Add tests to validate @addtaghelper directive.

- Fixed existing tests to work with new RazorParser.
- Validated directive syntax tree creation, errors and code generation.

#111

test/Microsoft.AspNet.Razor.Test/Framework/TestSpanBuilder.cs

@@ -300,6 +300,11 @@ namespace Microsoft.AspNet.Razor.Test.Framework
             return _self.With(new RazorDirectiveAttributeCodeGenerator(key, value));
         }
 
+        public SpanConstructor AsAddTagHelper(string lookupText)
+        {
+            return _self.With(new AddTagHelperCodeGenerator(lookupText));
+        }
+
         public SpanConstructor As(ISpanCodeGenerator codeGenerator)
         {
             return _self.With(codeGenerator);

test/Microsoft.AspNet.Razor.Test/Generator/CSharpRazorCodeGeneratorTest.cs

@@ -492,16 +492,41 @@ namespace Microsoft.AspNet.Razor.Test.Generator
             });
         }
 
-        private static LineMapping BuildLineMapping(int documentAbsoluteIndex, int documentLineIndex, int generatedAbsoluteIndex, int generatedLineIndex, int characterOffsetIndex, int contentLength)
+        protected static LineMapping BuildLineMapping(int documentAbsoluteIndex, 
+                                                      int documentLineIndex, 
+                                                      int generatedAbsoluteIndex, 
+                                                      int generatedLineIndex, 
+                                                      int characterOffsetIndex, 
+                                                      int contentLength)
         {
-            return BuildLineMapping(documentAbsoluteIndex, documentLineIndex, characterOffsetIndex, generatedAbsoluteIndex, generatedLineIndex, characterOffsetIndex, contentLength);
+            return BuildLineMapping(documentAbsoluteIndex, 
+                                    documentLineIndex, 
+                                    characterOffsetIndex, 
+                                    generatedAbsoluteIndex, 
+                                    generatedLineIndex, 
+                                    characterOffsetIndex, 
+                                    contentLength);
         }
 
-        private static LineMapping BuildLineMapping(int documentAbsoluteIndex, int documentLineIndex, int documentCharacterOffsetIndex, int generatedAbsoluteIndex, int generatedLineIndex, int generatedCharacterOffsetIndex, int contentLength)
+        protected static LineMapping BuildLineMapping(int documentAbsoluteIndex, 
+                                                      int documentLineIndex, 
+                                                      int documentCharacterOffsetIndex, 
+                                                      int generatedAbsoluteIndex, 
+                                                      int generatedLineIndex, 
+                                                      int generatedCharacterOffsetIndex, 
+                                                      int contentLength)
         {
             return new LineMapping(
-                        documentLocation: new MappingLocation(new SourceLocation(documentAbsoluteIndex, documentLineIndex, documentCharacterOffsetIndex), contentLength),
+                        documentLocation: new MappingLocation(
-                        generatedLocation: new MappingLocation(new SourceLocation(generatedAbsoluteIndex, generatedLineIndex, generatedCharacterOffsetIndex), contentLength)
+                            new SourceLocation(documentAbsoluteIndex, 
+                                               documentLineIndex, 
+                                               documentCharacterOffsetIndex), 
+                            contentLength),
+                        generatedLocation: new MappingLocation(
+                            new SourceLocation(generatedAbsoluteIndex, 
+                                               generatedLineIndex, 
+                                               generatedCharacterOffsetIndex), 
+                        contentLength)
                     );
         }
     }

test/Microsoft.AspNet.Razor.Test/Generator/CSharpTagHelperRenderingTest.cs

@@ -1,7 +1,9 @@
 // Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
+using System.Collections.Generic;
 using System.Reflection;
+using Microsoft.AspNet.Razor.Generator.Compiler;
 using Microsoft.AspNet.Razor.TagHelpers;
 using Moq;
 using Xunit;
@@ -10,6 +12,34 @@ namespace Microsoft.AspNet.Razor.Test.Generator
 {
     public class CSharpTagHelperRenderingTest : TagHelperTestBase
     {
+        [Fact]
+        public void CSharpCodeGenerator_CorrectlyGeneratesMappings_ForAddTagHelperDirective()
+        {
+            // Act & Assert
+            RunTagHelperTest("AddTagHelperDirective",
+                             designTimeMode: true,
+                             expectedDesignTimePragmas: new List<LineMapping>()
+                             {
+                                    BuildLineMapping(documentAbsoluteIndex: 14,
+                                                     documentLineIndex: 0,
+                                                     generatedAbsoluteIndex: 433,
+                                                     generatedLineIndex: 14,
+                                                     characterOffsetIndex: 14,
+                                                     contentLength: 11)
+                             });
+        }
+
+        [Fact]
+        public void TagHelpers_Directive_GenerateDesignTimeMappings()
+        {
+            // Act & Assert
+            RunTagHelperTest("AddTagHelperDirective",
+                             designTimeMode: true,
+                             tagHelperDescriptors: new[] {
+                                new TagHelperDescriptor("p", "pTagHelper", ContentBehavior.None)
+                             });
+        }
+
         [Theory]
         [InlineData("TagHelpersInSection")]
         [InlineData("TagHelpersInHelper")]
@@ -19,21 +49,20 @@ namespace Microsoft.AspNet.Razor.Test.Generator
             var propertyInfoMock = new Mock<PropertyInfo>();
             propertyInfoMock.Setup(propertyInfo => propertyInfo.PropertyType).Returns(typeof(string));
             propertyInfoMock.Setup(propertyInfo => propertyInfo.Name).Returns("BoundProperty");
-            var tagHelperDescriptorProvider = new TagHelperDescriptorProvider(
+            var tagHelperDescriptors = new TagHelperDescriptor[]
-                new TagHelperDescriptor[]
+            {
-                {
+                new TagHelperDescriptor("MyTagHelper",
-                    new TagHelperDescriptor("MyTagHelper",
+                                        "MyTagHelper",
-                                            "MyTagHelper",
+                                        ContentBehavior.None,
-                                            ContentBehavior.None,
+                                        new [] {
-                                            new [] {
+                                            new TagHelperAttributeDescriptor("BoundProperty",
-                                                new TagHelperAttributeDescriptor("BoundProperty", 
+                                                                             propertyInfoMock.Object)
-                                                                                 propertyInfoMock.Object)
+                                        }),
-                                            }),
+                new TagHelperDescriptor("NestedTagHelper", "NestedTagHelper", ContentBehavior.Modify)
-                    new TagHelperDescriptor("NestedTagHelper", "NestedTagHelper", ContentBehavior.Modify)
+            };
-                });
 
             // Act & Assert
-            RunTagHelperTest(testType, tagHelperDescriptorProvider: tagHelperDescriptorProvider);
+            RunTagHelperTest(testType, tagHelperDescriptors: tagHelperDescriptors);
         }
 
