Issue :
Converting on the v1.0.6991.18175 version of unityscript2csharp on Unity 2017.4.21f seems to give the following error, running from v1.0.6956.21054 doesn't appear to have this issues. The error cancels the porting process and leaves a nullpointer reference.

NullReferenceException: Object reference not set to an instance of an object
UnityEditor.Compilation.Assembly.<get_allReferences>m__0 (UnityEditor.Compilation.Assembly a) (at C:/buildslave/unity/build/Editor/Mono/Scripting/ScriptCompilation/CompilationPipeline.cs:26)
System.Linq.Enumerable+c__Iterator102[UnityEditor.Compilation.Assembly,System.String].MoveNext () System.Linq.Enumerable+<CreateConcatIterator>c__Iterator11[System.String].MoveNext ()
System.Collections.Generic.List1[System.String].AddEnumerable (IEnumerable1 enumerable) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.Collections.Generic/List.cs:128)
System.Collections.Generic.List1[System.String]..ctor (IEnumerable1 collection) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.Collections.Generic/List.cs:65)
System.Linq.Enumerable.ToArray[String] (IEnumerable1 source) UnityEditor.Compilation.Assembly.get_allReferences () (at C:/buildslave/unity/build/Editor/Mono/Scripting/ScriptCompilation/CompilationPipeline.cs:26) UnityScript2CSharpRunner.<ComputeConverterCommandLineArguments>m__1 (UnityEditor.Compilation.Assembly a) (at Assets/UnityScript2CSharp/Editor/UnityScript2CSharpRunner.cs:264) System.Linq.Enumerable+<CreateSelectManyIterator>c__Iterator122[UnityEditor.Compilation.Assembly,System.String].MoveNext ()
System.Linq.Enumerable+c__Iterator1D1[System.String].MoveNext () System.Linq.Enumerable+<CreateDistinctIterator>c__Iterator31[System.String].MoveNext ()
UnityScript2CSharpRunner.ComputeConverterCommandLineArguments (Boolean verboseLogging) (at Assets/UnityScript2CSharp/Editor/UnityScript2CSharpRunner.cs:268)
UnityScript2CSharpRunner.RunConverter (System.String converterPath) (at Assets/UnityScript2CSharp/Editor/UnityScript2CSharpRunner.cs:180)
UnityScript2CSharpRunner.Convert () (at Assets/UnityScript2CSharp/Editor/UnityScript2CSharpRunner.cs:97)

Specifications :
Unity 2017.4.21f, recently upgraded from 5.6.6f.
Running on Windows.

Steps to reproduce :
Install Unity Package, Go to Tools, Run Conversion Tool both the convert and verbose convert options seems to give this error.