alias this and associative arrays

[Steven Schveighoffer]

On 4/22/18 7:06 AM, Shachar Shemesh wrote:
> import std.exception;
> 
> struct AA(Key, Val) {
>      Val[Key] aa;
>      alias aa this;
> 
>      void opIndexAssign(inout Val value, Key key) pure {
>          aa[key] = value;
>      }
> }
> 
> void main() {
>      AA!(string, int) a;
>       //compile error -- no property 'remove' for type 
> 'CheckedAA!(string, int)'
>      a.remove("aaa");
> }
> 
> What's wrong here?

It's a bug. The remove function is not actually defined by the library, 
it's a compiler special that remaps to an extern(C) function _aaDelX. As 
far as I can tell, it's the only one that doesn't work. All the others 
seem to work (e.g. a.keys).

What I would guess is happening is the compiler is trying to call remove 
on the AA but has skipped the part that translates to _aaDelX.

It would be good to hoist this out of the compiler and make it a UFCS 
call, which would also fix the problem.

-Steve