         [Theory]
@@ -52,50 +81,48 @@ namespace Microsoft.AspNet.Razor.Test.Generator
             var checkedPropertyInfo = new Mock<PropertyInfo>();
             checkedPropertyInfo.Setup(propertyInfo => propertyInfo.PropertyType).Returns(typeof(bool));
             checkedPropertyInfo.Setup(propertyInfo => propertyInfo.Name).Returns("Checked");
-            var tagHelperDescriptorProvider = new TagHelperDescriptorProvider(
+            var tagHelperDescriptors = new TagHelperDescriptor[]
-                new TagHelperDescriptor[]
+            {
-                {
+                new TagHelperDescriptor("p",
-                    new TagHelperDescriptor("p",
+                                        "PTagHelper",
-                                            "PTagHelper", 
+                                        ContentBehavior.None,
-                                            ContentBehavior.None,
+                                        new [] {
-                                            new [] {
+                                            new TagHelperAttributeDescriptor("foo", pFooPropertyInfo.Object)
-                                                new TagHelperAttributeDescriptor("foo", pFooPropertyInfo.Object)
+                                        }),
-                                            }),
+                new TagHelperDescriptor("input",
-                    new TagHelperDescriptor("input",
+                                        "InputTagHelper",
-                                            "InputTagHelper",
+                                        ContentBehavior.None,
-                                            ContentBehavior.None,
+                                        new TagHelperAttributeDescriptor[] {
-                                            new TagHelperAttributeDescriptor[] {
+                                            new TagHelperAttributeDescriptor("type", inputTypePropertyInfo.Object)
-                                                new TagHelperAttributeDescriptor("type", inputTypePropertyInfo.Object)
+                                        }),
-                                            }),
+                new TagHelperDescriptor("input",
-                    new TagHelperDescriptor("input",
+                                        "InputTagHelper2",
-                                            "InputTagHelper2",
+                                        ContentBehavior.None,
-                                            ContentBehavior.None,
+                                        new TagHelperAttributeDescriptor[] {
-                                            new TagHelperAttributeDescriptor[] {
+                                            new TagHelperAttributeDescriptor("type", inputTypePropertyInfo.Object),
-                                                new TagHelperAttributeDescriptor("type", inputTypePropertyInfo.Object),
+                                            new TagHelperAttributeDescriptor("checked", checkedPropertyInfo.Object)
-                                                new TagHelperAttributeDescriptor("checked", checkedPropertyInfo.Object)
+                                        })
-                                            }),
+            };
-                });
 
             // Act & Assert
-            RunTagHelperTest(testType, tagHelperDescriptorProvider: tagHelperDescriptorProvider);
+            RunTagHelperTest(testType, tagHelperDescriptors: tagHelperDescriptors);
         }
 
         [Fact]
         public void TagHelpers_WithContentBehaviors_GenerateExpectedOutput()
         {
             // Arrange
-            var tagHelperDescriptorProvider = new TagHelperDescriptorProvider(
+            var tagHelperDescriptors = new TagHelperDescriptor[]
-                new TagHelperDescriptor[]
+            {
-                {
                     new TagHelperDescriptor("modify", "ModifyTagHelper", ContentBehavior.Modify),
                     new TagHelperDescriptor("none", "NoneTagHelper", ContentBehavior.None),
                     new TagHelperDescriptor("append", "AppendTagHelper", ContentBehavior.Append),
                     new TagHelperDescriptor("prepend", "PrependTagHelper", ContentBehavior.Prepend),
                     new TagHelperDescriptor("replace", "ReplaceTagHelper", ContentBehavior.Replace),
-                });
+            };
 
             // Act & Assert
-            RunTagHelperTest("ContentBehaviorTagHelpers", tagHelperDescriptorProvider: tagHelperDescriptorProvider);
+            RunTagHelperTest("ContentBehaviorTagHelpers", tagHelperDescriptors: tagHelperDescriptors);
         }
     }
 }

test/Microsoft.AspNet.Razor.Test/Generator/CodeTree/CSharpPaddingBuilderTests.cs

@@ -8,6 +8,7 @@ using System.Linq;
 using Microsoft.AspNet.Razor.Generator.Compiler.CSharp;
 using Microsoft.AspNet.Razor.Parser;
 using Microsoft.AspNet.Razor.Parser.SyntaxTree;
+using Microsoft.AspNet.Razor.TagHelpers;
 using Xunit;
 
 namespace Microsoft.AspNet.Razor.Test.Generator
@@ -221,7 +222,9 @@ namespace Microsoft.AspNet.Razor.Test.Generator
         {
             Assert.True(spanIndex > 0);
 
-            var parser = new RazorParser(new CSharpCodeParser(), new HtmlMarkupParser());
+            var parser = new RazorParser(new CSharpCodeParser(), 
+                                         new HtmlMarkupParser(),
+                                         tagHelperDescriptorResolver: null);
 
             Span[] spans;
 

test/Microsoft.AspNet.Razor.Test/Generator/TagHelperAttributeValueCodeRendererTest.cs

@@ -24,29 +24,28 @@ namespace Microsoft.AspNet.Razor.Test.Generator
             var checkedPropertyInfo = new Mock<PropertyInfo>();
             checkedPropertyInfo.Setup(propertyInfo => propertyInfo.PropertyType).Returns(typeof(bool));
             checkedPropertyInfo.Setup(propertyInfo => propertyInfo.Name).Returns("Checked");
-            var tagHelperDescriptorProvider = new TagHelperDescriptorProvider(
+            var tagHelperDescriptors = new TagHelperDescriptor[]
-                new TagHelperDescriptor[]
+            {
-                {
+                new TagHelperDescriptor("p", "PTagHelper", ContentBehavior.None),
-                    new TagHelperDescriptor("p", "PTagHelper", ContentBehavior.None),
+                new TagHelperDescriptor("input",
-                    new TagHelperDescriptor("input",
+                                        "InputTagHelper",
-                                            "InputTagHelper",
+                                        ContentBehavior.None,
-                                            ContentBehavior.None,
+                                        new TagHelperAttributeDescriptor[] {
-                                            new TagHelperAttributeDescriptor[] {
+                                            new TagHelperAttributeDescriptor("type", inputTypePropertyInfo.Object)
-                                                new TagHelperAttributeDescriptor("type", inputTypePropertyInfo.Object)
+                                        }),
-                                            }),
+                new TagHelperDescriptor("input",
-                    new TagHelperDescriptor("input",
+                                        "InputTagHelper2",
-                                            "InputTagHelper2",
+                                        ContentBehavior.None,
-                                            ContentBehavior.None,
+                                        new TagHelperAttributeDescriptor[] {
-                                            new TagHelperAttributeDescriptor[] {
+                                            new TagHelperAttributeDescriptor("type", inputTypePropertyInfo.Object),
-                                                new TagHelperAttributeDescriptor("type", inputTypePropertyInfo.Object),
+                                            new TagHelperAttributeDescriptor("checked", checkedPropertyInfo.Object)
-                                                new TagHelperAttributeDescriptor("checked", checkedPropertyInfo.Object)
+                                        })
-                                            }),
+            };
-                });
 
             // Act & Assert
             RunTagHelperTest(testName: "BasicTagHelpers",
                              baseLineName: "BasicTagHelpers.CustomAttributeCodeGenerator",
-                             tagHelperDescriptorProvider: tagHelperDescriptorProvider,
+                             tagHelperDescriptors: tagHelperDescriptors,
                              hostConfig: (host) =>
                              {
                                  return new CodeBuilderReplacingHost(host);

test/Microsoft.AspNet.Razor.Test/Generator/TagHelperTestBase.cs

@@ -2,9 +2,10 @@
 // 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.Linq;
+using Microsoft.AspNet.Razor.Generator.Compiler;
 using Microsoft.AspNet.Razor.Parser;
-using Microsoft.AspNet.Razor.Parser.TagHelpers.Internal;
 using Microsoft.AspNet.Razor.TagHelpers;
 
