1. It's currently not possible to overload opAssign for structs with a template because opAssign(T)(T rh) if(is(T == typeof(this)))

is not allowed (stated in the documentation). And templates can not overload non template functions (already a known bug).

2. It's not possible to use auto ref with opAssign because opAssign(T)(auto ref T rh) if(is(T == typeof(this))) is not allowed (partly the same issue as 1).

Why is this not allowed? (The documentation does not state any reason)

3. Calling a method that is overloaded with shared / const / immutable from within a function has to be done with this.method()
otherwise the compiler complains about ambugiosity. Is method() not the same as this.method() ??

-- 
Kind Regards
Benjamin Thaut

On 01/11/2012 05:58 PM, Benjamin Thaut wrote:
> 1. It's currently not possible to overload opAssign for structs with a
> template because opAssign(T)(T rh) if(is(T == typeof(this)))
>
> is not allowed (stated in the documentation). And templates can not
> overload non template functions (already a known bug).
>
> 2. It's not possible to use auto ref with opAssign because
> opAssign(T)(auto ref T rh) if(is(T == typeof(this))) is not allowed
> (partly the same issue as 1).
>
> Why is this not allowed? (The documentation does not state any reason)

There is no reason, and DMD accepts it. Maybe file a bug against the documentation?

struct S{
    auto opAssign(T)(auto ref T rhs) if(is(T==typeof(this))){return rhs;}
}

void main(){
    S a, b;
    a=b;
}

>
> 3. Calling a method that is overloaded with shared / const / immutable
> from within a function has to be done with this.method()
> otherwise the compiler complains about ambugiosity. Is method() not the
> same as this.method() ??
>

Yes it is. Has this been filed already?

Am 11.01.2012 20:05, schrieb Timon Gehr:
> On 01/11/2012 05:58 PM, Benjamin Thaut wrote:
>> 1. It's currently not possible to overload opAssign for structs with a
>> template because opAssign(T)(T rh) if(is(T == typeof(this)))
>>
>> is not allowed (stated in the documentation). And templates can not
>> overload non template functions (already a known bug).
>>
>> 2. It's not possible to use auto ref with opAssign because
>> opAssign(T)(auto ref T rh) if(is(T == typeof(this))) is not allowed
>> (partly the same issue as 1).
>>
>> Why is this not allowed? (The documentation does not state any reason)
>
> There is no reason, and DMD accepts it. Maybe file a bug against the
> documentation?
>
> struct S{
> auto opAssign(T)(auto ref T rhs) if(is(T==typeof(this))){return rhs;}
> }
>
> void main(){
> S a, b;
> a=b;
> }
>
>>
>> 3. Calling a method that is overloaded with shared / const / immutable
>> from within a function has to be done with this.method()
>> otherwise the compiler complains about ambugiosity. Is method() not the
>> same as this.method() ??
>>
>
> Yes it is. Has this been filed already?

The bugs are not filed yet as I wanted to make sure that they are actually bugs. I have repro cases for both of them, I just need to shrink them down. As soon as I have small repro cases I'm going to file them.

-- 
Kind Regards
Benjamin Thaut

Am 11.01.2012 20:05, schrieb Timon Gehr:
> On 01/11/2012 05:58 PM, Benjamin Thaut wrote:
>> 1. It's currently not possible to overload opAssign for structs with a
>> template because opAssign(T)(T rh) if(is(T == typeof(this)))
>>
>> is not allowed (stated in the documentation). And templates can not
>> overload non template functions (already a known bug).
>>
>> 2. It's not possible to use auto ref with opAssign because
>> opAssign(T)(auto ref T rh) if(is(T == typeof(this))) is not allowed
>> (partly the same issue as 1).
>>
>> Why is this not allowed? (The documentation does not state any reason)
>
> There is no reason, and DMD accepts it. Maybe file a bug against the
> documentation?
>
> struct S{
> auto opAssign(T)(auto ref T rhs) if(is(T==typeof(this))){return rhs;}
> }
>
> void main(){
> S a, b;
> a=b;
> }
>
>>
>> 3. Calling a method that is overloaded with shared / const / immutable
>> from within a function has to be done with this.method()
>> otherwise the compiler complains about ambugiosity. Is method() not the
>> same as this.method() ??
>>
>
> Yes it is. Has this been filed already?

