Why is D unpopular, redux.

[Timon Gehr]

On 24.05.22 07:31, Walter Bright wrote:
> 
>> https://issues.dlang.org/show_bug.cgi?id=2043
> 
> We have better tools to deal with 2043 today. Note that dgList exceeds 
> the lifetime of b, and should fail to compile for that reason.
> 
> Let's try it (adding import and @safe and updating the code to D2):
> ----
> import std.stdio;
> 
> @safe:
> 
> void delegate()[] dgList;
> 
> void test() {
> 
>          foreach(int i; [1, 2, 3]) {
>                  int b = 2;
>                  dgList ~= { writeln(b); };
>                  writeln(&b); // b will be the *same* on each iteration
>          }
> }
> ----
> 
>  > dmd test.c -preview=dip1000
> test.d(13): Error: reference to local variable `b` assigned to non-scope 
> parameter `_param_0`
> 
> Looks like we can close it now!

No. The correct behavior when a delegate literal outlives captured 
variables is to allocate a closure. This case is not an exception...