diff --git a/src/Microsoft.AspNet.Razor.Runtime.Precompilation/CodeAnalysisAttributeUtilities.cs b/src/Microsoft.AspNet.Razor.Runtime.Precompilation/CodeAnalysisAttributeUtilities.cs
index 80cb142361..b27c691e53 100644
--- a/src/Microsoft.AspNet.Razor.Runtime.Precompilation/CodeAnalysisAttributeUtilities.cs
+++ b/src/Microsoft.AspNet.Razor.Runtime.Precompilation/CodeAnalysisAttributeUtilities.cs
@@ -1,4 +1,4 @@
-// Copyright (c) .NET Foundation. All rights reserved.
+// Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
@@ -29,9 +29,14 @@ namespace Microsoft.AspNet.Razor.Runtime.Precompilation
         /// <typeparam name="TAttribute">The <see cref="Attribute"/> type.</typeparam>
         /// <param name="symbol">The <see cref="ISymbol"/> to find attributes on.</param>
         /// <returns></returns>
-        public static IEnumerable<TAttribute> GetCustomAttributes<TAttribute>([NotNull] ISymbol symbol)
+        public static IEnumerable<TAttribute> GetCustomAttributes<TAttribute>(ISymbol symbol)
             where TAttribute : Attribute
         {
+            if (symbol == null)
+            {
+                throw new ArgumentNullException(nameof(symbol));
+            }
+
             var attributes = symbol.GetAttributes();
             if (attributes.Length > 0)
             {
diff --git a/src/Microsoft.AspNet.Razor.Runtime.Precompilation/CodeAnalysisSymbolBasedPropertyInfo.cs b/src/Microsoft.AspNet.Razor.Runtime.Precompilation/CodeAnalysisSymbolBasedPropertyInfo.cs
index df39e07492..f94571436a 100644
--- a/src/Microsoft.AspNet.Razor.Runtime.Precompilation/CodeAnalysisSymbolBasedPropertyInfo.cs
+++ b/src/Microsoft.AspNet.Razor.Runtime.Precompilation/CodeAnalysisSymbolBasedPropertyInfo.cs
@@ -1,4 +1,4 @@
-// Copyright (c) .NET Foundation. All rights reserved.
+// Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
@@ -6,7 +6,6 @@ using System.Collections.Generic;
 using System.Diagnostics;
 using Microsoft.AspNet.Razor.Runtime.TagHelpers;
 using Microsoft.CodeAnalysis;
-using Microsoft.Framework.Internal;
 
 namespace Microsoft.AspNet.Razor.Runtime.Precompilation
 {
@@ -22,8 +21,13 @@ namespace Microsoft.AspNet.Razor.Runtime.Precompilation
         /// Initializes a new instance of <see cref="CodeAnalysisSymbolBasedPropertyInfo"/>.
         /// </summary>
         /// <param name="propertySymbol">The <see cref="IPropertySymbol"/>.</param>
-        public CodeAnalysisSymbolBasedPropertyInfo([NotNull] IPropertySymbol propertySymbol)
+        public CodeAnalysisSymbolBasedPropertyInfo(IPropertySymbol propertySymbol)
         {
+            if (propertySymbol == null)
+            {
+                throw new ArgumentNullException(nameof(propertySymbol));
+            }
+
             _propertySymbol = propertySymbol;
             PropertyType = new CodeAnalysisSymbolBasedTypeInfo(_propertySymbol.Type);
         }
diff --git a/src/Microsoft.AspNet.Razor.Runtime.Precompilation/CodeAnalysisSymbolBasedTypeInfo.cs b/src/Microsoft.AspNet.Razor.Runtime.Precompilation/CodeAnalysisSymbolBasedTypeInfo.cs
index 4d7d8ec776..3865b6e04b 100644
--- a/src/Microsoft.AspNet.Razor.Runtime.Precompilation/CodeAnalysisSymbolBasedTypeInfo.cs
+++ b/src/Microsoft.AspNet.Razor.Runtime.Precompilation/CodeAnalysisSymbolBasedTypeInfo.cs
@@ -1,4 +1,4 @@
-// Copyright (c) .NET Foundation. All rights reserved.
+// Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
@@ -9,7 +9,6 @@ using System.Reflection;
 using System.Text;
 using Microsoft.AspNet.Razor.Runtime.TagHelpers;
 using Microsoft.CodeAnalysis;
-using Microsoft.Framework.Internal;
 
 namespace Microsoft.AspNet.Razor.Runtime.Precompilation
 {
@@ -35,8 +34,13 @@ namespace Microsoft.AspNet.Razor.Runtime.Precompilation
         /// Initializes a new instance of <see cref="CodeAnalysisSymbolBasedTypeInfo"/>.
         /// </summary>
         /// <param name="propertySymbol">The <see cref="IPropertySymbol"/>.</param>
-        public CodeAnalysisSymbolBasedTypeInfo([NotNull] ITypeSymbol type)
+        public CodeAnalysisSymbolBasedTypeInfo(ITypeSymbol type)
         {
+            if (type == null)
+            {
+                throw new ArgumentNullException(nameof(type));
+            }
+
             _type = type;
             _underlyingType = UnwrapArrayType(type);
         }
@@ -174,10 +178,10 @@ namespace Microsoft.AspNet.Razor.Runtime.Precompilation
             ITypeSymbol sourceTypeSymbol,
             System.Reflection.TypeInfo targetTypeInfo)
         {
-                return string.Equals(
-                    targetTypeInfo.FullName,
-                    GetFullName(sourceTypeSymbol),
-                    StringComparison.Ordinal);
+            return string.Equals(
+                targetTypeInfo.FullName,
+                GetFullName(sourceTypeSymbol),
+                StringComparison.Ordinal);
         }
 
