Assertion at class-accessors.c:31, condition `mono_class_is_ginst (klass)' not met

[slide]

Steps to Reproduce

1. Unzip the attachment
2. Run mono ipy.exe doit.py
3. See assertion error

mono_assertion.zip

Current Behavior

The code is a reproduction of a test case in IronPython. When the iter method is called with a System.Array[int], an assertion is not met.

Expected Behavior

On MS.NET and previous versions of Mono, this behavior was not seen. The assertion did not occur and the code functioned as expected.

On which platforms did you notice this

[ ] macOS
[x] Linux
[ ] Windows

Version Used:

Mono JIT compiler version 5.8.0.108 (tarball Fri Jan 19 18:15:21 UTC 2018)
Copyright (C) 2002-2014 Novell, Inc, Xamarin Inc and Contributors. www.mono-project.com
TLS: __thread
SIGSEGV: altstack
Notifications: epoll
Architecture: amd64
Disabled: none
Misc: softdebug
LLVM: supported, not enabled.
GC: sgen (concurrent by default)

Stacktrace

* Assertion at class-accessors.c:31, condition `mono_class_is_ginst (klass)' not met

Stacktrace:

  at <unknown> <0xffffffff>
  at (wrapper managed-to-native) System.RuntimeTypeHandle.type_is_assignable_from (System.Type,System.Type) [0x0000b] in <2e7c1c96edae44d496118948ca617c11>:0
  at System.RuntimeTypeHandle.CanCastTo (System.RuntimeType,System.RuntimeType) [0x00000] in <2e7c1c96edae44d496118948ca617c11>:0
  at System.RuntimeType.IsAssignableFrom (System.Type) [0x00020] in <2e7c1c96edae44d496118948ca617c11>:0
  at IronPython.Runtime.Types.PythonTypeInfo.IterResolver (IronPython.Runtime.Types.PythonTypeInfo/MemberBinder,System.Type) [0x000df] in <83a1cf22159a4046b85a40a602cd8f81>:0
  at IronPython.Runtime.Types.PythonTypeInfo/OneOffResolver.ResolveMember (IronPython.Runtime.Types.PythonTypeInfo/MemberBinder,Microsoft.Scripting.Actions.MemberRequestKind,System.Type,string) [0x0000f] in <83a1cf22159a4046b85a40a602cd8f81>:0
  at IronPython.Runtime.Types.PythonTypeInfo.GetMemberGroup (IronPython.Runtime.Types.PythonTypeInfo/MemberBinder,Microsoft.Scripting.Actions.MemberRequestKind,System.Type,string) [0x0000a] in <83a1cf22159a4046b85a40a602cd8f81>:0
  at IronPython.Runtime.Types.PythonTypeInfo.GetMemberAll (IronPython.Runtime.Binding.PythonBinder,Microsoft.Scripting.Actions.MemberRequestKind,System.Type,string) [0x00006] in <83a1cf22159a4046b85a40a602cd8f81>:0
  at IronPython.Runtime.Binding.PythonBinder.GetMember (Microsoft.Scripting.Actions.MemberRequestKind,System.Type,string) [0x00015] in <83a1cf22159a4046b85a40a602cd8f81>:0
  at IronPython.Runtime.Binding.PythonGetMemberBinder.MakeGetMemberTarget<TSelfType_REF> (string,object,IronPython.Runtime.CodeContext) [0x00026] in <83a1cf22159a4046b85a40a602cd8f81>:0
  at IronPython.Runtime.Binding.PythonGetMemberBinder.BindDelegate<T_REF> (System.Runtime.CompilerServices.CallSite`1<T_REF>,object[]) [0x0029a] in <83a1cf22159a4046b85a40a602cd8f81>:0
