In my strive to add msgpacking support for std.container.Array I've been blocked by the fact that std.container.Array.opIndex only has one overload which is non-const probably because it returns a ref T. This doesn't place nicely with serialization.

Shouldn't inout be used here?

On Sunday, 28 September 2014 at 08:58:27 UTC, Nordlöw wrote:
> In my strive to add msgpacking support for std.container.Array I've been blocked by the fact that std.container.Array.opIndex only has one overload which is non-const probably because it returns a ref T. This doesn't place nicely with serialization.
>
> Shouldn't inout be used here?

Further I've tried tagging all opIndex in array.d with inout as

    inout ref T opIndex(size_t i) inout

but then I get another error

array.d(479,30): Error: cast(string)this._data.refCountedPayload()._payload[i] is not an lvalue

On Sunday, 28 September 2014 at 09:04:42 UTC, Nordlöw wrote:
> On Sunday, 28 September 2014 at 08:58:27 UTC, Nordlöw wrote:
>> In my strive to add msgpacking support for std.container.Array I've been blocked by the fact that std.container.Array.opIndex only has one overload which is non-const probably because it returns a ref T. This doesn't place nicely with serialization.
>>
>> Shouldn't inout be used here?
>
> Further I've tried tagging all opIndex in array.d with inout as
>
>     inout ref T opIndex(size_t i) inout
>
> but then I get another error
>
> array.d(479,30): Error: cast(string)this._data.refCountedPayload()._payload[i] is not an lvalue

Probably you want:

ref inout(T) opIndex(size_t i) inout

Instead. What you wrote was basically the same as:
ref T opIndex(size_t i) inout inout

While compiling, the "inout(T)" obtained from "_payload[i]" is "value-converted" into a "T" (makes it an lvalue), and then the return (which is "ref") fails.

This is the whole "function attributes on left side confusion" - fiasco thing...

On Sunday, 28 September 2014 at 20:27:32 UTC, monarch_dodra wrote:
> This is the whole "function attributes on left side confusion" - fiasco thing...

https://github.com/D-Programming-Language/phobos/pull/2573