         /// <summary>
@@ -185,8 +189,13 @@ namespace Microsoft.AspNet.Razor.Runtime.Precompilation
         /// </summary>
         /// <param name="symbol">The <see cref="ITypeSymbol" /> to generate the name for.</param>
         /// <returns>The assembly qualified name.</returns>
-        public static string GetAssemblyQualifiedName([NotNull] ITypeSymbol symbol)
+        public static string GetAssemblyQualifiedName(ITypeSymbol symbol)
         {
+            if (symbol == null)
+            {
+                throw new ArgumentNullException(nameof(symbol));
+            }
+
             var builder = new StringBuilder();
             GetAssemblyQualifiedName(builder, symbol);
 
diff --git a/src/Microsoft.AspNet.Razor.Runtime.Precompilation/PrecompilationTagHelperTypeResolver.cs b/src/Microsoft.AspNet.Razor.Runtime.Precompilation/PrecompilationTagHelperTypeResolver.cs
index eba15977fe..5622267dd0 100644
--- a/src/Microsoft.AspNet.Razor.Runtime.Precompilation/PrecompilationTagHelperTypeResolver.cs
+++ b/src/Microsoft.AspNet.Razor.Runtime.Precompilation/PrecompilationTagHelperTypeResolver.cs
@@ -6,7 +6,6 @@ using System.Collections.Generic;
 using System.Reflection;
 using Microsoft.AspNet.Razor.Runtime.TagHelpers;
 using Microsoft.CodeAnalysis;
-using Microsoft.Framework.Internal;
 
 namespace Microsoft.AspNet.Razor.Runtime.Precompilation
 {
@@ -24,14 +23,24 @@ namespace Microsoft.AspNet.Razor.Runtime.Precompilation
         /// Initializes a new instance of <see cref="PrecompilationTagHelperTypeResolver"/>.
         /// </summary>
         /// <param name="compilation">The <see cref="Compilation"/>.</param>
-        public PrecompilationTagHelperTypeResolver([NotNull] Compilation compilation)
+        public PrecompilationTagHelperTypeResolver(Compilation compilation)
         {
+            if (compilation == null)
+            {
+                throw new ArgumentNullException(nameof(compilation));
+            }
+
             _compilation = compilation;
         }
 
         /// <inheritdoc />
-        protected override IEnumerable<ITypeInfo> GetTopLevelExportedTypes([NotNull] AssemblyName assemblyName)
+        protected override IEnumerable<ITypeInfo> GetTopLevelExportedTypes(AssemblyName assemblyName)
         {
+            if (assemblyName == null)
+            {
+                throw new ArgumentNullException(nameof(assemblyName));
+            }
+
             lock (_assemblyLookupLock)
             {
                 IEnumerable<ITypeInfo> result;
diff --git a/src/Microsoft.AspNet.Razor.Runtime.Precompilation/project.json b/src/Microsoft.AspNet.Razor.Runtime.Precompilation/project.json
index 235b12f3f5..79d17c5352 100644
--- a/src/Microsoft.AspNet.Razor.Runtime.Precompilation/project.json
+++ b/src/Microsoft.AspNet.Razor.Runtime.Precompilation/project.json
@@ -9,10 +9,6 @@
         "warningsAsErrors": true
     },
     "dependencies": {
-        "Microsoft.Framework.NotNullAttribute.Sources": {
-            "version": "1.0.0-*",
-            "type": "build"
-        },
         "Microsoft.Framework.PropertyActivator.Sources": {
             "version": "1.0.0-*",
             "type": "build"
diff --git a/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/DefaultTagHelperContent.cs b/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/DefaultTagHelperContent.cs
index 6b06b93a71..6f68a8b4ef 100644
--- a/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/DefaultTagHelperContent.cs
+++ b/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/DefaultTagHelperContent.cs
@@ -132,72 +132,132 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         }
 
         /// <inheritdoc />
-        public override TagHelperContent AppendFormat([NotNull] string format, object arg0)
+        public override TagHelperContent AppendFormat(string format, object arg0)
         {
+            if (format == null)
+            {
+                throw new ArgumentNullException(nameof(format));
+            }
+
             Buffer.Append(string.Format(format, arg0));
             return this;
         }
 
         /// <inheritdoc />
-        public override TagHelperContent AppendFormat([NotNull] string format, object arg0, object arg1)
+        public override TagHelperContent AppendFormat(string format, object arg0, object arg1)
         {
+            if (format == null)
+            {
+                throw new ArgumentNullException(nameof(format));
+            }
+
             Buffer.Append(string.Format(format, arg0, arg1));
             return this;
         }
 
         /// <inheritdoc />
-        public override TagHelperContent AppendFormat([NotNull] string format, object arg0, object arg1, object arg2)
+        public override TagHelperContent AppendFormat(string format, object arg0, object arg1, object arg2)
         {
+            if (format == null)
+            {
+                throw new ArgumentNullException(nameof(format));
+            }
+
             Buffer.Append(string.Format(format, arg0, arg1, arg2));
             return this;
         }
 
         /// <inheritdoc />
-        public override TagHelperContent AppendFormat([NotNull] string format, params object[] args)
+        public override TagHelperContent AppendFormat(string format, params object[] args)
         {
+            if (format == null)
+            {
+                throw new ArgumentNullException(nameof(format));
+            }
+
             Buffer.Append(string.Format(format, args));
             return this;
         }
 
         /// <inheritdoc />
         public override TagHelperContent AppendFormat(
-            [NotNull] IFormatProvider provider,
-            [NotNull] string format,
+            IFormatProvider provider,
+            string format,
             object arg0)
         {
+            if (provider == null)
+            {
+                throw new ArgumentNullException(nameof(provider));
+            }
+
+            if (format == null)
+            {
+                throw new ArgumentNullException(nameof(format));
+            }
+
             Buffer.Append(string.Format(provider, format, arg0));
             return this;
         }
 
         /// <inheritdoc />
         public override TagHelperContent AppendFormat(
-            [NotNull] IFormatProvider provider,
-            [NotNull] string format,
+            IFormatProvider provider,
+            string format,
             object arg0,
             object arg1)
         {
+            if (provider == null)
+            {
+                throw new ArgumentNullException(nameof(provider));
+            }
+
+            if (format == null)
+            {
+                throw new ArgumentNullException(nameof(format));
+            }
+
             Buffer.Append(string.Format(provider, format, arg0, arg1));
             return this;
         }
 