  at System.Runtime.CompilerServices.CallSiteBinder.BindCore<T_REF> (System.Runtime.CompilerServices.CallSite`1<T_REF>,object[]) [0x00000] in <b0fca80f08474611b248e2d30bb75230>:0
  at System.Dynamic.UpdateDelegates.UpdateAndExecute2<T0_REF, T1_REF, TRet_REF> (System.Runtime.CompilerServices.CallSite,T0_REF,T1_REF) [0x000fc] in <b0fca80f08474611b248e2d30bb75230>:0
  at IronPython.Runtime.Types.PythonType.TryGetBoundAttr (IronPython.Runtime.CodeContext,object,string,object&) [0x00032] in <83a1cf22159a4046b85a40a602cd8f81>:0
  at IronPython.Runtime.Operations.PythonOps.TryGetBoundAttr (IronPython.Runtime.CodeContext,object,string,object&) [0x00006] in <83a1cf22159a4046b85a40a602cd8f81>:0
  at IronPython.Runtime.Operations.PythonOps.GetEnumeratorObject (IronPython.Runtime.CodeContext,object) [0x00000] in <83a1cf22159a4046b85a40a602cd8f81>:0
  at IronPython.Modules.Builtin.iter (IronPython.Runtime.CodeContext,object) [0x00000] in <83a1cf22159a4046b85a40a602cd8f81>:0
  at Microsoft.Scripting.Interpreter.FuncCallInstruction`3<T0_REF, T1_REF, TRet_REF>.Run (Microsoft.Scripting.Interpreter.InterpretedFrame) [0x00000] in <ecaef5a769d94bf4aaeff9acba121150>:0
  at Microsoft.Scripting.Interpreter.Interpreter.Run (Microsoft.Scripting.Interpreter.InterpretedFrame) [0x00016] in <ecaef5a769d94bf4aaeff9acba121150>:0
  at Microsoft.Scripting.Interpreter.LightLambda.Run4<T0_REF, T1_REF, T2_REF, T3_REF, TRet_REF> (T0_REF,T1_REF,T2_REF,T3_REF) [0x0006d] in <ecaef5a769d94bf4aaeff9acba121150>:0
  at System.Dynamic.UpdateDelegates.UpdateAndExecute3<T0_REF, T1_REF, T2_REF, TRet_REF> (System.Runtime.CompilerServices.CallSite,T0_REF,T1_REF,T2_REF) [0x0011a] in <b0fca80f08474611b248e2d30bb75230>:0
  at (wrapper delegate-invoke) <Module>.invoke_callvirt_object_Func`5<CallSite, CodeContext, object, object, object>_CallSite_CodeContext_object_object (System.Func`5<System.Runtime.CompilerServices.CallSite, IronPython.Runtime.CodeContext, object, object, object>,System.Runtime.CompilerServices.CallSite,IronPython.Runtime.CodeContext,object,object) [0x00048] in <2e7c1c96edae44d496118948ca617c11>:0
  at Microsoft.Scripting.Interpreter.FuncCallInstruction`6<T0_REF, T1_REF, T2_REF, T3_REF, T4_REF, TRet_REF>.Run (Microsoft.Scripting.Interpreter.InterpretedFrame) [0x00000] in <ecaef5a769d94bf4aaeff9acba121150>:0
  at Microsoft.Scripting.Interpreter.Interpreter.Run (Microsoft.Scripting.Interpreter.InterpretedFrame) [0x00016] in <ecaef5a769d94bf4aaeff9acba121150>:0
  at Microsoft.Scripting.Interpreter.LightLambda.Run4<T0_REF, T1_REF, T2_REF, T3_REF, TRet_REF> (T0_REF,T1_REF,T2_REF,T3_REF) [0x0006d] in <ecaef5a769d94bf4aaeff9acba121150>:0
  at IronPython.Compiler.Ast.CallExpression/Invoke1Instruction.Run (Microsoft.Scripting.Interpreter.InterpretedFrame) [0x00026] in <83a1cf22159a4046b85a40a602cd8f81>:0
  at Microsoft.Scripting.Interpreter.Interpreter.Run (Microsoft.Scripting.Interpreter.InterpretedFrame) [0x00016] in <ecaef5a769d94bf4aaeff9acba121150>:0
  at Microsoft.Scripting.Interpreter.LightLambda.Run1<T0_REF, TRet_REF> (T0_REF) [0x0003e] in <ecaef5a769d94bf4aaeff9acba121150>:0
