Re: IFTI in Eponymous Templates

[Hiemlick Hiemlicker via Digitalmars-d-learn]

On Wednesday, 29 June 2016 at 18:59:19 UTC, jmh530 wrote:
I was playing around with some Eponymous Templates. I had been 
under the impression that Implicit Function-Template 
Instantiation (IFTI) meant that you don't have to explicitly 
instantiate all functions. However, it seems like there are 
cases with eponymous templates with functions in them that you 
do. For instance, in the bar function below, I have to 
explicitly instantiate the inner function template.


template foo(T, U)
{
        T foo(T x, U y)
        {
                return x + cast(T)y;
        }
}

template bar(T)
{
        T bar(U)(T x, U y)
        {
                return x + cast(T)y;
        }
}

void main()
{
        int a = 1;
        long b = 2;
        auto x = foo(a, a);
        //auto y = bar(a, b); //error
        auto y = bar!(long)(a, b);
}

This seems like a bug?! U can clearly be deduced. The real 
question, is it needed?


template bar(T, U)
{
        T bar(T x, U y)
        {
                return x + cast(T)y;
        }
}