         /// <inheritdoc />
         public override TagHelperContent AppendFormat(
-            [NotNull] IFormatProvider provider,
-            [NotNull] string format,
+            IFormatProvider provider,
+            string format,
             object arg0,
             object arg1,
             object arg2)
         {
+            if (provider == null)
+            {
+                throw new ArgumentNullException(nameof(provider));
+            }
+
+            if (format == null)
+            {
+                throw new ArgumentNullException(nameof(format));
+            }
+
             Buffer.Append(string.Format(provider, format, arg0, arg1, arg2));
             return this;
         }
 
         /// <inheritdoc />
         public override TagHelperContent AppendFormat(
-            [NotNull] IFormatProvider provider,
-            [NotNull] string format,
+            IFormatProvider provider,
+            string format,
             params object[] args)
         {
+            if (provider == null)
+            {
+                throw new ArgumentNullException(nameof(provider));
+            }
+
+            if (format == null)
+            {
+                throw new ArgumentNullException(nameof(format));
+            }
+
             Buffer.Append(string.Format(provider, format, args));
             return this;
         }
@@ -232,8 +292,18 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         }
 
         /// <inheritdoc />
-        public override void WriteTo([NotNull] TextWriter writer, [NotNull] IHtmlEncoder encoder)
+        public override void WriteTo(TextWriter writer, IHtmlEncoder encoder)
         {
+            if (writer == null)
+            {
+                throw new ArgumentNullException(nameof(writer));
+            }
+
+            if (encoder == null)
+            {
+                throw new ArgumentNullException(nameof(encoder));
+            }
+
             Buffer.WriteTo(writer, encoder);
         }
 
diff --git a/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/OutputElementHintAttribute.cs b/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/OutputElementHintAttribute.cs
index 62e814f74c..3ed807c6fd 100644
--- a/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/OutputElementHintAttribute.cs
+++ b/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/OutputElementHintAttribute.cs
@@ -2,7 +2,6 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
-using Microsoft.Framework.Internal;
 
 namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
 {
@@ -18,8 +17,13 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         /// <param name="outputElement">
         /// The HTML element the <see cref="ITagHelper"/> may output.
         /// </param>
-        public OutputElementHintAttribute([NotNull] string outputElement)
+        public OutputElementHintAttribute(string outputElement)
         {
+            if (outputElement == null)
+            {
+                throw new ArgumentNullException(nameof(outputElement));
+            }
+
             OutputElement = outputElement;
         }
 
diff --git a/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/ReadOnlyTagHelperAttributeList.cs b/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/ReadOnlyTagHelperAttributeList.cs
index cb8904d48e..6cd5eebade 100644
--- a/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/ReadOnlyTagHelperAttributeList.cs
+++ b/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/ReadOnlyTagHelperAttributeList.cs
@@ -32,8 +32,13 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         /// <paramref name="attributes"/>.
         /// </summary>
         /// <param name="attributes">The collection to wrap.</param>
-        public ReadOnlyTagHelperAttributeList([NotNull] IEnumerable<TAttribute> attributes)
+        public ReadOnlyTagHelperAttributeList(IEnumerable<TAttribute> attributes)
         {
+            if (attributes == null)
+            {
+                throw new ArgumentNullException(nameof(attributes));
+            }
+
             Attributes = new List<TAttribute>(attributes);
         }
 
@@ -64,10 +69,15 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         /// matching <paramref name="name"/>.
         /// </returns>
         /// <remarks><paramref name="name"/> is compared case-insensitively.</remarks>
-        public TAttribute this[[NotNull] string name]
+        public TAttribute this[string name]
         {
             get
             {
+                if (name == null)
+                {
+                    throw new ArgumentNullException(nameof(name));
+                }
+
                 return Attributes.FirstOrDefault(attribute => NameEquals(name, attribute));
             }
         }
@@ -93,8 +103,13 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         /// <remarks>
         /// <paramref name="item"/>s <see cref="IReadOnlyTagHelperAttribute.Name"/> is compared case-insensitively.
         /// </remarks>
-        public bool Contains([NotNull] TAttribute item)
+        public bool Contains(TAttribute item)
         {
+            if (item == null)
+            {
+                throw new ArgumentNullException(nameof(item));
+            }
+
             return Attributes.Contains(item);
         }
 
@@ -109,8 +124,13 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         /// <see cref="IReadOnlyTagHelperAttribute.Name"/> exists in the collection; otherwise, <c>false</c>.
         /// </returns>
         /// <remarks><paramref name="name"/> is compared case-insensitively.</remarks>
-        public bool ContainsName([NotNull] string name)
+        public bool ContainsName(string name)
         {
+            if (name == null)
+            {
+                throw new ArgumentNullException(nameof(name));
+            }
+
             return Attributes.Any(attribute => NameEquals(name, attribute));
         }
 
@@ -124,8 +144,13 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         /// <remarks>
         /// <paramref name="item"/>s <see cref="IReadOnlyTagHelperAttribute.Name"/> is compared case-insensitively.
         /// </remarks>
-        public int IndexOf([NotNull] TAttribute item)
+        public int IndexOf(TAttribute item)
         {
+            if (item == null)
+            {
+                throw new ArgumentNullException(nameof(item));
+            }
+
             return Attributes.IndexOf(item);
         }
 
