When are associative arrays meant to throw a RangeError?

[Andrej Mitrovic]

On 2/19/12, Andrej Mitrovic <andrej.mitrovich at gmail.com> wrote:
> Chunk[] tempVar = chunks.get("CCCC", null) ~ new Chunk();

I've tried making a wrapper type that does this behind the scenes but
it won't work:

struct Hash(Key, Val)
{
    Val[Key] aa;

    Val opIndex(Key key)
    {
        return aa.get(key, Val.init);
    }

    alias aa this;
}

class Chunk { }
alias Hash!(string, Chunk) ChunkHash;

void main()
{
    ChunkHash chunks;
    Chunk[] tempVar = chunks["CCCC"] ~ new Chunk();
}

test.d(20): Error: incompatible types for ((chunks.opIndex("CCCC")) ~
(new Chunk)): 'test.Chunk' and 'test.Chunk'

Very odd..