ICSharpCode.ILSpy.AssertionFailedException

[greenozon]

Steps to reproduce

1. Save project
   https://www.sendspace.com/file/5zf6aw

Error message shown

Error decompiling @06001498 ---.get_Heads
in assembly "C:\IL_errs\err111.dll"
 ---> ICSharpCode.ILSpy.AssertionFailedException: 
   at ICSharpCode.ILSpy.ILSpyTraceListener.Fail(String message, String detailMessage) in offset 380
   at ICSharpCode.ILSpy.ILSpyTraceListener.Fail(String message) in offset 9
   at System.Diagnostics.TraceInternal.Fail(String message) in offset 55
   at System.Diagnostics.Debug.Assert(Boolean condition) in offset 6
   at ICSharpCode.Decompiler.IL.StLoc.CheckInvariant(ILPhase phase) in StLoc.cs:line 44
   at ICSharpCode.Decompiler.IL.ILInstruction.CheckInvariant(ILPhase phase) in ILInstruction.cs:line 95
   at ICSharpCode.Decompiler.IL.Block.CheckInvariant(ILPhase phase) in Block.cs:line 108
   at ICSharpCode.Decompiler.IL.ILInstruction.CheckInvariant(ILPhase phase) in ILInstruction.cs:line 95
   at ICSharpCode.Decompiler.IL.BlockContainer.CheckInvariant(ILPhase phase) in BlockContainer.cs:line 196
   at ICSharpCode.Decompiler.IL.ILInstruction.CheckInvariant(ILPhase phase) in ILInstruction.cs:line 95
   at ICSharpCode.Decompiler.IL.Block.CheckInvariant(ILPhase phase) in Block.cs:line 108
   at ICSharpCode.Decompiler.IL.ILInstruction.CheckInvariant(ILPhase phase) in ILInstruction.cs:line 95
   at ICSharpCode.Decompiler.IL.BlockContainer.CheckInvariant(ILPhase phase) in BlockContainer.cs:line 196
   at ICSharpCode.Decompiler.IL.ILInstruction.CheckInvariant(ILPhase phase) in ILInstruction.cs:line 95
   at ICSharpCode.Decompiler.IL.ILFunction.CheckInvariant(ILPhase phase) in ILFunction.cs:line 255
   at ICSharpCode.Decompiler.CSharp.CSharpDecompiler.DecompileBody(IMethod method, EntityDeclaration entityDecl, DecompileRun decompileRun, ITypeResolveContext decompilationContext) in CSharpDecompiler.cs:line 1509
-- continuing with outer exception (ICSharpCode.Decompiler.DecompilerException) --
   at ICSharpCode.Decompiler.CSharp.CSharpDecompiler.DecompileBody(IMethod method, EntityDeclaration entityDecl, DecompileRun decompileRun, ITypeResolveContext decompilationContext) in CSharpDecompiler.cs:line 1545
   at ICSharpCode.Decompiler.CSharp.CSharpDecompiler.DoDecompile(IMethod method, DecompileRun decompileRun, ITypeResolveContext decompilationContext) in CSharpDecompiler.cs:line 1444
   at ICSharpCode.Decompiler.CSharp.CSharpDecompiler.Decompile(IEnumerable`1 definitions) in CSharpDecompiler.cs:line 993
   at ICSharpCode.Decompiler.CSharp.CSharpDecompiler.Decompile(EntityHandle[] definitions) in CSharpDecompiler.cs:line 950
   at ICSharpCode.ILSpy.CSharpLanguage.DecompileMethod(IMethod method, ITextOutput output, DecompilationOptions options) in offset 246
   at ICSharpCode.ILSpy.TreeNodes.MethodTreeNode.Decompile(Language language, ITextOutput output, DecompilationOptions options) in offset 15
   at ICSharpCode.ILSpy.TextView.DecompilerTextView.DecompileNodes(DecompilationContext context, ITextOutput textOutput) in offset 143
   at ICSharpCode.ILSpy.TextView.DecompilerTextView.<>c__DisplayClass51_0.<DecompileAsync>b__0() in offset 38

