Automatic typing

[Timon Gehr]

On 07/01/2013 05:44 AM, JS wrote:
> On Monday, 1 July 2013 at 01:56:22 UTC, Timon Gehr wrote:
>> ...
>> The described strategy can easily result in non-termination, and which
>> template instantiations it performs can be non-obvious.
>>
>> auto foo(T)(T arg){
>>     static if(is(T==int)) return 1.0;
>>     else return 1;
>> }
>>
>> void main(){
>>     auto x;
>>     x = 1;
>>     x = foo(x);
>> }
>
> Sorry,

That's fine.

> it only results in non-termination if you don't check all return
> types out of a function.

Why is this relevant? I was specifically responding to the method lined 
out in the post I was answering. There have not been any other attempts 
to formalize the proposal so far.

> It is a rather easy case to handle by just
> following all the return types and choosing the largest one.

That neither handles the above case in a sensible way nor is it a 
solution for the general issue. (Hint: D's type system is Turing complete.)

> No big deal...  any other tries?

That's not how it goes. The proposed inference method has to be 
completely specified for all instances, not only for those instances 
that I can be bothered to provide to you as counterexamples.