ILSpy can't decompile itself!

[greenozon]

Input code

IL spy latest CI build can't decompile one of own assemblies

Erroneous output

Failed to decompile the assembly 'C:\tmp\IL8\ILSpy.dll':
System.AggregateException: One or more errors occurred. (Error decompiling @06000161 ICSharpCode.ILSpy.CSharpHighlightingTokenWriter.WriteKeyword)
 ---> Error decompiling @06000161 ICSharpCode.ILSpy.CSharpHighlightingTokenWriter.WriteKeyword
in assembly "C:\tmp\IL8\ILSpy.dll"
 ---> System.NullReferenceException: Object reference not set to an instance of an object.
   at ICSharpCode.Decompiler.IL.Transforms.SwitchOnStringTransform.MatchRoslynSwitchOnStringUsingLengthAndChar(Block block, Int32 i) in SwitchOnStringTransform.cs:line 1211
   at ICSharpCode.Decompiler.IL.Transforms.SwitchOnStringTransform.Run(ILFunction function, ILTransformContext context) in SwitchOnStringTransform.cs:line 81
   at ICSharpCode.Decompiler.CSharp.CSharpDecompiler.DecompileBody(IMethod method, EntityDeclaration entityDecl, DecompileRun decompileRun, ITypeResolveContext decompilationContext) in CSharpDecompiler.cs:line 1720
-- 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 1756
   at ICSharpCode.Decompiler.CSharp.CSharpDecompiler.DoDecompile(IMethod method, DecompileRun decompileRun, ITypeResolveContext decompilationContext) in CSharpDecompiler.cs:line 1605
   at ICSharpCode.Decompiler.CSharp.CSharpDecompiler.<>c__DisplayClass74_0.<DoDecompile>g__DoDecompileMember|0(IEntity entity, RecordDecompiler recordDecompiler, PartialTypeInfo partialType) in CSharpDecompiler.cs:line 1480
   at ICSharpCode.Decompiler.CSharp.CSharpDecompiler.DoDecompile(ITypeDefinition typeDef, DecompileRun decompileRun, ITypeResolveContext decompilationContext) in CSharpDecompiler.cs:line 1369
   at ICSharpCode.Decompiler.CSharp.CSharpDecompiler.DoDecompileTypes(IEnumerable`1 types, DecompileRun decompileRun, ITypeResolveContext decompilationContext, SyntaxTree syntaxTree) in CSharpDecompiler.cs:line 652
   at ICSharpCode.Decompiler.CSharp.CSharpDecompiler.DecompileTypes(IEnumerable`1 types) in CSharpDecompiler.cs:line 951
   at ICSharpCode.Decompiler.CSharp.ProjectDecompiler.WholeProjectDecompiler.<>c__DisplayClass46_0.<WriteCodeFilesInProject>b__5(IGrouping`2 file) in WholeProjectDecompiler.cs:line 274
   at System.Threading.Tasks.Parallel.<>c__DisplayClass44_0`2.<PartitionerForEachWorker>b__1(IEnumerator& partitionState, Int32 timeout, Boolean& replicationDelegateYieldedBeforeCompletion) in offset 719
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() in offset 17
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw(Exception source) in offset 0
   at System.Threading.Tasks.Parallel.<>c__DisplayClass44_0`2.<PartitionerForEachWorker>b__1(IEnumerator& partitionState, Int32 timeout, Boolean& replicationDelegateYieldedBeforeCompletion) in offset 719
   at System.Threading.Tasks.TaskReplicator.Replica.Execute() in offset 205
   --- End of inner exception stack trace ---
   at System.Threading.Tasks.TaskReplicator.Run[TState](ReplicatableUserAction`1 action, ParallelOptions options, Boolean stopOnFirstFailure)
   at System.Threading.Tasks.Parallel.PartitionerForEachWorker[TSource,TLocal](Partitioner`1 source, ParallelOptions parallelOptions, Action`1 simpleBody, Action`2 bodyWithState, Action`3 bodyWithStateAndIndex, Func`4 bodyWithStateAndLocal, Func`5 bodyWithEverything, Func`1 localInit, Action`1 localFinally)
--- End of stack trace from previous location ---
