Componentizing D's garbage collector

[Ola Fosheim Grøstad" <ola.fosheim.grostad+dlang at gmail.com>]

On Monday, 13 January 2014 at 17:45:26 UTC, Dmitry Olshansky 
wrote:
> How would it be expensive? I don't see a need to do anything to 
> "pin" a memory block, at the time of scanning there will be a 
> potential pointer to it (in the stack space of C function or 
> registers).

How do you know that it is a pointer?