Add support for 2-phase compile

src/Microsoft.AspNetCore.Mvc.Razor.Extensions.Version1_X/RazorExtensions.cs

@@ -20,7 +20,6 @@ namespace Microsoft.AspNetCore.Mvc.Razor.Extensions.Version1_X
             InjectDirective.Register(builder);
             ModelDirective.Register(builder);
 
-            FunctionsDirective.Register(builder);
             InheritsDirective.Register(builder);
 
             builder.Features.Add(new DefaultTagHelperDescriptorProvider());

src/Microsoft.AspNetCore.Mvc.Razor.Extensions.Version2_X/RazorExtensions.cs

@@ -22,7 +22,6 @@ namespace Microsoft.AspNetCore.Mvc.Razor.Extensions.Version2_X
             NamespaceDirective.Register(builder);
             PageDirective.Register(builder);
 
-            FunctionsDirective.Register(builder);
             InheritsDirective.Register(builder);
             SectionDirective.Register(builder);
 

src/Microsoft.AspNetCore.Mvc.Razor.Extensions/ExtensionInitializer.cs

@@ -2,6 +2,7 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using Microsoft.AspNetCore.Razor.Language;
+using Microsoft.AspNetCore.Razor.Language.Components;
 
 namespace Microsoft.AspNetCore.Mvc.Razor.Extensions
 {

src/Microsoft.AspNetCore.Mvc.Razor.Extensions/InjectDirective.cs

@@ -44,6 +44,13 @@ namespace Microsoft.AspNetCore.Mvc.Razor.Extensions
             
             protected override void ExecuteCore(RazorCodeDocument codeDocument, DocumentIntermediateNode documentNode)
             {
+                if (documentNode.DocumentKind != RazorPageDocumentClassifierPass.RazorPageDocumentKind &&
+                   documentNode.DocumentKind != MvcViewDocumentClassifierPass.MvcViewDocumentKind)
+                {
+                    // Not a MVC file. Skip.
+                    return;
+                }
+
                 var visitor = new Visitor();
                 visitor.Visit(documentNode);
                 var modelType = ModelDirective.GetModelType(documentNode);

src/Microsoft.AspNetCore.Mvc.Razor.Extensions/Microsoft.AspNetCore.Mvc.Razor.Extensions.csproj

@@ -7,9 +7,9 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <Compile Include="..\Microsoft.AspNetCore.Razor.Language\CodeGeneration\CodeWriterExtensions.cs">
+    <Compile Include="..\Microsoft.AspNetCore.Razor.Language\CodeGeneration\CodeWriterExtensions.cs" Link="Shared\CodeWriterExtensions.cs" />
-      <Link>Shared\CodeWriterExtensions.cs</Link>
+    <Compile Include="..\Microsoft.AspNetCore.Razor.Language\CSharpIdentifier.cs" Link="Shared\CSharpIdentifier.cs" />
-    </Compile>
+    <Compile Include="..\Microsoft.AspNetCore.Razor.Language\Checksum.cs" Link="Shared\Checksum.cs" />
   </ItemGroup>
 
   <ItemGroup>

src/Microsoft.AspNetCore.Mvc.Razor.Extensions/MvcViewDocumentClassifierPass.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 System.Text;
 using Microsoft.AspNetCore.Razor.Language;
 using Microsoft.AspNetCore.Razor.Language.Intermediate;
 
@@ -31,12 +30,12 @@ namespace Microsoft.AspNetCore.Mvc.Razor.Extensions
             {
                 // It's possible for a Razor document to not have a file path.
                 // Eg. When we try to generate code for an in memory document like default imports.
-                var checksum = BytesToString(codeDocument.Source.GetChecksum());
+                var checksum = Checksum.BytesToString(codeDocument.Source.GetChecksum());
                 @class.ClassName = $"AspNetCore_{checksum}";
             }
             else
             {
-                @class.ClassName = CSharpIdentifier.GetClassNameFromPath(filePath);
+                @class.ClassName = GetClassNameFromPath(filePath);
             }
 
             @class.BaseType = "global::Microsoft.AspNetCore.Mvc.Razor.RazorPage<TModel>";
@@ -51,21 +50,21 @@ namespace Microsoft.AspNetCore.Mvc.Razor.Extensions
             method.ReturnType = $"global::{typeof(System.Threading.Tasks.Task).FullName}";
         }
 
-        private static string BytesToString(byte[] bytes)
+        private static string GetClassNameFromPath(string path)
         {
-            if (bytes == null)
+            const string cshtmlExtension = ".cshtml";
+
+            if (string.IsNullOrEmpty(path))
             {
-                throw new ArgumentNullException(nameof(bytes));
+                return path;
             }
 
-            var result = new StringBuilder(bytes.Length);
+            if (path.EndsWith(cshtmlExtension, StringComparison.OrdinalIgnoreCase))
-            for (var i = 0; i < bytes.Length; i++)
             {
-                // The x2 format means lowercase hex, where each byte is a 2-character string.
+                path = path.Substring(0, path.Length - cshtmlExtension.Length);
-                result.Append(bytes[i].ToString("x2"));
             }
 
-            return result.ToString();
+            return CSharpIdentifier.SanitizeIdentifier(path);
         }
     }
 }

src/Microsoft.AspNetCore.Mvc.Razor.Extensions/NamespaceDirective.cs

@@ -115,7 +115,7 @@ namespace Microsoft.AspNetCore.Mvc.Razor.Extensions
             for (var i = 0; i < segments.Length - 1; i++)
             {
                 builder.Append('.');
-                builder.Append(CSharpIdentifier.SanitizeClassName(segments[i]));
+                builder.Append(CSharpIdentifier.SanitizeIdentifier(segments[i]));
             }
 
             return builder.ToString();

src/Microsoft.AspNetCore.Mvc.Razor.Extensions/RazorExtensions.cs

@@ -22,7 +22,6 @@ namespace Microsoft.AspNetCore.Mvc.Razor.Extensions
             NamespaceDirective.Register(builder);
             PageDirective.Register(builder);
 
-            FunctionsDirective.Register(builder);
             InheritsDirective.Register(builder);
             SectionDirective.Register(builder);
 

src/Microsoft.AspNetCore.Mvc.Razor.Extensions/RazorPageDocumentClassifierPass.cs

@@ -3,7 +3,6 @@
 
 using System;
 using System.Diagnostics;
-using System.Text;
 using Microsoft.AspNetCore.Razor.Language;
 using Microsoft.AspNetCore.Razor.Language.Extensions;
 using Microsoft.AspNetCore.Razor.Language.Intermediate;
@@ -58,12 +57,12 @@ namespace Microsoft.AspNetCore.Mvc.Razor.Extensions
             {
                 // It's possible for a Razor document to not have a file path.
                 // Eg. When we try to generate code for an in memory document like default imports.
-                var checksum = BytesToString(codeDocument.Source.GetChecksum());
+                var checksum = Checksum.BytesToString(codeDocument.Source.GetChecksum());
                 @class.ClassName = $"AspNetCore_{checksum}";
             }
             else
             {
-                @class.ClassName = CSharpIdentifier.GetClassNameFromPath(filePath);
+                @class.ClassName = GetClassNameFromPath(filePath);
             }
 
             @class.Modifiers.Clear();
@@ -144,21 +143,21 @@ namespace Microsoft.AspNetCore.Mvc.Razor.Extensions
             }
         }
 
-        private static string BytesToString(byte[] bytes)
+        private static string GetClassNameFromPath(string path)
         {
-            if (bytes == null)
+            const string cshtmlExtension = ".cshtml";
+
+            if (string.IsNullOrEmpty(path))
             {
-                throw new ArgumentNullException(nameof(bytes));
+                return path;
             }
 
-            var result = new StringBuilder(bytes.Length);
+            if (path.EndsWith(cshtmlExtension, StringComparison.OrdinalIgnoreCase))
-            for (var i = 0; i < bytes.Length; i++)
             {
-                // The x2 format means lowercase hex, where each byte is a 2-character string.
+                path = path.Substring(0, path.Length - cshtmlExtension.Length);
-                result.Append(bytes[i].ToString("x2"));
             }
 
-            return result.ToString();
+            return CSharpIdentifier.SanitizeIdentifier(path);
         }
     }
 }

src/Microsoft.AspNetCore.Razor.Language/CSharpIdentifier.cs

@@ -1,31 +1,13 @@
 // 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.Globalization;
 using System.Text;
 
-namespace Microsoft.AspNetCore.Mvc.Razor.Extensions
+namespace Microsoft.AspNetCore.Razor.Language
 {
     internal static class CSharpIdentifier
     {
-        private const string CshtmlExtension = ".cshtml";
-
-        public static string GetClassNameFromPath(string path)
-        {
-            if (string.IsNullOrEmpty(path))
-            {
-                return path;
-            }
-
-            if (path.EndsWith(CshtmlExtension, StringComparison.OrdinalIgnoreCase))
-            {
-                path = path.Substring(0, path.Length - CshtmlExtension.Length);
-            }
-
-            return SanitizeClassName(path);
-        }
-
         // CSharp Spec §2.4.2
         private static bool IsIdentifierStart(char character)
         {
@@ -51,7 +33,7 @@ namespace Microsoft.AspNetCore.Mvc.Razor.Extensions
                 category == UnicodeCategory.Format; // Cf
         }
 
-        public static string SanitizeClassName(string inputName)
+        public static string SanitizeIdentifier(string inputName)
         {
             if (!IsIdentifierStart(inputName[0]) && IsIdentifierPart(inputName[0]))
             {

src/Microsoft.AspNetCore.Razor.Language/Components/CodeGenerationConstants.cs

@@ -0,0 +1,27 @@
+// 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.
+
+namespace Microsoft.AspNetCore.Razor.Language.Components
+{
+    // Constants for method names used in code-generation
+    // Keep these in sync with the actual definitions
+    internal static class CodeGenerationConstants
+    {
+        public static class RazorComponent
+        {
+            public const string FullTypeName = "Microsoft.AspNetCore.Components.Component";
+            public const string BuildRenderTree = "BuildRenderTree";
+            public const string BuildRenderTreeParameter = "builder";
+        }
+
+        public static class RenderTreeBuilder
+        {
+            public const string FullTypeName = "Microsoft.AspNetCore.Components.RenderTree.RenderTreeBuilder";
+        }
+
+        public static class InjectDirective
+        {
+            public const string FullTypeName = "Microsoft.AspNetCore.Razor.Components.InjectAttribute";
+        }
+    }
+}

src/Microsoft.AspNetCore.Razor.Language/Components/ComponentDocumentClassifierPass.cs