 namespace Microsoft.AspNet.Razor.Test.Generator
@@ -13,43 +14,56 @@ namespace Microsoft.AspNet.Razor.Test.Generator
     {
         protected void RunTagHelperTest(string testName,
                                         string baseLineName = null,
-                                        TagHelperDescriptorProvider tagHelperDescriptorProvider = null,
+                                        bool designTimeMode = false,
-                                        Func<RazorEngineHost, RazorEngineHost> hostConfig = null)
+                                        IEnumerable<TagHelperDescriptor> tagHelperDescriptors = null,
+                                        Func<RazorEngineHost, RazorEngineHost> hostConfig = null,
+                                        IList<LineMapping> expectedDesignTimePragmas = null)
         {
             RunTest(name: testName,
                     baselineName: baseLineName,
+                    designTimeMode: designTimeMode,
+                    tabTest: TabTest.NoTabs,
                     templateEngineConfig: (engine) =>
                     {
-                        return new TagHelperTemplateEngine(engine, tagHelperDescriptorProvider);
+                        return new TagHelperTemplateEngine(engine, tagHelperDescriptors);
                     },
-                    hostConfig: hostConfig);
+                    hostConfig: hostConfig,
+                    expectedDesignTimePragmas: expectedDesignTimePragmas);
+        }
+
+        private class CustomTagHelperDescriptorResolver : ITagHelperDescriptorResolver
+        {
+            private IEnumerable<TagHelperDescriptor> _tagHelperDescriptors;
+
+            public CustomTagHelperDescriptorResolver(IEnumerable<TagHelperDescriptor> tagHelperDescriptors)
+            {
+                _tagHelperDescriptors = tagHelperDescriptors ?? Enumerable.Empty<TagHelperDescriptor>();
+            }
+
+            public IEnumerable<TagHelperDescriptor> Resolve(string lookupText)
+            {
+                return _tagHelperDescriptors;
+            }
         }
 
         private class TagHelperTemplateEngine : RazorTemplateEngine
         {
-            private TagHelperDescriptorProvider _tagHelperDescriptorProvider;
+            private IEnumerable<TagHelperDescriptor> _tagHelperDescriptors;
 
-            public TagHelperTemplateEngine(RazorTemplateEngine engine, TagHelperDescriptorProvider tagHelperDescriptorProvider)
+            public TagHelperTemplateEngine(RazorTemplateEngine engine,
+                                           IEnumerable<TagHelperDescriptor> tagHelperDescriptors)
                 : base(engine.Host)
             {
-                _tagHelperDescriptorProvider = tagHelperDescriptorProvider;
+                _tagHelperDescriptors = tagHelperDescriptors;
             }
 
             protected internal override RazorParser CreateParser()
             {
                 var parser = base.CreateParser();
-                var tagHelperParseTreeRewriter = new TagHelperParseTreeRewriter(_tagHelperDescriptorProvider);
 
-                for (var i = 0; i < parser.Optimizers.Count; i++)
+                return new RazorParser(parser.CodeParser,
-                {
+                                       parser.MarkupParser,
-                    if (parser.Optimizers[i] is TagHelperParseTreeRewriter)
+                                       new CustomTagHelperDescriptorResolver(_tagHelperDescriptors));
-                    {
-                        parser.Optimizers[i] = tagHelperParseTreeRewriter;
-                        break;
-                    }
-                }
-
-                return parser;
             }
         }
     }

test/Microsoft.AspNet.Razor.Test/Parser/CSharp/CSharpDirectivesTest.cs

@@ -12,6 +12,93 @@ namespace Microsoft.AspNet.Razor.Test.Parser.CSharp
 {
     public class CSharpDirectivesTest : CsHtmlCodeParserTestBase
     {
+        [Fact]
+        public void AddTagHelperDirective_Succeeds()
+        {
+            ParseBlockTest("@addtaghelper \"Foo\"",
+                new DirectiveBlock(
+                    Factory.CodeTransition(),
+                    Factory.MetaCode(SyntaxConstants.CSharp.AddTagHelperKeyword + " ")
+                           .Accepts(AcceptedCharacters.None),
+                    Factory.Code("\"Foo\"").AsAddTagHelper("Foo")));
+        }
+
+        [Fact]
+        public void AddTagHelperDirectiveSupportsSpaces()
+        {
+            ParseBlockTest("@addtaghelper   \"  Foo,   Bar \"   ",
+                new DirectiveBlock(
+                    Factory.CodeTransition(),
+                    Factory.MetaCode(SyntaxConstants.CSharp.AddTagHelperKeyword + "   ")
+                           .Accepts(AcceptedCharacters.None),
+                    Factory.Code("\"  Foo,   Bar \"   ").AsAddTagHelper("  Foo,   Bar ")));
+        }
+
+        [Fact]
+        public void AddTagHelperDirectiveRequiresValue()
+        {
+            ParseBlockTest("@addtaghelper ",
+                new DirectiveBlock(
+                    Factory.CodeTransition(),
+                    Factory.MetaCode(SyntaxConstants.CSharp.AddTagHelperKeyword + " ")
+                           .Accepts(AcceptedCharacters.None),
+                    Factory.EmptyCSharp().AsAddTagHelper(string.Empty)),
+                 new RazorError(
+                    RazorResources.FormatParseError_DirectiveMustHaveValue(SyntaxConstants.CSharp.AddTagHelperKeyword),
+                    absoluteIndex: 14, lineIndex: 0, columnIndex: 14));
+        }
+
+        [Fact]
+        public void AddTagHelperDirectiveWithStartQuoteRequiresDoubleQuotesAroundValue()
+        {
+            ParseBlockTest("@addtaghelper \"Foo",
+                new DirectiveBlock(
+                    Factory.CodeTransition(),
+                    Factory.MetaCode(SyntaxConstants.CSharp.AddTagHelperKeyword + " ")
+                           .Accepts(AcceptedCharacters.None),
+                    Factory.Code("\"Foo").AsAddTagHelper("Foo")),
+                 new RazorError(
+                     RazorResources.ParseError_Unterminated_String_Literal,
+                     absoluteIndex: 14, lineIndex: 0, columnIndex: 14),
+                 new RazorError(
+                     RazorResources.FormatParseError_DirectiveMustBeSurroundedByQuotes(
+                        SyntaxConstants.CSharp.AddTagHelperKeyword),
+                        absoluteIndex: 14, lineIndex: 0, columnIndex: 14));
+        }
+
+        [Fact]
+        public void AddTagHelperDirectiveWithEndQuoteRequiresDoubleQuotesAroundValue()
+        {
+            ParseBlockTest("@addtaghelper Foo\"",
+                new DirectiveBlock(
+                    Factory.CodeTransition(),
+                    Factory.MetaCode(SyntaxConstants.CSharp.AddTagHelperKeyword + " ")
+                           .Accepts(AcceptedCharacters.None),
+                    Factory.Code("Foo\"").AsAddTagHelper("Foo")),
+                 new RazorError(
+                     RazorResources.ParseError_Unterminated_String_Literal,
+                     absoluteIndex: 17, lineIndex: 0, columnIndex: 17),
+                 new RazorError(
+                     RazorResources.FormatParseError_DirectiveMustBeSurroundedByQuotes(
+                        SyntaxConstants.CSharp.AddTagHelperKeyword),
+                        absoluteIndex: 14, lineIndex: 0, columnIndex: 14));
+        }
+
+        [Fact]
+        public void AddTagHelperDirectiveRequiresDoubleQuotesAroundValue()
+        {
+            ParseBlockTest("@addtaghelper Foo",
+                new DirectiveBlock(
+                    Factory.CodeTransition(),
+                    Factory.MetaCode(SyntaxConstants.CSharp.AddTagHelperKeyword + " ")
+                           .Accepts(AcceptedCharacters.None),
+                    Factory.Code("Foo").AsAddTagHelper("Foo")),
+                 new RazorError(
+                     RazorResources.FormatParseError_DirectiveMustBeSurroundedByQuotes(
+                        SyntaxConstants.CSharp.AddTagHelperKeyword),
+                        absoluteIndex: 14, lineIndex: 0, columnIndex: 14));
+        }
+
         [Fact]
         public void InheritsDirective()
         {

test/Microsoft.AspNet.Razor.Test/Parser/RazorParserTest.cs

@@ -5,6 +5,7 @@ using System;
 using System.IO;
 using Microsoft.AspNet.Razor.Parser;
 using Microsoft.AspNet.Razor.Parser.SyntaxTree;
+using Microsoft.AspNet.Razor.TagHelpers;
 using Microsoft.AspNet.Razor.Test.Framework;
 using Xunit;
 
