[Issue 18691] assigning a std.regex.Captures with 3 or more groups causes double free

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=18691

--- Comment #2 from Martin Dorey <martin.dorey at hitachivantara.com> ---
How frustrating.  I can reproduce it on every one of the three machines I've
tried.  The output I raised the issue with was from today's master built on
Debian Jessie.  I found the problem originally on stock 2.079-0 from d-apt on
Debian Stretch... like the one below.  I was hoping for more symbolic debugging
but the -g doesn't seem to affect it for me.

mad at shuttle:~/tmp/D134366$ dmd --version
DMD64 D Compiler v2.079.0
Copyright (C) 1999-2018 by The D Language Foundation, All Rights Reserved
written by Walter Bright
mad at shuttle:~/tmp/D134366$ dmd -g utilimal.d && ./utilimal
*** Error in `./utilimal': double free or corruption (fasttop):
0x0000563fea6ca140 ***
======= Backtrace: =========
/lib/x86_64-linux-gnu/libc.so.6(+0x70bcb)[0x7f8c10084bcb]
/lib/x86_64-linux-gnu/libc.so.6(+0x76f96)[0x7f8c1008af96]
/lib/x86_64-linux-gnu/libc.so.6(+0x777de)[0x7f8c1008b7de]
./utilimal(_D3std5regex__T8CapturesTAyaZQo6__dtorMFNbNiNeZv+0x3b)[0x563fe94fda3f]
./utilimal(_Dmain+0xfd)[0x563fe94c6ea9]
./utilimal(_D2rt6dmain211_d_run_mainUiPPaPUAAaZiZ6runAllMFZ9__lambda1MFZv+0x28)[0x563fe9502b88]
./utilimal(_D2rt6dmain211_d_run_mainUiPPaPUAAaZiZ7tryExecMFMDFZvZv+0x20)[0x563fe9502a18]
./utilimal(_D2rt6dmain211_d_run_mainUiPPaPUAAaZiZ6runAllMFZv+0x8b)[0x563fe9502af7]
./utilimal(_D2rt6dmain211_d_run_mainUiPPaPUAAaZiZ7tryExecMFMDFZvZv+0x20)[0x563fe9502a18]
./utilimal(_d_run_main+0x1cf)[0x563fe9502983]
./utilimal(main+0x22)[0x563fe94febd6]
/lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xf1)[0x7f8c100342b1]
./utilimal(_start+0x2a)[0x563fe94c6c2a]
======= Memory map: ========
563fe9426000-563fe9569000 r-xp 00000000 08:07 76285143                  
/u2/home/mad/tmp/D134366/utilimal
563fe9769000-563fe976a000 r--p 00143000 08:07 76285143                  
/u2/home/mad/tmp/D134366/utilimal
563fe976a000-563fe979f000 rw-p 00144000 08:07 76285143                  
/u2/home/mad/tmp/D134366/utilimal
563fea6ca000-563fea6eb000 rw-p 00000000 00:00 0                          [heap]
7f8c0c000000-7f8c0c021000 rw-p 00000000 00:00 0 
7f8c0c021000-7f8c10000000 ---p 00000000 00:00 0 
7f8c10014000-7f8c101a9000 r-xp 00000000 08:01 1859659                   
/lib/x86_64-linux-gnu/libc-2.24.so
7f8c101a9000-7f8c103a9000 ---p 00195000 08:01 1859659                   
/lib/x86_64-linux-gnu/libc-2.24.so
7f8c103a9000-7f8c103ad000 r--p 00195000 08:01 1859659                   
/lib/x86_64-linux-gnu/libc-2.24.so
7f8c103ad000-7f8c103af000 rw-p 00199000 08:01 1859659                   
/lib/x86_64-linux-gnu/libc-2.24.so
7f8c103af000-7f8c103b3000 rw-p 00000000 00:00 0 
7f8c103b3000-7f8c103c9000 r-xp 00000000 08:01 1859854                   
/lib/x86_64-linux-gnu/libgcc_s.so.1
7f8c103c9000-7f8c105c8000 ---p 00016000 08:01 1859854                   
/lib/x86_64-linux-gnu/libgcc_s.so.1
