Can someone explain why i can change this immutable variable please?

[Daniel Davidson]

On Wednesday, 9 October 2013 at 15:46:29 UTC, Gary Willoughby 
wrote:
>
> So why does this give me an error i expect:
>
> 	import std.stdio;
>
> 	class Foo
> 	{
> 		public void change(string[] name)
> 		{
> 			name[0] = "tess";
> 			writeln(name);
> 		}
> 	}
>
> 	class Bar
> 	{
> 		private static immutable string name[] = ["gary"];
>
> 		public void test()
> 		{
> 			auto foo = new Foo();
> 			foo.change(this.name);
> 		}
> 	}
>
> 	void main(string[] args)
> 	{
> 		auto bar = new Bar();
> 		bar.test();
> 	}

Maybe this will help explain it:
void main() {
   pragma(msg, typeof(Bar.name));
   pragma(msg, typeof(Foo.change));
}
will print:

immutable(char[][])
void(string[] name)

The latter is really:

void(immutable(char)[] name)

The former is really:
immutable(immutable(immutable(char)[])[])

So for name the whole kit and kaboodle is immutable and you can 
not pass the whole immutable thing into something that is only 
immutable at one level.

Thanks
Dan