Improvement in pure functions specification

[Stefan Koch via Digitalmars-d]

On Wednesday, 21 December 2016 at 15:40:42 UTC, Andrei 
Alexandrescu wrote:
> On 12/20/2016 05:49 PM, Andrei Alexandrescu wrote:
>> https://github.com/dlang/dlang.org/pull/1528 -- Andrei
>
> Dropped the void functions. On to the next scandal:
>
>>A function that accepts only parameters without mutable 
>>indirections and
>>returns a result that has mutable indirections is called a $(I 
>>pure factory
>>function). An implementation may assume that all mutable memory 
>>returned by
>>the call is not referenced by any other part of the program, 
>>i.e. it is
>>newly allocated by the function.
>
>
> Andrei

Couldn't this be folded into :
"The implementation may not remove a call to a pure function if 
does allocate memory ?"

Since there is the concept of weakly pure functions the compiler 
cannot decide to remove functions on signature alone.
Meaning the body has to be available for it to even attempt to 
elide the call.

Therefore specifying implementation behavior based on the 
function signature is misleading IMO.