RefCounted / DMD bug

[Erik Smith via Digitalmars-d]

I'm getting a strange assertion/crash involving RefCounted and 
I've reduced it down to the isolated case (see below).  This is 
with D 2.071 and requires this version to compile.

I'm wondering if there is something I wrong in the way I'm using 
RefCounted.   I'm using using it to pass RC value types through 
chained calls, which should be ok.  This seems more like a 
compiler bug due to the strangeness of the fix lines. The 
compiler seems confused by the two methods names query in 
separate classes (removing the first def and the issue goes 
away).  The 2nd fix is on an unused RC.  It could also be that 
there is underlying memory corruption that is intermittent and I 
just haven't found the problem.

This is a big issue for my design so hopefully the problem can be 
identified.

erik


import std.typecons;

struct BasicDatabase(Impl) {
     alias Connection = BasicConnection!Impl;

     this(string defaultURI) {data = Data(null);}
     auto connection() {return Connection(this);}

     private:
     alias RefCounted!(Impl, RefCountedAutoInitialize.no) Data;
     Data data;
}

struct BasicConnection(Impl) {
     alias Statement = BasicStatement!Impl;
     alias Database = BasicDatabase!Impl;

     auto statement() {return Statement(this);}
     auto query() {return statement().query();} // === remove to 
fix 1

     this(Database db) {
         //database = db;
         data = Data(&db.data.refCountedPayload());
     }

     private:
     alias RefCounted!(Impl, RefCountedAutoInitialize.no) Data;
     Database database; // === remove to fix 2
     Data data;
}

struct BasicStatement(Impl) {
     alias Connection = BasicConnection!Impl;
     alias Result = BasicResult!Impl;

     this(Connection c) {
         con = c;
         data = Data(&con.data.refCountedPayload());
     }

     auto query() {return Result(this);}

     private:
     alias RefCounted!(Impl, RefCountedAutoInitialize.no) Data;
     Data data;
     Connection con;
}

struct BasicResult(Impl) {
     alias Statement = BasicStatement!Impl;

     this(Statement s) {
         stmt = s;
         data = Data(&stmt.data.refCountedPayload());
     }

     private:
     alias RefCounted!(Impl, RefCountedAutoInitialize.no) Data;
     Statement stmt;
     Data data;
}

struct Payload {
     this(Payload *p) {}
}

void main() {
     auto db = BasicDatabase!Payload("source");
     auto s = db.connection().statement();
     auto r = s.query();
}



core.exception.AssertError at std/typecons.d(4860): Assertion failure
----------------
4   bug                                 0x00000001063c3f20 
_d_assert + 104
5   bug                                 0x00000001063dc3ca void 
std.typecons.__assert(int) + 38
6   bug                                 0x00000001063bae4e 
nothrow @nogc void 
std.typecons.__T10RefCountedTS3bug7PayloadVE3std8typecons24RefCountedAutoInitializei0Z.RefCounted.__dtor() + 54
7   bug                                 0x00000001063ba8c5 
nothrow @nogc void 
bug.BasicStatement!(bug.Payload).BasicStatement.__fieldDtor() + 29
8   bug                                 0x00000001063ba096 _Dmain 
+ 210
9   bug                                 0x00000001063d48b3 
D2rt6dmain211_d_run_mainUiPPaPUAAaZiZ6runAllMFZ9__lambda1MFZv + 39
10  bug                                 0x00000001063d47e7 void 
rt.dmain2._d_run_main(int, char**, extern (C) int 
function(char[][])*).tryExec(scope void delegate()) + 35
11  bug                                 0x00000001063d4858 void 
rt.dmain2._d_run_main(int, char**, extern (C) int 
function(char[][])*).runAll() + 44
12  bug                                 0x00000001063d47e7 void 
rt.dmain2._d_run_main(int, char**, extern (C) int 
function(char[][])*).tryExec(scope void delegate()) + 35
13  bug                                 0x00000001063d474d 
_d_run_main + 497
14  bug                                 0x00000001063ba19b main + 
15
15  libdyld.dylib                       0x00007fff977f35ac start 
+ 0
16  ???                                 0x0000000000000000 0x0 + 0
bug(39873,0x7fff7838d000) malloc: *** error for object 
0x7fdea9c03d18: incorrect checksum for freed object - object was 
probably modified after being freed.
*** set a breakpoint in malloc_error_break to debug
Abort trap: 6