ASAN output from my @primes = grep { .is-prime }, 1 .. *; my @p = gather for 4000, 5, 100, 2000 -> $n { take start { @primes[$n] }; }; .say for await @p;

gistfile1.txt

=================================================================
==9311== ERROR: AddressSanitizer: attempting double-free on 0xb4da2c20:
    #0 0xb61b79b4 (/usr/lib/i386-linux-gnu/libasan.so.0+0x169b4)
    #1 0xb582e5bc in MVM_realloc /home/dogbert/repos/rakudo/nqp/MoarVM/src/core/alloc.h:20
    #2 0xb582e5bc in set_size_internal /home/dogbert/repos/rakudo/nqp/MoarVM/src/6model/reprs/VMArray.c:352
    #3 0xb582e5bc in push /home/dogbert/repos/rakudo/nqp/MoarVM/src/6model/reprs/VMArray.c:460
    #4 0xb56f2fa1 in MVM_interp_run /home/dogbert/repos/rakudo/nqp/MoarVM/src/core/interp.c:2202
    #5 0xb57686e7 in start_thread /home/dogbert/repos/rakudo/nqp/MoarVM/src/core/threads.c:80
    #6 0xb5a6ca1a in uv__thread_start /home/dogbert/repos/rakudo/nqp/MoarVM/3rdparty/libuv/src/unix/thread.c:49
    #7 0xb61bb9c6 (/usr/lib/i386-linux-gnu/libasan.so.0+0x1a9c6)
    #8 0xb54a3f8d (/lib/i386-linux-gnu/libc.so.6+0xebf8d)
0xb4da2c20 is located 0 bytes inside of 64-byte region [0xb4da2c20,0xb4da2c60)
freed by thread T2 here:
    #0 0xb61b79b4 (/usr/lib/i386-linux-gnu/libasan.so.0+0x169b4)
    #1 0xb582e5bc in MVM_realloc /home/dogbert/repos/rakudo/nqp/MoarVM/src/core/alloc.h:20
    #2 0xb582e5bc in set_size_internal /home/dogbert/repos/rakudo/nqp/MoarVM/src/6model/reprs/VMArray.c:352
    #3 0xb582e5bc in push /home/dogbert/repos/rakudo/nqp/MoarVM/src/6model/reprs/VMArray.c:460
    #4 0xb56f2fa1 in MVM_interp_run /home/dogbert/repos/rakudo/nqp/MoarVM/src/core/interp.c:2202
    #5 0xb57686e7 in start_thread /home/dogbert/repos/rakudo/nqp/MoarVM/src/core/threads.c:80
    #6 0xb5a6ca1a in uv__thread_start /home/dogbert/repos/rakudo/nqp/MoarVM/3rdparty/libuv/src/unix/thread.c:49
    #7 0xb61bb9c6 (/usr/lib/i386-linux-gnu/libasan.so.0+0x1a9c6)
    #8 0xb54a3f8d (/lib/i386-linux-gnu/libc.so.6+0xebf8d)
previously allocated by thread T2 here:
    #0 0xb61b79b4 (/usr/lib/i386-linux-gnu/libasan.so.0+0x169b4)
    #1 0xb582e5bc in MVM_realloc /home/dogbert/repos/rakudo/nqp/MoarVM/src/core/alloc.h:20
    #2 0xb582e5bc in set_size_internal /home/dogbert/repos/rakudo/nqp/MoarVM/src/6model/reprs/VMArray.c:352
    #3 0xb582e5bc in push /home/dogbert/repos/rakudo/nqp/MoarVM/src/6model/reprs/VMArray.c:460
    #4 0xb56f2fa1 in MVM_interp_run /home/dogbert/repos/rakudo/nqp/MoarVM/src/core/interp.c:2202
    #5 0xb57686e7 in start_thread /home/dogbert/repos/rakudo/nqp/MoarVM/src/core/threads.c:80
    #6 0xb5a6ca1a in uv__thread_start /home/dogbert/repos/rakudo/nqp/MoarVM/3rdparty/libuv/src/unix/thread.c:49
    #7 0xb61bb9c6 (/usr/lib/i386-linux-gnu/libasan.so.0+0x1a9c6)
    #8 0xb54a3f8d (/lib/i386-linux-gnu/libc.so.6+0xebf8d)
Thread T3 created by T0 here:
    #0 0xb61ab1d0 (/usr/lib/i386-linux-gnu/libasan.so.0+0xa1d0)
    #1 0xb5a6ca88 in uv_thread_create /home/dogbert/repos/rakudo/nqp/MoarVM/3rdparty/libuv/src/unix/thread.c:66
    #2 0xb5769424 in MVM_thread_run /home/dogbert/repos/rakudo/nqp/MoarVM/src/core/threads.c:132
    #3 0xb56ddccf in MVM_interp_run /home/dogbert/repos/rakudo/nqp/MoarVM/src/core/interp.c:4003
    #4 0xb5a412f2 in MVM_vm_run_file /home/dogbert/repos/rakudo/nqp/MoarVM/src/moar.c:310
    #5 0x8049125 in main /home/dogbert/repos/rakudo/nqp/MoarVM/src/main.c:212
    #6 0xb53d1af2 (/lib/i386-linux-gnu/libc.so.6+0x19af2)
Thread T2 created by T0 here:
    #0 0xb61ab1d0 (/usr/lib/i386-linux-gnu/libasan.so.0+0xa1d0)
    #1 0xb5a6ca88 in uv_thread_create /home/dogbert/repos/rakudo/nqp/MoarVM/3rdparty/libuv/src/unix/thread.c:66
    #2 0xb5769424 in MVM_thread_run /home/dogbert/repos/rakudo/nqp/MoarVM/src/core/threads.c:132
    #3 0xb56ddccf in MVM_interp_run /home/dogbert/repos/rakudo/nqp/MoarVM/src/core/interp.c:4003
    #4 0xb5a412f2 in MVM_vm_run_file /home/dogbert/repos/rakudo/nqp/MoarVM/src/moar.c:310
    #5 0x8049125 in main /home/dogbert/repos/rakudo/nqp/MoarVM/src/main.c:212
    #6 0xb53d1af2 (/lib/i386-linux-gnu/libc.so.6+0x19af2)
SUMMARY: AddressSanitizer: double-free ??:0 ??
==9311== ABORTING