@@ -0,0 +1,139 @@
+// 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.IO;
+using System.Text;
+using Microsoft.AspNetCore.Razor.Language.Intermediate;
+
+namespace Microsoft.AspNetCore.Razor.Language.Components
+{
+    internal class ComponentDocumentClassifierPass : DocumentClassifierPassBase
+    {
+        public static readonly string ComponentDocumentKind = "component.1.0";
+        private static readonly object BuildRenderTreeBaseCallAnnotation = new object();
+        private static readonly char[] PathSeparators = new char[] { '/', '\\' };
+        private static readonly char[] NamespaceSeparators = new char[] { '.' };
+
+        protected override string DocumentKind => ComponentDocumentKind;
+
+        // Ensure this runs before the MVC classifiers which have Order = 0
+        public override int Order => -100;
+
+        protected override bool IsMatch(RazorCodeDocument codeDocument, DocumentIntermediateNode documentNode)
+        {
+            return codeDocument.GetInputDocumentKind() == InputDocumentKind.Component;
+        }
+
+        protected override void OnDocumentStructureCreated(RazorCodeDocument codeDocument, NamespaceDeclarationIntermediateNode @namespace, ClassDeclarationIntermediateNode @class, MethodDeclarationIntermediateNode method)
+        {
+            base.OnDocumentStructureCreated(codeDocument, @namespace, @class, method);
+
+            if (!TryComputeNamespaceAndClass(
+                   codeDocument.Source.FilePath,
+                   codeDocument.Source.RelativePath,
+                   out var computedNamespace,
+                   out var computedClass))
+            {
+                // If we can't compute a nice namespace (no relative path) then just generate something
+                // mangled.
+                computedNamespace = "AspNetCore";
+                var checksum = Checksum.BytesToString(codeDocument.Source.GetChecksum());
+                computedClass = $"AspNetCore_{checksum}";
+            }
+
+            @namespace.Content = computedNamespace;
+
+            @class.ClassName = computedClass;
+            @class.BaseType = $"global::{CodeGenerationConstants.RazorComponent.FullTypeName}";
+            var filePath = codeDocument.Source.RelativePath ?? codeDocument.Source.FilePath;
+            if (string.IsNullOrEmpty(filePath))
+            {
+                // It's possible for a Razor document to not have a file path.
+                // Eg. When we try to generate code for an in memory document like default imports.
+                var checksum = Checksum.BytesToString(codeDocument.Source.GetChecksum());
+                @class.ClassName = $"AspNetCore_{checksum}";
+            }
+            else
+            {
+                @class.ClassName = CSharpIdentifier.SanitizeIdentifier(Path.GetFileNameWithoutExtension(filePath));
+            }
+
+            @class.Modifiers.Clear();
+            @class.Modifiers.Add("public");
+            @class.Modifiers.Add("sealed");
+
+            method.MethodName = CodeGenerationConstants.RazorComponent.BuildRenderTree;
+            method.ReturnType = "void";
+            method.Modifiers.Clear();
+            method.Modifiers.Add("public");
+            method.Modifiers.Add("override");
+
+            method.Parameters.Clear();
+            method.Parameters.Add(new MethodParameter()
+            {
+                TypeName = CodeGenerationConstants.RenderTreeBuilder.FullTypeName,
+                ParameterName = CodeGenerationConstants.RazorComponent.BuildRenderTreeParameter,
+            });
+
+            // We need to call the 'base' method as the first statement.
+            var callBase = new CSharpCodeIntermediateNode();
+            callBase.Annotations.Add(BuildRenderTreeBaseCallAnnotation, true);
+            callBase.Children.Add(new IntermediateToken
+            {
+                Kind = TokenKind.CSharp,
+                Content = $"base.{CodeGenerationConstants.RazorComponent.BuildRenderTree}({CodeGenerationConstants.RazorComponent.BuildRenderTreeParameter});"
+            });
+            method.Children.Insert(0, callBase);
+        }
+
+        private bool TryComputeNamespaceAndClass(string filePath, string relativePath, out string @namespace, out string @class)
+        {
+            if (filePath == null || relativePath == null || filePath.Length <= relativePath.Length)
+            {
+                @namespace = null;
+                @class = null;
+                return false;
+            }
+
+            // Try and infer a namespace from the project directory. We don't yet have the ability to pass
+            // the namespace through from the project.
+            var trimLength = relativePath.Length + (relativePath.StartsWith("/") ? 0 : 1);
+            var baseDirectory = filePath.Substring(0, filePath.Length - trimLength);
+
+            var lastSlash = baseDirectory.LastIndexOfAny(PathSeparators);
+            var baseNamespace = lastSlash == -1 ? baseDirectory : baseDirectory.Substring(lastSlash + 1);
+            if (string.IsNullOrEmpty(baseNamespace))
+            {
+                @namespace = null;
+                @class = null;
+                return false;
+            }
+
+            var builder = new StringBuilder();
+
+            // Sanitize the base namespace, but leave the dots.
+            var segments = baseNamespace.Split(NamespaceSeparators, StringSplitOptions.RemoveEmptyEntries);
+            builder.Append(CSharpIdentifier.SanitizeIdentifier(segments[0]));
+            for (var i = 1; i < segments.Length; i++)
+            {
+                builder.Append('.');
+                builder.Append(CSharpIdentifier.SanitizeIdentifier(segments[i]));
+            }
+
+            segments = relativePath.Split(PathSeparators, StringSplitOptions.RemoveEmptyEntries);
+
+            // Skip the last segment because it's the FileName.
+            for (var i = 0; i < segments.Length - 1; i++)
+            {
+                builder.Append('.');
+                builder.Append(CSharpIdentifier.SanitizeIdentifier(segments[i]));
+            }
+
+            @namespace = builder.ToString();
+            @class = CSharpIdentifier.SanitizeIdentifier(Path.GetFileNameWithoutExtension(relativePath));
+
+            return true;
+        }
+    }
+}

src/Microsoft.AspNetCore.Razor.Language/Components/ComponentExtensions.cs

@@ -0,0 +1,22 @@
+// 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 Microsoft.AspNetCore.Razor.Language.Extensions;
+
+namespace Microsoft.AspNetCore.Razor.Language.Components
+{
+    public static class ComponentExtensions
+    {
+        public static void Register(RazorProjectEngineBuilder builder)
+        {
+            if (builder == null)
+            {
+                throw new ArgumentNullException(nameof(builder));
+            }
+
+            FunctionsDirective.Register(builder);
+            builder.Features.Add(new ComponentDocumentClassifierPass());
+        }
+    }
+}

src/Microsoft.AspNetCore.Razor.Language/DefaultRazorCodeGenerationOptions.cs

@@ -10,13 +10,15 @@ namespace Microsoft.AspNetCore.Razor.Language
             int indentSize, 
             bool designTime, 
             bool suppressChecksum,
-            bool supressMetadataAttributes)
+            bool supressMetadataAttributes,
+            bool suppressPrimaryMethodBody)
         {
             IndentWithTabs = indentWithTabs;
             IndentSize = indentSize;
             DesignTime = designTime;
             SuppressChecksum = suppressChecksum;
             SuppressMetadataAttributes = supressMetadataAttributes;
+            SuppressPrimaryMethodBody = suppressPrimaryMethodBody;
         }
 
         public override bool DesignTime { get; }

src/Microsoft.AspNetCore.Razor.Language/DefaultRazorCodeGenerationOptionsBuilder.cs

@@ -34,7 +34,13 @@ namespace Microsoft.AspNetCore.Razor.Language
 
         public override RazorCodeGenerationOptions Build()
         {
-            return new DefaultRazorCodeGenerationOptions(IndentWithTabs, IndentSize, DesignTime, SuppressChecksum, SuppressMetadataAttributes);
+            return new DefaultRazorCodeGenerationOptions(
+                IndentWithTabs,
+                IndentSize,
+                DesignTime,
+                SuppressChecksum,
+                SuppressMetadataAttributes,
+                SuppressPrimaryMethodBody);
         }
 
         public override void SetDesignTime(bool designTime)

src/Microsoft.AspNetCore.Razor.Language/Extensions/EliminateMethodBodyPass.cs

@@ -0,0 +1,71 @@
+// 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 Microsoft.AspNetCore.Razor.Language.Intermediate;
+
+namespace Microsoft.AspNetCore.Razor.Language.Extensions
+{
+    internal sealed class EliminateMethodBodyPass : IntermediateNodePassBase, IRazorOptimizationPass
+    {
+        // Run early in the optimization phase
+        public override int Order => int.MinValue;
+
+        protected override void ExecuteCore(RazorCodeDocument codeDocument, DocumentIntermediateNode documentNode)
+        {
+            if (codeDocument == null)
+            {
+                throw new ArgumentNullException(nameof(codeDocument));
+            }
+
+            if (documentNode == null)
+            {
+                throw new ArgumentNullException(nameof(documentNode));
+            }
+
+            var codeGenerationOptions = codeDocument.GetCodeGenerationOptions();
+            if (codeGenerationOptions == null || !codeGenerationOptions.SuppressPrimaryMethodBody)
+            {
+                return;
+            }
+
+            var method = documentNode.FindPrimaryMethod();
+            if (method == null)
+            {
+                return;
+            }
+
+            method.Children.Clear();
+
+            // After we clear all of the method body there might be some unused fields, which can be
+            // blocking if compiling with warnings as errors. Suppress this warning so that it doesn't
+            // get annoying in VS.
+            documentNode.Children.Insert(documentNode.Children.IndexOf(documentNode.FindPrimaryNamespace()), new CSharpCodeIntermediateNode()
+            {
+                Children =
+                {
+                    // Field is assigned but never used
+                    new IntermediateToken()
+                    {
+                        Content = "#pragma warning disable 0414" + Environment.NewLine,
+                        Kind = TokenKind.CSharp,
+                    },
+
+                    // Field is never assigned
+                    new IntermediateToken()
+                    {
+                        Content = "#pragma warning disable 0649" + Environment.NewLine,
+                        Kind = TokenKind.CSharp,
+                    },
+
+                    // Field is never used
+                    new IntermediateToken()
+                    {
+                        Content = "#pragma warning disable 0169" + Environment.NewLine,
+                        Kind = TokenKind.CSharp,
+                    },
+                },
+            });
+        }
+    }
+}

src/Microsoft.AspNetCore.Razor.Language/Intermediate/InputDocumentKind.cs

@@ -0,0 +1,12 @@
+// 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.
+
+namespace Microsoft.AspNetCore.Razor.Language.Intermediate
+{
+    internal static class InputDocumentKind
+    {
+        public static readonly string Component = "component";
+
+        public static readonly string MvcFile = "mvc";
+    }
+}

src/Microsoft.AspNetCore.Razor.Language/RazorCodeDocumentExtensions.cs

@@ -169,6 +169,26 @@ namespace Microsoft.AspNetCore.Razor.Language
             document.Items[typeof(RazorCodeGenerationOptions)] = codeGenerationOptions;
         }
 
