Constructor template -- bug?

[Jacob Carlborg]

On 2011-03-02 09:07, Jonathan M Davis wrote:
> On Tuesday 01 March 2011 23:52:38 Jacob Carlborg wrote:
>> On 2011-03-02 08:47, Jonathan M Davis wrote:
>>> On Tuesday 01 March 2011 23:43:27 Jonathan M Davis wrote:
>>>> On Tuesday 01 March 2011 22:18:49 Bekenn wrote:
>>>>> Code:
>>>>> 	class MyException : Exception
>>>>> 	{
>>>>> 	
>>>>> 		this(string message, string file, size_t line, Throwable next =
> null)
>>>>> 		{
>>>>> 		
>>>>> 			super(message, file, line, next);
>>>>> 		
>>>>> 		}
>>>>> 		
>>>>> 		this(string file = __FILE__, size_t line = __LINE__)(string
> message,
>>>>>
>>>>> Throwable next = null)
>>>>>
>>>>> 		{
>>>>> 		
>>>>> 			this(message, file, line, next);
>>>>> 		
>>>>> 		}
>>>>> 	
>>>>> 	}
>>>>> 	
>>>>> 	void main()
>>>>> 	{
>>>>> 	
>>>>> 		throw new MyException("Bluh!");
>>>>> 	
>>>>> 	}
>>>>>
>>>>> Error message:
>>>>> 	test.d(8): Error: template test.MyException.__ctor(string file =
>>>>>
>>>>> __FILE__,size_t line = __LINE__) conflicts with constructor
>>>>> test.MyException.this at test.d(3)
>>>>>
>>>>> If I remove the normal constructor and call super instead of this from
>>>>>
>>>>> the constructor template, then I get this slightly different error message:
>>>>> 	test.d(1): Error: constructor test.MyException.this conflicts with
>>>>>
>>>>> template test.MyException.__ctor(string file = __FILE__,uint line =
>>>>> __LINE__) at test.d(3)
>>>>>
>>>>> Is this a compiler bug, or am I Doing It Wrong?
>>>>
>>>> You cannot currently templatize class constructors:
>>>>
>>>> http://d.puremagic.com/issues/show_bug.cgi?id=435
>>>>
>>>> And currently if one overload of a function is templatized, _all_
>>>> overloads of that function must templatized:
>>>>
>>>> http://d.puremagic.com/issues/show_bug.cgi?id=2972
>>>> http://d.puremagic.com/issues/show_bug.cgi?id=4749
>>>
>>> I should also point out that there is absolutely no need to use template
>>> for what you're trying to do. Just declare the constructor like so:
>>>
>>> this(string message, string file = __FILE__, size_t line = __LINE__
>>> Throwable next = null) { ... }
>>>
>>> - Jonathan M Davis
>>
>> I guess the reason why he would do that is to catch the file and line
>> number where the constructor is called.
>
> Except that that works with normal default arguments. I assume that he did not
> realize that.
>
> - Jonathan M Davis

Neither did I.

-- 
/Jacob Carlborg