@@ -12,25 +13,15 @@ namespace Microsoft.AspNet.Razor.Test.Parser
 {
     public class RazorParserTest
     {
-        [Fact]
-        public void ConstructorRequiresNonNullCodeParser()
-        {
-            Assert.Throws<ArgumentNullException>("codeParser", () => new RazorParser(null, new HtmlMarkupParser()));
-        }
-
-        [Fact]
-        public void ConstructorRequiresNonNullMarkupParser()
-        {
-            Assert.Throws<ArgumentNullException>("markupParser", () => new RazorParser(new CSharpCodeParser(), null));
-        }
-
         [Fact]
         public void ParseMethodCallsParseDocumentOnMarkupParserAndReturnsResults()
         {
             var factory = SpanFactory.CreateCsHtml();
 
             // Arrange
-            RazorParser parser = new RazorParser(new CSharpCodeParser(), new HtmlMarkupParser());
+            RazorParser parser = new RazorParser(new CSharpCodeParser(), 
+                                                 new HtmlMarkupParser(),
+                                                 tagHelperDescriptorResolver: null);
 
             // Act/Assert
             ParserTestBase.EvaluateResults(parser.Parse(new StringReader("foo @bar baz")),
@@ -50,7 +41,9 @@ namespace Microsoft.AspNet.Razor.Test.Parser
             var factory = SpanFactory.CreateCsHtml();
 
             // Arrange
-            RazorParser parser = new RazorParser(new CSharpCodeParser(), new HtmlMarkupParser());
+            RazorParser parser = new RazorParser(new CSharpCodeParser(), 
+                                                 new HtmlMarkupParser(),
+                                                 tagHelperDescriptorResolver: null);
 
             // Act
             ParserResults results = parser.Parse(new StringReader("foo @bar baz"));
@@ -78,7 +71,7 @@ namespace Microsoft.AspNet.Razor.Test.Parser
             // Arrange
             ParserBase markupParser = new MockMarkupParser();
             ParserBase codeParser = new CSharpCodeParser();
-            RazorParser parser = new RazorParser(codeParser, markupParser);
+            RazorParser parser = new RazorParser(codeParser, markupParser, tagHelperDescriptorResolver: null);
             TextReader expectedReader = new StringReader("foo");
 
             // Act

test/Microsoft.AspNet.Razor.Test/TestFiles/CodeGenerator/CS/Output/AddTagHelperDirective.cs

@@ -0,0 +1,33 @@
+namespace TestOutput
+{
+    using System;
+    using System.Threading.Tasks;
+
+    public class AddTagHelperDirective
+    {
+        private static object @__o;
+        private void @__RazorDesignTimeHelpers__()
+        {
+            #pragma warning disable 219
+            string __tagHelperDirectiveSyntaxHelper = null;
+            __tagHelperDirectiveSyntaxHelper = 
+#line 1 "AddTagHelperDirective.cshtml"
+              "something"
+
+#line default
+#line hidden
+            ;
+            #pragma warning restore 219
+        }
+        #line hidden
+        public AddTagHelperDirective()
+        {
+        }
+
+        #pragma warning disable 1998
+        public override async Task ExecuteAsync()
+        {
+        }
+        #pragma warning restore 1998
+    }
+}

test/Microsoft.AspNet.Razor.Test/TestFiles/CodeGenerator/CS/Output/BasicTagHelpers.CustomAttributeCodeGenerator.cs

@@ -1,4 +1,4 @@
-#pragma checksum "BasicTagHelpers.cshtml" "{ff1816ec-aa5e-4d10-87f7-6f4963833460}" "8d60e58d54168749dc71a0d6d3a95887b2adb5e7"
+#pragma checksum "BasicTagHelpers.cshtml" "{ff1816ec-aa5e-4d10-87f7-6f4963833460}" "897cb2042003c7f319b5265ba8e1878fb3043e8e"
 namespace TestOutput
 {
     using Microsoft.AspNet.Razor.Runtime.TagHelpers;
@@ -22,8 +22,8 @@ namespace TestOutput
         #pragma warning disable 1998
         public override async Task ExecuteAsync()
         {
-            Instrumentation.BeginContext(0, 47, true);
+            Instrumentation.BeginContext(27, 49, true);
-            WriteLiteral("<div class=\"randomNonTagHelperAttribute\">\r\n    ");
+            WriteLiteral("\r\n<div class=\"randomNonTagHelperAttribute\">\r\n    ");
             Instrumentation.EndContext();
             __tagHelperExecutionContext = __tagHelperScopeManager.Begin("p");
             __PTagHelper = CreateTagHelper<PTagHelper>();
@@ -31,7 +31,7 @@ namespace TestOutput
             __tagHelperExecutionContext.AddHtmlAttribute("class", "Hello World");
             __tagHelperExecutionContext.Output = __tagHelperRunner.RunAsync(__tagHelperExecutionContext).Result;
             WriteLiteral(__tagHelperExecutionContext.Output.GenerateStartTag());
-            Instrumentation.BeginContext(70, 10, true);
+            Instrumentation.BeginContext(99, 10, true);
             WriteLiteral("\r\n        ");
             Instrumentation.EndContext();
             __tagHelperExecutionContext = __tagHelperScopeManager.Begin("p");
@@ -41,7 +41,7 @@ namespace TestOutput
             WriteLiteral(__tagHelperExecutionContext.Output.GenerateStartTag());
             WriteLiteral(__tagHelperExecutionContext.Output.GenerateEndTag());
             __tagHelperExecutionContext = __tagHelperScopeManager.End();
-            Instrumentation.BeginContext(87, 10, true);
+            Instrumentation.BeginContext(116, 10, true);
             WriteLiteral("\r\n        ");
             Instrumentation.EndContext();
             __tagHelperExecutionContext = __tagHelperScopeManager.Begin("input");
@@ -56,7 +56,7 @@ namespace TestOutput
             WriteLiteral(__tagHelperExecutionContext.Output.GenerateStartTag());
             WriteLiteral(__tagHelperExecutionContext.Output.GenerateEndTag());
             __tagHelperExecutionContext = __tagHelperScopeManager.End();
-            Instrumentation.BeginContext(118, 10, true);
+            Instrumentation.BeginContext(147, 10, true);
             WriteLiteral("\r\n        ");
             Instrumentation.EndContext();
             __tagHelperExecutionContext = __tagHelperScopeManager.Begin("input");
@@ -73,12 +73,12 @@ namespace TestOutput
             WriteLiteral(__tagHelperExecutionContext.Output.GenerateStartTag());
             WriteLiteral(__tagHelperExecutionContext.Output.GenerateEndTag());
             __tagHelperExecutionContext = __tagHelperScopeManager.End();
-            Instrumentation.BeginContext(167, 6, true);
+            Instrumentation.BeginContext(196, 6, true);
             WriteLiteral("\r\n    ");
             Instrumentation.EndContext();
             WriteLiteral(__tagHelperExecutionContext.Output.GenerateEndTag());
             __tagHelperExecutionContext = __tagHelperScopeManager.End();
-            Instrumentation.BeginContext(177, 8, true);
+            Instrumentation.BeginContext(206, 8, true);
             WriteLiteral("\r\n</div>");
             Instrumentation.EndContext();
         }

test/Microsoft.AspNet.Razor.Test/TestFiles/CodeGenerator/CS/Output/BasicTagHelpers.cs