+        public static string GetInputDocumentKind(this RazorCodeDocument document)
+        {
+            if (document == null)
+            {
+                throw new ArgumentNullException(nameof(document));
+            }
+
+            return (string)document.Items[typeof(InputDocumentKind)];
+        }
+
+        public static void SetInputDocumentKind(this RazorCodeDocument document, string kind)
+        {
+            if (document == null)
+            {
+                throw new ArgumentNullException(nameof(document));
+            }
+
+            document.Items[typeof(InputDocumentKind)] = kind;
+        }
+
         private class ImportSyntaxTreesHolder
         {
             public ImportSyntaxTreesHolder(IReadOnlyList<RazorSyntaxTree> syntaxTrees)

src/Microsoft.AspNetCore.Razor.Language/RazorCodeGenerationOptions.cs

@@ -14,7 +14,8 @@ namespace Microsoft.AspNetCore.Razor.Language
                 indentSize: 4,
                 designTime: false,
                 suppressChecksum: false,
-                supressMetadataAttributes: false);
+                supressMetadataAttributes: false,
+                suppressPrimaryMethodBody: false);
         }
 
         public static RazorCodeGenerationOptions CreateDesignTimeDefault()
@@ -24,7 +25,8 @@ namespace Microsoft.AspNetCore.Razor.Language
                 indentSize: 4,
                 designTime: true,
                 suppressChecksum: false,
-                supressMetadataAttributes: true);
+                supressMetadataAttributes: true,
+                suppressPrimaryMethodBody: false);
         }
 
         public static RazorCodeGenerationOptions Create(Action<RazorCodeGenerationOptionsBuilder> configure)
@@ -93,5 +95,10 @@ namespace Microsoft.AspNetCore.Razor.Language
         /// </para>
         /// </remarks>
         public virtual bool SuppressMetadataAttributes { get; protected set; }
+
+        /// <summary>
+        /// Gets or sets a value that determines if an empty body is generated for the primary method.
+        /// </summary>
+        public virtual bool SuppressPrimaryMethodBody { get; protected set; }
     }
 }

src/Microsoft.AspNetCore.Razor.Language/RazorCodeGenerationOptionsBuilder.cs

@@ -42,6 +42,11 @@ namespace Microsoft.AspNetCore.Razor.Language
         /// </remarks>
         public virtual bool SuppressMetadataAttributes { get; set; }
 
+        /// <summary>
+        /// Gets or sets a value that determines if an empty body is generated for the primary method.
+        /// </summary>
+        public virtual bool SuppressPrimaryMethodBody { get; set; }
+
         public abstract RazorCodeGenerationOptions Build();
 
         public virtual void SetDesignTime(bool designTime)

src/Microsoft.AspNetCore.Razor.Language/RazorProjectEngine.cs

@@ -3,8 +3,8 @@
 
 using System;
 using System.Collections.Generic;
-using System.Reflection;
 using System.Threading.Tasks;
+using Microsoft.AspNetCore.Razor.Language.Components;
 using Microsoft.AspNetCore.Razor.Language.Extensions;
 
 namespace Microsoft.AspNetCore.Razor.Language
@@ -176,6 +176,7 @@ namespace Microsoft.AspNetCore.Razor.Language
             features.Add(new DirectiveRemovalOptimizationPass());
             features.Add(new DefaultTagHelperOptimizationPass());
             features.Add(new PreallocatedTagHelperAttributeOptimizationPass());
+            features.Add(new EliminateMethodBodyPass());
 
             // Default Code Target Extensions
             var targetExtensionFeature = new DefaultRazorTargetExtensionFeature();
@@ -217,10 +218,15 @@ namespace Microsoft.AspNetCore.Razor.Language
                 // For now we only handle AssemblyExtension - which is not user-constructable. We're keeping a tight
                 // lid on how things work until we add official support for extensibility everywhere. So, this is
                 // intentionally inflexible for the time being.
-                var extension = extensions[i] as AssemblyExtension;
+                if (extensions[i] is AssemblyExtension extension)
-                var initializer = extension?.CreateInitializer();
+                {
+                    var initializer = extension.CreateInitializer();
                     initializer?.Initialize(builder);
                 }
             }
+
+            // Default extensions.
+            ComponentExtensions.Register(builder);
+        }
     }
 }

src/Microsoft.AspNetCore.Razor.Language/TagHelperConventions.cs

@@ -6,5 +6,7 @@ namespace Microsoft.AspNetCore.Razor.Language
     public static class TagHelperConventions
     {
         public static readonly string DefaultKind = "ITagHelper";
+
+        public static readonly string ComponentKind = "IComponent";
     }
 }

src/Microsoft.AspNetCore.Razor.Tools/DiscoverCommand.cs

@@ -141,6 +141,7 @@ namespace Microsoft.AspNetCore.Razor.Tools
                 b.Features.Add(new DefaultMetadataReferenceFeature() { References = metadataReferences });
                 b.Features.Add(new CompilationTagHelperFeature());
                 b.Features.Add(new DefaultTagHelperDescriptorProvider());
+                b.Features.Add(new ComponentTagHelperDescriptorProvider());
             });
 
             var feature = engine.Engine.Features.OfType<ITagHelperFeature>().Single();

src/Microsoft.AspNetCore.Razor.Tools/GenerateCommand.cs

@@ -5,8 +5,10 @@ using System;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.IO;
+using System.Linq;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Razor.Language;
+using Microsoft.AspNetCore.Razor.Language.Intermediate;
 using Microsoft.Extensions.CommandLineUtils;
 using Microsoft.VisualStudio.LanguageServices.Razor.Serialization;
 using Newtonsoft.Json;
@@ -21,12 +23,14 @@ namespace Microsoft.AspNetCore.Razor.Tools
             Sources = Option("-s", ".cshtml files to compile", CommandOptionType.MultipleValue);
             Outputs = Option("-o", "Generated output file path", CommandOptionType.MultipleValue);
             RelativePaths = Option("-r", "Relative path", CommandOptionType.MultipleValue);
+            DocumentKinds = Option("-k", "Document kind", CommandOptionType.MultipleValue);
             ProjectDirectory = Option("-p", "project root directory", CommandOptionType.SingleValue);
             TagHelperManifest = Option("-t", "tag helper manifest file", CommandOptionType.SingleValue);
             Version = Option("-v|--version", "Razor language version", CommandOptionType.SingleValue);
             Configuration = Option("-c", "Razor configuration name", CommandOptionType.SingleValue);
             ExtensionNames = Option("-n", "extension name", CommandOptionType.MultipleValue);
             ExtensionFilePaths = Option("-e", "extension file path", CommandOptionType.MultipleValue);
+            GenerateDeclaration = Option("--generate-declaration", "Generate declaration", CommandOptionType.NoValue);
         }
 
         public CommandOption Sources { get; }
@@ -35,6 +39,8 @@ namespace Microsoft.AspNetCore.Razor.Tools
 
         public CommandOption RelativePaths { get; }
 
+        public CommandOption DocumentKinds { get; }
+
         public CommandOption ProjectDirectory { get; }
 
         public CommandOption TagHelperManifest { get; }
@@ -47,6 +53,8 @@ namespace Microsoft.AspNetCore.Razor.Tools
 
         public CommandOption ExtensionFilePaths { get; }
 
+        public CommandOption GenerateDeclaration { get; }
+
         protected override Task<int> ExecuteCoreAsync()
         {
             if (!Parent.Checker.Check(ExtensionFilePaths.Values))
@@ -66,13 +74,13 @@ namespace Microsoft.AspNetCore.Razor.Tools
             var version = RazorLanguageVersion.Parse(Version.Value());
             var configuration = RazorConfiguration.Create(version, Configuration.Value(), extensions);
 
+            var sourceItems = GetSourceItems(ProjectDirectory.Value(), Sources.Values, Outputs.Values, RelativePaths.Values, DocumentKinds.Values);
+
             var result = ExecuteCore(
                 configuration: configuration,
                 projectDirectory: ProjectDirectory.Value(),
                 tagHelperManifest: TagHelperManifest.Value(),
-                sources: Sources.Values,
+                sourceItems: sourceItems);
-                outputs: Outputs.Values,
-                relativePaths: RelativePaths.Values);
 
             return Task.FromResult(result);
         }
@@ -88,11 +96,21 @@ namespace Microsoft.AspNetCore.Razor.Tools
             if (Outputs.Values.Count != Sources.Values.Count)
             {
                 Error.WriteLine($"{Sources.Description} has {Sources.Values.Count}, but {Outputs.Description} has {Outputs.Values.Count} values.");
+                return false;
             }
 
             if (RelativePaths.Values.Count != Sources.Values.Count)
             {
                 Error.WriteLine($"{Sources.Description} has {Sources.Values.Count}, but {RelativePaths.Description} has {RelativePaths.Values.Count} values.");
+                return false;
+            }
+
+            if (DocumentKinds.Values.Count != 0 && DocumentKinds.Values.Count != Sources.Values.Count)
+            {
+                // 2.x tasks do not specify DocumentKinds - in which case, no values will be present. If a kind for one document is specified, we expect as many kind entries
+                // as sources.
+                Error.WriteLine($"{Sources.Description} has {Sources.Values.Count}, but {DocumentKinds.Description} has {DocumentKinds.Values.Count} values.");
+                return false;
             }
 
             if (string.IsNullOrEmpty(ProjectDirectory.Value()))
@@ -138,26 +156,30 @@ namespace Microsoft.AspNetCore.Razor.Tools
             RazorConfiguration configuration,
             string projectDirectory,
             string tagHelperManifest,
-            List<string> sources,
+            SourceItem[] sourceItems)
-            List<string> outputs,
-            List<string> relativePaths)
         {
             tagHelperManifest = Path.Combine(projectDirectory, tagHelperManifest);
 
             var tagHelpers = GetTagHelpers(tagHelperManifest);
-            var inputItems = GetInputItems(projectDirectory, sources, outputs, relativePaths);
+
             var compositeFileSystem = new CompositeRazorProjectFileSystem(new[]
             {
-                GetVirtualRazorProjectSystem(inputItems),
+                GetVirtualRazorProjectSystem(sourceItems),
                 RazorProjectFileSystem.Create(projectDirectory),
             });
 
             var engine = RazorProjectEngine.Create(configuration, compositeFileSystem, b =>
             {
                 b.Features.Add(new StaticTagHelperFeature() { TagHelpers = tagHelpers, });
+                b.Features.Add(new InputDocumentKindClassifierPass(sourceItems));
+
+                if (GenerateDeclaration.HasValue())
+                {
+                    b.Features.Add(new SetSuppressPrimaryMethodBodyOptionFeature());
+                }
             });
 
