Add input validation

src/Scripting/Core/Hosting/ObjectFormatter/CommonTypeNameFormatter.cs

@@ -240,7 +240,7 @@ private string FormatGenericTypeName(TypeInfo typeInfo, Options options)
                 if (options.ShowNamespaces)
                 {
                     var @namespace = nestedTypes.Last().Namespace;
-                    if (@namespace.Length > 0)
+                    if (@namespace != null)
                     {
                         builder.Append(@namespace + ".");
                     }

src/Scripting/Core/Hosting/ObjectFormatter/MemberDisplayFormat.cs

@@ -23,7 +23,7 @@ public enum MemberDisplayFormat
         Hidden,
     }
 
-    internal static partial class EnumBounds
+    internal static partial class MemberDisplayFormatExtensions
     {
         internal static bool IsValid(this MemberDisplayFormat value)
         {

src/Scripting/Core/Hosting/ObjectFormatter/NumberRadix.cs

+// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+namespace Microsoft.CodeAnalysis.Scripting.Hosting
+{
+    public enum NumberRadix : byte
+    {
+        Decimal = 10,
+        Hexadecimal = 16,
+    }
+
+    internal static class NumberRadixExtensions
+    {
+        internal static bool IsValid(this NumberRadix radix)
+        {
+            switch(radix)
+            {
+                case NumberRadix.Decimal:
+                case NumberRadix.Hexadecimal:
+                    return true;
+                default:
+                    return false;
+            }
+        }
+    }
+}
\ No newline at end of file

src/Scripting/Core/Hosting/PrintOptions.cs

 // Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
+using System;
+
 namespace Microsoft.CodeAnalysis.Scripting.Hosting
 {
     public class PrintOptions
     {
-        public NumberRadix NumberRadix { get; set; } = NumberRadix.Decimal;
-        public MemberDisplayFormat MemberDisplayFormat { get; set; }
-        public bool EscapeNonPrintableCharacters { get; set; }
-        public int MaximumOutputLength { get; set; } = 1024;
-    }
+        private NumberRadix _numberRadix = NumberRadix.Decimal;
+        private MemberDisplayFormat _memberDisplayFormat;
+        private bool _escapeNonPrintableCharacters;
+        private int _maximumOutputLength = 1024;
 
-    public enum NumberRadix : byte
-    {
-        Decimal = 10,
-        Hexadecimal = 16,
-    }
+        public NumberRadix NumberRadix
+        {
+            get
+            {
+                return _numberRadix;
+            }
 
-    internal static class NumberRadixExtensions
-    {
-        internal static bool IsValid(this NumberRadix radix)
+            set
+            {
+                if (!value.IsValid())
+                {
+                    throw new ArgumentOutOfRangeException(nameof(value));
+                }
+
+                _numberRadix = value;
+            }
+        }
+
+        public MemberDisplayFormat MemberDisplayFormat
+        {
+            get
+            {
+                return _memberDisplayFormat;
+            }
+
+            set
+            {
+                if (!value.IsValid())
+                {
+                    throw new ArgumentOutOfRangeException(nameof(value));
+                }
+
+                _memberDisplayFormat = value;
+            }
+        }
+
+        public bool EscapeNonPrintableCharacters
         {
-            switch(radix)
+            get
             {
-                case NumberRadix.Decimal:
-                case NumberRadix.Hexadecimal:
-                    return true;
-                default:
-                    return false;
+                return _escapeNonPrintableCharacters;
+            }
+
+            set
+            {
+                _escapeNonPrintableCharacters = value;
+            }
+        }
+
+        public int MaximumOutputLength
+        {
+            get
+            {
+                return _maximumOutputLength;
+            }
+
+            set
+            {
+                if (value <= 0)
+                {
+                    throw new ArgumentOutOfRangeException(nameof(value));
+                }
+
+                _maximumOutputLength = value;
             }
         }
     }

src/Scripting/Core/Scripting.csproj

@@ -84,6 +84,7 @@
     <Compile Include="Hosting\ObjectFormatter\CommonTypeNameFormatter.Options.cs" />
     <Compile Include="Hosting\ObjectFormatter\CommonTypeNameFormatter.cs" />
     <Compile Include="Hosting\CommonStackTraceRewriter.cs" />
+    <Compile Include="Hosting\ObjectFormatter\NumberRadix.cs" />
     <Compile Include="Hosting\StackFrame.cs" />
     <Compile Include="Hosting\StackTraceRewriter.cs" />
     <Compile Include="Hosting\PrintOptions.cs" />