  at IronPython.Compiler.RuntimeScriptCode.InvokeTarget (Microsoft.Scripting.Runtime.Scope) [0x0006a] in <83a1cf22159a4046b85a40a602cd8f81>:0
  at IronPython.Compiler.RuntimeScriptCode.Run (Microsoft.Scripting.Runtime.Scope) [0x00000] in <83a1cf22159a4046b85a40a602cd8f81>:0
  at IronPython.Hosting.PythonCommandLine.RunFileWorker (string) [0x000e5] in <83a1cf22159a4046b85a40a602cd8f81>:0
  at IronPython.Hosting.PythonCommandLine.RunFile (string) [0x0000f] in <83a1cf22159a4046b85a40a602cd8f81>:0
  at Microsoft.Scripting.Hosting.Shell.CommandLine.Run () [0x0003a] in <ecaef5a769d94bf4aaeff9acba121150>:0
  at IronPython.Hosting.PythonCommandLine.Run () [0x000d8] in <83a1cf22159a4046b85a40a602cd8f81>:0
  at Microsoft.Scripting.Hosting.Shell.CommandLine.Run (Microsoft.Scripting.Hosting.ScriptEngine,Microsoft.Scripting.Hosting.Shell.IConsole,Microsoft.Scripting.Hosting.Shell.ConsoleOptions) [0x0003c] in <ecaef5a769d94bf4aaeff9acba121150>:0
  at Microsoft.Scripting.Hosting.Shell.ConsoleHost.RunCommandLine () [0x00053] in <ecaef5a769d94bf4aaeff9acba121150>:0
  at Microsoft.Scripting.Hosting.Shell.ConsoleHost.ExecuteInternal () [0x00051] in <ecaef5a769d94bf4aaeff9acba121150>:0
  at PythonConsoleHost.ExecuteInternal () [0x00025] in <5b243a89d89c4e9bbe51fb0f289f69a4>:0
  at Microsoft.Scripting.Hosting.Shell.ConsoleHost.Execute () [0x00032] in <ecaef5a769d94bf4aaeff9acba121150>:0
  at Microsoft.Scripting.Hosting.Shell.ConsoleHost.Run (string[]) [0x0015b] in <ecaef5a769d94bf4aaeff9acba121150>:0
  at PythonConsoleHost.Main (string[]) [0x00020] in <5b243a89d89c4e9bbe51fb0f289f69a4>:0
  at (wrapper runtime-invoke) <Module>.runtime_invoke_int_object (object,intptr,intptr,intptr) [0x00054] in <5b243a89d89c4e9bbe51fb0f289f69a4>:0
/proc/self/maps:
00400000-007d4000 r-xp 00000000 fd:00 7078252                            /usr/bin/mono-sgen
009d3000-009d4000 r--p 003d3000 fd:00 7078252                            /usr/bin/mono-sgen
009d4000-009d7000 rw-p 003d4000 fd:00 7078252                            /usr/bin/mono-sgen
009d7000-00a2d000 rw-p 00000000 00:00 0 
02492000-030da000 rw-p 00000000 00:00 0                                  [heap]
406f6000-40706000 rwxp 00000000 00:00 0 
41c4f000-41d6f000 rwxp 00000000 00:00 0 
7fdd60000000-7fdd60021000 rw-p 00000000 00:00 0 
7fdd60021000-7fdd64000000 ---p 00000000 00:00 0 
7fdd669c4000-7fdd66a44000 rw-p 00000000 00:00 0 
7fdd66a48000-7fdd66c00000 r--p 00000000 fd:00 2498064                    /home/USER/Projects/debug/IronPython.dll
7fdd66c00000-7fdd66d00000 rw-p 00000000 00:00 0 
7fdd66d3e000-7fdd66d4e000 rwxp 00000000 00:00 0 
7fdd66d4e000-7fdd6704f000 r--p 00000000 fd:00 7078582                    /usr/lib/mono/gac/System.Xml/4.0.0.0__b77a5c561934e089/System.Xml.dll
7fdd6704f000-7fdd672ee000 r--p 00000000 fd:00 7078761                    /usr/lib/mono/gac/System/4.0.0.0__b77a5c561934e089/System.dll
