core.memory.GC allocation functions are not marked as @safe

[Steven Schveighoffer]

On 12/19/18 8:18 AM, Eduard Staniloiu wrote:
> Hello, everybody.
> 
> While working at [this 
> PR](https://github.com/dlang/phobos/pull/6811/files), reviews are 
> welcome :D, I noticed that none of the `core.memory.GC` allocation 
> functions are marked as `@safe`.
> 
> I believe that `GC.malloc`, `GC.calloc`, `GC.qalloc` and `GC.expand` 
> should all be `@safe`, as they either give you the **fresh** memory that 
> you requested, or they fail.
> 
> What are your thoughts on this?

malloc, calloc, qalloc and expand should all be safe (the first three 
are all different APIs to the same core feature anyway). realloc and 
free are obviously not.

There are actually a lot of functions in there that should be @safe. For 
instance getAttr, or getSize.

One key thing is not so much that it gives you fresh memory, but that it 
also does not leave dangling pointers.

To do this *right*, what is needed is to first mark the extern(C) 
functions @safe, in both the prototype and the implementation, and then 
add @trusted escapes where necessary in the implementation. Second, you 
can then change the GC struct wrapper functions to @safe.

-Steve