@@ -1,4 +1,4 @@
-#pragma checksum "BasicTagHelpers.cshtml" "{ff1816ec-aa5e-4d10-87f7-6f4963833460}" "8d60e58d54168749dc71a0d6d3a95887b2adb5e7"
+#pragma checksum "BasicTagHelpers.cshtml" "{ff1816ec-aa5e-4d10-87f7-6f4963833460}" "897cb2042003c7f319b5265ba8e1878fb3043e8e"
 namespace TestOutput
 {
     using Microsoft.AspNet.Razor.Runtime.TagHelpers;
@@ -23,8 +23,8 @@ namespace TestOutput
         #pragma warning disable 1998
         public override async Task ExecuteAsync()
         {
-            Instrumentation.BeginContext(0, 47, true);
+            Instrumentation.BeginContext(27, 49, true);
-            WriteLiteral("<div class=\"randomNonTagHelperAttribute\">\r\n    ");
+            WriteLiteral("\r\n<div class=\"randomNonTagHelperAttribute\">\r\n    ");
             Instrumentation.EndContext();
             __tagHelperExecutionContext = __tagHelperScopeManager.Begin("p");
             __PTagHelper = CreateTagHelper<PTagHelper>();
@@ -32,7 +32,7 @@ namespace TestOutput
             __tagHelperExecutionContext.AddHtmlAttribute("class", "Hello World");
             __tagHelperExecutionContext.Output = __tagHelperRunner.RunAsync(__tagHelperExecutionContext).Result;
             WriteLiteral(__tagHelperExecutionContext.Output.GenerateStartTag());
-            Instrumentation.BeginContext(70, 10, true);
+            Instrumentation.BeginContext(99, 10, true);
             WriteLiteral("\r\n        ");
             Instrumentation.EndContext();
             __tagHelperExecutionContext = __tagHelperScopeManager.Begin("p");
@@ -42,7 +42,7 @@ namespace TestOutput
             WriteLiteral(__tagHelperExecutionContext.Output.GenerateStartTag());
             WriteLiteral(__tagHelperExecutionContext.Output.GenerateEndTag());
             __tagHelperExecutionContext = __tagHelperScopeManager.End();
-            Instrumentation.BeginContext(87, 10, true);
+            Instrumentation.BeginContext(116, 10, true);
             WriteLiteral("\r\n        ");
             Instrumentation.EndContext();
             __tagHelperExecutionContext = __tagHelperScopeManager.Begin("input");
@@ -57,7 +57,7 @@ namespace TestOutput
             WriteLiteral(__tagHelperExecutionContext.Output.GenerateStartTag());
             WriteLiteral(__tagHelperExecutionContext.Output.GenerateEndTag());
             __tagHelperExecutionContext = __tagHelperScopeManager.End();
-            Instrumentation.BeginContext(118, 10, true);
+            Instrumentation.BeginContext(147, 10, true);
             WriteLiteral("\r\n        ");
             Instrumentation.EndContext();
             __tagHelperExecutionContext = __tagHelperScopeManager.Begin("input");
@@ -74,12 +74,12 @@ namespace TestOutput
             WriteLiteral(__tagHelperExecutionContext.Output.GenerateStartTag());
             WriteLiteral(__tagHelperExecutionContext.Output.GenerateEndTag());
             __tagHelperExecutionContext = __tagHelperScopeManager.End();
-            Instrumentation.BeginContext(167, 6, true);
+            Instrumentation.BeginContext(196, 6, true);
             WriteLiteral("\r\n    ");
             Instrumentation.EndContext();
             WriteLiteral(__tagHelperExecutionContext.Output.GenerateEndTag());
             __tagHelperExecutionContext = __tagHelperScopeManager.End();
-            Instrumentation.BeginContext(177, 8, true);
+            Instrumentation.BeginContext(206, 8, true);
             WriteLiteral("\r\n</div>");
             Instrumentation.EndContext();
         }

test/Microsoft.AspNet.Razor.Test/TestFiles/CodeGenerator/CS/Output/ComplexTagHelpers.cs

@@ -1,4 +1,4 @@
-#pragma checksum "ComplexTagHelpers.cshtml" "{ff1816ec-aa5e-4d10-87f7-6f4963833460}" "7540f76029963ad4e3c0a02077a63d0fe2cb0157"
+#pragma checksum "ComplexTagHelpers.cshtml" "{ff1816ec-aa5e-4d10-87f7-6f4963833460}" "cce31144cd1c3c35d241b49e41c4fc04ff044565"
 namespace TestOutput
 {
     using Microsoft.AspNet.Razor.Runtime.TagHelpers;
@@ -23,7 +23,10 @@ namespace TestOutput
         #pragma warning disable 1998
         public override async Task ExecuteAsync()
         {
-#line 1 "ComplexTagHelpers.cshtml"
+            Instrumentation.BeginContext(27, 2, true);
+            WriteLiteral("\r\n");
+            Instrumentation.EndContext();
+#line 3 "ComplexTagHelpers.cshtml"
  if (true)
 {
     var checkbox = "checkbox";
@@ -32,7 +35,7 @@ namespace TestOutput
 #line default
 #line hidden
 
-            Instrumentation.BeginContext(49, 55, true);
+            Instrumentation.BeginContext(78, 55, true);
             WriteLiteral("    <div class=\"randomNonTagHelperAttribute\">\r\n        ");
             Instrumentation.EndContext();
             __tagHelperExecutionContext = __tagHelperScopeManager.Begin("p");
@@ -40,7 +43,7 @@ namespace TestOutput
             __tagHelperExecutionContext.Add(__PTagHelper);
             StartWritingScope();
             WriteLiteral("Current Time: ");
-#line 6 "ComplexTagHelpers.cshtml"
+#line 8 "ComplexTagHelpers.cshtml"
 Write(DateTime.Now);
 
 #line default
@@ -49,23 +52,23 @@ Write(DateTime.Now);
             __tagHelperExecutionContext.AddHtmlAttribute("time", __tagHelperStringValueBuffer.ToString());
             __tagHelperExecutionContext.Output = __tagHelperRunner.RunAsync(__tagHelperExecutionContext).Result;
             WriteLiteral(__tagHelperExecutionContext.Output.GenerateStartTag());
-            Instrumentation.BeginContext(142, 34, true);
+            Instrumentation.BeginContext(171, 34, true);
             WriteLiteral("\r\n            <h1>Set Time:</h1>\r\n");
             Instrumentation.EndContext();
-#line 8 "ComplexTagHelpers.cshtml"
+#line 10 "ComplexTagHelpers.cshtml"
             
 
 #line default
 #line hidden
 
-#line 8 "ComplexTagHelpers.cshtml"
+#line 10 "ComplexTagHelpers.cshtml"
              if (false)
             {
 
