Where should the destruction of aggregate members take place?

[Henning Pohl]

a) In the so-called "whole dtor" which calls the dtors of all 
members including the dtor declared (if any). The attributes of 
the "whole dtor" are deduced.

b) Everything takes place in the dtor declared (if any). If the 
dtor is pure/nothrow/safe, it is guaranteed that the object can 
be destructed purely/without throwing/safely. This will break 
existing code.

-----
struct S { ~this() { } }
struct SX { S s; pure ~this() { } }
-----

a) Compiles.
b) Error: S.s.~this is impure

Both behaviors are available on github:
a) https://github.com/D-Programming-Language/dmd/pull/2006
b) https://github.com/D-Programming-Language/dmd/pull/2003

You can apply this to postblit, too.