Should print something like this:
std.concurrency.OwnerTerminated@std/concurrency.d(223): Owner terminated

Because main thread is terminated, because types do not match

this will work 
import std.stdio;
import std.concurrency;

void fun()
{
receive( (immutable (int)[] v) => writeln(v) );
}

int main(string[] args)
{
immutable int[] arr = [1,2,3,4,5];
auto t = spawn(&fun);
t.send(arr);
return 0;
}

On Fri, Nov 24, 2017 at 1:06 PM, SrMordred via Digitalmars-d-learn <digitalmars-d-learn@puremagic.com> wrote:
On Friday, 24 November 2017 at 12:05:16 UTC, SrMordred wrote:
immutable int[] arr = [1,2,3,4,5];
auto t = spawn({ receive( (immutable int[] v) => writeln(v) );});
t.send(arr);

whats the problem here?

Nothing prints out