diff --git a/src/Libraries/NRefactory/Project/Src/Lexer/CSharp/KeywordList.txt b/src/Libraries/NRefactory/Project/Src/Lexer/CSharp/KeywordList.txt
index 78ac086439..3903be4821 100644
--- a/src/Libraries/NRefactory/Project/Src/Lexer/CSharp/KeywordList.txt
+++ b/src/Libraries/NRefactory/Project/Src/Lexer/CSharp/KeywordList.txt
@@ -161,7 +161,7 @@ OverloadableBinaryOp("+", "-", "*", "/", "%", "&", "|", "^", "<<", "==", "!=", "
 TypeKW("char", "bool", "object", "string", "sbyte", "byte", "short", "ushort", "int", "uint", "long", "ulong", "float", "double", "decimal")
 UnaryHead("+", "-", "!", "~", "*", "++", "--", "&")
 AssnStartOp("+", "-", "!", "~", "*")
-CastFollower(Identifier, Literal, "(", "new", "this", "base", "null", "checked", "unchecked", "typeof", "sizeof", "delegate", @OverloadableUnaryOp)
+CastFollower(Identifier, Literal, "(", "new", "this", "base", "null", "checked", "unchecked", "typeof", "sizeof", "delegate", @OverloadableUnaryOp, @UnaryOp)
 AssgnOps("=", "+=", "-=", "*=", "/=", "%=", "&=", "|=", "<<=")
 UnaryOp("+", "-", "!", "~", "*", "++", "--", "&")
 TypeDeclarationKW("class", "interface", "struct", "enum", "delegate")
diff --git a/src/Libraries/NRefactory/Project/Src/Lexer/CSharp/Tokens.cs b/src/Libraries/NRefactory/Project/Src/Lexer/CSharp/Tokens.cs
index 8a3c439214..01a8f24e53 100644
--- a/src/Libraries/NRefactory/Project/Src/Lexer/CSharp/Tokens.cs
+++ b/src/Libraries/NRefactory/Project/Src/Lexer/CSharp/Tokens.cs
@@ -158,7 +158,7 @@ namespace ICSharpCode.NRefactory.Parser.CSharp
 		public static BitArray TypeKW = NewSet(Char, Bool, Object, String, Sbyte, Byte, Short, Ushort, Int, Uint, Long, Ulong, Float, Double, Decimal);
 		public static BitArray UnaryHead = NewSet(Plus, Minus, Not, BitwiseComplement, Times, Increment, Decrement, BitwiseAnd);
 		public static BitArray AssnStartOp = NewSet(Plus, Minus, Not, BitwiseComplement, Times);
-		public static BitArray CastFollower = NewSet(Identifier, Literal, OpenParenthesis, New, This, Base, Null, Checked, Unchecked, Typeof, Sizeof, Delegate, Minus, Not, BitwiseComplement, Increment, Decrement, True, False);
+		public static BitArray CastFollower = NewSet(Identifier, Literal, OpenParenthesis, New, This, Base, Null, Checked, Unchecked, Typeof, Sizeof, Delegate, Minus, Not, BitwiseComplement, Increment, Decrement, True, False, Plus, Minus, Not, BitwiseComplement, Times, Increment, Decrement, BitwiseAnd);
 		public static BitArray AssgnOps = NewSet(Assign, PlusAssign, MinusAssign, TimesAssign, DivAssign, ModAssign, BitwiseAndAssign, BitwiseOrAssign, ShiftLeftAssign);
 		public static BitArray UnaryOp = NewSet(Plus, Minus, Not, BitwiseComplement, Times, Increment, Decrement, BitwiseAnd);
 		public static BitArray TypeDeclarationKW = NewSet(Class, Interface, Struct, Enum, Delegate);
diff --git a/src/Libraries/NRefactory/Test/Parser/Expressions/ConditionalExpressionTests.cs b/src/Libraries/NRefactory/Test/Parser/Expressions/ConditionalExpressionTests.cs
index 65623a03be..f78edc471c 100644
--- a/src/Libraries/NRefactory/Test/Parser/Expressions/ConditionalExpressionTests.cs
+++ b/src/Libraries/NRefactory/Test/Parser/Expressions/ConditionalExpressionTests.cs
@@ -38,6 +38,16 @@ namespace ICSharpCode.NRefactory.Tests.Ast
 			Assert.IsTrue(ce.FalseExpression is FieldReferenceExpression);
 		}
 		
+		[Test]
+		public void CSharpConditionalIsWithNullableExpressionTest()
+		{
+			ConditionalExpression ce = ParseUtilCSharp.ParseExpression<ConditionalExpression>("a is b? ? a() : a.B");
+			
+			Assert.IsTrue(ce.Condition is TypeOfIsExpression);
+			Assert.IsTrue(ce.TrueExpression is InvocationExpression);
+			Assert.IsTrue(ce.FalseExpression is FieldReferenceExpression);
+		}
+		
 		[Test]
 		public void CSharpConditionalIsExpressionTest2()
 		{
@@ -68,6 +78,16 @@ namespace ICSharpCode.NRefactory.Tests.Ast
 			Assert.IsTrue(ce.TrueExpression is UnaryOperatorExpression);
 			Assert.IsTrue(ce.FalseExpression is PrimitiveExpression);
 		}
+		
+		[Test]
+		public void CSharpConditionalIsWithExplicitPositiveValue()
+		{
+			ConditionalExpression ce = ParseUtilCSharp.ParseExpression<ConditionalExpression>("a is b ? +1 : 1");
+			
+			Assert.IsTrue(ce.Condition is TypeOfIsExpression);
+			Assert.IsTrue(ce.TrueExpression is UnaryOperatorExpression);
+			Assert.IsTrue(ce.FalseExpression is PrimitiveExpression);
+		}
 		#endregion
 		
 		#region VB.NET