second, Third, Fourth, Fifth, Sixth> = Function(First first, Second second, Third third, Fourth fourth);
<<<
typedef LongfunctionType<First, Second,
        Third, Fourth, Fifth, Sixth>
    = Function(
        First first,
        Second second,
        Third third,
        Fourth fourth);
>>> both type parameter lists split
typedef LongfunctionType<First, Second, Third, Fourth, Fifth, Sixth> = Function<Seventh>(First first, Second second, Third third, Fourth fourth);
<<<
typedef LongfunctionType<First, Second,
        Third, Fourth, Fifth, Sixth>
    = Function<Seventh>(
        First first,
        Second second,
        Third third,
        Fourth fourth);
>>> all three parameter lists split
typedef LongfunctionType<First, Second, Third, Fourth, Fifth, Sixth> = Function<Seventh, Eighth, Ninth, Tenth, Eleventh, Twelfth, Thirteenth>(First first, Second second, Third third, Fourth fourth);
<<<
typedef LongfunctionType<First, Second,
        Third, Fourth, Fifth, Sixth>
    = Function<
            Seventh,
            Eighth,
            Ninth,
            Tenth,
            Eleventh,
            Twelfth,
            Thirteenth>(
        First first,
        Second second,
        Third third,
        Fourth fourth);
>>> old generic typedef syntax
typedef Foo  <  T  ,S  >(T t,S s);
<<<
typedef Foo<T, S> = Function(T t, S s);
>>> non-generic in typedef
typedef   SomeFunc=ReturnType  Function(int param,   double other);
<<<
typedef SomeFunc = ReturnType Function(
    int param, double other);
>>> generic in typedef
typedef Generic = T Function<T>(T param, double other);
<<<
typedef Generic = T Function<T>(
    T param, double other);
>>> no return type
typedef SomeFunc = Function();
<<<
typedef SomeFunc = Function();
>>> nested
typedef SomeFunc = Function(int first, Function(int first, bool second, String third) second, String third);
<<<
typedef SomeFunc = Function(
    int first,
    Function(int first, bool second,
            String third)
        second,
    String third);
>>> without param names
typedef F = Function(int, bool, String);
<<<
typedef F = Function(int, bool, String);
>>> generic
typedef    Foo < A ,B>=Function ( A a,   B b );
<<<
typedef Foo<A, B> = Function(A a, B b);
>>> generic function
typedef    Foo  =Function  < A ,B  >   ( A a,B b );
<<<
typedef Foo = Function<A, B>(A a, B b);
>>> simple typedef
typedef int Foo(int x);
<<<
typedef Foo = int Function(int x);
>>> generic typedef
typedef S Foo<S extends num>(S x);
<<<
typedef Foo<S extends num> = S Function(
    S x);
>>> named argument
typedef int Foo({x});
<<<
typedef Foo = int Function({dynamic x});
>>> optional positional argument
typedef int Foo([x]);
<<<
typedef Foo = int Function([dynamic x]);
>>> metadata and keywords
typedef int Foo(@meta v1, final v2, var v3, /*c*/ v4);
<<<
typedef Foo = int Function(
    @meta dynamic v1,
    final dynamic v2,
    var dynamic v3,
    /*c*/ dynamic v4);
>>> metadata and keywords optional positional
typedef int Foo([@meta v1, final v2, var v3, /*c*/ v4]);
<<<
typedef Foo = int Function(
    [@meta dynamic v1,
    final dynamic v2,
    var dynamic v3,
    /*c*/ dynamic v4]);
>>> metadata and keywords named
typedef int Foo({@meta v1, final v2, var v3, /*c*/ v4});
<<<
typedef Foo = int Function(
    {@meta dynamic v1,
    final dynamic v2,
    var dynamic v3,
    /*c*/ dynamic v4});
>>> function argument
typedef int Foo(int callback(int x));
<<<
typedef Foo = int Function(
    int Function(int x) callback);
>>> nested Function type
typedef int Foo(int cb(int Function(int) cb2));
<<<
typedef Foo = int Function(
    int Function(int Function(int) cb2)
        cb);
>>> nested generic function
typedef T Foo<T>(T cb<S>(T cb2(S x)));
<<<
typedef Foo<T> = T Function(
    T Function<S>(T Function(S x) cb2)
        cb);
>>> new-style function type unchanged
typedef int Foo(int Function(int) cb);
<<<
typedef Foo = int Function(
    int Function(int) cb);
>>> don't change correct typedef
typedef Foo = int Function(int);
<<<
typedef Foo = int Function(int);
>>> simple typedef, no types
typedef Foo(x);
<<<
typedef Foo = Function(dynamic x);
>>> nested function types, no types
typedef Foo(foo(x));
<<<
typedef Foo = Function(
    Function(dynamic x) foo);
>>> block comments in typedef
typedef/*0*/void/*1*/Foo/*2*/<T>/*3*/(/*4*/T/*5*/foo(/*6*/x));
<<<
typedef /*1*/ Foo /*2*/ <T>
    = /*0*/ void Function /*3*/ (
        /*4*/ T Function(
            /*6*/ dynamic x) /*5*/ foo);
>>> eol comments in typedef
typedef//0
void//1
Foo//2
<T>//3
(//4
T//5
foo(//6
x));
<<<
typedef //1
    Foo //2
    <T>
    = //0
    void Function //3
    (
        //4
        T Function(
                //6
                dynamic x) //5
            foo);