   at System.Threading.Tasks.Parallel.ThrowSingleCancellationExceptionOrOtherException(ICollection exceptions, CancellationToken cancelToken, Exception otherException)
   at System.Threading.Tasks.Parallel.PartitionerForEachWorker[TSource,TLocal](Partitioner`1 source, ParallelOptions parallelOptions, Action`1 simpleBody, Action`2 bodyWithState, Action`3 bodyWithStateAndIndex, Func`4 bodyWithStateAndLocal, Func`5 bodyWithEverything, Func`1 localInit, Action`1 localFinally)
   at System.Threading.Tasks.Parallel.ForEach[TSource](Partitioner`1 source, ParallelOptions parallelOptions, Action`1 body)
   at ICSharpCode.Decompiler.CSharp.ProjectDecompiler.WholeProjectDecompiler.<>c__DisplayClass46_0.<WriteCodeFilesInProject>g__ProcessFiles|3(List`1 files) in /_/ICSharpCode.Decompiler/CSharp/ProjectDecompiler/WholeProjectDecompiler.cs:line 255
   at ICSharpCode.Decompiler.CSharp.ProjectDecompiler.WholeProjectDecompiler.WriteCodeFilesInProject(PEFile module, IList`1 partialTypes, CancellationToken cancellationToken) in /_/ICSharpCode.Decompiler/CSharp/ProjectDecompiler/WholeProjectDecompiler.cs:line 221
   at ICSharpCode.Decompiler.CSharp.ProjectDecompiler.WholeProjectDecompiler.DecompileProject(PEFile moduleDefinition, String targetDirectory, TextWriter projectFileWriter, CancellationToken cancellationToken) in /_/ICSharpCode.Decompiler/CSharp/ProjectDecompiler/WholeProjectDecompiler.cs:line 154
   at ICSharpCode.ILSpy.CSharpLanguage.DecompileAssembly(LoadedAssembly assembly, ITextOutput output, DecompilationOptions options)
   at ICSharpCode.ILSpy.SolutionWriter.WriteProject(LoadedAssembly loadedAssembly, Language language, String targetDirectory, CancellationToken ct)
-------------
Failed to decompile the assembly 'C:\tmp\IL8\ICSharpCode.Decompiler.dll':
System.AggregateException: One or more errors occurred. (Error decompiling @060001DB ICSharpCode.Decompiler.TextTokenWriter.WritePrimitiveType)
 ---> Error decompiling @060001DB ICSharpCode.Decompiler.TextTokenWriter.WritePrimitiveType
in assembly "C:\tmp\IL8\ICSharpCode.Decompiler.dll"
 ---> System.NullReferenceException: Object reference not set to an instance of an object.
   at ICSharpCode.Decompiler.IL.Transforms.SwitchOnStringTransform.MatchRoslynSwitchOnStringUsingLengthAndChar(Block block, Int32 i) in SwitchOnStringTransform.cs:line 1211
   at ICSharpCode.Decompiler.IL.Transforms.SwitchOnStringTransform.Run(ILFunction function, ILTransformContext context) in SwitchOnStringTransform.cs:line 81
   at ICSharpCode.Decompiler.CSharp.CSharpDecompiler.DecompileBody(IMethod method, EntityDeclaration entityDecl, DecompileRun decompileRun, ITypeResolveContext decompilationContext) in CSharpDecompiler.cs:line 1720
-- 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 1756
   at ICSharpCode.Decompiler.CSharp.CSharpDecompiler.DoDecompile(IMethod method, DecompileRun decompileRun, ITypeResolveContext decompilationContext) in CSharpDecompiler.cs:line 1605
   at ICSharpCode.Decompiler.CSharp.CSharpDecompiler.<>c__DisplayClass74_0.<DoDecompile>g__DoDecompileMember|0(IEntity entity, RecordDecompiler recordDecompiler, PartialTypeInfo partialType) in CSharpDecompiler.cs:line 1480
   at ICSharpCode.Decompiler.CSharp.CSharpDecompiler.DoDecompile(ITypeDefinition typeDef, DecompileRun decompileRun, ITypeResolveContext decompilationContext) in CSharpDecompiler.cs:line 1369