-            var results = GenerateCode(engine, inputItems);
+            var results = GenerateCode(engine, sourceItems);
 
             var success = true;
 
@@ -229,13 +251,15 @@ namespace Microsoft.AspNetCore.Razor.Tools
             }
         }
 
-        private SourceItem[] GetInputItems(string projectDirectory, List<string> sources, List<string> outputs, List<string> relativePath)
+        private SourceItem[] GetSourceItems(string projectDirectory, List<string> sources, List<string> outputs, List<string> relativePath, List<string> documentKinds)
         {
             var items = new SourceItem[sources.Count];
             for (var i = 0; i < items.Length; i++)
             {
                 var outputPath = Path.Combine(projectDirectory, outputs[i]);
-                items[i] = new SourceItem(sources[i], outputs[i], relativePath[i]);
+                var documentKind = documentKinds.Count > 0 ? documentKinds[i] : "mvc";
+
+                items[i] = new SourceItem(sources[i], outputs[i], relativePath[i], documentKind);
             }
 
             return items;
@@ -271,9 +295,9 @@ namespace Microsoft.AspNetCore.Razor.Tools
             public RazorCSharpDocument CSharpDocument { get; }
         }
 
-        private struct SourceItem
+        private readonly struct SourceItem
         {
-            public SourceItem(string sourcePath, string outputPath, string physicalRelativePath)
+            public SourceItem(string sourcePath, string outputPath, string physicalRelativePath, string documentKind)
             {
                 SourcePath = sourcePath;
                 OutputPath = outputPath;
@@ -281,6 +305,7 @@ namespace Microsoft.AspNetCore.Razor.Tools
                 FilePath = '/' + physicalRelativePath
                     .Replace(Path.DirectorySeparatorChar, '/')
                     .Replace("//", "/");
+                DocumentKind = documentKind;
             }
 
             public string SourcePath { get; }
@@ -290,6 +315,8 @@ namespace Microsoft.AspNetCore.Razor.Tools
             public string RelativePhysicalPath { get; }
 
             public string FilePath { get; }
+
+            public string DocumentKind { get; }
         }
 
         private class StaticTagHelperFeature : ITagHelperFeature
@@ -300,5 +327,46 @@ namespace Microsoft.AspNetCore.Razor.Tools
 
             public IReadOnlyList<TagHelperDescriptor> GetDescriptors() => TagHelpers;
         }
+
+        private class SetSuppressPrimaryMethodBodyOptionFeature : RazorEngineFeatureBase, IConfigureRazorCodeGenerationOptionsFeature
+        {
+            public int Order { get; set; }
+
+            public void Configure(RazorCodeGenerationOptionsBuilder options)
+            {
+                if (options == null)
+                {
+                    throw new ArgumentNullException(nameof(options));
+                }
+
+                options.SuppressPrimaryMethodBody = true;
+            }
+        }
+
+        private class InputDocumentKindClassifierPass : RazorEngineFeatureBase, IRazorDocumentClassifierPass
+        {
+            public InputDocumentKindClassifierPass(SourceItem[] sourceItems)
+            {
+                DocumentKinds = new Dictionary<string, string>(sourceItems.Length, StringComparer.OrdinalIgnoreCase);
+                for (var i = 0; i < sourceItems.Length; i++)
+                {
+                    var item = sourceItems[i];
+                    DocumentKinds[item.SourcePath] = item.DocumentKind;
+                }
+            }
+
+            // Run before other document classifiers
+            public int Order => -1000;
+
+            public Dictionary<string, string> DocumentKinds { get; }
+
+            public void Execute(RazorCodeDocument codeDocument, DocumentIntermediateNode documentNode)
+            {
+                if (DocumentKinds.TryGetValue(codeDocument.Source.FilePath, out var kind))
+                {
+                    codeDocument.SetInputDocumentKind(kind);
+                }
+            }
+        }
     }
 }

src/Microsoft.AspNetCore.Razor.Tools/Microsoft.AspNetCore.Razor.Tools.csproj

@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
     <Description>Razor is a markup syntax for adding server-side logic to web pages. This assembly contains infrastructure supporting Razor MSBuild integration.</Description>

src/Microsoft.AspNetCore.Razor.Tools/ServerProtocol/RequestArgument.cs

@@ -18,7 +18,7 @@ namespace Microsoft.AspNetCore.Razor.Tools
     /// Strings are encoded via a length prefix as a signed
     /// 32-bit integer, followed by an array of characters.
     /// </summary>
-    internal struct RequestArgument
+    internal readonly struct RequestArgument
     {
         public readonly ArgumentId Id;
         public readonly int ArgumentIndex;
@@ -63,5 +63,10 @@ namespace Microsoft.AspNetCore.Razor.Tools
             // The directory to use for temporary operations.
             TempDirectory,
         }
+
+        public override string ToString()
+        {
+            return $"{Id} {Value}";
+        }
     }
 }

src/Microsoft.CodeAnalysis.Razor/ComponentTagHelperDescriptorProvider.cs

@@ -0,0 +1,132 @@
+// 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 Microsoft.AspNetCore.Razor.Language;
+
+namespace Microsoft.CodeAnalysis.Razor
+{
+    public class ComponentTagHelperDescriptorProvider : RazorEngineFeatureBase, ITagHelperDescriptorProvider
+    {
+        public int Order { get; set; }
+
+        public void Execute(TagHelperDescriptorProviderContext context)
+        {
+            if (context == null)
+            {
+                throw new ArgumentNullException(nameof(context));
+            }
+
+            var compilation = context.GetCompilation();
+            if (compilation == null)
+            {
+                // No compilation, nothing to do.
+                return;
+            }
+
+            var componentSymbol = compilation.GetTypeByMetadataName(TagHelperTypes.IComponent);
+            if (componentSymbol == null || componentSymbol.TypeKind == TypeKind.Error)
+            {
+                // Could not find attributes we care about in the compilation. Nothing to do.
+                return;
+            }
+
+            var types = new List<INamedTypeSymbol>();
+            var visitor = new ComponentTypeVisitor(componentSymbol, types);
+
+            // We always visit the global namespace.
+            visitor.Visit(compilation.Assembly.GlobalNamespace);
+
+            foreach (var reference in compilation.References)
+            {
+                if (compilation.GetAssemblyOrModuleSymbol(reference) is IAssemblySymbol assembly)
+                {
+                    if (IsTagHelperAssembly(assembly))
+                    {
+                        visitor.Visit(assembly.GlobalNamespace);
+                    }
+                }
+            }
+
+            for (var i = 0; i < types.Count; i++)
+            {
+                var type = types[i];
+                var descriptor = CreateDescriptor(type);
+
+                if (descriptor != null)
+                {
+                    context.Results.Add(descriptor);
+                }
+            }
+        }
+
+        private static TagHelperDescriptor CreateDescriptor(INamedTypeSymbol type)
+        {
+            var typeName = type.ToDisplayString(DefaultTagHelperDescriptorFactory.FullNameTypeDisplayFormat);
+            var assemblyName = type.ContainingAssembly.Identity.Name;
+
+            var descriptorBuilder = TagHelperDescriptorBuilder.Create(TagHelperConventions.ComponentKind, typeName, assemblyName);
+            descriptorBuilder.SetTypeName(typeName);
+            descriptorBuilder.Metadata[TagHelperMetadata.Runtime.Name] = TagHelperConventions.ComponentKind;
+
+            // Components have very simple matching rules. The type name (short) matches the tag name.
+            descriptorBuilder.TagMatchingRule(r => r.TagName = type.Name);
+
+            var descriptor = descriptorBuilder.Build();
+            return descriptor;
+        }
+
+        private bool IsTagHelperAssembly(IAssemblySymbol assembly)
+        {
+            return assembly.Name != null && !assembly.Name.StartsWith("System.", StringComparison.Ordinal);
+        }
+
+        // Visits top-level types and finds interface implementations.
+        internal class ComponentTypeVisitor : SymbolVisitor
+        {
+            private readonly INamedTypeSymbol _componentSymbol;
+            private readonly List<INamedTypeSymbol> _results;
+
+            public ComponentTypeVisitor(INamedTypeSymbol componentSymbol, List<INamedTypeSymbol> results)
+            {
+                _componentSymbol = componentSymbol;
+                _results = results;
+            }
+
+            public override void VisitNamedType(INamedTypeSymbol symbol)
+            {
+                if (IsComponent(symbol))
+                {
+                    _results.Add(symbol);
+                }
+            }
+
+            public override void VisitNamespace(INamespaceSymbol symbol)
+            {
+                foreach (var member in symbol.GetMembers())
+                {
+                    Visit(member);
+                }
+            }
+
+            public override void VisitAssembly(IAssemblySymbol symbol)
+            {
+                // This as a simple yet high-value optimization that excludes the vast majority of
+                // assemblies that (by definition) can't contain a component.
+                if (symbol.Name != null && !symbol.Name.StartsWith("System.", StringComparison.Ordinal))
+                {
+                    Visit(symbol.GlobalNamespace);
+                }
+            }
+
+            internal bool IsComponent(INamedTypeSymbol symbol)
+            {
+                return
+                    symbol.DeclaredAccessibility == Accessibility.Public &&
+                    !symbol.IsAbstract &&
+                    symbol.AllInterfaces.Contains(_componentSymbol);
+            }
+        }
+    }
+}

src/Microsoft.CodeAnalysis.Razor/DefaultTagHelperDescriptorFactory.cs

@@ -23,7 +23,7 @@ namespace Microsoft.CodeAnalysis.Razor
         private readonly INamedTypeSymbol _restrictChildrenAttributeSymbol;
         private readonly INamedTypeSymbol _editorBrowsableAttributeSymbol;
 
-        private static readonly SymbolDisplayFormat FullNameTypeDisplayFormat =
+        internal static readonly SymbolDisplayFormat FullNameTypeDisplayFormat =
             SymbolDisplayFormat.FullyQualifiedFormat
                 .WithGlobalNamespaceStyle(SymbolDisplayGlobalNamespaceStyle.Omitted)
                 .WithMiscellaneousOptions(SymbolDisplayFormat.FullyQualifiedFormat.MiscellaneousOptions & (~SymbolDisplayMiscellaneousOptions.UseSpecialTypes));
@@ -434,6 +434,6 @@ namespace Microsoft.CodeAnalysis.Razor
             return false;
         }
 