7f8c105c8000-7f8c105c9000 r--p 00015000 08:01 1859854                   
/lib/x86_64-linux-gnu/libgcc_s.so.1
7f8c105c9000-7f8c105ca000 rw-p 00016000 08:01 1859854                   
/lib/x86_64-linux-gnu/libgcc_s.so.1
7f8c105ca000-7f8c105cd000 r-xp 00000000 08:01 1859704                   
/lib/x86_64-linux-gnu/libdl-2.24.so
7f8c105cd000-7f8c107cc000 ---p 00003000 08:01 1859704                   
/lib/x86_64-linux-gnu/libdl-2.24.so
7f8c107cc000-7f8c107cd000 r--p 00002000 08:01 1859704                   
/lib/x86_64-linux-gnu/libdl-2.24.so
7f8c107cd000-7f8c107ce000 rw-p 00003000 08:01 1859704                   
/lib/x86_64-linux-gnu/libdl-2.24.so
7f8c107ce000-7f8c107d5000 r-xp 00000000 08:01 1859828                   
/lib/x86_64-linux-gnu/librt-2.24.so
7f8c107d5000-7f8c109d4000 ---p 00007000 08:01 1859828                   
/lib/x86_64-linux-gnu/librt-2.24.so
7f8c109d4000-7f8c109d5000 r--p 00006000 08:01 1859828                   
/lib/x86_64-linux-gnu/librt-2.24.so
7f8c109d5000-7f8c109d6000 rw-p 00007000 08:01 1859828                   
/lib/x86_64-linux-gnu/librt-2.24.so
7f8c109d6000-7f8c10ad9000 r-xp 00000000 08:01 1859707                   
/lib/x86_64-linux-gnu/libm-2.24.so
7f8c10ad9000-7f8c10cd8000 ---p 00103000 08:01 1859707                   
/lib/x86_64-linux-gnu/libm-2.24.so
7f8c10cd8000-7f8c10cd9000 r--p 00102000 08:01 1859707                   
/lib/x86_64-linux-gnu/libm-2.24.so
7f8c10cd9000-7f8c10cda000 rw-p 00103000 08:01 1859707                   
/lib/x86_64-linux-gnu/libm-2.24.so
7f8c10cda000-7f8c10cf2000 r-xp 00000000 08:01 1859816                   
/lib/x86_64-linux-gnu/libpthread-2.24.so
7f8c10cf2000-7f8c10ef1000 ---p 00018000 08:01 1859816                   
/lib/x86_64-linux-gnu/libpthread-2.24.so
7f8c10ef1000-7f8c10ef2000 r--p 00017000 08:01 1859816                   
/lib/x86_64-linux-gnu/libpthread-2.24.so
7f8c10ef2000-7f8c10ef3000 rw-p 00018000 08:01 1859816                   
/lib/x86_64-linux-gnu/libpthread-2.24.so
7f8c10ef3000-7f8c10ef7000 rw-p 00000000 00:00 0 
7f8c10ef7000-7f8c10f1a000 r-xp 00000000 08:01 1859630                   
/lib/x86_64-linux-gnu/ld-2.24.so
7f8c10fe6000-7f8c110eb000 rw-p 00000000 00:00 0 
7f8c11116000-7f8c1111a000 rw-p 00000000 00:00 0 
7f8c1111a000-7f8c1111b000 r--p 00023000 08:01 1859630                   
/lib/x86_64-linux-gnu/ld-2.24.so
7f8c1111b000-7f8c1111c000 rw-p 00024000 08:01 1859630                   
/lib/x86_64-linux-gnu/ld-2.24.so
7f8c1111c000-7f8c1111d000 rw-p 00000000 00:00 0 
7ffe6f231000-7ffe6f252000 rw-p 00000000 00:00 0                         
[stack]
7ffe6f3f4000-7ffe6f3f6000 r--p 00000000 00:00 0                          [vvar]
7ffe6f3f6000-7ffe6f3f8000 r-xp 00000000 00:00 0                          [vdso]
ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0                 
[vsyscall]
Aborted
mad at shuttle:~/tmp/D134366$ 

Perhaps Debian's libc has more debugging configured than others but surely
valgrind ought to behave roughly the same:

mad at shuttle:~/tmp/D134366$ valgrind --version
valgrind-3.12.0.SVN
mad at shuttle:~/tmp/D134366$

--