   at ICSharpCode.Decompiler.CSharp.CSharpDecompiler.DoDecompileTypes(IEnumerable`1 types, DecompileRun decompileRun, ITypeResolveContext decompilationContext, SyntaxTree syntaxTree) in CSharpDecompiler.cs:line 652
   at ICSharpCode.Decompiler.CSharp.CSharpDecompiler.DecompileTypes(IEnumerable`1 types) in CSharpDecompiler.cs:line 951
   at ICSharpCode.Decompiler.CSharp.ProjectDecompiler.WholeProjectDecompiler.<>c__DisplayClass46_0.<WriteCodeFilesInProject>b__5(IGrouping`2 file) in WholeProjectDecompiler.cs:line 274
   at System.Threading.Tasks.Parallel.<>c__DisplayClass44_0`2.<PartitionerForEachWorker>b__1(IEnumerator& partitionState, Int32 timeout, Boolean& replicationDelegateYieldedBeforeCompletion) in offset 259
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() in offset 17
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw(Exception source) in offset 0
   at System.Threading.Tasks.Parallel.<>c__DisplayClass44_0`2.<PartitionerForEachWorker>b__1(IEnumerator& partitionState, Int32 timeout, Boolean& replicationDelegateYieldedBeforeCompletion) in offset 609
   at System.Threading.Tasks.TaskReplicator.Replica`1.ExecuteAction(Boolean& yieldedBeforeCompletion) in offset 0
   at System.Threading.Tasks.TaskReplicator.Replica.Execute() in offset 0
   --- End of inner exception stack trace ---
   at System.Threading.Tasks.TaskReplicator.Run[TState](ReplicatableUserAction`1 action, ParallelOptions options, Boolean stopOnFirstFailure)
   at System.Threading.Tasks.Parallel.PartitionerForEachWorker[TSource,TLocal](Partitioner`1 source, ParallelOptions parallelOptions, Action`1 simpleBody, Action`2 bodyWithState, Action`3 bodyWithStateAndIndex, Func`4 bodyWithStateAndLocal, Func`5 bodyWithEverything, Func`1 localInit, Action`1 localFinally)
--- End of stack trace from previous location ---
   at System.Threading.Tasks.Parallel.ThrowSingleCancellationExceptionOrOtherException(ICollection exceptions, CancellationToken cancelToken, Exception otherException)
   at System.Threading.Tasks.Parallel.PartitionerForEachWorker[TSource,TLocal](Partitioner`1 source, ParallelOptions parallelOptions, Action`1 simpleBody, Action`2 bodyWithState, Action`3 bodyWithStateAndIndex, Func`4 bodyWithStateAndLocal, Func`5 bodyWithEverything, Func`1 localInit, Action`1 localFinally)
   at System.Threading.Tasks.Parallel.ForEach[TSource](Partitioner`1 source, ParallelOptions parallelOptions, Action`1 body)
   at ICSharpCode.Decompiler.CSharp.ProjectDecompiler.WholeProjectDecompiler.<>c__DisplayClass46_0.<WriteCodeFilesInProject>g__ProcessFiles|3(List`1 files) in /_/ICSharpCode.Decompiler/CSharp/ProjectDecompiler/WholeProjectDecompiler.cs:line 255
   at ICSharpCode.Decompiler.CSharp.ProjectDecompiler.WholeProjectDecompiler.WriteCodeFilesInProject(PEFile module, IList`1 partialTypes, CancellationToken cancellationToken) in /_/ICSharpCode.Decompiler/CSharp/ProjectDecompiler/WholeProjectDecompiler.cs:line 221
   at ICSharpCode.Decompiler.CSharp.ProjectDecompiler.WholeProjectDecompiler.DecompileProject(PEFile moduleDefinition, String targetDirectory, TextWriter projectFileWriter, CancellationToken cancellationToken) in /_/ICSharpCode.Decompiler/CSharp/ProjectDecompiler/WholeProjectDecompiler.cs:line 154
   at ICSharpCode.ILSpy.CSharpLanguage.DecompileAssembly(LoadedAssembly assembly, ITextOutput output, DecompilationOptions options)
   at ICSharpCode.ILSpy.SolutionWriter.WriteProject(LoadedAssembly loadedAssembly, Language language, String targetDirectory, CancellationToken ct)
-------------