7fdd672ee000-7fdd673e6000 r--p 00000000 fd:00 8683440                    /usr/lib/mono/gac/System.Core/4.0.0.0__b77a5c561934e089/System.Core.dll
7fdd673e6000-7fdd674eb000 r--p 00000000 fd:00 2498068                    /home/USER/Projects/debug/Microsoft.Dynamic.dll
7fdd674eb000-7fdd67a2a000 r-xp 00000000 fd:00 7093298                    /usr/lib/mono/aot-cache/amd64/mscorlib.dll.so
7fdd67a2a000-7fdd67c29000 ---p 0053f000 fd:00 7093298                    /usr/lib/mono/aot-cache/amd64/mscorlib.dll.so
7fdd67c29000-7fdd67c2a000 r--p 0053e000 fd:00 7093298                    /usr/lib/mono/aot-cache/amd64/mscorlib.dll.so
7fdd67c2a000-7fdd67c2b000 rw-p 0053f000 fd:00 7093298                    /usr/lib/mono/aot-cache/amd64/mscorlib.dll.so
7fdd67c2b000-7fdd67c48000 rw-p 00000000 00:00 0 
7fdd67c48000-7fdd67fff000 r--p 00000000 fd:00 7078552                    /usr/lib/mono/4.5/mscorlib.dll
7fdd67fff000-7fdd68fff000 rw-p 00000000 00:00 0 
7fdd68fff000-7fdd69000000 ---p 00000000 00:00 0 
7fdd69000000-7fdd69c00000 rw-p 00000000 00:00 0 
7fdd69c01000-7fdd69cae000 r--p 00000000 fd:00 2498065                    /home/USER/Projects/debug/IronPython.Modules.dll
7fdd69cae000-7fdd69cca000 r--p 00000000 fd:00 13370443                   /usr/lib/mono/gac/System.Numerics/4.0.0.0__b77a5c561934e089/System.Numerics.dll
7fdd69cca000-7fdd69ccb000 ---p 00000000 00:00 0 
7fdd69ccb000-7fdd69cd3000 ---p 00000000 00:00 0 
7fdd69cd3000-7fdd69ecb000 rw-p 00000000 00:00 0 
7fdd69ecb000-7fdd6a1a7000 r--p 00000000 fd:00 7081075                    /usr/lib/locale/locale-archive
7fdd6a1a7000-7fdd6a37d000 r-xp 00000000 fd:00 12845138                   /lib/x86_64-linux-gnu/libc-2.26.so
7fdd6a37d000-7fdd6a57d000 ---p 001d6000 fd:00 12845138                   /lib/x86_64-linux-gnu/libc-2.26.so
7fdd6a57d000-7fdd6a581000 r--p 001d6000 fd:00 12845138                   /lib/x86_64-linux-gnu/libc-2.26.so
7fdd6a581000-7fdd6a583000 rw-p 001da000 fd:00 12845138                   /lib/x86_64-linux-gnu/libc-2.26.so
7fdd6a583000-7fdd6a587000 rw-p 00000000 00:00 0 
7fdd6a587000-7fdd6a59d000 r-xp 00000000 fd:00 12849638                   /lib/x86_64-linux-gnu/libgcc_s.so.1
7fdd6a59d000-7fdd6a79c000 ---p 00016000 fd:00 12849638                   /lib/x86_64-linux-gnu/libgcc_s.so.1
7fdd6a79c000-7fdd6a79d000 r--p 00015000 fd:00 12849638                   /lib/x86_64-linux-gnu/libgcc_s.so.1
7fdd6a79d000-7fdd6a79e000 rw-p 00016000 fd:00 12849638                   /lib/x86_64-linux-gnu/libgcc_s.so.1
7fdd6a79e000-7fdd6a7b8000 r-xp 00000000 fd:00 12845153                   /lib/x86_64-linux-gnu/libpthread-2.26.so
7fdd6a7b8000-7fdd6a9b7000 ---p 0001a000 fd:00 12845153                   /lib/x86_64-linux-gnu/libpthread-2.26.so
7fdd6a9b7000-7fdd6a9b8000 r--p 00019000 fd:00 12845153                   /lib/x86_64-linux-gnu/libpthread-2.26.so
7fdd6a9b8000-7fdd6a9b9000 rw-p 0001a000 fd:00 12845153                   /lib/x86_64-linux-gnu/libpthread-2.26.so
7fdd6a9b9000-7fdd6a9bd000 rw-p 00000000 00:00 0 
