Phobos addition formal review: std.experimental.allocator

[Tofu Ninja via Digitalmars-d]

Something I thought about today, if a class or struct is 
allocated by an allocator(say a malloc based allocator) and one 
of its fields is populated with a reference to GCed memory, will 
the GC know to scan the allocator memory to keep that GCed memory 
alive?