Why does this not pass

[Imperatorn]

On Tuesday, 23 February 2021 at 09:21:44 UTC, Imperatorn wrote:
> Why does all these pass:
>     static assert(is(ElementEncodingType!(char[]) == char));
>     static assert(is(ElementEncodingType!(wstring) == 
> immutable(wchar)));
>     static assert(is(ElementEncodingType!(byte[]) == byte));
>     static assert(is(ElementEncodingType!(ubyte[]) == ubyte));
>
>     auto range = iota(0, 10);
>     static assert(is(ElementEncodingType!(typeof(range)) == 
> int));
>     static assert(is(ElementEncodingType!(immutable(ubyte)[]) 
> == immutable(ubyte)));
>
> But not this:
>     static assert(is(ElementEncodingType!(AsciiChar[]) == 
> AsciiChar));

omg forgot to import std.range 🙄

But the question is kinda still valid, like in the case of 
std.array.appender.

The original poster:
"Appender defines its element type with ElementEncodingType which 
only passes immutability through for built-in string types"