Worst ideas/features in programming languages?

[H. S. Teoh]

On Fri, Nov 05, 2021 at 09:22:12PM +0000, victoroak via Digitalmars-d wrote:
> On Friday, 5 November 2021 at 17:02:05 UTC, Atila Neves wrote:
> > 
> > > - @safe `void` initialization
> > 
> > For what types? It doesn't compile for pointers, for instance, and I
> > don't see why void initialising an int would be unsafe.
> > 
> > > - .init
> > 
> > Because?
> > 
> 
> Well, I can't answer for him but `void` initialization and `.init`
> makes it impossible to have any meaningful constraint on a type. And
> some types may depend on these constraints to maintain safety.
> 
> ```d
> import std.stdio;
> 
> struct LimitedInt(int min, int max)
> {
>     @disable this();
> 
>     this(int number)
>     {
>         assert(number >= min);
>         assert(number <= max);
>         _number = number;
>     }
> 
>     private int _number;
> }
> 
> void main() @safe
> {
>     LimitedInt!(1, 1000) x = void;
>     auto y = LimitedInt!(1, 1000).init;
>     writeln(x);
>     writeln(y);
> }
> ```
> 
> It's `@safe` in this example but there's no way to enforce these
> constraints when you have those.

@safe does not mean enforcing type constraints.  It means *memory*
safety.  The above code exhibits no memory unsafety, even though
constraints are violated and the output is, ostensibly, wrong because of
broken constraints.


T

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