Why is D unpopular?

[Walter Bright]

On 5/19/2022 3:15 AM, Siarhei Siamashka wrote:
> Regarding safety and avoiding various sources of undefined behavior. Do you 
> agree that "Implementation Defined: The built-in associative arrays do not 
> preserve the order of the keys inserted into the array. In particular, in a 
> foreach loop the order in which the elements are iterated is typically 
> unspecified." from https://dlang.org/spec/hash-map.html can be a source of bugs 
> in the user code?

Yes.

But still, languages draw a distinction between implementation defined and 
undefined.

There are many implementation defined behaviors in D, like the precise layout of 
struct fields.