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ElementType of MapResult is a delegate??
Dec 08, 2018
Yuxuan Shui
Dec 08, 2018
John Chapman
December 08, 2018
Gravatar of Yuxuan ShuiPosted by Yuxuan ShuiReply
Yuxuan Shui
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This surprised me A LOT:

https://d.godbolt.org/z/82a_GZ

So if I call something.map!().array, I get an array of delegates? That makes no sense to me.
December 08, 2018
Gravatar of John ChapmanPosted by John Chapman
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John Chapman
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On Saturday, 8 December 2018 at 13:02:00 UTC, Yuxuan Shui wrote:
> This surprised me A LOT:
>
> https://d.godbolt.org/z/82a_GZ
>
> So if I call something.map!().array, I get an array of delegates? That makes no sense to me.

But in your example, "(a) =>" returns "{return tmp;}", which is a delegate. Just write "(a) => tmp", or invoke the delegate by turning it into a call: "{return tmp;}()".
December 09, 2018
Gravatar of Steven SchveighofferPosted by Steven Schveighoffer
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Steven Schveighoffer
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On 12/8/18 8:19 AM, John Chapman wrote:
> On Saturday, 8 December 2018 at 13:02:00 UTC, Yuxuan Shui wrote:
>> This surprised me A LOT:
>>
>> https://d.godbolt.org/z/82a_GZ
>>
>> So if I call something.map!().array, I get an array of delegates? That makes no sense to me.
> 
> But in your example, "(a) =>" returns "{return tmp;}", which is a delegate. Just write "(a) => tmp", or invoke the delegate by turning it into a call: "{return tmp;}()".

This is exactly why (a) => {return tmp;} should not compile.

Almost everyone has made that mistake.

-Steve