Expected result:

public double[] get_Heads()
{
	double[] array = new double[this.m_heads.Count];
	for (int i = 0; i < this.m_heads.Count; i++)
	{
		array[i] = (double)(this.m_heads[i] as double);
	}
	return array;
}

Details

• Product in use: e.g. ILSpy / ICSharpCode.Decompiler nuget package / VS extension
  ILSpy version 7.1.0.6580
  .NET version 4.8.3928.0

[siegfriedpammer]

Cannot reproduce this. The current output seems correct, the isinst + unbox sequence found in the original code produces a NullReferenceException iff obj is not a double, just like (double)((obj is double) ? obj : null).

public double[] Heads
{
	get
	{
		double[] array = null;
		array = new double[m_heads.Count];
		for (int i = 0; i < m_heads.Count; i++)
		{
			ref double reference = ref array[i];
			object obj = m_heads[i];
			reference = (double)((obj is double) ? obj : null);
		}
		return array;
	}
}

@greenozon can you confirm?

[greenozon]

Grabbed latest debug ILSpy, still see it
lets sync our settings?

ILSpy version 7.2.0.6660-preview1
.NET version 4.8.3928.0

C#7.3

save code:

in assembly "C:\IL_errs\err111.dll"
 ---> ICSharpCode.ILSpy.AssertionFailedException: 
   at ICSharpCode.ILSpy.ILSpyTraceListener.Fail(String message, String detailMessage) in offset 380
   at ICSharpCode.ILSpy.ILSpyTraceListener.Fail(String message) in offset 9
   at System.Diagnostics.TraceInternal.Fail(String message) in offset 55
   at System.Diagnostics.Debug.Assert(Boolean condition) in offset 6
   at ICSharpCode.Decompiler.IL.BlockContainer.CheckInvariant(ILPhase phase) in BlockContainer.cs:line 212
   at ICSharpCode.Decompiler.IL.ILInstruction.CheckInvariant(ILPhase phase) in ILInstruction.cs:line 95
   at ICSharpCode.Decompiler.IL.Block.CheckInvariant(ILPhase phase) in Block.cs:line 108
   at ICSharpCode.Decompiler.IL.ILInstruction.CheckInvariant(ILPhase phase) in ILInstruction.cs:line 95
   at ICSharpCode.Decompiler.IL.BlockContainer.CheckInvariant(ILPhase phase) in BlockContainer.cs:line 196
   at ICSharpCode.Decompiler.IL.ILInstruction.CheckInvariant(ILPhase phase) in ILInstruction.cs:line 95
   at ICSharpCode.Decompiler.IL.Block.CheckInvariant(ILPhase phase) in Block.cs:line 108
   at ICSharpCode.Decompiler.IL.ILInstruction.CheckInvariant(ILPhase phase) in ILInstruction.cs:line 95
   at ICSharpCode.Decompiler.IL.BlockContainer.CheckInvariant(ILPhase phase) in BlockContainer.cs:line 196
   at ICSharpCode.Decompiler.IL.ILInstruction.CheckInvariant(ILPhase phase) in ILInstruction.cs:line 95
   at ICSharpCode.Decompiler.IL.ILFunction.CheckInvariant(ILPhase phase) in ILFunction.cs:line 255
   at ICSharpCode.Decompiler.CSharp.CSharpDecompiler.DecompileBody(IMethod method, EntityDeclaration entityDecl, DecompileRun decompileRun, ITypeResolveContext decompilationContext) in CSharpDecompiler.cs:line 1550
-- continuing with outer exception (ICSharpCode.Decompiler.DecompilerException) --
   at ICSharpCode.Decompiler.CSharp.CSharpDecompiler.DecompileBody(IMethod method, EntityDeclaration entityDecl, DecompileRun decompileRun, ITypeResolveContext decompilationContext) in CSharpDecompiler.cs:line 1586
   at ICSharpCode.Decompiler.CSharp.CSharpDecompiler.DoDecompile(IMethod method, DecompileRun decompileRun, ITypeResolveContext decompilationContext) in CSharpDecompiler.cs:line 1470
   at ICSharpCode.Decompiler.CSharp.CSharpDecompiler.DoDecompile(ITypeDefinition typeDef, DecompileRun decompileRun, ITypeResolveContext decompilationContext) in CSharpDecompiler.cs:line 1308
   at ICSharpCode.Decompiler.CSharp.CSharpDecompiler.DoDecompileTypes(IEnumerable`1 types, DecompileRun decompileRun, ITypeResolveContext decompilationContext, SyntaxTree syntaxTree) in CSharpDecompiler.cs:line 574
   at ICSharpCode.Decompiler.CSharp.CSharpDecompiler.DecompileTypes(IEnumerable`1 types) in CSharpDecompiler.cs:line 894
   at ICSharpCode.Decompiler.CSharp.ProjectDecompiler.WholeProjectDecompiler.<>c__DisplayClass45_0.<WriteCodeFilesInProject>b__2(IGrouping`2 file) in WholeProjectDecompiler.cs:line 239
   at System.Threading.Tasks.Parallel.<>c__DisplayClass42_0`2.<PartitionerForEachWorker>b__1() in offset 713
   at System.Threading.Tasks.Task.InnerInvokeWithArg(Task childTask) in offset 6
   at System.Threading.Tasks.Task.<>c__DisplayClass176_0.<ExecuteSelfReplicating>b__0(Object <p0>) in offset 134