@@ -141,8 +166,13 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         /// <returns><c>true</c> if a <typeparamref name="TAttribute"/> with the same
         /// <see cref="IReadOnlyTagHelperAttribute.Name"/> exists in the collection; otherwise, <c>false</c>.</returns>
         /// <remarks><paramref name="name"/> is compared case-insensitively.</remarks>
-        public bool TryGetAttribute([NotNull] string name, out TAttribute attribute)
+        public bool TryGetAttribute(string name, out TAttribute attribute)
         {
+            if (name == null)
+            {
+                throw new ArgumentNullException(nameof(name));
+            }
+
             attribute = Attributes.FirstOrDefault(attr => NameEquals(name, attr));
 
             return attribute != null;
@@ -160,8 +190,13 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         /// <returns><c>true</c> if at least one <typeparamref name="TAttribute"/> with the same
         /// <see cref="IReadOnlyTagHelperAttribute.Name"/> exists in the collection; otherwise, <c>false</c>.</returns>
         /// <remarks><paramref name="name"/> is compared case-insensitively.</remarks>
-        public bool TryGetAttributes([NotNull] string name, out IEnumerable<TAttribute> attributes)
+        public bool TryGetAttributes(string name, out IEnumerable<TAttribute> attributes)
         {
+            if (name == null)
+            {
+                throw new ArgumentNullException(nameof(name));
+            }
+
             attributes = Attributes.Where(attribute => NameEquals(name, attribute));
 
             return attributes.Any();
@@ -187,8 +222,13 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         /// <param name="attribute">The attribute to compare against.</param>
         /// <returns><c>true</c> if <paramref name="name"/> case-insensitively matches <paramref name="attribute"/>s
         /// <see cref="TagHelperAttribute.Name"/>.</returns>
-        protected static bool NameEquals(string name, [NotNull] TAttribute attribute)
+        protected static bool NameEquals(string name, TAttribute attribute)
         {
+            if (attribute == null)
+            {
+                throw new ArgumentNullException(nameof(attribute));
+            }
+
             return string.Equals(name, attribute.Name, StringComparison.OrdinalIgnoreCase);
         }
     }
diff --git a/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/RuntimePropertyInfo.cs b/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/RuntimePropertyInfo.cs
index b79ff696d7..a889ca1c81 100644
--- a/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/RuntimePropertyInfo.cs
+++ b/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/RuntimePropertyInfo.cs
@@ -1,11 +1,10 @@
-// Copyright (c) .NET Foundation. All rights reserved.
+// Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
 using System.Collections.Generic;
 using System.Reflection;
 using Microsoft.AspNet.Razor.Runtime.TagHelpers;
-using Microsoft.Framework.Internal;
 
 namespace Microsoft.AspNet.Razor.Runtime
 {
@@ -18,8 +17,13 @@ namespace Microsoft.AspNet.Razor.Runtime
         /// Initializes a new instance of <see cref="RuntimePropertyInfo"/>.
         /// </summary>
         /// <param name="propertyInfo">The <see cref="PropertyInfo"/> instance to adapt.</param>
-        public RuntimePropertyInfo([NotNull] PropertyInfo propertyInfo)
+        public RuntimePropertyInfo(PropertyInfo propertyInfo)
         {
+            if (propertyInfo == null)
+            {
+                throw new ArgumentNullException(nameof(propertyInfo));
+            }
+
             Property = propertyInfo;
         }
 
diff --git a/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/RuntimeTypeInfo.cs b/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/RuntimeTypeInfo.cs
index c8148f1f19..c67d732d9b 100644
--- a/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/RuntimeTypeInfo.cs
+++ b/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/RuntimeTypeInfo.cs
@@ -1,4 +1,4 @@
-// Copyright (c) .NET Foundation. All rights reserved.
+// Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
@@ -27,8 +27,13 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         /// Initializes a new instance of <see cref="RuntimeTypeInfo"/>
         /// </summary>
         /// <param name="propertyInfo">The <see cref="System.Reflection.TypeInfo"/> instance to adapt.</param>
-        public RuntimeTypeInfo([NotNull] TypeInfo typeInfo)
+        public RuntimeTypeInfo(TypeInfo typeInfo)
         {
+            if (typeInfo == null)
+            {
+                throw new ArgumentNullException(nameof(typeInfo));
+            }
+
             TypeInfo = typeInfo;
         }
 
diff --git a/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/TagHelperAttribute.cs b/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/TagHelperAttribute.cs
index f9fada7a01..8b38c978ec 100644
--- a/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/TagHelperAttribute.cs
+++ b/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/TagHelperAttribute.cs
@@ -2,7 +2,6 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
-using Microsoft.Framework.Internal;
 
 namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
 {
@@ -25,9 +24,14 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         /// <paramref name="attribute"/>.
         /// </summary>
         /// <param name="attribute">A <see cref="IReadOnlyTagHelperAttribute"/> whose values should be copied.</param>
-        public TagHelperAttribute([NotNull] IReadOnlyTagHelperAttribute attribute)
-            : this (attribute?.Name, attribute?.Value)
+        public TagHelperAttribute(IReadOnlyTagHelperAttribute attribute)
+            : this(attribute?.Name, attribute?.Value)
         {
+            if (attribute == null)
+            {
+                throw new ArgumentNullException(nameof(attribute));
+            }
+
             Minimized = attribute.Minimized;
         }
 
diff --git a/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/TagHelperAttributeList.cs b/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/TagHelperAttributeList.cs
index feaa5da34b..abfde82719 100644
--- a/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/TagHelperAttributeList.cs
+++ b/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/TagHelperAttributeList.cs
@@ -25,9 +25,13 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         /// <paramref name="attributes"/>.
         /// </summary>
         /// <param name="attributes">The collection to wrap.</param>
-        public TagHelperAttributeList([NotNull] IEnumerable<TagHelperAttribute> attributes)
+        public TagHelperAttributeList(IEnumerable<TagHelperAttribute> attributes)
             : base(attributes)
         {
+            if (attributes == null)
+            {
+                throw new ArgumentNullException(nameof(attributes));
+            }
         }
 
