What does std.traits.hasAliasing do

[Venkat]

On Sunday, 29 July 2018 at 01:05:19 UTC, Venkat wrote:
> struct SomeStruct {
> 	string p;
> 	string q;
> 	string[] pq;
> }
>
Session session = req.session;
session.get!SomeStruct("registerBody");
>
> /home/venkat/.dub/packages/vibe-d-0.8.4/vibe-d/http/vibe/http/session.d(83,3): Error: static assert:  "Type SomeStruct contains references, which is not supported for session storage."
>
>
> vibe.d session won't let me put in a simple struct with an 
> array or an associative array. session.put calls 
> std.traits.hasAliasing which is returning true when I have 
> either an array or an associative array. I looked through the 
> std.traits.hasAliasing code. I can't make a whole lot of sense 
> there.
>
> The hasAliasing function documentation says as long as the 
> array or associative array are not immutable it should return 
> true. Since session.put does !hasAliasing I changed string[] to 
> immutable, that throws a whole lot of other compilation error 
> messages.
>
> What is hasAliasing doing ?

Posted the wrong code. Fixed it above. Reposting below for 
clarity. For the record both session.get and session.put call 
hasAliasing.

struct SomeStruct {
	string p;
	string q;
	string[] pq;
}

Session session = req.session;
session.get!SomeStruct("registerBody");