err111.zip

[siegfriedpammer]

Still cannot reproduce this... maybe its because I am missing the other references? The assembly you sent has many references, which I do not have access to. Maybe you can send the whole package via email? Thanks!

[greenozon]

You are right!
I'm also not able to reproduce the issue on the same build after I did the View -> Options -> Reset to defaults
mystery!

but there is another element which throws exception if you search for it and then click on it
Search for AddFlushingEvent
see this output on click:

in assembly "C:\IL_errs\err111.dll"
 ---> ICSharpCode.ILSpy.AssertionFailedException: 
   at ICSharpCode.ILSpy.ILSpyTraceListener.Fail(String message, String detailMessage) in offset 380
   at ICSharpCode.ILSpy.ILSpyTraceListener.Fail(String message) in offset 9
   at System.Diagnostics.TraceInternal.Fail(String message) in offset 55
   at System.Diagnostics.Debug.Assert(Boolean condition) in offset 6
   at ICSharpCode.Decompiler.IL.BlockContainer.CheckInvariant(ILPhase phase) in BlockContainer.cs:line 212
   at ICSharpCode.Decompiler.IL.ILInstruction.CheckInvariant(ILPhase phase) in ILInstruction.cs:line 95
   at ICSharpCode.Decompiler.IL.Block.CheckInvariant(ILPhase phase) in Block.cs:line 108
   at ICSharpCode.Decompiler.IL.ILInstruction.CheckInvariant(ILPhase phase) in ILInstruction.cs:line 95
   at ICSharpCode.Decompiler.IL.BlockContainer.CheckInvariant(ILPhase phase) in BlockContainer.cs:line 196
   at ICSharpCode.Decompiler.IL.ILInstruction.CheckInvariant(ILPhase phase) in ILInstruction.cs:line 95
   at ICSharpCode.Decompiler.IL.Block.CheckInvariant(ILPhase phase) in Block.cs:line 108
   at ICSharpCode.Decompiler.IL.ILInstruction.CheckInvariant(ILPhase phase) in ILInstruction.cs:line 95
   at ICSharpCode.Decompiler.IL.BlockContainer.CheckInvariant(ILPhase phase) in BlockContainer.cs:line 196
   at ICSharpCode.Decompiler.IL.ILInstruction.CheckInvariant(ILPhase phase) in ILInstruction.cs:line 95
   at ICSharpCode.Decompiler.IL.ILFunction.CheckInvariant(ILPhase phase) in ILFunction.cs:line 255
   at ICSharpCode.Decompiler.CSharp.CSharpDecompiler.DecompileBody(IMethod method, EntityDeclaration entityDecl, DecompileRun decompileRun, ITypeResolveContext decompilationContext) in CSharpDecompiler.cs:line 1550
-- continuing with outer exception (ICSharpCode.Decompiler.DecompilerException) --
   at ICSharpCode.Decompiler.CSharp.CSharpDecompiler.DecompileBody(IMethod method, EntityDeclaration entityDecl, DecompileRun decompileRun, ITypeResolveContext decompilationContext) in CSharpDecompiler.cs:line 1586