7fdd6a9bd000-7fdd6a9c0000 r-xp 00000000 fd:00 12845141                   /lib/x86_64-linux-gnu/libdl-2.26.so
7fdd6a9c0000-7fdd6abbf000 ---p 00003000 fd:00 12845141                   /lib/x86_64-linux-gnu/libdl-2.26.so
7fdd6abbf000-7fdd6abc0000 r--p 00002000 fd:00 12845141                   /lib/x86_64-linux-gnu/libdl-2.26.so
7fdd6abc0000-7fdd6abc1000 rw-p 00003000 fd:00 12845141                   /lib/x86_64-linux-gnu/libdl-2.26.so
7fdd6abc1000-7fdd6abc8000 r-xp 00000000 fd:00 12849536                   /lib/x86_64-linux-gnu/librt-2.26.so
7fdd6abc8000-7fdd6adc7000 ---p 00007000 fd:00 12849536                   /lib/x86_64-linux-gnu/librt-2.26.so
7fdd6adc7000-7fdd6adc8000 r--p 00006000 fd:00 12849536                   /lib/x86_64-linux-gnu/librt-2.26.so
7fdd6adc8000-7fdd6adc9000 rw-p 00007000 fd:00 12849536                   /lib/x86_64-linux-gnu/librt-2.26.so
7fdd6adc9000-7fdd6af1e000 r-xp 00000000 fd:00 12845142                   /lib/x86_64-linux-gnu/libm-2.26.so
7fdd6af1e000-7fdd6b11d000 ---p 00155000 fd:00 12845142                   /lib/x86_64-linux-gnu/libm-2.26.so
7fdd6b11d000-7fdd6b11e000 r--p 00154000 fd:00 12845142                   /lib/x86_64-linux-gnu/libm-2.26.so
7fdd6b11e000-7fdd6b11f000 rw-p 00155000 fd:00 12845142                   /lib/x86_64-linux-gnu/libm-2.26.so
7fdd6b11f000-7fdd6b146000 r-xp 00000000 fd:00 12845062                   /lib/x86_64-linux-gnu/ld-2.26.so
7fdd6b146000-7fdd6b192000 r--p 00000000 fd:00 7079139                    /usr/lib/mono/gac/Mono.Security/4.0.0.0__0738eb9f132ed756/Mono.Security.dll
7fdd6b192000-7fdd6b1b0000 r--p 00000000 fd:00 7078650                    /usr/lib/mono/gac/System.Configuration/4.0.0.0__b03f5f7f11d50a3a/System.Configuration.dll
7fdd6b1b0000-7fdd6b1d3000 r--p 00000000 fd:00 2498069                    /home/USER/Projects/debug/Microsoft.Scripting.dll
7fdd6b1d3000-7fdd6b284000 rw-p 00000000 00:00 0 
7fdd6b285000-7fdd6b2b7000 rw-p 00000000 00:00 0 
7fdd6b2b7000-7fdd6b316000 ---p 00000000 00:00 0 
7fdd6b316000-7fdd6b31d000 rw-p 00000000 00:00 0 
7fdd6b325000-7fdd6b333000 rw-p 00000000 00:00 0 
7fdd6b333000-7fdd6b338000 r--p 00000000 fd:00 2498067                    /home/USER/Projects/debug/ipy.exe
7fdd6b338000-7fdd6b345000 rw-p 00000000 00:00 0 
7fdd6b345000-7fdd6b346000 rw-s 00000000 00:18 7                          /dev/shm/mono.16795
7fdd6b346000-7fdd6b347000 r--p 00027000 fd:00 12845062                   /lib/x86_64-linux-gnu/ld-2.26.so
7fdd6b347000-7fdd6b348000 rw-p 00028000 fd:00 12845062                   /lib/x86_64-linux-gnu/ld-2.26.so
7fdd6b348000-7fdd6b349000 rw-p 00000000 00:00 0 
7ffdbbd39000-7ffdbbd41000 ---p 00000000 00:00 0 
7ffdbc517000-7ffdbc538000 rw-p 00000000 00:00 0                          [stack]
7ffdbc53a000-7ffdbc53d000 r--p 00000000 00:00 0                          [vvar]
7ffdbc53d000-7ffdbc53f000 r-xp 00000000 00:00 0                          [vdso]
ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0                  [vsyscall]

