fixed NullReferenceException-bug in VBLexer; allow empty arguments (optional arguments) in VB argument list

ICSharpCode.NRefactory.VB/Lexer/VBLexer.cs

@@ -28,7 +28,7 @@ namespace ICSharpCode.NRefactory.VB.Parser
 		
 		public VBLexer(TextReader reader)
 		{
-			reader = new LATextReader(reader);
+			this.reader = new LATextReader(reader);
 			ef = new ExpressionFinder();
 		}
 		

ICSharpCode.NRefactory.VB/Parser/Parser.cs

@@ -2964,9 +2964,7 @@ partial class VBParser
 		List<Expression> parameters = null;
 		Expect(37);
 		Location start = t.Location;
-		if (StartOf(24)) {
 		ArgumentList(out parameters);
-		}
 		Expect(38);
 		pexpr = new InvocationExpression(pexpr, parameters);
 
@@ -3356,11 +3354,15 @@ partial class VBParser
 		arguments = new List<Expression>();
 		Expression expr = null;
 
+		if (StartOf(24)) {
 			Argument(out expr);
+		}
 		while (la.kind == 22) {
 			Get();
 			arguments.Add(expr ?? Expression.Null); expr = null;
+			if (StartOf(24)) {
 				Argument(out expr);
+			}
 			if (expr == null) expr = Expression.Null;
 		}
 		if (expr != null) arguments.Add(expr);
@@ -4450,9 +4452,7 @@ partial class VBParser
 		string name = t.val;
 		if (la.kind == 37) {
 			Get();
-			if (StartOf(24)) {
 			ArgumentList(out arguments);
-			}
 			Expect(38);
 		}
 		statement = new RaiseEventStatement(name, arguments);

ICSharpCode.NRefactory.VB/Parser/vb.atg

@@ -1928,7 +1928,7 @@ InvocationExpression<ref Expression pexpr>
 (. List<Expression> parameters = null; .)
 =
 	"(" (. Location start = t.Location; .)
-	[ ArgumentList<out parameters> ]
+	ArgumentList<out parameters>
 	")"
 	(.
 		pexpr = new InvocationExpression(pexpr, parameters);
@@ -2620,9 +2620,9 @@ ArgumentList<.out List<Expression> arguments.>
 		arguments = new List<Expression>();
 		Expression expr = null;
 	.) =
-	Argument<out expr>
+	[ Argument<out expr> ]
 	{ "," (. arguments.Add(expr ?? Expression.Null); expr = null; .)
-		Argument<out expr>
+		[ Argument<out expr> ]
 		(. if (expr == null) expr = Expression.Null; .)
 	}
 	(. if (expr != null) arguments.Add(expr); .)
@@ -3135,7 +3135,7 @@ RaiseEventStatement<out Statement statement>
 (. List<Expression> arguments = null; .)
 =
 	"RaiseEvent" Identifier (. string name = t.val; .)
-	[ "(" [ ArgumentList<out arguments> ] ")" ]
+	[ "(" ArgumentList<out arguments> ")" ]
 	(. statement = new RaiseEventStatement(name, arguments); .)
 .