If the output fails to re-compile, provide the compiler error message.
If the output has the wrong behavior, explain how it differs from the expected behavior.

Details

• Product in use: e.g. ILSpy CI build
• Version in use: ILSpy version 8.1.0.7490
• .NET version 6.0.20-servicing.23320.17+a08d9ce2caf02455c0b825bcdc32974bdf769a80

[greenozon]

Similar issue on standard assembly from .NET collection -

in assembly "C:\Program Files\dotnet\shared\Microsoft.NETCore.App\3.1.20\System.Private.CoreLib.dll"
 ---> System.NullReferenceException: Object reference not set to an instance of an object.
   at ICSharpCode.Decompiler.IL.Transforms.SwitchOnStringTransform.MatchRoslynSwitchOnStringUsingLengthAndChar(Block block, Int32 i) in SwitchOnStringTransform.cs:line 1211
   at ICSharpCode.Decompiler.IL.Transforms.SwitchOnStringTransform.Run(ILFunction function, ILTransformContext context) in SwitchOnStringTransform.cs:line 81
   at ICSharpCode.Decompiler.CSharp.CSharpDecompiler.DecompileBody(IMethod method, EntityDeclaration entityDecl, DecompileRun decompileRun, ITypeResolveContext decompilationContext) in CSharpDecompiler.cs:line 1720
-- 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 1756
   at ICSharpCode.Decompiler.CSharp.CSharpDecompiler.DoDecompile(IMethod method, DecompileRun decompileRun, ITypeResolveContext decompilationContext) in CSharpDecompiler.cs:line 1605
   at ICSharpCode.Decompiler.CSharp.CSharpDecompiler.<>c__DisplayClass74_0.<DoDecompile>g__DoDecompileMember|0(IEntity entity, RecordDecompiler recordDecompiler, PartialTypeInfo partialType) in CSharpDecompiler.cs:line 1480
   at ICSharpCode.Decompiler.CSharp.CSharpDecompiler.DoDecompile(ITypeDefinition typeDef, DecompileRun decompileRun, ITypeResolveContext decompilationContext) in CSharpDecompiler.cs:line 1369
   at ICSharpCode.Decompiler.CSharp.CSharpDecompiler.DoDecompileTypes(IEnumerable`1 types, DecompileRun decompileRun, ITypeResolveContext decompilationContext, SyntaxTree syntaxTree) in CSharpDecompiler.cs:line 652
   at ICSharpCode.Decompiler.CSharp.CSharpDecompiler.DecompileTypes(IEnumerable`1 types) in CSharpDecompiler.cs:line 951
   at ICSharpCode.Decompiler.CSharp.ProjectDecompiler.WholeProjectDecompiler.<>c__DisplayClass46_0.<WriteCodeFilesInProject>b__5(IGrouping`2 file) in WholeProjectDecompiler.cs:line 274
   at System.Threading.Tasks.Parallel.<>c__DisplayClass44_0`2.<PartitionerForEachWorker>b__1(IEnumerator& partitionState, Int32 timeout, Boolean& replicationDelegateYieldedBeforeCompletion) in offset 719
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() in offset 17
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw(Exception source) in offset 0
   at System.Threading.Tasks.Parallel.<>c__DisplayClass44_0`2.<PartitionerForEachWorker>b__1(IEnumerator& partitionState, Int32 timeout, Boolean& replicationDelegateYieldedBeforeCompletion) in offset 719
   at System.Threading.Tasks.TaskReplicator.Replica.Execute() in offset 205
   --- End of inner exception stack trace ---
   at System.Threading.Tasks.TaskReplicator.Run[TState](ReplicatableUserAction`1 action, ParallelOptions options, Boolean stopOnFirstFailure)
   at System.Threading.Tasks.Parallel.PartitionerForEachWorker[TSource,TLocal](Partitioner`1 source, ParallelOptions parallelOptions, Action`1 simpleBody, Action`2 bodyWithState, Action`3 bodyWithStateAndIndex, Func`4 bodyWithStateAndLocal, Func`5 bodyWithEverything, Func`1 localInit, Action`1 localFinally)
--- End of stack trace from previous location ---
   at System.Threading.Tasks.Parallel.ThrowSingleCancellationExceptionOrOtherException(ICollection exceptions, CancellationToken cancelToken, Exception otherException)
   at System.Threading.Tasks.Parallel.PartitionerForEachWorker[TSource,TLocal](Partitioner`1 source, ParallelOptions parallelOptions, Action`1 simpleBody, Action`2 bodyWithState, Action`3 bodyWithStateAndIndex, Func`4 bodyWithStateAndLocal, Func`5 bodyWithEverything, Func`1 localInit, Action`1 localFinally)
   at System.Threading.Tasks.Parallel.ForEach[TSource](Partitioner`1 source, ParallelOptions parallelOptions, Action`1 body)
   at ICSharpCode.Decompiler.CSharp.ProjectDecompiler.WholeProjectDecompiler.<>c__DisplayClass46_0.<WriteCodeFilesInProject>g__ProcessFiles|3(List`1 files) in /_/ICSharpCode.Decompiler/CSharp/ProjectDecompiler/WholeProjectDecompiler.cs:line 255
   at ICSharpCode.Decompiler.CSharp.ProjectDecompiler.WholeProjectDecompiler.WriteCodeFilesInProject(PEFile module, IList`1 partialTypes, CancellationToken cancellationToken) in /_/ICSharpCode.Decompiler/CSharp/ProjectDecompiler/WholeProjectDecompiler.cs:line 221
   at ICSharpCode.Decompiler.CSharp.ProjectDecompiler.WholeProjectDecompiler.DecompileProject(PEFile moduleDefinition, String targetDirectory, TextWriter projectFileWriter, CancellationToken cancellationToken) in /_/ICSharpCode.Decompiler/CSharp/ProjectDecompiler/WholeProjectDecompiler.cs:line 154
   at ICSharpCode.ILSpy.CSharpLanguage.DecompileAssembly(LoadedAssembly assembly, ITextOutput output, DecompilationOptions options)
   at ICSharpCode.ILSpy.SolutionWriter.WriteProject(LoadedAssembly loadedAssembly, Language language, String targetDirectory, CancellationToken ct)
-------------