 #line default
 #line hidden
 
-            Instrumentation.BeginContext(216, 16, true);
+            Instrumentation.BeginContext(245, 16, true);
             WriteLiteral("                ");
             Instrumentation.EndContext();
             __tagHelperExecutionContext = __tagHelperScopeManager.Begin("p");
@@ -73,7 +76,7 @@ Write(DateTime.Now);
             __tagHelperExecutionContext.Add(__PTagHelper);
             __tagHelperExecutionContext.Output = __tagHelperRunner.RunAsync(__tagHelperExecutionContext).Result;
             WriteLiteral(__tagHelperExecutionContext.Output.GenerateStartTag());
-            Instrumentation.BeginContext(235, 10, true);
+            Instrumentation.BeginContext(264, 10, true);
             WriteLiteral("New Time: ");
             Instrumentation.EndContext();
             __tagHelperExecutionContext = __tagHelperScopeManager.Begin("input");
@@ -92,10 +95,10 @@ Write(DateTime.Now);
             __tagHelperExecutionContext = __tagHelperScopeManager.End();
             WriteLiteral(__tagHelperExecutionContext.Output.GenerateEndTag());
             __tagHelperExecutionContext = __tagHelperScopeManager.End();
-            Instrumentation.BeginContext(315, 2, true);
+            Instrumentation.BeginContext(344, 2, true);
             WriteLiteral("\r\n");
             Instrumentation.EndContext();
-#line 11 "ComplexTagHelpers.cshtml"
+#line 13 "ComplexTagHelpers.cshtml"
             }
             else
             {
@@ -103,7 +106,7 @@ Write(DateTime.Now);
 #line default
 #line hidden
 
-            Instrumentation.BeginContext(365, 16, true);
+            Instrumentation.BeginContext(394, 16, true);
             WriteLiteral("                ");
             Instrumentation.EndContext();
             __tagHelperExecutionContext = __tagHelperScopeManager.Begin("p");
@@ -111,14 +114,14 @@ Write(DateTime.Now);
             __tagHelperExecutionContext.Add(__PTagHelper);
             __tagHelperExecutionContext.Output = __tagHelperRunner.RunAsync(__tagHelperExecutionContext).Result;
             WriteLiteral(__tagHelperExecutionContext.Output.GenerateStartTag());
-            Instrumentation.BeginContext(384, 14, true);
+            Instrumentation.BeginContext(413, 14, true);
             WriteLiteral("Current Time: ");
             Instrumentation.EndContext();
             __tagHelperExecutionContext = __tagHelperScopeManager.Begin("input");
             __InputTagHelper = CreateTagHelper<InputTagHelper>();
             __tagHelperExecutionContext.Add(__InputTagHelper);
             StartWritingScope();
-#line 14 "ComplexTagHelpers.cshtml"
+#line 16 "ComplexTagHelpers.cshtml"
 Write(checkbox);
 
 #line default
@@ -137,14 +140,14 @@ Write(checkbox);
             __tagHelperExecutionContext = __tagHelperScopeManager.End();
             WriteLiteral(__tagHelperExecutionContext.Output.GenerateEndTag());
             __tagHelperExecutionContext = __tagHelperScopeManager.End();
-            Instrumentation.BeginContext(439, 18, true);
+            Instrumentation.BeginContext(468, 18, true);
             WriteLiteral("\r\n                ");
             Instrumentation.EndContext();
             __tagHelperExecutionContext = __tagHelperScopeManager.Begin("input");
             __InputTagHelper = CreateTagHelper<InputTagHelper>();
             __tagHelperExecutionContext.Add(__InputTagHelper);
             StartWritingScope();
-#line 15 "ComplexTagHelpers.cshtml"
+#line 17 "ComplexTagHelpers.cshtml"
 Write(true ? "checkbox" : "anything");
 
 #line default
@@ -159,28 +162,28 @@ Write(true ? "checkbox" : "anything");
             WriteLiteral(__tagHelperExecutionContext.Output.GenerateStartTag());
             WriteLiteral(__tagHelperExecutionContext.Output.GenerateEndTag());
             __tagHelperExecutionContext = __tagHelperScopeManager.End();
-            Instrumentation.BeginContext(507, 18, true);
+            Instrumentation.BeginContext(536, 18, true);
             WriteLiteral("\r\n                ");
             Instrumentation.EndContext();
             __tagHelperExecutionContext = __tagHelperScopeManager.Begin("input");
             __InputTagHelper = CreateTagHelper<InputTagHelper>();
             __tagHelperExecutionContext.Add(__InputTagHelper);
             StartWritingScope();
-#line 16 "ComplexTagHelpers.cshtml"
+#line 18 "ComplexTagHelpers.cshtml"
 if(true) {
 
 #line default
 #line hidden
 
             WriteLiteral(" checkbox ");
-#line 16 "ComplexTagHelpers.cshtml"
+#line 18 "ComplexTagHelpers.cshtml"
 } else {
 
 #line default
 #line hidden
 
             WriteLiteral(" anything ");
-#line 16 "ComplexTagHelpers.cshtml"
+#line 18 "ComplexTagHelpers.cshtml"
 }
 
 #line default
@@ -196,24 +199,24 @@ if(true) {
             WriteLiteral(__tagHelperExecutionContext.Output.GenerateStartTag());
             WriteLiteral(__tagHelperExecutionContext.Output.GenerateEndTag());
             __tagHelperExecutionContext = __tagHelperScopeManager.End();
-            Instrumentation.BeginContext(608, 2, true);
+            Instrumentation.BeginContext(637, 2, true);
             WriteLiteral("\r\n");
             Instrumentation.EndContext();
-#line 17 "ComplexTagHelpers.cshtml"
+#line 19 "ComplexTagHelpers.cshtml"
             }
 
 #line default
 #line hidden
 
-            Instrumentation.BeginContext(625, 8, true);
+            Instrumentation.BeginContext(654, 8, true);
             WriteLiteral("        ");
             Instrumentation.EndContext();
             WriteLiteral(__tagHelperExecutionContext.Output.GenerateEndTag());
             __tagHelperExecutionContext = __tagHelperScopeManager.End();
-            Instrumentation.BeginContext(637, 14, true);
+            Instrumentation.BeginContext(666, 14, true);
             WriteLiteral("\r\n    </div>\r\n");
             Instrumentation.EndContext();
-#line 20 "ComplexTagHelpers.cshtml"
+#line 22 "ComplexTagHelpers.cshtml"
 }
 
 #line default

test/Microsoft.AspNet.Razor.Test/TestFiles/CodeGenerator/CS/Output/ContentBehaviorTagHelpers.cs

@@ -1,4 +1,4 @@
-#pragma checksum "ContentBehaviorTagHelpers.cshtml" "{ff1816ec-aa5e-4d10-87f7-6f4963833460}" "27af4f673a178e8b27e320ea0d869aaf6a16a18b"
+#pragma checksum "ContentBehaviorTagHelpers.cshtml" "{ff1816ec-aa5e-4d10-87f7-6f4963833460}" "5aeeb0a2b5283b353efaff2cd2fb0c739020b899"
 namespace TestOutput
 {
     using Microsoft.AspNet.Razor.Runtime.TagHelpers;
@@ -25,6 +25,9 @@ namespace TestOutput
         #pragma warning disable 1998
         public override async Task ExecuteAsync()
         {
+            Instrumentation.BeginContext(27, 2, true);
+            WriteLiteral("\r\n");
+            Instrumentation.EndContext();
             __tagHelperExecutionContext = __tagHelperScopeManager.Begin("modify");
             __ModifyTagHelper = CreateTagHelper<ModifyTagHelper>();
             __tagHelperExecutionContext.Add(__ModifyTagHelper);

test/Microsoft.AspNet.Razor.Test/TestFiles/CodeGenerator/CS/Output/SingleTagHelper.cs

