Return type deduction

[Andrea Fontana via Digitalmars-d]

On Thursday, 8 September 2016 at 13:28:15 UTC, Steven 
Schveighoffer wrote:
> Right, but there is a problem here. The connection of the 
> simple return type to the simple template parameter is not 
> necessarily guaranteed. That is, there is no guarantee 
> simple!int is going to return int (for any template).
>
> This means the compiler has to determine how to make simple 
> return an int, and this isn't always obvious, or easy to 
> determine.

I don't know how compiler works, but my logic was:

- I have T simple(T) { ... }
- return type == template argument
- int ... = simple() => T == int => simple!int

I undestand that if it was:

auto simple(T) { ... } it should be difficult

Probably I'm missing someting about compiler internal structure, 
not my field.

Andrea