Error about constructor calls in loops/labels, but there are no loops and labels?

[Steven Schveighoffer]

On 5/20/18 6:56 AM, Yuxuan Shui wrote:
> On Sunday, 20 May 2018 at 00:05:39 UTC, Jonathan M Davis wrote:
>> because it tends to become very difficult to get right in all cases 
>> and results in situations where the programmer is forced to do 
>> something in order to make the compiler shut up
> 
> Well, doesn't this post show exactly this problem, and that's because 
> the compiler is too dumb?
> 
> Making the compiler smarter will only decrease the number of these cases.

There is something to be said for keeping the compiler dumb:

1. Dumb is easy to implement, explain, and understand -- if you set the 
bar low then more compilers will be able to handle the use cases. Having 
code that compiles with all available compilers is better than something 
that you need a specific "really smart" compiler to work.
2. No matter how smart you make the compiler, you will get into 
situations that it can't figure out (halting problem). If you are going 
to have some situations that it doesn't handle, then it's really just a 
matter of where to draw the line. D has this problem with forward 
references -- it's a never ending battle of shuffling things around 
sometimes. The smarter you get, the more odd and difficult to deal with 
the cases that won't work become.

With inner functions, it's really easy to satisfy the compiler here. You 
just have to make a few changes in your code, I don't see it being a 
huge problem.

I've been using Swift in the past few years quite a bit, and it always 
amuses me when it can't figure out some kind of inference that seems 
trivial, but it just gives up because the compiler takes too long to 
determine: "This [one line] statement is too difficult, please split 
into multiple statements." This is the kind of stuff you would be 
encountering.

-Steve