@@ -1,4 +1,4 @@
-#pragma checksum "SingleTagHelper.cshtml" "{ff1816ec-aa5e-4d10-87f7-6f4963833460}" "2c9b5f2ce383fe784f68f84cbb669ab04077c417"
+#pragma checksum "SingleTagHelper.cshtml" "{ff1816ec-aa5e-4d10-87f7-6f4963833460}" "61bf4cc89584cdbbac4478b202fe04797ddeb68a"
 namespace TestOutput
 {
     using Microsoft.AspNet.Razor.Runtime.TagHelpers;
@@ -21,6 +21,9 @@ namespace TestOutput
         #pragma warning disable 1998
         public override async Task ExecuteAsync()
         {
+            Instrumentation.BeginContext(27, 2, true);
+            WriteLiteral("\r\n");
+            Instrumentation.EndContext();
             __tagHelperExecutionContext = __tagHelperScopeManager.Begin("p");
             __PTagHelper = CreateTagHelper<PTagHelper>();
             __tagHelperExecutionContext.Add(__PTagHelper);
@@ -29,7 +32,7 @@ namespace TestOutput
             __tagHelperExecutionContext.AddHtmlAttribute("class", "Hello World");
             __tagHelperExecutionContext.Output = __tagHelperRunner.RunAsync(__tagHelperExecutionContext).Result;
             WriteLiteral(__tagHelperExecutionContext.Output.GenerateStartTag());
-            Instrumentation.BeginContext(34, 11, true);
+            Instrumentation.BeginContext(63, 11, true);
             WriteLiteral("Body of Tag");
             Instrumentation.EndContext();
             WriteLiteral(__tagHelperExecutionContext.Output.GenerateEndTag());

test/Microsoft.AspNet.Razor.Test/TestFiles/CodeGenerator/CS/Output/TagHelpersInHelper.cs

@@ -1,4 +1,4 @@
-#pragma checksum "TagHelpersInHelper.cshtml" "{ff1816ec-aa5e-4d10-87f7-6f4963833460}" "522348d1a7650330b24372fade70f418f61027bd"
+#pragma checksum "TagHelpersInHelper.cshtml" "{ff1816ec-aa5e-4d10-87f7-6f4963833460}" "864bdf0afabc2aecf57904d5793a20bb6d12a6a3"
 namespace TestOutput
 {
     using Microsoft.AspNet.Razor.Runtime.TagHelpers;
@@ -8,20 +8,20 @@ namespace TestOutput
     public class TagHelpersInHelper
     {
 public static Template 
-#line 1 "TagHelpersInHelper.cshtml"
+#line 3 "TagHelpersInHelper.cshtml"
 MyHelper(string val)
 {
 
 #line default
 #line hidden
         return new Template((__razor_helper_writer) => {
-#line 2 "TagHelpersInHelper.cshtml"
+#line 4 "TagHelpersInHelper.cshtml"
  
 
 #line default
 #line hidden
 
-            Instrumentation.BeginContext(33, 19, true);
+            Instrumentation.BeginContext(62, 19, true);
             WriteLiteralTo(__razor_helper_writer, "    <div>\r\n        ");
             Instrumentation.EndContext();
             __tagHelperExecutionContext = __tagHelperScopeManager.Begin("mytaghelper");
@@ -29,7 +29,7 @@ MyHelper(string val)
             __tagHelperExecutionContext.Add(__MyTagHelper);
             StartWritingScope();
             WriteLiteral("Current Time: ");
-#line 4 "TagHelpersInHelper.cshtml"
+#line 6 "TagHelpersInHelper.cshtml"
 Write(DateTime.Now);
 
 #line default
@@ -39,7 +39,7 @@ Write(DateTime.Now);
             __tagHelperExecutionContext.AddTagHelperAttribute("BoundProperty", __MyTagHelper.BoundProperty);
             StartWritingScope();
             WriteLiteral("Current Time: ");
-#line 4 "TagHelpersInHelper.cshtml"
+#line 6 "TagHelpersInHelper.cshtml"
 Write(DateTime.Now);
 
 #line default
@@ -48,7 +48,7 @@ Write(DateTime.Now);
             __tagHelperExecutionContext.AddHtmlAttribute("unboundproperty", __tagHelperStringValueBuffer.ToString());
             __tagHelperExecutionContext.Output = __tagHelperRunner.RunAsync(__tagHelperExecutionContext).Result;
             WriteLiteralTo(__razor_helper_writer, __tagHelperExecutionContext.Output.GenerateStartTag());
-            Instrumentation.BeginContext(155, 52, true);
+            Instrumentation.BeginContext(184, 52, true);
             WriteLiteralTo(__razor_helper_writer, "\r\n            In None ContentBehavior.\r\n            ");
             Instrumentation.EndContext();
             __tagHelperExecutionContext = __tagHelperScopeManager.Begin("nestedtaghelper");
@@ -56,7 +56,7 @@ Write(DateTime.Now);
             __tagHelperExecutionContext.Add(__NestedTagHelper);
             StartWritingScope();
             WriteLiteral("Some buffered values with a value of ");
-#line 6 "TagHelpersInHelper.cshtml"
+#line 8 "TagHelpersInHelper.cshtml"
                                             Write(val);
 
 #line default
@@ -67,22 +67,22 @@ Write(DateTime.Now);
             WriteLiteralTo(__razor_helper_writer, __tagHelperExecutionContext.Output.GenerateContent());
             WriteLiteralTo(__razor_helper_writer, __tagHelperExecutionContext.Output.GenerateEndTag());
             __tagHelperExecutionContext = __tagHelperScopeManager.End();
-            Instrumentation.BeginContext(283, 10, true);
+            Instrumentation.BeginContext(312, 10, true);
             WriteLiteralTo(__razor_helper_writer, "\r\n        ");
             Instrumentation.EndContext();
             WriteLiteralTo(__razor_helper_writer, __tagHelperExecutionContext.Output.GenerateEndTag());
             __tagHelperExecutionContext = __tagHelperScopeManager.End();
-            Instrumentation.BeginContext(307, 14, true);
+            Instrumentation.BeginContext(336, 14, true);
             WriteLiteralTo(__razor_helper_writer, "\r\n    </div>\r\n");
             Instrumentation.EndContext();
-#line 9 "TagHelpersInHelper.cshtml"
+#line 11 "TagHelpersInHelper.cshtml"
 
 #line default
 #line hidden
 
         }
         );
-#line 9 "TagHelpersInHelper.cshtml"
+#line 11 "TagHelpersInHelper.cshtml"
 }
 
 #line default
@@ -103,13 +103,16 @@ Write(DateTime.Now);
         #pragma warning disable 1998
         public override async Task ExecuteAsync()
         {
+            Instrumentation.BeginContext(27, 2, true);
+            WriteLiteral("\r\n");
+            Instrumentation.EndContext();
             __tagHelperExecutionContext = __tagHelperScopeManager.Begin("mytaghelper");
             __MyTagHelper = CreateTagHelper<MyTagHelper>();
             __tagHelperExecutionContext.Add(__MyTagHelper);
             __tagHelperExecutionContext.Output = __tagHelperRunner.RunAsync(__tagHelperExecutionContext).Result;
             WriteLiteral(__tagHelperExecutionContext.Output.GenerateStartTag());
-            Instrumentation.BeginContext(338, 9, false);
+            Instrumentation.BeginContext(367, 9, false);
-#line 10 "TagHelpersInHelper.cshtml"
+#line 12 "TagHelpersInHelper.cshtml"
 Write(MyHelper(item => new Template((__razor_template_writer) => {
     __tagHelperExecutionContext = __tagHelperScopeManager.Begin("nestedtaghelper");
     __NestedTagHelper = CreateTagHelper<NestedTagHelper>();
@@ -131,7 +134,7 @@ Write(MyHelper(item => new Template((__razor_template_writer) => {
             Instrumentation.EndContext();
             WriteLiteral(__tagHelperExecutionContext.Output.GenerateEndTag());
             __tagHelperExecutionContext = __tagHelperScopeManager.End();
-            Instrumentation.BeginContext(410, 2, true);
+            Instrumentation.BeginContext(439, 2, true);
             WriteLiteral("\r\n");
             Instrumentation.EndContext();
         }

test/Microsoft.AspNet.Razor.Test/TestFiles/CodeGenerator/CS/Output/TagHelpersInSection.cs