[tshaug]

I can confirm this observation.
When decompiling I receive the following exception (using .NET 7 and ICSharpCode Decompiler 8.1.0.7455 on Windows 10)
C:\dev\dotnet\SharpMetrics-master\4-Development\Workspace\Application\SharpMetrics.UI.Windows\bin\Debug\ICSharpCode.Decompiler.dll"
---> System.NullReferenceException: Object reference not set to an instance of an object.
at ICSharpCode.Decompiler.IL.Transforms.SwitchOnStringTransform.MatchRoslynSwitchOnStringUsingLengthAndChar(InstructionCollection1 instructions, Int32& i) in SwitchOnStringTransform.cs:line 1197 at ICSharpCode.Decompiler.IL.Transforms.SwitchOnStringTransform.Run(ILFunction function, ILTransformContext context) in SwitchOnStringTransform.cs:line 81 at ICSharpCode.Decompiler.CSharp.CSharpDecompiler.DecompileBody(IMethod method, EntityDeclaration entityDecl, DecompileRun decompileRun, ITypeResolveContext decompilationContext) in CSharpDecompiler.cs:line 1720 -- 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 1756 at ICSharpCode.Decompiler.CSharp.CSharpDecompiler.DoDecompile(IMethod method, DecompileRun decompileRun, ITypeResolveContext decompilationContext) in CSharpDecompiler.cs:line 1605 at ICSharpCode.Decompiler.CSharp.CSharpDecompiler.<>c__DisplayClass74_0.<DoDecompile>g__DoDecompileMember|0(IEntity entity, RecordDecompiler recordDecompiler, PartialTypeInfo partialType) in CSharpDecompiler.cs:line 1480 at ICSharpCode.Decompiler.CSharp.CSharpDecompiler.DoDecompile(ITypeDefinition typeDef, DecompileRun decompileRun, ITypeResolveContext decompilationContext) in CSharpDecompiler.cs:line 1369 at ICSharpCode.Decompiler.CSharp.CSharpDecompiler.DoDecompileTypes(IEnumerable1 types, DecompileRun decompileRun, ITypeResolveContext decompilationContext, SyntaxTree syntaxTree) in CSharpDecompiler.cs:line 652
at ICSharpCode.Decompiler.CSharp.CSharpDecompiler.DecompileWholeModuleAsSingleFile(Boolean sortTypes) in CSharpDecompiler.cs:line 686

[greenozon]

@tshaug thanks
could you please enclose your traceback into markdown block?
it is very easy to use:
before the lines put three back quotes like
```
and same in the end

[tshaug]

@tshaug thanks could you please enclose your traceback into markdown block? it is very easy to use: before the lines put three back quotes like ``` and same in the end

@greenozon : yes I will do so in future - sorry!