Voldemort structs no longer work?

[Iain Buclaw]

On 15 December 2012 19:58, Iain Buclaw <ibuclaw at ubuntu.com> wrote:

> On 15 December 2012 19:45, H. S. Teoh <hsteoh at quickfur.ath.cx> wrote:
>
>> On Sat, Dec 15, 2012 at 11:31:22AM -0800, Jonathan M Davis wrote:
>> > On Saturday, December 15, 2012 19:50:34 Iain Buclaw wrote:
>> > > On Saturday, 15 December 2012 at 18:38:29 UTC, H. S. Teoh wrote:
>> > > > With latest git dmd:
>> > > >   auto makeVoldemort(int x) {
>> > > >
>> > > >           struct Voldemort {
>> > > >
>> > > >                   @property int value() { return x; }
>> > > >
>> > > >           }
>> > > >           return Voldemort();
>> > > >
>> > > >   }
>> > > >   void main() {
>> > > >
>> > > >           auto v = makeVoldemort();
>> > > >           writeln(v.value);
>> > > >
>> > > >   }
>> > > >
>> > > > Compile error:
>> > > >   test.d(3): Error: function test.makeVoldemort.Voldemort.value
>> > > >
>> > > > cannot access frame of function test.makeVoldemort
>> > > >
>> > > > Changing 'struct' to 'class' works. Is this deliberate, or is it a
>> > > > bug?  It is certainly inconsistent with Walter's article on
>> > > > Voldemort types, which uses structs as examples.
>> [...]
>> > > Pretty certain it's deliberate.  No closure is created for nested
>> > > structs to access it's parent, complying with it's POD behaviour.
>> >
>> > static nested structs don't have access to their outer scopes.
>> > Non-static structs do. This reeks of a bug.
>> [...]
>>
>> Found the reference in TDPL, §7.1.9 (p.263):
>>
>>         Nested structs embed the magic "frame pointer" that allows them
>>         to access outer values such as a and b in the example above.
>>         [...] If you want to define a nested struct without that
>>         baggage, just prefix struct with static in the definition of
>>         Local, which makes Local a regular struct and consequently
>>         prevents it from accessing a and b.
>>
>> Ironically enough, Andrei in the subsequent paragraph discourages the
>> use of such nested structs, whereas Walter's article promotes the use of
>> such Voldemort types as a "happy discovery". :)
>>
>> Anyway, filed a bug:
>>
>>         http://d.puremagic.com/issues/show_bug.cgi?id=9162
>>
>>
> If it is one, it's a bug in FuncDeclaration::getLevel.
>
>
And if it isn't FuncDeclaration::getLevel(), then it is a bug because the
struct Voldemort does not represent itself as a nested type.

-- 
Iain Buclaw

*(p < e ? p++ : p) = (c & 0x0f) + '0';
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