Unix - antlr4 doesn't suceed to parse the HSGrammar.g4

[aNewGitHubUser]

Hello,
When I try to build the project as it is using VisualStudioCode, antlr4 seems to not being able to work properly.
Here are the error I get :

.nuget/packages/antlr4.codegenerator/4.6.5-beta001/build/Antlr4.CodeGenerator.targets(121,5): error AC1000: Unknown build error: Exception in thread "main" cli.System.NotImplementedException: The method or operation is not implemented.
.nuget/packages/antlr4.codegenerator/4.6.5-beta001/build/Antlr4.CodeGenerator.targets(121,5): error AC1000: Unknown build error: at cli.System.Reflection.MemberInfo.get_Module(Unknown Source)
.nuget/packages/antlr4.codegenerator/4.6.5-beta001/build/Antlr4.CodeGenerator.targets(121,5): error AC1000: Unknown build error: at cli.System.Reflection.Emit.FieldBuilder.get_Module(Unknown Source)
.nuget/packages/antlr4.codegenerator/4.6.5-beta001/build/Antlr4.CodeGenerator.targets(121,5): error AC1000: Unknown build error: at IKVM.Internal.FieldWrapper.ResolveField(Unknown Source)
.nuget/packages/antlr4.codegenerator/4.6.5-beta001/build/Antlr4.CodeGenerator.targets(121,5): error AC1000: Unknown build error: at IKVM.NativeCode.sun.reflect.ReflectionFactory+FieldAccessorImplBase+FieldAccessor1[[System.Object, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]].lazySet(Unknown Source) .nuget/packages/antlr4.codegenerator/4.6.5-beta001/build/Antlr4.CodeGenerator.targets(121,5): error AC1000: Unknown build error: at IKVM.NativeCode.sun.reflect.ReflectionFactory+FieldAccessorImplBase+FieldAccessor1[[System.Object, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]].lazySet(Unknown Source)
.nuget/packages/antlr4.codegenerator/4.6.5-beta001/build/Antlr4.CodeGenerator.targets(121,5): error AC1000: Unknown build error: at IKVM.NativeCode.sun.reflect.ReflectionFactory+FieldAccessorImplBase+ObjectField.set(Unknown Source)
.nuget/packages/antlr4.codegenerator/4.6.5-beta001/build/Antlr4.CodeGenerator.targets(121,5): error AC1000: Unknown build error: at java.lang.reflect.Field.set(Field.java:689)
.nuget/packages/antlr4.codegenerator/4.6.5-beta001/build/Antlr4.CodeGenerator.targets(121,5): error AC1000: Unknown build error: at org.antlr.v4.Tool.handleArgs(Tool.java:226)

Any known issues or must do configuration regarding this ?
Thanks by advance