immutable singleton pattern with static opCall

[Justin Johansson]

Michal Minich wrote:
> On Sun, 27 Jun 2010 09:36:04 +0930, Justin Johansson wrote:
> 
>> immutable class Foo
>> {
>>     static private Foo instance;
>>
>>     static this() {			// line 9
>>        instance = new Foo;
>>     }
>>
>>     static Foo opCall() {		// line 13
>>        return instance;
>>     }
>> }
>>
>> test.d(9): Error: function test.Foo._staticCtor2 without 'this' cannot
>> be const/immutable
>> test.d(13): Error: function test.Foo.opCall without 'this' cannot be
>> const/immutable
> 
> there is bug report on this subject
> 
> http://d.puremagic.com/issues/show_bug.cgi?id=3598
> 
> Your example also uses static variable, which was not considered in the 
> bug report. This makes things more complex to design properly, because it 
> seems now that one does not want static functions to be affected by  
> immutable attribute of class, but it should affect static data...

Thanks for your quick response and analysis.

I agree that "it should affect static data".  Since this bug impedes
the use of good functional style, imho this is a *serious* bug.