         /// <inheritdoc />
@@ -40,9 +44,13 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
             {
                 return base[index];
             }
-            [param: NotNull]
             set
             {
+                if (value == null)
+                {
+                    throw new ArgumentNullException(nameof(value));
+                }
+
                 if (value.Name == null)
                 {
                     throw new ArgumentException(
@@ -83,15 +91,29 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         /// attributes["name"] = new TagHelperAttribute("name", "value");
         /// </code>
         /// </example>
-        public new TagHelperAttribute this[[NotNull] string name]
+        public new TagHelperAttribute this[string name]
         {
             get
             {
+                if (name == null)
+                {
+                    throw new ArgumentNullException(nameof(name));
+                }
+
                 return base[name];
             }
-            [param: NotNull]
             set
             {
+                if (name == null)
+                {
+                    throw new ArgumentNullException(nameof(name));
+                }
+
+                if (value == null)
+                {
+                    throw new ArgumentNullException(nameof(value));
+                }
+
                 // Name will be null if user attempts to set the attribute via an implicit conversion:
                 // output.Attributes["someName"] = "someValue"
                 if (value.Name == null)
@@ -152,8 +174,13 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         /// </summary>
         /// <param name="name">The <see cref="TagHelperAttribute.Name"/> of the attribute to add.</param>
         /// <param name="value">The <see cref="TagHelperAttribute.Value"/> of the attribute to add.</param>
-        public void Add([NotNull] string name, object value)
+        public void Add(string name, object value)
         {
+            if (name == null)
+            {
+                throw new ArgumentNullException(nameof(name));
+            }
+
             Attributes.Add(new TagHelperAttribute(name, value));
         }
 
@@ -161,8 +188,13 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         /// <remarks>
         /// <paramref name="attribute"/>'s <see cref="TagHelperAttribute.Name"/> must not be <c>null</c>.
         /// </remarks>
-        public void Add([NotNull] TagHelperAttribute attribute)
+        public void Add(TagHelperAttribute attribute)
         {
+            if (attribute == null)
+            {
+                throw new ArgumentNullException(nameof(attribute));
+            }
+
             if (attribute.Name == null)
             {
                 throw new ArgumentException(
@@ -179,8 +211,13 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         /// <remarks>
         /// <paramref name="attribute"/>'s <see cref="TagHelperAttribute.Name"/> must not be <c>null</c>.
         /// </remarks>
-        public void Insert(int index, [NotNull] TagHelperAttribute attribute)
+        public void Insert(int index, TagHelperAttribute attribute)
         {
+            if (attribute == null)
+            {
+                throw new ArgumentNullException(nameof(attribute));
+            }
+
             if (attribute.Name == null)
             {
                 throw new ArgumentException(
@@ -194,8 +231,13 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         }
 
         /// <inheritdoc />
-        public void CopyTo([NotNull] TagHelperAttribute[] array, int index)
+        public void CopyTo(TagHelperAttribute[] array, int index)
         {
+            if (array == null)
+            {
+                throw new ArgumentNullException(nameof(array));
+            }
+
             Attributes.CopyTo(array, index);
         }
 
@@ -203,8 +245,13 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         /// <remarks>
         /// <paramref name="attribute"/>s <see cref="TagHelperAttribute.Name"/> is compared case-insensitively.
         /// </remarks>
-        public bool Remove([NotNull] TagHelperAttribute attribute)
+        public bool Remove(TagHelperAttribute attribute)
         {
+            if (attribute == null)
+            {
+                throw new ArgumentNullException(nameof(attribute));
+            }
+
             return Attributes.Remove(attribute);
         }
 
@@ -225,8 +272,13 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         /// <c>true</c> if at least 1 <see cref="TagHelperAttribute"/> was removed; otherwise, <c>false</c>.
         /// </returns>
         /// <remarks><paramref name="name"/> is compared case-insensitively.</remarks>
-        public bool RemoveAll([NotNull] string name)
+        public bool RemoveAll(string name)
         {
+            if (name == null)
+            {
+                throw new ArgumentNullException(nameof(name));
+            }
+
             return Attributes.RemoveAll(attribute => NameEquals(name, attribute)) > 0;
         }
 
diff --git a/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/TagHelperContext.cs b/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/TagHelperContext.cs
index 3ee7ba85fc..96cdbc971b 100644
--- a/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/TagHelperContext.cs
+++ b/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/TagHelperContext.cs
@@ -5,7 +5,6 @@ using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Threading.Tasks;
-using Microsoft.Framework.Internal;
 
 namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
 {
@@ -26,11 +25,31 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         /// <param name="getChildContentAsync">A delegate used to execute and retrieve the rendered child content
         /// asynchronously.</param>
         public TagHelperContext(
-            [NotNull] IEnumerable<IReadOnlyTagHelperAttribute> allAttributes,
-            [NotNull] IDictionary<object, object> items,
-            [NotNull] string uniqueId,
-            [NotNull] Func<bool, Task<TagHelperContent>> getChildContentAsync)
+            IEnumerable<IReadOnlyTagHelperAttribute> allAttributes,
+            IDictionary<object, object> items,
+            string uniqueId,
+            Func<bool, Task<TagHelperContent>> getChildContentAsync)
         {
+            if (allAttributes == null)
+            {
+                throw new ArgumentNullException(nameof(allAttributes));
+            }
+
+            if (items == null)
+            {
+                throw new ArgumentNullException(nameof(items));
+            }
+
+            if (uniqueId == null)
+            {
+                throw new ArgumentNullException(nameof(uniqueId));
+            }
+
+            if (getChildContentAsync == null)
+            {
+                throw new ArgumentNullException(nameof(getChildContentAsync));
+            }
+
             AllAttributes = new ReadOnlyTagHelperAttributeList<IReadOnlyTagHelperAttribute>(
                 allAttributes.Select(attribute => new TagHelperAttribute(attribute.Name, attribute.Value)));
             Items = items;
diff --git a/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/TagHelperDescriptorFactory.cs b/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/TagHelperDescriptorFactory.cs
index 9b7cd6bf34..7a91562a44 100644
--- a/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/TagHelperDescriptorFactory.cs
+++ b/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/TagHelperDescriptorFactory.cs
@@ -8,7 +8,6 @@ using System.Linq;
 using System.Reflection;
 using System.Text.RegularExpressions;
 using Microsoft.AspNet.Razor.TagHelpers;
-using Microsoft.Framework.Internal;
 
 namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
 {
@@ -54,10 +53,20 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         /// </returns>
         public static IEnumerable<TagHelperDescriptor> CreateDescriptors(
             string assemblyName,
-            [NotNull] ITypeInfo typeInfo,
+            ITypeInfo typeInfo,
             bool designTime,
-            [NotNull] ErrorSink errorSink)
+            ErrorSink errorSink)
         {
+            if (typeInfo == null)
+            {
+                throw new ArgumentNullException(nameof(typeInfo));
+            }
+
+            if (errorSink == null)
+            {
+                throw new ArgumentNullException(nameof(errorSink));
+            }
+
             if (ShouldSkipDescriptorCreation(designTime, typeInfo))
             {
                 return Enumerable.Empty<TagHelperDescriptor>();
diff --git a/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/TagHelperDescriptorResolver.cs b/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/TagHelperDescriptorResolver.cs
index d1a292a20d..4a48651e89 100644
--- a/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/TagHelperDescriptorResolver.cs
+++ b/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/TagHelperDescriptorResolver.cs
@@ -8,7 +8,6 @@ using System.Linq;
 using System.Text.RegularExpressions;
 using Microsoft.AspNet.Razor.Parser;
 using Microsoft.AspNet.Razor.TagHelpers;
-using Microsoft.Framework.Internal;
 
 namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
 {
@@ -52,8 +51,13 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         }
 
         /// <inheritdoc />
-        public IEnumerable<TagHelperDescriptor> Resolve([NotNull] TagHelperDescriptorResolutionContext context)
+        public IEnumerable<TagHelperDescriptor> Resolve(TagHelperDescriptorResolutionContext context)
         {
+            if (context == null)
+            {
+                throw new ArgumentNullException(nameof(context));
+            }
+
             var resolvedDescriptors = new HashSet<TagHelperDescriptor>(TagHelperDescriptorComparer.Default);
 
             // tagHelperPrefix directives do not affect which TagHelperDescriptors are added or removed from the final
diff --git a/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/TagHelperDesignTimeDescriptorFactory.cs b/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/TagHelperDesignTimeDescriptorFactory.cs
index b1f3d9d73d..22f7ce1d36 100644
--- a/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/TagHelperDesignTimeDescriptorFactory.cs
+++ b/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/TagHelperDesignTimeDescriptorFactory.cs
@@ -1,4 +1,4 @@
-// Copyright (c) .NET Foundation. All rights reserved.
+// Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 #if !DNXCORE50 // Cannot accurately resolve the location of the documentation XML file in coreclr.
@@ -9,7 +9,6 @@ using System.IO;
 using System.Linq;
 using System.Reflection;
 using Microsoft.AspNet.Razor.TagHelpers;
-using Microsoft.Framework.Internal;
 
 namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
 {
@@ -27,8 +26,13 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         /// </param>
         /// <returns>A <see cref="TagHelperDesignTimeDescriptor"/> that describes design time specific information
         /// for the given <paramref name="type"/>.</returns>
-        public static TagHelperDesignTimeDescriptor CreateDescriptor([NotNull] Type type)
+        public static TagHelperDesignTimeDescriptor CreateDescriptor(Type type)
         {
+            if (type == null)
+            {
+                throw new ArgumentNullException(nameof(type));
+            }
+
             var id = XmlDocumentationProvider.GetId(type);
             var documentationDescriptor = CreateDocumentationDescriptor(type.Assembly, id);
 
@@ -62,8 +66,13 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         /// <returns>A <see cref="TagHelperAttributeDesignTimeDescriptor"/> that describes design time specific
         /// information for the given <paramref name="propertyInfo"/>.</returns>
         public static TagHelperAttributeDesignTimeDescriptor CreateAttributeDescriptor(
-            [NotNull] PropertyInfo propertyInfo)
+            PropertyInfo propertyInfo)
         {
+            if (propertyInfo == null)
+            {
+                throw new ArgumentNullException(nameof(propertyInfo));
+            }
+
             var id = XmlDocumentationProvider.GetId(propertyInfo);
             var declaringAssembly = propertyInfo.DeclaringType.Assembly;
             var documentationDescriptor = CreateDocumentationDescriptor(declaringAssembly, id);
diff --git a/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/TagHelperExecutionContext.cs b/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/TagHelperExecutionContext.cs
index 363b35b4b0..9dcd7ed21d 100644
--- a/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/TagHelperExecutionContext.cs
+++ b/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/TagHelperExecutionContext.cs
@@ -4,7 +4,6 @@
 using System;
 using System.Collections.Generic;
 using System.Threading.Tasks;
-using Microsoft.Framework.Internal;
 
 namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
 {
@@ -45,14 +44,44 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         /// <param name="startTagHelperWritingScope">A delegate used to start a writing scope in a Razor page.</param>
         /// <param name="endTagHelperWritingScope">A delegate used to end a writing scope in a Razor page.</param>
         public TagHelperExecutionContext(
-            [NotNull] string tagName,
+            string tagName,
             TagMode tagMode,
-            [NotNull] IDictionary<object, object> items,
-            [NotNull] string uniqueId,
-            [NotNull] Func<Task> executeChildContentAsync,
-            [NotNull] Action startTagHelperWritingScope,
-            [NotNull] Func<TagHelperContent> endTagHelperWritingScope)
+            IDictionary<object, object> items,
+            string uniqueId,
+            Func<Task> executeChildContentAsync,
+            Action startTagHelperWritingScope,
+            Func<TagHelperContent> endTagHelperWritingScope)
         {
+            if (tagName == null)
+            {
+                throw new ArgumentNullException(nameof(tagName));
+            }
+
+            if (items == null)
+            {
+                throw new ArgumentNullException(nameof(items));
+            }
+
+            if (uniqueId == null)
+            {
+                throw new ArgumentNullException(nameof(uniqueId));
+            }
+
+            if (executeChildContentAsync == null)
+            {
+                throw new ArgumentNullException(nameof(executeChildContentAsync));
+            }
+
+            if (startTagHelperWritingScope == null)
+            {
+                throw new ArgumentNullException(nameof(startTagHelperWritingScope));
+            }
+
+            if (endTagHelperWritingScope == null)
+            {
+                throw new ArgumentNullException(nameof(endTagHelperWritingScope));
+            }
+
             _tagHelpers = new List<ITagHelper>();
             _executeChildContentAsync = executeChildContentAsync;
             _startTagHelperWritingScope = startTagHelperWritingScope;
@@ -127,8 +156,13 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         /// Tracks the given <paramref name="tagHelper"/>.
         /// </summary>
         /// <param name="tagHelper">The tag helper to track.</param>
-        public void Add([NotNull] ITagHelper tagHelper)
+        public void Add(ITagHelper tagHelper)
         {
+            if (tagHelper == null)
+            {
+                throw new ArgumentNullException(nameof(tagHelper));
+            }
+
             _tagHelpers.Add(tagHelper);
         }
 