-        private static string GetFullName(ITypeSymbol type) => type.ToDisplayString(FullNameTypeDisplayFormat);
+        protected static string GetFullName(ITypeSymbol type) => type.ToDisplayString(FullNameTypeDisplayFormat);
     }
 }

src/Microsoft.CodeAnalysis.Razor/TagHelperTypes.cs

@@ -7,6 +7,8 @@ namespace Microsoft.CodeAnalysis.Razor
     {
         public const string ITagHelper = "Microsoft.AspNetCore.Razor.TagHelpers.ITagHelper";
 
+        public const string IComponent = "Microsoft.AspNetCore.Components.IComponent";
+
         public const string IDictionary = "System.Collections.Generic.IDictionary`2";
 
         public const string HtmlAttributeNameAttribute = "Microsoft.AspNetCore.Razor.TagHelpers.HtmlAttributeNameAttribute";

src/Microsoft.NET.Sdk.Razor/RazorGenerate.cs

@@ -17,6 +17,7 @@ namespace Microsoft.AspNetCore.Razor.Tasks
         };
 
         private const string GeneratedOutput = "GeneratedOutput";
+        private const string DocumentKind = "DocumentKind";
         private const string TargetPath = "TargetPath";
         private const string FullPath = "FullPath";
         private const string Identity = "Identity";
@@ -41,6 +42,8 @@ namespace Microsoft.AspNetCore.Razor.Tasks
         [Required]
         public string TagHelperManifest { get; set; }
 
+        public bool GenerateDeclaration { get; set; }
+
         internal override string Command => "generate";
 
         protected override bool ValidateParameters()
@@ -99,6 +102,13 @@ namespace Microsoft.AspNetCore.Razor.Tasks
                 builder.AppendLine("-o");
                 var outputPath = Path.Combine(ProjectRoot, input.GetMetadata(GeneratedOutput));
                 builder.AppendLine(outputPath);
+
+                var kind = input.GetMetadata(DocumentKind);
+                if (!string.IsNullOrEmpty(kind))
+                {
+                    builder.AppendLine("-k");
+                    builder.AppendLine(kind);
+                }
             }
 
             builder.AppendLine("-p");
@@ -113,6 +123,11 @@ namespace Microsoft.AspNetCore.Razor.Tasks
             builder.AppendLine("-c");
             builder.AppendLine(Configuration[0].GetMetadata(Identity));
 
+            if (GenerateDeclaration)
+            {
+                builder.AppendLine("--generate-declaration");
+            }
+
             for (var i = 0; i < Extensions.Length; i++)
             {
                 builder.AppendLine("-n");

src/Microsoft.NET.Sdk.Razor/build/netstandard2.0/Microsoft.NET.Sdk.Razor.CodeGeneration.targets

@@ -70,10 +70,15 @@ Copyright (c) .NET Foundation. All rights reserved.
     </ItemGroup>
   </Target>
 
+  <Target
+    Name="_RazorEnsureCompiled"
+    Condition="!Exists('$(_RazorGenerateTargetReferenceAssembly)')"
+    DependsOnTargets="Compile" />
+
   <Target
     Name="ResolveTagHelperRazorGenerateInputs"
-    DependsOnTargets="_EnsureRazorTasksAssemblyDefined;Compile"
+    Inputs="$(MSBuildAllProjects);@(RazorReferencePath);$(_RazorGenerateTargetReferenceAssembly)"
-    Inputs="$(MSBuildAllProjects);@(RazorReferencePath)"
+    DependsOnTargets="_RazorEnsureCompiled"
     Outputs="$(_RazorTagHelperInputCache)"
     Condition="'@(RazorGenerateWithTargetPath)' != ''">
 
@@ -100,7 +105,7 @@ Copyright (c) .NET Foundation. All rights reserved.
       Version="$(RazorLangVersion)"
       Configuration="@(ResolvedRazorConfiguration)"
       Extensions="@(ResolvedRazorExtension)"
-      Assemblies="@(RazorReferencePath)"
+      Assemblies="@(RazorReferencePath);$(_RazorGenerateTargetReferenceAssembly)"
       ProjectRoot="$(MSBuildProjectDirectory)"
       TagHelperManifest="$(_RazorTagHelperOutputCache)">
       <Output
@@ -121,7 +126,6 @@ Copyright (c) .NET Foundation. All rights reserved.
 
   <PropertyGroup>
     <RazorCoreGenerateDependsOn>
-      _EnsureRazorTasksAssemblyDefined;
       _HashRazorGenerateInputs;
       _ResolveRazorGenerateOutputs;
     </RazorCoreGenerateDependsOn>
@@ -167,14 +171,10 @@ Copyright (c) .NET Foundation. All rights reserved.
 
   <Target Name="_ResolveGeneratedRazorCompileInputs">
     <ItemGroup>
-      <RazorCompile Include="@(_RazorGenerateOutput)" />
+      <RazorCompile 
+        Include="%(RazorGenerateWithTargetPath.GeneratedOutput)" 
+        Condition="'%(RazorGenerateWithTargetPath.DocumentKind)'=='mvc'" />
     </ItemGroup>
   </Target>
 
-  <Target Name="_EnsureRazorTasksAssemblyDefined">
-    <Error
-      Text="Assembly location for Razor SDK Tasks was not specified. The most likely cause is an older incompatible version of Microsoft.NET.Sdk.Razor, or Microsoft.NET.Sdk.Web used by this project. Please target a newer version of the .NET Core SDK."
-      Condition="'$(RazorSdkBuildTasksAssembly)' == ''" />
-  </Target>
-
 </Project>

src/Microsoft.NET.Sdk.Razor/build/netstandard2.0/Microsoft.NET.Sdk.Razor.Compilation.targets

@@ -54,6 +54,7 @@ Copyright (c) .NET Foundation. All rights reserved.
           Inputs="$(MSBuildAllProjects);
                   @(RazorCompile);
                   $(AssemblyOriginatorKeyFile);
+                  $(_RazorCompileTargetReferenceAssembly);
                   @(RazorReferencePath);
                   @(CompiledLicenseFile);
                   @(LinkResource);
@@ -147,7 +148,7 @@ Copyright (c) .NET Foundation. All rights reserved.
          Prefer32Bit="$(Prefer32Bit)"
          PreferredUILang="$(PreferredUILang)"
          ProvideCommandLineArgs="$(ProvideCommandLineArgs)"
-         References="@(RazorReferencePath)"
+         References="@(RazorReferencePath);$(_RazorCompileTargetReferenceAssembly)"
          ReportAnalyzer="$(ReportAnalyzer)"
          Resources="@(_RazorCoreCompileResourceInputs);@(CompiledLicenseFile)"
          ResponseFiles="$(CompilerResponseFile)"

src/Microsoft.NET.Sdk.Razor/build/netstandard2.0/Microsoft.NET.Sdk.Razor.Component.targets

