Template specification conflict

[Dmitry Olshansky]

On 02.08.2011 16:18, simendsjo wrote:
> On 02.08.2011 14:13, Dmitry Olshansky wrote:
>> On 02.08.2011 16:06, simendsjo wrote:
>>> On 02.08.2011 13:55, Dmitry Olshansky wrote:
>>>> On 02.08.2011 15:06, simendsjo wrote:
>>>>> The following program gives me
>>>>> "Error: template t.S.__ctor(C) if(isSomeChar!(C)) conflicts with
>>>>> constructor t.S.this at t.d(4)"
>>>>>
>>>>> Is this because char etc can be converted to uint? Shouldn't the
>>>>> template specification make this unambiguous?
>>>>>
>>>>> import std.traits;
>>>>>
>>>>> struct S {
>>>>> this(uint i) {}
>>>>> this(C)(C c) if(isSomeChar!C) {}
>>>>> }
>>>>>
>>>>> void main() {}
>>>>
>>>> struct S {
>>>> this()(uint i) {}
>>>> this(C)(C c) if(isSomeChar!C) {}
>>>> }
>>>>
>>>> should do it, though it (and workaround) looks like a bug to me.
>>>>
>>>
>>> With the empty templated this, I get other errors though:
>>> "t.d(5): Error: constructor t.S.this conflicts with template
>>> t.S.__ctor() at t.d(4)"
>>>
>>> struct S {
>>> this()(int a) {} // 4
>>> this(int a, int b) {} // 5
>>> }
>>>
>> Same logic here once you have template constructor, all others need to
>> be template, empty spec is a trick to get anything to be a template. And
>> in this example you really do not need empty spec () in 4.
>>
>
> So my first example is a bug, and the second is a wrong error message?
> Wondering what I should post in a potential bug report, and if it's 
> one or two bugs.
I think there is only one bug: template constructor (and functions IIRC) 
can't be overloaded with non-template.
Both your examples show this bug, since this()(int a){} and this(C)(C c) 
if(isSomeChar!C) {}  are template constructors, while others are not.
I think the bug was there for quite some time and likely to be filed 
already, so check Bugzilla first.

-- 
Dmitry Olshansky