Bug 17393 – AllocatorList leaks memory in "ouroboros mode"

The following bails out at the last assertion because there is still a DummyAllocator with allocated memory left over: --- import std.experimental.allocator; import std.experimental.allocator.mallocator; import std.experimental.allocator.building_blocks.allocator_list; import std.experimental.allocator.building_blocks.region; import std.experimental.allocator.building_blocks.null_allocator; import std.algorithm; // simple region allocator that keeps track of the number of active references struct DummyAllocator { import std.typecons : Ternary; static int cnt; void[] mem; size_t ptr; enum alignment = ulong.alignof; this(size_t sz) { mem = new void[](sz); cnt++; } this(this) { if (mem.ptr) cnt++; } ~this() { if (mem.ptr) cnt--; } Ternary owns(void[] slc) const { return slc.ptr >= mem.ptr && slc.ptr + slc.length <= mem.ptr + mem.length ? Ternary.yes : Ternary.no; } void[] allocate(size_t n) { if (!mem.ptr) { mem = new void[](1024*1024); cnt++; } if (mem.length - ptr < n) return null; auto ret = mem[ptr .. ptr + n]; ptr += n; return ret; } bool deallocateAll() { if (mem.ptr) { ptr = 0; delete mem; cnt--; } return true; } } void main() { assert(DummyAllocator.cnt == 0); { auto a = AllocatorList!(n => DummyAllocator(max(n, 1024*1024)), NullAllocator).init; a.allocate(1000); a.deallocateAll(); } assert(DummyAllocator.cnt == 0); } --- The deallocateAll() call in particular doesn't get forwarded to DummyAllocator and its destructor isn't called either. If NullAllocator is exchanged for Mallocator, this issue doesn't show up.

Hi This should be solved by https://github.com/dlang/phobos/pull/5894 Thanks, Alex