Bug ticket for issue 3: http://d.puremagic.com/issues/show_bug.cgi?id=7276

-- 
Kind Regards
Benjamin Thaut

Am 11.01.2012 20:05, schrieb Timon Gehr:
> On 01/11/2012 05:58 PM, Benjamin Thaut wrote:
>> 1. It's currently not possible to overload opAssign for structs with a
>> template because opAssign(T)(T rh) if(is(T == typeof(this)))
>>
>> is not allowed (stated in the documentation). And templates can not
>> overload non template functions (already a known bug).
>>
>> 2. It's not possible to use auto ref with opAssign because
>> opAssign(T)(auto ref T rh) if(is(T == typeof(this))) is not allowed
>> (partly the same issue as 1).
>>
>> Why is this not allowed? (The documentation does not state any reason)
>
> There is no reason, and DMD accepts it. Maybe file a bug against the
> documentation?
>
> struct S{
> auto opAssign(T)(auto ref T rhs) if(is(T==typeof(this))){return rhs;}
> }
>
> void main(){
> S a, b;
> a=b;
> }
>
>>
>> 3. Calling a method that is overloaded with shared / const / immutable
>> from within a function has to be done with this.method()
>> otherwise the compiler complains about ambugiosity. Is method() not the
>> same as this.method() ??
>>
>
> Yes it is. Has this been filed already?

I have a repro case for issue 1+2. It seems to be connected to the bostplit constructor. Does the postblit constructor infer with opAssign overloading?

struct Array(T){
  T[] data;

  alias typeof(this) this_t;

  this(this)
  {
    data = data.dup;
  }

  this_t opAssign(U)(auto ref U rh) if(is(U == this_t))
  {
    data = rh.data;
    return rh;
  }

  auto opAssign(U)(U rh) if(is(U == T[]))
  {
    data = rh;
    return rh;
  }
}

int main(string[] argv)
{
   Array!int bla;
   bla = [1,2,3];
   return 0;
}

main.d(15): Error: function main.Array!(int).Array.opAssign conflicts with template main.Array!(int).Array.opAssign(U) if (is(U == this_t)) at main.d(25)
main.d(40): Error: template instance main.Array!(int) error instantiating

-- 
Kind Regards
Benjamin Thaut

The definition of postblit generates an non-templated built-in
opAssign implicitly.
And it conflicts with your templated opAssign.

It is already filed in bugzilla.

Issue 4424 - Copy constructor and templated opAssign cannot coexist http://d.puremagic.com/issues/show_bug.cgi?id=4424

Kenji Hara

2012/1/12 Benjamin Thaut <code@benjamin-thaut.de>:
> Am 11.01.2012 20:05, schrieb Timon Gehr:
>>
>> On 01/11/2012 05:58 PM, Benjamin Thaut wrote:
>>
>>> 1. It's currently not possible to overload opAssign for structs with a
>>> template because opAssign(T)(T rh) if(is(T == typeof(this)))
>>>
>>> is not allowed (stated in the documentation). And templates can not
>>> overload non template functions (already a known bug).
>>>
>>> 2. It's not possible to use auto ref with opAssign because
>>> opAssign(T)(auto ref T rh) if(is(T == typeof(this))) is not allowed
>>> (partly the same issue as 1).
>>>
>>> Why is this not allowed? (The documentation does not state any reason)
>>
>>
>> There is no reason, and DMD accepts it. Maybe file a bug against the documentation?
>>
>> struct S{
>> auto opAssign(T)(auto ref T rhs) if(is(T==typeof(this))){return rhs;}
>> }
>>
>> void main(){
>> S a, b;
>> a=b;
>> }
>>
>>>
>>> 3. Calling a method that is overloaded with shared / const / immutable
>>> from within a function has to be done with this.method()
>>> otherwise the compiler complains about ambugiosity. Is method() not the
>>> same as this.method() ??
>>>
>>
>> Yes it is. Has this been filed already?
>
>
> I have a repro case for issue 1+2. It seems to be connected to the bostplit constructor. Does the postblit constructor infer with opAssign overloading?
>
> struct Array(T){
>  T[] data;
>
>  alias typeof(this) this_t;
>
>  this(this)
>  {
>    data = data.dup;
>  }
>
>  this_t opAssign(U)(auto ref U rh) if(is(U == this_t))
>  {
>    data = rh.data;
>    return rh;
>  }
>
>  auto opAssign(U)(U rh) if(is(U == T[]))
>  {
>    data = rh;
>    return rh;
>  }
> }
>
> int main(string[] argv)
> {
>   Array!int bla;
>   bla = [1,2,3];
>   return 0;
> }
>
> main.d(15): Error: function main.Array!(int).Array.opAssign conflicts with
> template main.Array!(int).Array.opAssign(U) if (is(U == this_t)) at
> main.d(25)
> main.d(40): Error: template instance main.Array!(int) error instantiating
>
>
> --
> Kind Regards
> Benjamin Thaut