@@ -136,8 +170,13 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         /// Tracks the minimized HTML attribute in <see cref="AllAttributes"/> and <see cref="HTMLAttributes"/>.
         /// </summary>
         /// <param name="name">The minimized HTML attribute name.</param>
-        public void AddMinimizedHtmlAttribute([NotNull] string name)
+        public void AddMinimizedHtmlAttribute(string name)
         {
+            if (name == null)
+            {
+                throw new ArgumentNullException(nameof(name));
+            }
+
             HTMLAttributes.Add(
                 new TagHelperAttribute
                 {
@@ -157,8 +196,13 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         /// </summary>
         /// <param name="name">The HTML attribute name.</param>
         /// <param name="value">The HTML attribute value.</param>
-        public void AddHtmlAttribute([NotNull] string name, object value)
+        public void AddHtmlAttribute(string name, object value)
         {
+            if (name == null)
+            {
+                throw new ArgumentNullException(nameof(name));
+            }
+
             HTMLAttributes.Add(name, value);
             AllAttributes.Add(name, value);
         }
@@ -168,8 +212,13 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         /// </summary>
         /// <param name="name">The bound attribute name.</param>
         /// <param name="value">The attribute value.</param>
-        public void AddTagHelperAttribute([NotNull] string name, object value)
+        public void AddTagHelperAttribute(string name, object value)
         {
+            if (name == null)
+            {
+                throw new ArgumentNullException(nameof(name));
+            }
+
             AllAttributes.Add(name, value);
         }
 
diff --git a/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/TagHelperOutput.cs b/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/TagHelperOutput.cs
index bba143fce4..2bda595413 100644
--- a/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/TagHelperOutput.cs
+++ b/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/TagHelperOutput.cs
@@ -1,7 +1,7 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
-using Microsoft.Framework.Internal;
+using System;
 
 namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
 {
@@ -23,8 +23,13 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         /// <param name="attributes">The HTML attributes.</param>
         public TagHelperOutput(
             string tagName,
-            [NotNull] TagHelperAttributeList attributes)
+            TagHelperAttributeList attributes)
         {
+            if (attributes == null)
+            {
+                throw new ArgumentNullException(nameof(attributes));
+            }
+
             TagName = tagName;
             Attributes = new TagHelperAttributeList(attributes);
         }
diff --git a/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/TagHelperRunner.cs b/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/TagHelperRunner.cs
index fdd5b40f53..101d6e41d0 100644
--- a/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/TagHelperRunner.cs
+++ b/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/TagHelperRunner.cs
@@ -1,9 +1,9 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
+using System;
 using System.Linq;
 using System.Threading.Tasks;
-using Microsoft.Framework.Internal;
 
 namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
 {
@@ -19,8 +19,13 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         /// </param>
         /// <returns>Resulting <see cref="TagHelperOutput"/> from processing all of the
         /// <paramref name="executionContext"/>'s <see cref="ITagHelper"/>s.</returns>
-        public async Task<TagHelperOutput> RunAsync([NotNull] TagHelperExecutionContext executionContext)
+        public async Task<TagHelperOutput> RunAsync(TagHelperExecutionContext executionContext)
         {
+            if (executionContext == null)
+            {
+                throw new ArgumentNullException(nameof(executionContext));
+            }
+
             var tagHelperContext = new TagHelperContext(
                 executionContext.AllAttributes,
                 executionContext.Items,
diff --git a/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/TagHelperScopeManager.cs b/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/TagHelperScopeManager.cs
index 4464b83fd9..4b6ebfe35b 100644
--- a/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/TagHelperScopeManager.cs
+++ b/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/TagHelperScopeManager.cs
@@ -34,13 +34,38 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         /// <param name="endTagHelperWritingScope">A delegate used to end a writing scope in a Razor page.</param>
         /// <returns>A <see cref="TagHelperExecutionContext"/> to use.</returns>
         public TagHelperExecutionContext Begin(
-            [NotNull] string tagName,
+            string tagName,
             TagMode tagMode,
-            [NotNull] string uniqueId,
-            [NotNull] Func<Task> executeChildContentAsync,
-            [NotNull] Action startTagHelperWritingScope,
-            [NotNull] Func<TagHelperContent> endTagHelperWritingScope)
+            string uniqueId,
+            Func<Task> executeChildContentAsync,
+            Action startTagHelperWritingScope,
+            Func<TagHelperContent> endTagHelperWritingScope)
         {
+            if (tagName == null)
+            {
+                throw new ArgumentNullException(nameof(tagName));
+            }
+
+            if (uniqueId == null)
+            {
+                throw new ArgumentNullException(nameof(uniqueId));
+            }
+
+            if (executeChildContentAsync == null)
+            {
+                throw new ArgumentNullException(nameof(executeChildContentAsync));
+            }
+
+            if (startTagHelperWritingScope == null)
+            {
+                throw new ArgumentNullException(nameof(startTagHelperWritingScope));
+            }
+
+            if (endTagHelperWritingScope == null)
+            {
+                throw new ArgumentNullException(nameof(endTagHelperWritingScope));
+            }
+
             IDictionary<object, object> items;
 