@@ -0,0 +1,285 @@
+<!--
+***********************************************************************************************
+Microsoft.NET.Sdk.Razor.Component.targets
+
+WARNING:  DO NOT MODIFY this file unless you are knowledgeable about MSBuild and have
+          created a backup copy.  Incorrect changes to this file will make it
+          impossible to load or build your projects from the command-line or the IDE.
+
+Copyright (c) .NET Foundation. All rights reserved.
+***********************************************************************************************
+-->
+
+<Project ToolsVersion="14.0">
+
+  <PropertyGroup>
+    <!-- Used for tracking inputs to component generation -->
+    <_RazorComponentInputHash></_RazorComponentInputHash>
+    <_RazorComponentInputCacheFile>$(IntermediateOutputPath)$(MSBuildProjectName).RazorComponent.input.cache</_RazorComponentInputCacheFile>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <!-- Path used for the temporary compilation we produce for component discovery -->
+    <_RazorComponentDeclarationAssembly Include="$(_RazorComponentDeclarationOutputPath)$(TargetName).dll" />
+  </ItemGroup>
+
+  <Target Name="_HashRazorComponentInputs" Condition="'@(RazorComponentWithTargetPath->Count())'!='0'">
+    <Hash ItemsToHash="@(RazorComponentWithTargetPath)">
+      <Output TaskParameter="HashResult" PropertyName="_RazorComponentInputHash" />
+    </Hash>
+
+    <MakeDir
+      Directories="$(IntermediateOutputPath)"
+      Condition="!Exists('$(IntermediateOutputPath)')" />
+
+    <WriteLinesToFile
+      Lines="$(_RazorComponentInputHash)"
+      File="$(_RazorComponentInputCacheFile)"
+      Overwrite="True"
+      WriteOnlyWhenDifferent="True" />
+
+    <ItemGroup>
+      <FileWrites Include="$(_RazorComponentInputCacheFile)" />
+    </ItemGroup>
+  </Target>
+
+  <Target Name="_ResolveRazorComponentOutputs" Condition="'@(RazorComponentWithTargetPath->Count())'!='0'">
+    <Error
+      Text="RazorComponentWithTargetPath item '%(RazorComponentWithTargetPath.Identity)' does not specify required metadata 'GeneratedDeclaration'."
+      Condition="'%(RazorComponentWithTargetPath.GeneratedDeclaration)' == ''" />
+
+    <ItemGroup>
+      <_RazorComponentDeclaration Include="%(RazorComponentWithTargetPath.GeneratedDeclaration)" />
+      <_RazorComponentDefinition Include="%(RazorComponentWithTargetPath.GeneratedOutput)" />
+    </ItemGroup>
+  </Target>
+
+  <PropertyGroup>
+    <RazorGenerateComponentDeclarationDependsOn>
+      _HashRazorComponentInputs;
+      _ResolveRazorComponentOutputs;
+    </RazorGenerateComponentDeclarationDependsOn>
+  </PropertyGroup>
+
+  <!--
+    Generates 'declaration' files for each component, that only have that class and member declarations.
+    These files participate in the design-time-build for intellisense, and are used at build-time
+    when discovering components for a 'real' build.
+  -->
+  <Target
+    Name="RazorGenerateComponentDeclaration"
+    DependsOnTargets="$(RazorGenerateComponentDeclarationDependsOn)"
+    Inputs="$(MSBuildAllProjects);@(RazorComponentWithTargetPath);$(_RazorComponentInputCacheFile)"
+    Outputs="@(_RazorComponentDeclaration)"
+    Condition="'@(RazorComponentWithTargetPath->Count())'!='0'">
+
+    <ItemGroup>
+      <_RazorComponentDeclarationSources Include="@(RazorComponentWithTargetPath)">
+        <GeneratedOutput>%(RazorComponentWithTargetPath.GeneratedDeclaration)</GeneratedOutput>
+      </_RazorComponentDeclarationSources>
+    </ItemGroup>
+
+    <MakeDir
+      Directories="%(_RazorComponentDeclaration.RelativeDir)"
+      Condition="!Exists('%(_RazorComponentDeclaration.RelativeDir)')" />
+
+    <PropertyGroup>
+      <!-- This file will not exist, but we need some value -->
+      <_RazorComponentDeclarationManifest>$(IntermediateOutputPath)$(MSBuildProjectName).RazorComponents.declaration.json</_RazorComponentDeclarationManifest>
+    </PropertyGroup>
+
+    <RazorGenerate
+      Debug="$(_RazorDebugGenerateCodeTask)"
+      DebugTool="$(_RazorDebugGenerateCodeTool)"
+      ToolAssembly="$(_RazorToolAssembly)"
+      UseServer="$(UseRazorBuildServer)"
+      ForceServer="$(_RazorForceBuildServer)"
+      PipeName="$(_RazorBuildServerPipeName)"
+      Version="$(RazorLangVersion)"
+      Configuration="@(ResolvedRazorConfiguration)"
+      Extensions="@(ResolvedRazorExtension)"
+      Sources="@(_RazorComponentDeclarationSources)"
+      ProjectRoot="$(MSBuildProjectDirectory)"
+      TagHelperManifest="$(_RazorComponentDeclarationManifest)"
+      GenerateDeclaration="true" />
+
+    <ItemGroup>
+      <FileWrites Include="@(_RazorComponentDeclaration)" />
+    </ItemGroup>
+
+    <ItemGroup Condition="'$(DesignTimeBuild)'=='true'">
+      <Compile Include="@(_RazorComponentDeclaration)" />
+    </ItemGroup>
+  </Target>
+
+  <Target
+    Name="RazorCompileComponentDeclaration"
+    Inputs="
+      $(MSBuildAllProjects);
+      @(_RazorComponentDeclaration);
+      @(Compile);
+      $(AssemblyOriginatorKeyFile);
+      @(ReferencePathWithRefAssemblies);
+      @(CompiledLicenseFile);
+      @(LinkResource);
+      $(ResolvedCodeAnalysisRuleSet);
+      @(AdditionalFiles)"
+    Outputs="@(_RazorComponentDeclarationAssembly);$(NonExistentFile)"
+    Condition="'$(DesignTimeBuild)'!='true' AND '$(Language)'=='C#' AND '@(_RazorComponentDeclaration)' != ''">
+
+    <MakeDir Directories="%(_RazorComponentDeclarationAssembly.RelativeDir)" />
+
+    <!-- These two compiler warnings are raised when a reference is bound to a different version
+             than specified in the assembly reference version number.  MSBuild raises the same warning in this case,
+             so the compiler warning would be redundant. -->
+    <PropertyGroup Condition="('$(TargetFrameworkVersion)' != 'v1.0') and ('$(TargetFrameworkVersion)' != 'v1.1')">
+      <NoWarn>$(NoWarn);1701;1702</NoWarn>
+    </PropertyGroup>
+
+    <PropertyGroup>
+      <!-- To match historical behavior, when inside VS11+ disable the warning from csc.exe indicating that no sources were passed in-->
+      <NoWarn Condition="'$(BuildingInsideVisualStudio)' == 'true' AND '$(VisualStudioVersion)' != '' AND '$(VisualStudioVersion)' &gt; '10.0'">$(NoWarn);2008</NoWarn>
+    </PropertyGroup>
+
+    <ItemGroup Condition="'$(TargetingClr2Framework)' == 'true'">
+      <ReferencePathWithRefAssemblies>
+        <EmbedInteropTypes />
+      </ReferencePathWithRefAssemblies>
+    </ItemGroup>
+
+    <PropertyGroup>
+      <!-- If the user has specified AppConfigForCompiler, we'll use it. If they have not, but they set UseAppConfigForCompiler,
+                 then we'll use AppConfig -->
+      <AppConfigForCompiler Condition="'$(AppConfigForCompiler)' == '' AND '$(UseAppConfigForCompiler)' == 'true'">$(AppConfig)</AppConfigForCompiler>
+    </PropertyGroup>
+
+    <!-- Prefer32Bit was introduced in .NET 4.5. Set it to false if we are targeting 4.0 -->
+    <PropertyGroup Condition="('$(TargetFrameworkVersion)' == 'v4.0')">
+      <Prefer32Bit>false</Prefer32Bit>
+    </PropertyGroup>
+
+    <!-- TODO: Remove this ItemGroup once it has been moved to "_GenerateCompileInputs" target in Microsoft.Common.CurrentVersion.targets.
+         https://github.com/dotnet/roslyn/issues/12223 -->
+    <ItemGroup Condition="('$(AdditionalFileItemNames)' != '')">
+      <AdditionalFileItems Include="$(AdditionalFileItemNames)" />
+      <AdditionalFiles Include="@(%(AdditionalFileItems.Identity))" />
+    </ItemGroup>
+
+    <PropertyGroup Condition="'$(UseSharedCompilation)' == ''">
+      <UseSharedCompilation>true</UseSharedCompilation>
+    </PropertyGroup>
+
+    <Csc
+         AdditionalLibPaths="$(AdditionalLibPaths)"
+         AddModules="@(AddModules)"
+         AdditionalFiles="@(AdditionalFiles)"
+         AllowUnsafeBlocks="$(AllowUnsafeBlocks)"
+         Analyzers="@(Analyzer)"
+         ApplicationConfiguration="$(AppConfigForCompiler)"
+         BaseAddress="$(BaseAddress)"
+         CheckForOverflowUnderflow="$(CheckForOverflowUnderflow)"
+         ChecksumAlgorithm="$(ChecksumAlgorithm)"
+         CodeAnalysisRuleSet="$(ResolvedCodeAnalysisRuleSet)"
+         CodePage="$(CodePage)"
+         DebugType="$(DebugType)"
+         DefineConstants="$(DefineConstants)"
+         DelaySign="$(DelaySign)"
+         DisabledWarnings="$(NoWarn)"
+         EmitDebugInformation="$(DebugSymbols)"
+         EnvironmentVariables="$(CscEnvironment)"
+         ErrorEndLocation="$(ErrorEndLocation)"
+         ErrorLog="$(ErrorLog)"
+         ErrorReport="$(ErrorReport)"
+         Features="$(Features)"
+         FileAlignment="$(FileAlignment)"
+         GenerateFullPaths="$(GenerateFullPaths)"
+         HighEntropyVA="$(HighEntropyVA)"
+         Instrument="$(Instrument)"
+         KeyContainer="$(KeyContainerName)"
+         KeyFile="$(KeyOriginatorFile)"
+         LangVersion="$(LangVersion)"
+         LinkResources="@(LinkResource)"
+         MainEntryPoint="$(StartupObject)"
+         ModuleAssemblyName="$(ModuleAssemblyName)"
+         NoConfig="true"
+         NoLogo="$(NoLogo)"
+         NoStandardLib="$(NoCompilerStandardLib)"
+         NoWin32Manifest="$(NoWin32Manifest)"
+         Optimize="$(Optimize)"
+         Deterministic="$(Deterministic)"
+         PublicSign="$(PublicSign)"
+         OutputAssembly="@(_RazorComponentDeclarationAssembly)"
+         Platform="$(PlatformTarget)"
+         Prefer32Bit="$(Prefer32Bit)"
+         PreferredUILang="$(PreferredUILang)"
+         ProvideCommandLineArgs="$(ProvideCommandLineArgs)"
+         References="@(ReferencePathWithRefAssemblies)"
+         ReportAnalyzer="$(ReportAnalyzer)"
+         Resources="@(CompiledLicenseFile)"
+         ResponseFiles="$(CompilerResponseFile)"
+         RuntimeMetadataVersion="$(RuntimeMetadataVersion)"
+         SharedCompilationId="$(SharedCompilationId)"
+         SkipCompilerExecution="$(SkipCompilerExecution)"
+         Sources="@(_RazorComponentDeclaration);@(Compile)"
+         SubsystemVersion="$(SubsystemVersion)"
+         TargetType="$(OutputType)"
+         ToolExe="$(CscToolExe)"
+         ToolPath="$(CscToolPath)"
+         TreatWarningsAsErrors="$(TreatWarningsAsErrors)"
+         UseHostCompilerIfAvailable="$(UseHostCompilerIfAvailable)"
+         UseSharedCompilation="$(UseSharedCompilation)"
+         Utf8Output="$(Utf8Output)"
+         VsSessionGuid="$(VsSessionGuid)"
+         WarningLevel="$(WarningLevel)"
+         WarningsAsErrors="$(WarningsAsErrors)"
+         WarningsNotAsErrors="$(WarningsNotAsErrors)"
+         PathMap="$(PathMap)"
+         SourceLink="$(SourceLink)">
+      <Output TaskParameter="CommandLineArgs" ItemName="CscCommandLineArgs" />
+    </Csc>
+
+    <ItemGroup>
+      <FileWrites Include="@(_RazorComponentDeclarationAssembly)" Condition="Exists('@(_RazorComponentDeclarationAssembly)')" />
+    </ItemGroup>
+  </Target>
+
+  <Target Name="_ResolveComponentRazorGenerateInputs">
+    <ItemGroup>
+      <!-- Add RazorComponent files to the set of files to be code-gened. -->
+      <RazorGenerateWithTargetPath Include="@(RazorComponentWithTargetPath)" />
+    </ItemGroup>
+
+    <!-- Point to the declaration assembly to perform taghelper discovery -->
+    <PropertyGroup>
+      <_RazorGenerateTargetReferenceAssembly>@(_RazorComponentDeclarationAssembly->Metadata('FullPath'))</_RazorGenerateTargetReferenceAssembly>
+    </PropertyGroup>
+  </Target>
+
+  <!-- 
+    Once RazorCompileComponentDeclaration is completed, we have all the inputs required for code generation of
+    RazorComponents and RazorGenerate items. We'll initialize the inputs for RazorGenerate and invoke it.
+    This should result in RazorGenerate \ RazorTagHelper targets no-oping when it get invoked as 
+    part of PrepareForRun \ PrepareForPublish for non-components (.cshtml) files.
+   -->
+  <Target
+    Name="RazorGenerateComponentDefinition"
+    DependsOnTargets="_ResolveComponentRazorGenerateInputs;RazorGenerate"
+    Condition="'$(DesignTimeBuild)' != 'true' AND '@(_RazorComponentDefinition->Count())' != '0' AND Exists('@(_RazorComponentDeclarationAssembly)')">
+
+    <ItemGroup Condition="'$(DesignTimeBuild)' != 'true'">
+      <Compile Include="@(_RazorComponentDefinition)" />
+    </ItemGroup>
+  </Target>
+
+  <PropertyGroup>
+    <RazorComponentGenerateCoreDependsOn>
+      RazorGenerateComponentDeclaration;
+      RazorCompileComponentDeclaration;
+      RazorGenerateComponentDefinition;
+    </RazorComponentGenerateCoreDependsOn>
+  </PropertyGroup>
+
+  <Target Name="RazorComponentGenerateCore" DependsOnTargets="$(RazorComponentGenerateCoreDependsOn)">
+  </Target>
+
+</Project>

src/Microsoft.NET.Sdk.Razor/build/netstandard2.0/Sdk.Razor.CurrentVersion.props

@@ -29,6 +29,11 @@ Copyright (c) .NET Foundation. All rights reserved.
     -->
     <EnableDefaultRazorGenerateItems Condition="'$(EnableDefaultRazorGenerateItems)'==''">true</EnableDefaultRazorGenerateItems>
 
+    <!--
+      Set to true to automatically include Razor (.razor) files in @(RazorComponent) from @(Content).
+    -->
+    <EnableDefaultRazorComponentItems Condition="'$(EnableDefaultRazorComponentItems)'==''">true</EnableDefaultRazorComponentItems>
+
     <!--
       Set to true to copy RazorGenerate items (.cshtml) to the publish directory.
 