   at ICSharpCode.Decompiler.CSharp.CSharpDecompiler.DoDecompile(IMethod method, DecompileRun decompileRun, ITypeResolveContext decompilationContext) in CSharpDecompiler.cs:line 1470
   at ICSharpCode.Decompiler.CSharp.CSharpDecompiler.Decompile(IEnumerable`1 definitions) in CSharpDecompiler.cs:line 995
   at ICSharpCode.Decompiler.CSharp.CSharpDecompiler.Decompile(EntityHandle[] definitions) in CSharpDecompiler.cs:line 952
   at ICSharpCode.ILSpy.CSharpLanguage.DecompileMethod(IMethod method, ITextOutput output, DecompilationOptions options) in offset 246
   at ICSharpCode.ILSpy.TreeNodes.MethodTreeNode.Decompile(Language language, ITextOutput output, DecompilationOptions options) in offset 15
   at ICSharpCode.ILSpy.TextView.DecompilerTextView.DecompileNodes(DecompilationContext context, ITextOutput textOutput) in offset 143
   at ICSharpCode.ILSpy.TextView.DecompilerTextView.<>c__DisplayClass51_0.<DecompileAsync>b__0() in offset 38

[greenozon]

Another elements leading to exception when navigating to it:

• GetShouldLoadControlOverrides
• GetShouldLoadFireDemands
• GetShouldLoadPipeBreaks
• GetShouldLoadPipeShutDowns
• GetShouldLoadPowerOutages
• GetShouldLoadSCADANormalDemandAdjustments
• GetShouldLoadSCADAUnitDemandAdjustments
• get_PressureEngineSuctionSideVSPControlNodeMustBeTankMessageKey
• GetShouldLoadEPSTimeOptions

[siegfriedpammer]

I think that these are all different problems, might be better to split this into multiple issues.

[siegfriedpammer]

• GetShouldLoadControlOverrides: This is a problem with our FixLoneIsInst transform: If the instruction extracted by FixLoneIsInst is part of a "special" block (container) the extraction violates our assumptions, e.g., that the switch instruction is the first instruction of the entry-point.
• GetShouldLoadFireDemands: see above
• GetShouldLoadPipeBreaks: see above
• GetShouldLoadPipeShutDowns: see above
• SCADADomainEngineAdapterImpl.GetShouldLoadSCADANormalDemandAdjustments: see above
• SCADADomainEngineAdapterImpl.GetShouldLoadSCADAUnitDemandAdjustments: see above
• get_PressureEngineSuctionSideVSPControlNodeMustBeTankMessageKey: same as ICSharpCode.ILSpy.AssertionFailedException #2459
• AlabamaDomainEngineAdapterImpl.GetShouldLoadEPSTimeOptions: see above

[dgrunwald]

Then that's a bug in Extract, it needs to find a valid place to extract to, or it should do nothing and return null.
It already checks for BlockKind.ControlFlow to ensure we don't extract into blocks with special semantics; but it will also need to check the BlockContainerKind.
In case we're dealing with the first instruction of the first block in a switch container, we could extract further into the switch's parent block,