Fix crash when TypeVar has no arguments

src/Analysis/Engine/Impl/Parsing/Parser.cs

@@ -60,7 +60,6 @@ public class Parser{
  private bool _alwaysAllowContextDependentSyntax;
  private bool _stubFile;
 
- private static Encoding _utf8throwing;
  private static Regex _codingRegex;
 
  #region Construction

src/Analysis/Engine/Impl/Values/TypingModuleInfo.cs

@@ -53,11 +53,17 @@ private IAnalysisSet GetFunction(Node node, AnalysisUnit unit, string name, Call
 
  private IAnalysisSet NewType_Call(Node node, AnalysisUnit unit, IAnalysisSet[] args, NameExpression[] keywordArgNames){
  return unit.InterpreterScope.GetOrMakeNodeValue(node, Analyzer.NodeValueKind.TypeAnnotation, n =>{
- var name = PythonAnalyzer.GetArg(args, keywordArgNames, null, 0).GetConstantValueAsString().FirstOrDefault(x => !string.IsNullOrEmpty(x));
+ if (args.Length == 0){
+ return AnalysisSet.Empty; // No arguments given
+ }
+
+ var arg = PythonAnalyzer.GetArg(args, keywordArgNames, null, 0);
+ var name = arg.GetConstantValueAsString().FirstOrDefault(x => !string.IsNullOrEmpty(x));
  var baseTypeSet = PythonAnalyzer.GetArg(args, keywordArgNames, null, 1) ?? unit.State.ClassInfos[BuiltinTypeId.Object].Instance;
  if (string.IsNullOrEmpty(name)){
  return baseTypeSet;
  }
+
  var instPi = new ProtocolInfo(unit.ProjectEntry, unit.State);
  var np = new NameProtocol(instPi, name, memberType: PythonMemberType.Instance, typeId: BuiltinTypeId.Type);
  var cls = new NamespaceProtocol(instPi, "__class__"); // Declares class type

src/Analysis/Engine/Test/AnalysisTest.cs

@@ -4303,6 +4303,19 @@ def first(l: Sequence[T]) -> T: # Generic function
  }
  }
 
+ [TestMethod, Priority(0)]
+ public async Task TypeVarIncomplete(){
+ var code = @"
+from typing import TypeVar
+
+_ = TypeVar()
+"
+ using (var server = await CreateServerAsync(PythonVersions.LatestAvailable3X)){
+ var analysis = await server.OpenDefaultDocumentAndGetAnalysisAsync(code);
+ analysis.Should().HaveVariable("_").WithNoTypes();
+ }
+ }
+
  [TestMethod, Priority(0)]
  public async Task Defaults(){
  var text = @"