@@ -1,4 +1,4 @@
-#pragma checksum "TagHelpersInSection.cshtml" "{ff1816ec-aa5e-4d10-87f7-6f4963833460}" "bfe8d61279682f87dc473aa71134e86af554f55e"
+#pragma checksum "TagHelpersInSection.cshtml" "{ff1816ec-aa5e-4d10-87f7-6f4963833460}" "2571c1678f925672aa18f5e7ae50916089e8f5cb"
 namespace TestOutput
 {
     using System;
@@ -21,18 +21,21 @@ namespace TestOutput
         #pragma warning disable 1998
         public override async Task ExecuteAsync()
         {
-#line 1 "TagHelpersInSection.cshtml"
+            Instrumentation.BeginContext(27, 2, true);
+            WriteLiteral("\r\n");
+            Instrumentation.EndContext();
+#line 3 "TagHelpersInSection.cshtml"
   
     var code = "some code";
 
 #line default
 #line hidden
 
-            Instrumentation.BeginContext(34, 4, true);
+            Instrumentation.BeginContext(63, 4, true);
             WriteLiteral("\r\n\r\n");
             Instrumentation.EndContext();
             DefineSection("MySection", new Template((__razor_template_writer) => {
-                Instrumentation.BeginContext(58, 21, true);
+                Instrumentation.BeginContext(87, 21, true);
                 WriteLiteralTo(__razor_template_writer, "\r\n    <div>\r\n        ");
                 Instrumentation.EndContext();
                 __tagHelperExecutionContext = __tagHelperScopeManager.Begin("mytaghelper");
@@ -40,7 +43,7 @@ namespace TestOutput
                 __tagHelperExecutionContext.Add(__MyTagHelper);
                 StartWritingScope();
                 WriteLiteral("Current Time: ");
-#line 7 "TagHelpersInSection.cshtml"
+#line 9 "TagHelpersInSection.cshtml"
 Write(DateTime.Now);
 
 #line default
@@ -50,7 +53,7 @@ Write(DateTime.Now);
                 __tagHelperExecutionContext.AddTagHelperAttribute("BoundProperty", __MyTagHelper.BoundProperty);
                 StartWritingScope();
                 WriteLiteral("Current Time: ");
-#line 7 "TagHelpersInSection.cshtml"
+#line 9 "TagHelpersInSection.cshtml"
 Write(DateTime.Now);
 
 #line default
@@ -59,7 +62,7 @@ Write(DateTime.Now);
                 __tagHelperExecutionContext.AddHtmlAttribute("unboundproperty", __tagHelperStringValueBuffer.ToString());
                 __tagHelperExecutionContext.Output = __tagHelperRunner.RunAsync(__tagHelperExecutionContext).Result;
                 WriteLiteralTo(__razor_template_writer, __tagHelperExecutionContext.Output.GenerateStartTag());
-                Instrumentation.BeginContext(182, 52, true);
+                Instrumentation.BeginContext(211, 52, true);
                 WriteLiteralTo(__razor_template_writer, "\r\n            In None ContentBehavior.\r\n            ");
                 Instrumentation.EndContext();
                 __tagHelperExecutionContext = __tagHelperScopeManager.Begin("nestedtaghelper");
@@ -67,7 +70,7 @@ Write(DateTime.Now);
                 __tagHelperExecutionContext.Add(__NestedTagHelper);
                 StartWritingScope();
                 WriteLiteral("Some buffered values with ");
-#line 9 "TagHelpersInSection.cshtml"
+#line 11 "TagHelpersInSection.cshtml"
                                  Write(code);
 
 #line default
@@ -78,12 +81,12 @@ Write(DateTime.Now);
                 WriteLiteralTo(__razor_template_writer, __tagHelperExecutionContext.Output.GenerateContent());
                 WriteLiteralTo(__razor_template_writer, __tagHelperExecutionContext.Output.GenerateEndTag());
                 __tagHelperExecutionContext = __tagHelperScopeManager.End();
-                Instrumentation.BeginContext(300, 10, true);
+                Instrumentation.BeginContext(329, 10, true);
                 WriteLiteralTo(__razor_template_writer, "\r\n        ");
                 Instrumentation.EndContext();
                 WriteLiteralTo(__razor_template_writer, __tagHelperExecutionContext.Output.GenerateEndTag());
                 __tagHelperExecutionContext = __tagHelperScopeManager.End();
-                Instrumentation.BeginContext(324, 14, true);
+                Instrumentation.BeginContext(353, 14, true);
                 WriteLiteralTo(__razor_template_writer, "\r\n    </div>\r\n");
                 Instrumentation.EndContext();
             }

test/Microsoft.AspNet.Razor.Test/TestFiles/CodeGenerator/CS/Source/AddTagHelperDirective.cshtml

@@ -0,0 +1 @@
+@addtaghelper "something"

test/Microsoft.AspNet.Razor.Test/TestFiles/CodeGenerator/CS/Source/BasicTagHelpers.cshtml

@@ -1,4 +1,6 @@
-<div class="randomNonTagHelperAttribute">
+@addtaghelper "something"
+
+<div class="randomNonTagHelperAttribute">
     <p class="Hello World">
         <p></p>
         <input type="text" />

test/Microsoft.AspNet.Razor.Test/TestFiles/CodeGenerator/CS/Source/ComplexTagHelpers.cshtml

@@ -1,4 +1,6 @@
-@if (true)
+@addtaghelper "something"
+
+@if (true)
 {
     var checkbox = "checkbox";
 

test/Microsoft.AspNet.Razor.Test/TestFiles/CodeGenerator/CS/Source/ContentBehaviorTagHelpers.cshtml

@@ -1,4 +1,6 @@
-<modify>
+@addtaghelper "something"
+
+<modify>
     <none>
         <append>
             <prepend>

test/Microsoft.AspNet.Razor.Test/TestFiles/CodeGenerator/CS/Source/SingleTagHelper.cshtml

@@ -1 +1,3 @@
-<p class="Hello World" foo="1337">Body of Tag</p>
+@addtaghelper "something"
+
+<p class="Hello World" foo="1337">Body of Tag</p>

test/Microsoft.AspNet.Razor.Test/TestFiles/CodeGenerator/CS/Source/TagHelpersInHelper.cshtml

@@ -1,4 +1,6 @@
-@helper MyHelper(string val)
+@addtaghelper "something"
+
+@helper MyHelper(string val)
 {
     <div>
         <mytaghelper boundproperty="Current Time: @DateTime.Now" unboundproperty="Current Time: @DateTime.Now">

test/Microsoft.AspNet.Razor.Test/TestFiles/CodeGenerator/CS/Source/TagHelpersInSection.cshtml

@@ -1,4 +1,6 @@
-@{
+@addtaghelper "something"
+
+@{
     var code = "some code";
 }