Bug 892 – Another bug in the new GC - pointers in mixins

This is actually with DMD version 1.003 (and I suspect 1.001, and 1.002). This program destroys the object from the mixin even though it is still very much referenced by live objects in the program. ------ import std.stdio; static import std.gc; class SomeObject { this() { writefln("SomeObject created"); } ~this() { writefln("SomeObject destroyed"); } } template Mix() { void init() { ptr = new SomeObject; } SomeObject ptr; } class Container { this() { init(); } mixin Mix; } void main() { auto x = new Container; writefln("---Pre collect"); std.gc.fullCollect(); writefln("---Post collect"); }

OK, the compiler was being a bit too smart apparently, realizing that x would no longer be used. That makes the test appear to fail all the way back to DMD 0.176. So I should have put writeflns in at the end to make sure the data had a reason to stick around. Upon doing that, the example works in DMD 1.0 and fails in 1.001--1.003 (I went ahead and tried them all). Here's the modified test: ----------------- import std.stdio; static import std.gc; class SomeObject { this() { writefln("SomeObject created"); } ~this() { writefln("SomeObject destroyed"); } } template Mix() { void init() { ptr = new SomeObject; } SomeObject ptr; } class Container { this() { init(); } mixin Mix; int v = 10; } void main() { auto x = new Container; writefln("---Pre collect"); std.gc.fullCollect(); writefln("---Post collect"); writefln(x.v); writefln(x.ptr); }

Gone in 1.004.