@@ -61,14 +66,21 @@ Copyright (c) .NET Foundation. All rights reserved.
     <!--
     Configures the file extension used for generated C# files.
     -->
-    <RazorGenerateOutputFileExtension>.g.cshtml.cs</RazorGenerateOutputFileExtension>
+    <RazorGenerateOutputFileExtension>.g.cs</RazorGenerateOutputFileExtension>
+
+    <!--
+    Configures the file extension used for the generated C# definition files.
+    -->
+    <RazorGenerateOutputDefinitionFileExtension>.g.i.cs</RazorGenerateOutputDefinitionFileExtension>
 
     <PreserveCompilationContext>true</PreserveCompilationContext>
   </PropertyGroup>
 
   <ItemGroup Condition="'$(EnableDefaultItems)' == 'true' And '$(EnableDefaultContentItems)' == 'true'">
     <Content Include="**\*.cshtml" CopyToPublishDirectory="PreserveNewest" Exclude="$(DefaultItemExcludes);$(DefaultExcludesInProjectFolder);$(DefaultWebContentItemExcludes)" />
+    <Content Include="**\*.razor" Exclude="$(DefaultItemExcludes);$(DefaultExcludesInProjectFolder);$(DefaultWebContentItemExcludes)" />
     <None Remove="**\*.cshtml" />
+    <None Remove="**\*.razor" />
   </ItemGroup>
 
 </Project>

src/Microsoft.NET.Sdk.Razor/build/netstandard2.0/Sdk.Razor.CurrentVersion.targets

@@ -50,12 +50,23 @@ Copyright (c) .NET Foundation. All rights reserved.
       ResolveTagHelperRazorGenerateInputs
     </PrepareForRazorGenerateDependsOn>
 
+    <PrepareForRazorComponentGenerateDependsOn>
+      ResolveRazorConfiguration;
+      ResolveRazorComponentInputs;
+      AssignRazorComponentTargetPaths;
+    </PrepareForRazorComponentGenerateDependsOn>
+
     <RazorGenerateDependsOn>
       PrepareForRazorGenerate;
       _CheckForMissingRazorCompiler;
       RazorCoreGenerate
     </RazorGenerateDependsOn>
 
+    <RazorComponentGenerateDependsOn>
+      PrepareForRazorComponentGenerate;
+      RazorComponentGenerateCore
+    </RazorComponentGenerateDependsOn>
+
     <PrepareForRazorCompileDependsOn>
       RazorGenerate;
       ResolveRazorCompileInputs;
@@ -81,6 +92,11 @@ Copyright (c) .NET Foundation. All rights reserved.
       _RazorAddDebugSymbolsProjectOutputGroupOutput
     </DebugSymbolsProjectOutputGroupDependsOn>
 
+    <CoreCompileDependsOn>
+      RazorComponentGenerate;
+      $(CoreCompileDependsOn)
+    </CoreCompileDependsOn>
+
     <PrepareForBuildDependsOn>
       $(PrepareForBuildDependsOn);
       ResolveRazorGenerateInputs
@@ -128,6 +144,8 @@ Copyright (c) .NET Foundation. All rights reserved.
     <!-- Output directory used for generated files -->
     <RazorGenerateIntermediateOutputPath Condition="'$(RazorGenerateIntermediateOutputPath)'==''">$(IntermediateOutputPath)Razor\</RazorGenerateIntermediateOutputPath>
 
+    <_RazorComponentDeclarationOutputPath Condition="'$(_RazorComponentDeclarationOutputPath)'==''">$(IntermediateOutputPath)RazorDeclaration\</_RazorComponentDeclarationOutputPath>
+
     <!--
       Use the suffix .Views when producing compiled view assemblies. This matches the requirements for Mvc's ViewsFeatureProvider.
     -->
@@ -246,6 +264,8 @@ Copyright (c) .NET Foundation. All rights reserved.
   <!-- For projects targeting 3.x and later, use the compiler that ships in the Sdk -->
   <Import Project="Microsoft.NET.Sdk.Razor.CodeGeneration.targets" Condition="'$(_EnableAllInclusiveRazorSdk)' == 'true'" />
 
+  <Import Project="Microsoft.NET.Sdk.Razor.Component.targets" />
+
   <Import Project="Microsoft.NET.Sdk.Razor.GenerateAssemblyInfo.targets" />
 
   <!-- 
@@ -258,9 +278,15 @@ Copyright (c) .NET Foundation. All rights reserved.
   <Target Name="PrepareForRazorGenerate" DependsOnTargets="$(PrepareForRazorGenerateDependsOn)">
   </Target>
 
+  <Target Name="PrepareForRazorComponentGenerate" DependsOnTargets="$(PrepareForRazorComponentGenerateDependsOn)">
+  </Target>
+
   <Target Name="RazorGenerate" DependsOnTargets="$(RazorGenerateDependsOn)">
   </Target>
 
+  <Target Name="RazorComponentGenerate" DependsOnTargets="$(RazorComponentGenerateDependsOn)">
+  </Target>
+
   <Target Name="PrepareForRazorCompile" DependsOnTargets="$(PrepareForRazorCompileDependsOn)">
   </Target>
 
@@ -366,6 +392,40 @@ Copyright (c) .NET Foundation. All rights reserved.
     </ItemGroup>
   </Target>
 
+  <Target Name="ResolveRazorComponentInputs">
+    <!--
+    Gathers input source files for Razor component generation. This is a separate target so that we can avoid
+    lots of work when there are no inputs for code generation.
+
+    NOTE: This target is called as part of an incremental build scenario in VS. Do not perform any work
+    outside of calculating RazorComponent items in this target.
+    -->
+
+    <ItemGroup Condition="'$(EnableDefaultRazorComponentItems)'=='true'">
+      <RazorComponent Include="@(Content)" Condition="'%(Content.Extension)'=='.razor'" />
+    </ItemGroup>
+  </Target>
+
+  <Target Name="AssignRazorComponentTargetPaths" Condition="'@(RazorComponent)' != ''">
+    <AssignTargetPath Files="@(RazorComponent)" RootFolder="$(MSBuildProjectDirectory)">
+      <Output TaskParameter="AssignedFiles" ItemName="RazorComponentWithTargetPath" />
+    </AssignTargetPath>
+
+    <ItemGroup>
+      <RazorComponentWithTargetPath Condition="'%(RazorComponentWithTargetPath.GeneratedOutput)' == ''">
+        <GeneratedOutput>$(RazorGenerateIntermediateOutputPath)%(RazorComponentWithTargetPath.TargetPath)$(RazorGenerateOutputFileExtension)</GeneratedOutput>
+      </RazorComponentWithTargetPath>
+
+      <RazorComponentWithTargetPath Condition="'%(RazorComponentWithTargetPath.GeneratedDeclaration)' == ''">
+        <GeneratedDeclaration>$(_RazorComponentDeclarationOutputPath)%(RazorComponentWithTargetPath.TargetPath)$(RazorGenerateOutputFileExtension)</GeneratedDeclaration>
+      </RazorComponentWithTargetPath>
+
+      <RazorComponentWithTargetPath Condition="'%(RazorComponentWithTargetPath.DocumentKind)' == ''">
+        <DocumentKind>component</DocumentKind>
+      </RazorComponentWithTargetPath>
+    </ItemGroup>
+  </Target>
+
   <Target Name="AssignRazorGenerateTargetPaths" Condition="'@(RazorGenerate)' != ''">
     <AssignTargetPath Files="@(RazorGenerate)" RootFolder="$(MSBuildProjectDirectory)">
       <Output TaskParameter="AssignedFiles" ItemName="RazorGenerateWithTargetPath" />
@@ -373,7 +433,11 @@ Copyright (c) .NET Foundation. All rights reserved.
 
     <ItemGroup>
       <RazorGenerateWithTargetPath Condition="'%(RazorGenerateWithTargetPath.GeneratedOutput)' == ''">
-        <GeneratedOutput>$(RazorGenerateIntermediateOutputPath)$([System.IO.Path]::ChangeExtension('%(RazorGenerateWithTargetPath.TargetPath)', '$(RazorGenerateOutputFileExtension)'))</GeneratedOutput>
+        <GeneratedOutput>$(RazorGenerateIntermediateOutputPath)%(RazorGenerateWithTargetPath.TargetPath)$(RazorGenerateOutputFileExtension)</GeneratedOutput>
+      </RazorGenerateWithTargetPath>
+
+      <RazorGenerateWithTargetPath Condition="'%(RazorGenerateWithTargetPath.DocumentKind)' == ''">
+        <DocumentKind>mvc</DocumentKind>
       </RazorGenerateWithTargetPath>
     </ItemGroup>
   </Target>
@@ -386,8 +450,20 @@ Copyright (c) .NET Foundation. All rights reserved.
     DependsOnTargets="ResolveReferences">
     <ItemGroup>
       <RazorReferencePath Include="@(ReferencePath)"/>
-      <RazorReferencePath Include="$([System.IO.Path]::GetFullPath('$(IntermediateOutputPath)$(TargetName)$(TargetExt)'))"/>
     </ItemGroup>
+
+    <PropertyGroup>
+      <!--
+        Assembly of the project used as input in RazorGenerate. This property is overwritten to point to the definition assembly when components are present.
+      -->
+      <_RazorGenerateTargetReferenceAssembly Condition="'$(_RazorGenerateTargetReferenceAssembly)'==''">
+        @(IntermediateAssembly->Metadata('FullPath'))
+      </_RazorGenerateTargetReferenceAssembly>
+
+      <_RazorCompileTargetReferenceAssembly Condition="'$(_RazorCompileTargetReferenceAssembly)'==''">
+        @(IntermediateAssembly->Metadata('FullPath'))
+      </_RazorCompileTargetReferenceAssembly>
+    </PropertyGroup>
   </Target>
 
