Worst ideas/features in programming languages?

[kdevel]

On Monday, 15 November 2021 at 17:48:35 UTC, H. S. Teoh wrote:
[...]
> Why can't you just write:
>
> 	MyAbility ability;
>
> 	switch (ability) with(MyAbility)
> 	{
> 	 case SOMETHING_1: break;
> 	 case SOMETHING_2: break;
> 	 case SOMETHING_3: break;
> 	 case SOMETHING_4: break;
> 	 case SOMETHING_5: break;
> 	}
>
> ?  The `with` keyword was designed specifically for this 
> purpose.

Nice. What about

    import std.stdio;
    enum SAB {
       a = 1,
    }
    void main ()
    {
       with (SAB) if (a == 1) writeln ("true");
       with (SAB) void foo () { writeln (a); } // no complaints!
       foo(); // Error: undefined identifier `foo`
    }