I have something like this:

enum isValid(T) = is(T == MyClass1);

class MyClass1 {}

class MyContainer(T)
{
   T value;
   alias value this;
}

void main()
{
	assert(isValid!MyClass1, "MyClass1 isn't valid");
	assert(isValid!(MyContainer!MyClass1), "MyContainer!MyClass1 isn't valid");
}

second assert conditions is false. But in normal code MyContainer!Myclass1 is casted automagically to MyClass1 and works almost as MyClass1.

Is there a way to check this at compile time?

On Tuesday, 17 December 2013 at 16:50:18 UTC, Andrea Fontana wrote:
> I have something like this:
>
> enum isValid(T) = is(T == MyClass1);
>
> class MyClass1 {}
>
> class MyContainer(T)
> {
>    T value;
>    alias value this;
> }
>
> void main()
> {
> 	assert(isValid!MyClass1, "MyClass1 isn't valid");
> 	assert(isValid!(MyContainer!MyClass1), "MyContainer!MyClass1 isn't valid");
> }
>
> second assert conditions is false. But in normal code MyContainer!Myclass1 is casted automagically to MyClass1 and
> works almost as MyClass1.
>
> Is there a way to check this at compile time?

is(T : MyClass1)

On Tuesday, 17 December 2013 at 17:19:26 UTC, anonymous wrote:
> On Tuesday, 17 December 2013 at 16:50:18 UTC, Andrea Fontana wrote:
>> I have something like this:
>>
>> enum isValid(T) = is(T == MyClass1);
>>
>> class MyClass1 {}
>>
>> class MyContainer(T)
>> {
>>   T value;
>>   alias value this;
>> }
>>
>> void main()
>> {
>> 	assert(isValid!MyClass1, "MyClass1 isn't valid");
>> 	assert(isValid!(MyContainer!MyClass1), "MyContainer!MyClass1 isn't valid");
>> }
>>
>> second assert conditions is false. But in normal code MyContainer!Myclass1 is casted automagically to MyClass1 and
>> works almost as MyClass1.

Hey didn't this mean "is derived from"? :)
>>
>> Is there a way to check this at compile time?
>
> is(T : MyClass1)

On Tuesday, 17 December 2013 at 21:28:12 UTC, Andrea Fontana wrote:
> Hey didn't this mean "is derived from"? :)
>>>
>>> Is there a way to check this at compile time?
>>
>> is(T : MyClass1)

It actually means "is implicitly convertable to", which "is derived from" satisfies.