Motive behind !empty() with front() instead of Optional front()

[Paul Backus]

On Wednesday, 7 April 2021 at 21:31:38 UTC, Q. Schroll wrote:
> Template type deduction alone (C++ has 4 different rule sets 
> about type deduction) is complicated. One reason for stripping 
> `ref` from the argument types unless they explicitly bind to 
> `ref` parameters is that references should act like aliases:
> ```C++
> int i;
> int& r = i;
> f(i);
> f(r);
> ```
> Here, `f(r)` should act the same as `f(i)` irrespective of how 
> `f` is defined. `f` could take `int`, `int&`, `const int&`, or 
> `T`, `const T&`, or `T&&` for some `T` that can implicitly 
> constructed from `int`. For `int&&` or `T&`it wouldn't compile. 
> References as type constructors are weird.

References as type constructors are weird *in C++* because of 
specific choices made by the designers of C++ (such as: 
"references should act like aliases"). There is nothing inherent 
to the concept of a reference type that implies this kind of 
weirdness. D does not have to make the same choices as C++, and 
`ref(T)` in D does not have to suffer from the issues that 
references suffer from in C++.