Why the @ in @safe? & UDAs

[Shammah Chancellor]

On 2013-11-07 02:04:36 +0000, Adam D. Ruppe said:

> On Thursday, 7 November 2013 at 00:13:49 UTC, Shammah Chancellor wrote:
>> My understanding is that @ attributes were for used-defined behavior only.
> 
> It is all a historical thing... at first, all new things were done as 
> keywords. Then around the time @safe came around, they were changing 
> their minds and new things became @keywords. Then, some time after 
> that, UDAs came around and used the @ syntax.
> 
> But the reason it is pure and @safe instead of @pure @safe or pure and 
> safe is just historical accident - they were introduced in that 
> particular phase, and now the worry is changing it will annoyingly 
> break too much code for very little real benefit.

There's an easy solution to that.   Put warnings on pure, nothrow, and 
immutable ( in the function tag context) and add @pure, @nothrow, 
@immutable etc.  Fix it going forward and eventually remove it.