function overload on full signature?

[Timon Gehr]

On 11/15/2012 07:09 PM, Sönke Ludwig wrote:
> Am 14.11.2012 20:07, schrieb Timon Gehr:
>> On 11/14/2012 06:30 PM, Rob T wrote:
>>> On Wednesday, 14 November 2012 at 09:16:13 UTC, Walter Bright wrote:
>>>>> I'm not requesting this to be a feature of D, I'm only asking why it
>>>>> is not
>>>>> being done.
>>>>
>>>> Because types are resolved bottom-up, and if the return type were part
>>>> of the overloading, there would be no sensible rule to determine the
>>>> types.
>>>
>>> But doesn't the compiler already have to perform overload-like decision
>>> making on return types in the "alias this" case, esp once multiple
>>> conversions are allowed?
>>>
>>> class A{
>>>     int i;
>>>     bool b;
>>>     alias i this;
>>>     alias b this;
>>> }
>>>
>>> main()
>>> {
>>>     auto a = new A;
>>>     int i = a;
>>>     bool b = a;
>>> }
>>>
>>> --rt
>>
>> alias this is not the best example, but the necessary logic is basically already in the compiler.
>> Lambda parameter type deduction based on the expected type is a similar task.
>>
>> It is not being done because it is not being done. Full type inference would be even more fun.
>
> In the lambda case it's return type deduction and not overload resolution. Those are actually two
> very different things.
>

Yes, lambda _return_ type deduction is less related, but I have never 
claimed otherwise.

Another case that shows how a compiler must be able to take into account 
the left hand side of an assignment in order to type check the right 
hand side:

int foo(int);
double foo(int);

void main(){
     double function(int) fun = &foo;
}