PDB Generation is confused by enhanced using statements

[cateyes99]

Steps to reproduce

1. Tried both ILSpy & ilspycmd to generate PDB for Newtonsoft.Json.dll 12.0.3, found both throwing System.ArgumentOutOfRangeException and resulted in producing a size 0 Newtonsoft.Json.pdb.

2. Tried the same for C:\Program Files\dotnet\shared\Microsoft.NETCore.App\3.1.5\System.Linq.dll & C:\Program Files\dotnet\shared\Microsoft.NETCore.App\3.1.5\System.Linq.Expressions.dll as well, got the same issue.

Error message shown

• When using ILSpy, here is what it shows:

System.ArgumentOutOfRangeException: Specified argument was out of the range of valid values.
Parameter name: value
   at System.Reflection.Throw.ValueArgumentOutOfRange()
   at ICSharpCode.Decompiler.DebugInfo.PortablePdbWriter.EncodeSequencePoints(MetadataBuilder metadata, Int32 localSignatureRowId, List`1 sequencePoints)
   at ICSharpCode.Decompiler.DebugInfo.PortablePdbWriter.<>c__DisplayClass2_0.<WritePdb>g__ProcessMethod|7(MethodDefinitionHandle method, DocumentHandle document, List`1 sequencePoints, SyntaxTree syntaxTree)
   at ICSharpCode.Decompiler.DebugInfo.PortablePdbWriter.WritePdb(PEFile file, CSharpDecompiler decompiler, DecompilerSettings settings, Stream targetStream, Boolean noLogo)
   at ICSharpCode.ILSpy.GeneratePdbContextMenuEntry.<>c__DisplayClass3_0.<GeneratePdbForAssembly>b__2()
   at System.Threading.Tasks.Task`1.InnerInvoke()
   at System.Threading.Tasks.Task.Execute()

• When using command ilspycmd Newtonsoft.Json.dll -genpdb, I got:

System.ArgumentOutOfRangeException: Specified argument was out of the range of valid values. (Parameter 'value')
   at System.Reflection.Throw.ValueArgumentOutOfRange()
   at System.Reflection.Metadata.BlobWriterImpl.WriteCompressedInteger(BlobBuilder writer, UInt32 value)
   at ICSharpCode.Decompiler.DebugInfo.PortablePdbWriter.EncodeSequencePoints(MetadataBuilder metadata, Int32 localSignatureRowId, List`1 sequencePoints)
   at ICSharpCode.Decompiler.DebugInfo.PortablePdbWriter.<>c__DisplayClass2_0.<WritePdb>g__ProcessMethod|7(MethodDefinitionHandle method, DocumentHandle docuandle method, DocumentHandle document, List`1 sequencePoints, SyntaxTree syntaxTree)
   at ICSharpCode.Decompiler.DebugInfo.PortablePdbWriter.WritePdb(PEFile file, CSharpDecompiler decompiler, DecompilerSettings settings, Stream targetStream,gs settings, Stream targetStream, Boolean noLogo)
   at ICSharpCode.Decompiler.Console.ILSpyCmdProgram.GeneratePdbForAssembly(String assemblyFileName, String pdbFileName, CommandLineApplication app) in D:\GimandLineApplication app) in D:\GitWorkspace\ILSpy\ICSharpCode.Decompiler.Console\IlspyCmdProgram.cs:line 216
   at ICSharpCode.Decompiler.Console.ILSpyCmdProgram.OnExecute(CommandLineApplication app) in D:\GitWorkspace\ILSpy\ICSharpCode.Decompiler.Console\IlspyCmdProde.Decompiler.Console\IlspyCmdProgram.cs:line 109

• At the end, both produces a size 0 Newtonsoft.Json.pdb.
  

Details

• Product in use: ILSpy / ICSharpCode.Decompiler nuget package
• Version in use: 6.2.0.6124
• Any other relevant information to the issue, or your interest in contributing a fix.

[cateyes99]

Today I tried JetBrains' dotPeek 64-bit 2020.2.3, and it generated PDB successfully for Newtonsoft.Json.dll 12.0.3. As a result, I managed to debug from my .NET Core C# Web API project into Newtonsoft.Json.dll 12.0.3 by using the generated PDB!

[siegfriedpammer]

Triage: this is caused by the use of enhanced using statements. The omission of the block syntax needs to be special-cased in PDB generation as well.