Goto skips declaration

[Rubn]

On Saturday, 3 November 2018 at 03:52:12 UTC, Michelle Long wrote:
> On Tuesday, 30 October 2018 at 23:31:46 UTC, luckoverthere 
> wrote:
>> On Tuesday, 30 October 2018 at 21:21:22 UTC, Michelle Long 
>> wrote:
>>>
>>> You take examples WAY to literal. Sheesh, do you really think 
>>> life is that simple? Do you need every detail spelled out for 
>>> things to make sense?
>>>
>>> foreach(x; Y)
>>> {
>>>     if (something or another which I won't spell out no 
>>> matter how much you cry)
>>>         goto Q; // compiler complains here about x
>>>     int x;
>>> }
>>> Q:
>>>
>>> There is no reason why the compiler should have a problem 
>>> with this.. the fact that using brackets around int x; 
>>> satisfies the compiler proves this.
>>
>>
>> struct Magic
>> {
>>     ~Magic()
>>     {
>>         writeln("blah");
>>     }
>> ]
>>
>> void test()
>> {
>>     if(cond)
>>         goto Y;
>>
>>     Magic magic;
>>
>>     Y:
>>     writeln("stuff");
>>
>>     // calls ~Magic();
>> }
>>
>> You'd need a bunch of extra information to know what is and 
>> wasn't actually declared and initialized.
>>
>> "Putting brackets around it proves it".
>>
>> void test()
>> {
>>     if(cond)
>>         goto Y;
>>
>>     {
>>         Magic magic;
>>
>>         // calls ~Magic();
>>     }
>>
>>     Y:
>>     writeln("stuff");
>>
>> }
>>
>> There is no more conflict with brackets, yes. But expecting 
>> the compiler to do this changes the behavior of the code. Sure 
>> if there's no destructor it could work around it, but it would 
>> complicated code generation. Adding a bunch of time looking 
>> for these circumstances.
>>
>> It's just not worth it, use brackets like you are now or move 
>> the declarations of your variables up to the top of the scope 
>> before any gotos. Pretty simple workarounds.
>
>
> You are not understanding the problem. The goto must be in the 
> same scope as the local variable:
>
> {
>
>    goto Y;
>    int x;
> }
> Y:
>
> The compiler will complain(I'm doing it in a foreach loop) that 
> x is skipped!!!
>
> Do you understand?
>
> The goto will always bypass x being declared so it doesn't 
> matter. The compiler may optimize out the simple case above, 
> but that is irrelevant to the problem.
>
> The problem is simple: The compiler thinks that the declared 
> variables are used after the goto but it is impossible since 
> the goto skips out of the block and the local variables cease 
> to exist.
>
> The compiler treats the problem as if it is
>
> {
>     goto Y:
>     int x;
>     Y:
> }
>
> and that is a totally different problem. They are not the same 
> but the compiler treats them the same.
>
> In the second case the goto does skip over the declaration, in 
> the first case it does not. In the second case it is a problem 
> but in the first case it cannot be.
>
> Again, adding the brackets proves it.


The problem you describe doesn't exist.

https://run.dlang.io/is/Snpt3l

If that isn't the issue, then actually give a runable source 
example with the associated error that it produces.