dmd 1.070 and 2.055 release

[Timon Gehr]

On 09/12/2011 09:38 AM, Max Samukha wrote:
> On 09/11/2011 08:57 PM, Walter Bright wrote:
>> On 9/11/2011 9:08 AM, Max Samukha wrote:
>>> This test case
>>>
>>> struct S
>>> {
>>> @disable this();
>>> this(int x)
>>> {
>>> }
>>> }
>>>
>>> class C
>>> {
>>> S s;
>>> this()
>>> {
>>> s = S(42);
>>> }
>>> }
>>>
>>> void main()
>>> {
>>> auto c = new C;
>>> }
>>>
>>> yields Error: default construction is disabled for type C
>>>
>>> Is it a bug?
>>
>> No, it's a feature!
>
> That's sad. The question should rather have been: what do I do to use
> member structs that have default constructors disabled? Initially I
> thought that the compiler would treat the first assignment in the
> constructor specially as initializer. The error message "Error:
> constructor test.C.this field s must be initialized in constructor"
> suggested that. I was wrong.
>

You were right, it does. You just cannot default construct C if S cannot 
be default constructed. This works:

struct S {
     @disable this();
     this(int x) {
     }
}

class C {
     S s;
     this(int) {
	s = S(42); // comment out this line and it does not compile
     }
}

void main() {
     auto c = new C(0);
}

And that implies that the 'feature' of infectious default constructor 
disabling for classes is worthless. But it makes perfect sense for structs.