Am 12.01.2012 08:15, schrieb kenji hara:
> The definition of postblit generates an non-templated built-in
> opAssign implicitly.
> And it conflicts with your templated opAssign.
>
> It is already filed in bugzilla.
>
> Issue 4424 - Copy constructor and templated opAssign cannot coexist
> http://d.puremagic.com/issues/show_bug.cgi?id=4424
>
> Kenji Hara
>
> 2012/1/12 Benjamin Thaut<code@benjamin-thaut.de>:
>> Am 11.01.2012 20:05, schrieb Timon Gehr:
>>>
>>> On 01/11/2012 05:58 PM, Benjamin Thaut wrote:
>>>
>>>> 1. It's currently not possible to overload opAssign for structs with a
>>>> template because opAssign(T)(T rh) if(is(T == typeof(this)))
>>>>
>>>> is not allowed (stated in the documentation). And templates can not
>>>> overload non template functions (already a known bug).
>>>>
>>>> 2. It's not possible to use auto ref with opAssign because
>>>> opAssign(T)(auto ref T rh) if(is(T == typeof(this))) is not allowed
>>>> (partly the same issue as 1).
>>>>
>>>> Why is this not allowed? (The documentation does not state any reason)
>>>
>>>
>>> There is no reason, and DMD accepts it. Maybe file a bug against the
>>> documentation?
>>>
>>> struct S{
>>> auto opAssign(T)(auto ref T rhs) if(is(T==typeof(this))){return rhs;}
>>> }
>>>
>>> void main(){
>>> S a, b;
>>> a=b;
>>> }
>>>
>>>>
>>>> 3. Calling a method that is overloaded with shared / const / immutable
>>>> from within a function has to be done with this.method()
>>>> otherwise the compiler complains about ambugiosity. Is method() not the
>>>> same as this.method() ??
>>>>
>>>
>>> Yes it is. Has this been filed already?
>>
>>
>> I have a repro case for issue 1+2. It seems to be connected to the bostplit
>> constructor. Does the postblit constructor infer with opAssign overloading?
>>
>> struct Array(T){
>>   T[] data;
>>
>>   alias typeof(this) this_t;
>>
>>   this(this)
>>   {
>>     data = data.dup;
>>   }
>>
>>   this_t opAssign(U)(auto ref U rh) if(is(U == this_t))
>>   {
>>     data = rh.data;
>>     return rh;
>>   }
>>
>>   auto opAssign(U)(U rh) if(is(U == T[]))
>>   {
>>     data = rh;
>>     return rh;
>>   }
>> }
>>
>> int main(string[] argv)
>> {
>>    Array!int bla;
>>    bla = [1,2,3];
>>    return 0;
>> }
>>
>> main.d(15): Error: function main.Array!(int).Array.opAssign conflicts with
>> template main.Array!(int).Array.opAssign(U) if (is(U == this_t)) at
>> main.d(25)
>> main.d(40): Error: template instance main.Array!(int) error instantiating
>>
>>
>> --
>> Kind Regards
>> Benjamin Thaut

Thanks for the info. It's nice that there is already a pull request to fix this.

-- 
Kind Regards
Benjamin Thaut