Cleverness of GC Scanning

[rsw0x via Digitalmars-d]

On Friday, 7 August 2015 at 17:23:18 UTC, deadalnix wrote:
> On Friday, 7 August 2015 at 12:17:19 UTC, David Nadlinger wrote:
>> On Friday, 7 August 2015 at 12:05:01 UTC, Per Nordlöw wrote:
>>> Is the current Phobos GC smart enough to *not* scan 
>>> GC-allocated arrays when the elements don't contain any 
>>> indirections (references/pointers).
>>
>> Yes (mostly). Have a look at the NO_SCAN attribute (and 
>> similar) in the druntime docs.
>>
>>  — David
>
> This attribute exists, but how much grinding in the type system 
> dmd and the runtime are doing ?

Not a whole lot IIRC.

Probably a question for Martin Nowak as he seems to do a lot of 
the GC work - but I'm curious why the GC takes basically zero 
advantage of D's compile time magic(allocations are funneled 
through a C API,) is it because build times would be too slow?