Is there a generic Task.WaitAll?

Question

I start a few parallel tasks, like this:

var tasks =
    Enumerable.Range(1, 500)
    .Select(i => Task.Factory.StartNew<int>(ProduceSomeMagicIntValue))
    .ToArray();

and then join them with

Task.WaitAll(tasks);

On this last line I get a blue squiggly marker under tasks, with a warning message:

Co-variant array conversion from Task[] to Task[] 
can cause run-time exception on write operation.

I understand why I get this message, but is there a way around that? (for example, like a generic version of Task.WaitAll()?)

Answer 1

I'm pretty sure it's a safe operation even with the warning, but if you really wanted to get around it a better option than creating your own implementation would be just to convert your tasks parameter into the type it wants:

Task.WaitAll(tasks.Cast<Task>().ToArray())

That kills the blue squiggles for me, lets me keep my tasks variable generic and doesn't force me to create a whole lot of new scary code that's ultimately unnecessary.