             // If we're not wrapped by another TagHelper, then there will not be a parentExecutionContext.
diff --git a/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/TagHelperTypeResolver.cs b/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/TagHelperTypeResolver.cs
index 8a5ea0b43d..2e3bf850d9 100644
--- a/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/TagHelperTypeResolver.cs
+++ b/src/Microsoft.AspNet.Razor.Runtime/TagHelpers/TagHelperTypeResolver.cs
@@ -5,7 +5,6 @@ using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Reflection;
-using Microsoft.Framework.Internal;
 
 namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
 {
@@ -29,8 +28,13 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         public IEnumerable<ITypeInfo> Resolve(
             string name,
             SourceLocation documentLocation,
-            [NotNull] ErrorSink errorSink)
+            ErrorSink errorSink)
         {
+            if (errorSink == null)
+            {
+                throw new ArgumentNullException(nameof(errorSink));
+            }
+
             if (string.IsNullOrEmpty(name))
             {
                 var errorLength = name == null ? 1 : Math.Max(name.Length, 1);
@@ -71,8 +75,13 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         /// <returns>
         /// An <see cref="IEnumerable{ITypeInfo}"/> of types exported from the given <paramref name="assemblyName"/>.
         /// </returns>
-        protected virtual IEnumerable<ITypeInfo> GetTopLevelExportedTypes([NotNull] AssemblyName assemblyName)
+        protected virtual IEnumerable<ITypeInfo> GetTopLevelExportedTypes(AssemblyName assemblyName)
         {
+            if (assemblyName == null)
+            {
+                throw new ArgumentNullException(nameof(assemblyName));
+            }
+
             var exportedTypeInfos = GetExportedTypes(assemblyName);
 
             return exportedTypeInfos
diff --git a/src/Microsoft.AspNet.Razor.Runtime/XMLDocumentationProvider.cs b/src/Microsoft.AspNet.Razor.Runtime/XMLDocumentationProvider.cs
index 7132cc1f80..c78a8e4e92 100644
--- a/src/Microsoft.AspNet.Razor.Runtime/XMLDocumentationProvider.cs
+++ b/src/Microsoft.AspNet.Razor.Runtime/XMLDocumentationProvider.cs
@@ -1,4 +1,4 @@
-// Copyright (c) .NET Foundation. All rights reserved.
+// Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 #if !DNXCORE50
@@ -8,7 +8,6 @@ using System.Linq;
 using System.Reflection;
 using System.Text;
 using System.Xml.Linq;
-using Microsoft.Framework.Internal;
 
 namespace Microsoft.AspNet.Razor.Runtime
 {
@@ -76,8 +75,13 @@ namespace Microsoft.AspNet.Razor.Runtime
         /// </summary>
         /// <param name="type">The <see cref="Type"/> to get the identifier for.</param>
         /// <returns>The <see cref="string"/> identifier for the given <paramref name="type"/>.</returns>
-        public static string GetId([NotNull] Type type)
+        public static string GetId(Type type)
         {
+            if (type == null)
+            {
+                throw new ArgumentNullException(nameof(type));
+            }
+
             return $"T:{type.FullName}";
         }
 
@@ -86,8 +90,13 @@ namespace Microsoft.AspNet.Razor.Runtime
         /// </summary>
         /// <param name="propertyInfo">The <see cref="PropertyInfo"/> to get the identifier for.</param>
         /// <returns>The <see cref="string"/> identifier for the given <paramref name="propertyInfo"/>.</returns>
-        public static string GetId([NotNull] PropertyInfo propertyInfo)
+        public static string GetId(PropertyInfo propertyInfo)
         {
+            if (propertyInfo == null)
+            {
+                throw new ArgumentNullException(nameof(propertyInfo));
+            }
+
             var declaringTypeInfo = propertyInfo.DeclaringType;
             return $"P:{declaringTypeInfo.FullName}.{propertyInfo.Name}";
         }
diff --git a/src/Microsoft.AspNet.Razor.Runtime/project.json b/src/Microsoft.AspNet.Razor.Runtime/project.json
index 73e4a85112..4a35ed012a 100644
--- a/src/Microsoft.AspNet.Razor.Runtime/project.json
+++ b/src/Microsoft.AspNet.Razor.Runtime/project.json
@@ -19,10 +19,6 @@
     "Microsoft.Framework.CopyOnWriteDictionary.Sources": {
       "type": "build",
       "version": "1.0.0-*"
-    },
-    "Microsoft.Framework.NotNullAttribute.Sources": {
-      "type": "build",
-      "version": "1.0.0-*"
     }
   },
   "frameworks": {
diff --git a/test/Microsoft.AspNet.Razor.Runtime.Test/TagHelpers/TagHelperExecutionContextTest.cs b/test/Microsoft.AspNet.Razor.Runtime.Test/TagHelpers/TagHelperExecutionContextTest.cs
index d8f0dcf94e..ac2759fa66 100644
--- a/test/Microsoft.AspNet.Razor.Runtime.Test/TagHelpers/TagHelperExecutionContextTest.cs
+++ b/test/Microsoft.AspNet.Razor.Runtime.Test/TagHelpers/TagHelperExecutionContextTest.cs
@@ -58,7 +58,7 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
             var executionContext = new TagHelperExecutionContext(
                 "p",
                 tagMode: TagMode.StartTagAndEndTag,
-                items: null,
+                items: new Dictionary<object, object>(),
                 uniqueId: string.Empty,
                 executeChildContentAsync: () =>
                 {
@@ -91,7 +91,7 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
             var executionContext = new TagHelperExecutionContext(
                 "p",
                 tagMode: TagMode.StartTagAndEndTag,
-                items: null,
+                items: new Dictionary<object, object>(),
                 uniqueId: string.Empty,
                 executeChildContentAsync: () =>
                 {
@@ -120,7 +120,7 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
             var executionContext = new TagHelperExecutionContext(
                 "p",
                 tagMode: TagMode.StartTagAndEndTag,
-                items: null,
+                items: new Dictionary<object, object>(),
                 uniqueId: string.Empty,
                 executeChildContentAsync: () => { return Task.FromResult(result: true); },
                 startTagHelperWritingScope: () => { },
@@ -145,7 +145,7 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
             var executionContext = new TagHelperExecutionContext(
                 "p",
                 tagMode: TagMode.StartTagAndEndTag,
-                items: null,
+                items: new Dictionary<object, object>(),
                 uniqueId: string.Empty,
                 executeChildContentAsync: () =>
                 {