Native stacktrace:

	mono() [0x4b3419]
	/lib/x86_64-linux-gnu/libpthread.so.0(+0x13150) [0x7fdd6a7b1150]
	/lib/x86_64-linux-gnu/libc.so.6(gsignal+0xcb) [0x7fdd6a1de0bb]
	/lib/x86_64-linux-gnu/libc.so.6(abort+0x16d) [0x7fdd6a1dff5d]
	mono() [0x6903d9]
	mono(monoeg_g_logv+0x4d) [0x6a543d]
	mono(monoeg_assertion_message+0xa3) [0x6a55d3]
	mono() [0x56ab1f]
	mono() [0x56ab41]
	mono(mono_class_is_assignable_from+0x393) [0x567ab3]
	[0x41c51652]

Debug info from gdb:

[New LWP 16797]
[New LWP 16798]
Mono support loaded.
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
0x00007fdd6a7b0a4a in __waitpid (pid=16799, stat_loc=0x7ffdbc53433c, options=0) at ../sysdeps/unix/sysv/linux/waitpid.c:29
29	../sysdeps/unix/sysv/linux/waitpid.c: No such file or directory.
  Id   Target Id         Frame 
* 1    Thread 0x7fdd6b316780 (LWP 16795) "mono" 0x00007fdd6a7b0a4a in __waitpid (pid=16799, stat_loc=0x7ffdbc53433c, options=0) at ../sysdeps/unix/sysv/linux/waitpid.c:29
  2    Thread 0x7fdd697ff700 (LWP 16797) "SGen worker" 0x00007fdd6a7ac072 in futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0xa2ae68) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
  3    Thread 0x7fdd69eca700 (LWP 16798) "Finalizer" 0x00007fdd6a7aef96 in futex_abstimed_wait_cancelable (private=0, abstime=0x0, expected=0, futex_word=0xa1bfc0) at ../sysdeps/unix/sysv/linux/futex-internal.h:205

Thread 3 (Thread 0x7fdd69eca700 (LWP 16798)):
#0  0x00007fdd6a7aef96 in futex_abstimed_wait_cancelable (private=0, abstime=0x0, expected=0, futex_word=0xa1bfc0) at ../sysdeps/unix/sysv/linux/futex-internal.h:205
#1  do_futex_wait (sem=sem@entry=0xa1bfc0, abstime=0x0) at sem_waitcommon.c:111
#2  0x00007fdd6a7af054 in __new_sem_wait_slow (sem=sem@entry=0xa1bfc0, abstime=0x0) at sem_waitcommon.c:181
#3  0x00007fdd6a7af144 in __new_sem_wait (sem=0xa1bfc0) at sem_wait.c:42
#4  0x000000000062ad37 in ?? ()
#5  0x00000000005ef12c in ?? ()
#6  0x00007fdd6a7a57fc in start_thread (arg=0x7fdd69eca700) at pthread_create.c:465
#7  0x00007fdd6a2bbb5f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 2 (Thread 0x7fdd697ff700 (LWP 16797)):
#0  0x00007fdd6a7ac072 in futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0xa2ae68) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
#1  __pthread_cond_wait_common (abstime=0x0, mutex=0xa2ae80, cond=0xa2ae40) at pthread_cond_wait.c:502
#2  __pthread_cond_wait (cond=0xa2ae40, mutex=0xa2ae80) at pthread_cond_wait.c:655
#3  0x0000000000685f9f in ?? ()
#4  0x00007fdd6a7a57fc in start_thread (arg=0x7fdd697ff700) at pthread_create.c:465
#5  0x00007fdd6a2bbb5f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 1 (Thread 0x7fdd6b316780 (LWP 16795)):
#0  0x00007fdd6a7b0a4a in __waitpid (pid=16799, stat_loc=0x7ffdbc53433c, options=0) at ../sysdeps/unix/sysv/linux/waitpid.c:29
#1  0x00000000004b34f6 in ?? ()
#2  <signal handler called>
#3  __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:51
#4  0x00007fdd6a1dff5d in __GI_abort () at abort.c:90
#5  0x00000000006903d9 in ?? ()
#6  0x00000000006a543d in monoeg_g_logv ()
#7  0x00000000006a55d3 in monoeg_assertion_message ()
#8  0x000000000056ab1f in ?? ()
#9  0x000000000056ab41 in ?? ()
#10 0x0000000000567ab3 in mono_class_is_assignable_from ()
#11 0x0000000041c51652 in ?? ()
#12 0x0000000000000004 in ?? ()
#13 0x00007fdd6b280f40 in ?? ()
#14 0x00007fdd6b280f40 in ?? ()
#15 0x00007fdd6b2190c0 in ?? ()
#16 0x00007fdd6b280f40 in ?? ()
#17 0x00000000024cd890 in ?? ()
#18 0x0000000000000000 in ?? ()

