...function()` → `void delegate() immutable` → `void delegate() const` → `void delegate()`

The first is...

...102.0

-----
module test;

void call(void delegate(int i) const cb) {
    cb(42);
}

struct...

...A(S = string)
    {
    @safe:
        S s;
        void delegate() c;
    }

    struct B(S = string)
    {
    @safe:
        @disable...

...C)
int(char[][]) function).tryExec(scope void() delegate) ()
#31 0x00005644ce1dda43 in rt.dmain2._d_run...

...dmd.mtype.Parameter, ulong, dmd.mtype.Parameter) delegate, ulong,
dmd.mtype.Parameter, ref ulong, dmd...

...M(int value) {
  int opApply(scope int delegate(ref int i) dg) {
    int v = value...

...void fun(scope void delegate(      int []))       {}
    void fun(scope void delegate(const(int)[])) const {}
}

unittest...

...getArr(scope void delegate(int[]) fn) { fn(arr); }
    void getArr(scope void delegate(const(int...

...f)); // extern (C) int delegate()

//void h(extern (C) int delegate() dg) { } // does not parse
```

--

...scope int
delegate(immutable(object.ModuleInfo*))) [0x102cf5507]
??:? int object.ModuleInfo.opApply(scope int delegate(object...