=================================================================
Got a SIGABRT while executing native code. This usually indicates
a fatal error in the mono runtime or one of the native libraries 
used by your application.
=================================================================

[slide]

Similarly, the following code causes the same assertion failure

import clr
import System
help(System.Array[int])

[marek-safar]

@lambdageek does it look familiar?

[lambdageek]

Standalone repro - calling IsAssignableFrom on an "array special" generic type definition asserts.

using System;
using System.Reflection;
using System.Collections.Generic;

public class Repro {
	public static void Main () {
		var t = typeof (IEnumerable<>);
		var a = new int[] {1, 2, 3};
		Console.WriteLine (t.IsAssignableFrom (a.GetType ()));
	}
}

Actual result:

* Assertion at class-accessors.c:38, condition `mono_class_is_ginst (klass)' not met

Stacktrace:

  at <unknown> <0xffffffff>
  at (wrapper managed-to-native) System.RuntimeTypeHandle.type_is_assignable_from (System.Type,System.Type) [0x0000b] in <43638e5eaf024a37bfbcb08e1c4046d0>:0
  at System.RuntimeTypeHandle.CanCastTo (System.RuntimeType,System.RuntimeType) [0x00000] in <43638e5eaf024a37bfbcb08e1c4046d0>:0
  at System.RuntimeType.IsAssignableFrom (System.Type) [0x00020] in <43638e5eaf024a37bfbcb08e1c4046d0>:0
  at Repro.Main () [0x00024] in <8dcf8cb29af54b1c95cc3f4f069a17ea>:0
  at (wrapper runtime-invoke) object.runtime_invoke_void (object,intptr,intptr,intptr) [0x0004c] in <43638e5eaf024a37bfbcb08e1c4046d0>:0

Native stacktrace:

        0   mono                                0x00000001017e0781 mono_handle_native_crash + 257
        1   libsystem_platform.dylib            0x00007fff7a687f5a _sigtramp + 26
        2   ???                                 0x000000010ac05608 0x0 + 4475344392
        3   libsystem_c.dylib                   0x00007fff7a4b2312 abort + 127
        4   mono                                0x00000001019f4b9f mono_log_write_logfile + 351
        5   mono                                0x0000000101a0db93 monoeg_g_logv + 83
        6   mono                                0x0000000101a0ddaf monoeg_assertion_message + 143
        7   mono                                0x00000001018b8f1c mono_class_get_generic_class + 60
        8   mono                                0x00000001018ab26a mono_class_is_assignable_from + 522
        9   ???                                 0x0000000101d6f4c4 0x0 + 4325831876
        10  mono                                0x0000000101737099 mono_jit_runtime_invoke + 1401
        11  mono                                0x0000000101930814 do_runtime_invoke + 100
        12  mono                                0x00000001019345be do_exec_main_checked + 174
        13  mono                                0x00000001017a2d89 mono_jit_exec + 297
        14  mono                                0x00000001017a5bb1 mono_main + 10705
        15  mono                                0x0000000101726d38 main + 264
        16  libdyld.dylib                       0x00007fff7a406115 start + 1
        17  ???     

Expected result (according to .NET Framework):

False

The non-"array special" codepath in mono_class_is_assignable_from works as expected.