   <!--

src/RazorPageGenerator/Program.cs

@@ -61,7 +61,6 @@ Examples:
                         @class.Modifiers.Add("internal");
                     });
 
-                FunctionsDirective.Register(builder);
                 InheritsDirective.Register(builder);
                 SectionDirective.Register(builder);
 

test/Microsoft.AspNetCore.Mvc.Razor.Extensions.Test/InjectDirectiveTest.cs

@@ -194,22 +194,9 @@ namespace Microsoft.AspNetCore.Mvc.Razor.Extensions
                 }
             }
 
-            return codeDocument.GetDocumentIntermediateNode();
+            var irDocument = codeDocument.GetDocumentIntermediateNode();
-        }
+            irDocument.DocumentKind = MvcViewDocumentClassifierPass.MvcViewDocumentKind;
-
+            return irDocument;
-        private string GetCSharpContent(IntermediateNode node)
-        {
-            var builder = new StringBuilder();
-            for (var i = 0; i < node.Children.Count; i++)
-            {
-                var child = node.Children[i] as IntermediateToken;
-                if (child.Kind == TokenKind.CSharp)
-                {
-                    builder.Append(child.Content);
-                }
-            }
-
-            return builder.ToString();
         }
 
         private class ClassNodeVisitor : IntermediateNodeWalker

test/Microsoft.AspNetCore.Mvc.Razor.Extensions.Test/TestFiles/IntegrationTests/InstrumentationPassIntegrationTest/BasicTest.codegen.cs

@@ -1,118 +0,0 @@
-#pragma checksum "TestFiles/IntegrationTests/InstrumentationPassIntegrationTest/BasicTest.cshtml" "{ff1816ec-aa5e-4d10-87f7-6f4963833460}" "78993008d95836bec2b9175d4294bf7bd5f5f109"
-// <auto-generated/>
-#pragma warning disable 1591
-[assembly: global::Microsoft.AspNetCore.Razor.Hosting.RazorCompiledItemAttribute(typeof(Razor.Template), @"default", @"/TestFiles/IntegrationTests/InstrumentationPassIntegrationTest/BasicTest.cshtml")]
-namespace Razor
-{
-    #line hidden
-    [global::Microsoft.AspNetCore.Razor.Hosting.RazorSourceChecksumAttribute(@"SHA1", @"78993008d95836bec2b9175d4294bf7bd5f5f109", @"/TestFiles/IntegrationTests/InstrumentationPassIntegrationTest/BasicTest.cshtml")]
-    public class Template
-    {
-        private static readonly global::Microsoft.AspNetCore.Razor.TagHelpers.TagHelperAttribute __tagHelperAttribute_0 = new global::Microsoft.AspNetCore.Razor.TagHelpers.TagHelperAttribute("value", "Hello", global::Microsoft.AspNetCore.Razor.TagHelpers.HtmlAttributeValueStyle.DoubleQuotes);
-        private static readonly global::Microsoft.AspNetCore.Razor.TagHelpers.TagHelperAttribute __tagHelperAttribute_1 = new global::Microsoft.AspNetCore.Razor.TagHelpers.TagHelperAttribute("type", new global::Microsoft.AspNetCore.Html.HtmlString("text"), global::Microsoft.AspNetCore.Razor.TagHelpers.HtmlAttributeValueStyle.SingleQuotes);
-        private static readonly global::Microsoft.AspNetCore.Razor.TagHelpers.TagHelperAttribute __tagHelperAttribute_2 = new global::Microsoft.AspNetCore.Razor.TagHelpers.TagHelperAttribute("unbound", new global::Microsoft.AspNetCore.Html.HtmlString("foo"), global::Microsoft.AspNetCore.Razor.TagHelpers.HtmlAttributeValueStyle.DoubleQuotes);
-        #line hidden
-        #pragma warning disable 0169
-        private string __tagHelperStringValueBuffer;
-        #pragma warning restore 0169
-        private global::Microsoft.AspNetCore.Razor.Runtime.TagHelpers.TagHelperExecutionContext __tagHelperExecutionContext;
-        private global::Microsoft.AspNetCore.Razor.Runtime.TagHelpers.TagHelperRunner __tagHelperRunner = new global::Microsoft.AspNetCore.Razor.Runtime.TagHelpers.TagHelperRunner();
-        private global::Microsoft.AspNetCore.Razor.Runtime.TagHelpers.TagHelperScopeManager __backed__tagHelperScopeManager = null;
-        private global::Microsoft.AspNetCore.Razor.Runtime.TagHelpers.TagHelperScopeManager __tagHelperScopeManager
-        {
-            get
-            {
-                if (__backed__tagHelperScopeManager == null)
-                {
-                    __backed__tagHelperScopeManager = new global::Microsoft.AspNetCore.Razor.Runtime.TagHelpers.TagHelperScopeManager(StartTagHelperWritingScope, EndTagHelperWritingScope);
-                }
-                return __backed__tagHelperScopeManager;
-            }
-        }
-        private global::FormTagHelper __FormTagHelper;
-        private global::InputTagHelper __InputTagHelper;
-        #pragma warning disable 1998
-        public async override global::System.Threading.Tasks.Task ExecuteAsync()
-        {
-            BeginContext(31, 28, true);
-            WriteLiteral("<span someattr>Hola</span>\r\n");
-            EndContext();
-            BeginContext(61, 7, false);
-#line 3 "TestFiles/IntegrationTests/InstrumentationPassIntegrationTest/BasicTest.cshtml"
-Write("Hello");
-
-#line default
-#line hidden
-            EndContext();
-            BeginContext(69, 2, true);
-            WriteLiteral("\r\n");
-            EndContext();
-            BeginContext(71, 87, false);
-            __tagHelperExecutionContext = __tagHelperScopeManager.Begin("form", global::Microsoft.AspNetCore.Razor.TagHelpers.TagMode.StartTagAndEndTag, "test", async() => {
-                BeginContext(91, 6, true);
-                WriteLiteral("\r\n    ");
-                EndContext();
-                BeginContext(97, 52, false);
-                __tagHelperExecutionContext = __tagHelperScopeManager.Begin("input", global::Microsoft.AspNetCore.Razor.TagHelpers.TagMode.SelfClosing, "test", async() => {
-                }
-                );
-                __InputTagHelper = CreateTagHelper<global::InputTagHelper>();
-                __tagHelperExecutionContext.Add(__InputTagHelper);
-                __InputTagHelper.FooProp = (string)__tagHelperAttribute_0.Value;
-                __tagHelperExecutionContext.AddTagHelperAttribute(__tagHelperAttribute_0);
-#line 5 "TestFiles/IntegrationTests/InstrumentationPassIntegrationTest/BasicTest.cshtml"
-__InputTagHelper.BarProp = DateTime.Now;
-
-#line default
-#line hidden
-                __tagHelperExecutionContext.AddTagHelperAttribute("date", __InputTagHelper.BarProp, global::Microsoft.AspNetCore.Razor.TagHelpers.HtmlAttributeValueStyle.DoubleQuotes);
-                __tagHelperExecutionContext.AddHtmlAttribute(__tagHelperAttribute_1);
-                await __tagHelperRunner.RunAsync(__tagHelperExecutionContext);
-                if (!__tagHelperExecutionContext.Output.IsContentModified)
-                {
-                    await __tagHelperExecutionContext.SetOutputContentAsync();
-                }
-                Write(__tagHelperExecutionContext.Output);
-                __tagHelperExecutionContext = __tagHelperScopeManager.End();
-                EndContext();
-                BeginContext(149, 2, true);
-                WriteLiteral("\r\n");
-                EndContext();
-            }
-            );
-            __FormTagHelper = CreateTagHelper<global::FormTagHelper>();
-            __tagHelperExecutionContext.Add(__FormTagHelper);
-            __tagHelperExecutionContext.AddHtmlAttribute(__tagHelperAttribute_2);
-            await __tagHelperRunner.RunAsync(__tagHelperExecutionContext);
-            if (!__tagHelperExecutionContext.Output.IsContentModified)
-            {
-                await __tagHelperExecutionContext.SetOutputContentAsync();
-            }
-            Write(__tagHelperExecutionContext.Output);
-            __tagHelperExecutionContext = __tagHelperScopeManager.End();
-            EndContext();
-            BeginContext(158, 31, true);
-            WriteLiteral("\r\n\r\n<span>Here is some content ");
-            EndContext();
-            BeginContext(207, 9, true);
-            WriteLiteral("</span>\r\n");
-            EndContext();
-            BeginContext(217, 29, false);
-#line 9 "TestFiles/IntegrationTests/InstrumentationPassIntegrationTest/BasicTest.cshtml"
-Write(Foo(item => new Template(async(__razor_template_writer) => {
-    PushWriter(__razor_template_writer);
-    BeginContext(222, 24, true);
-    WriteLiteral("<span>Hello world</span>");
-    EndContext();
-    PopWriter();
-}
-)));
-
-#line default
-#line hidden
-            EndContext();
-        }
-        #pragma warning restore 1998
-    }
-}
-#pragma warning restore 1591

test/Microsoft.AspNetCore.Mvc.Razor.Extensions.Test/TestFiles/IntegrationTests/InstrumentationPassIntegrationTest/BasicTest.cshtml

@@ -1,9 +0,0 @@
-@addTagHelper *, TestAssembly
-<span someattr>Hola</span>
-@("Hello")
-<form unbound="foo">
-    <input value=Hello date=@DateTime.Now type='text' />
-</form>
-
-<span>Here is some content @*with a comment*@</span>
-@Foo(@<span>Hello world</span>)

test/Microsoft.AspNetCore.Mvc.Razor.Extensions.Test/TestFiles/IntegrationTests/InstrumentationPassIntegrationTest/BasicTest.ir.txt

@@ -1,100 +0,0 @@
-Document - 
-    RazorCompiledItemAttribute - 
-    NamespaceDeclaration -  - Razor
-        RazorSourceChecksumAttribute - 
-        ClassDeclaration -  - public - Template -  - 
-            PreallocatedTagHelperPropertyValue -  - __tagHelperAttribute_0 - value - Hello - HtmlAttributeValueStyle.DoubleQuotes
-            PreallocatedTagHelperHtmlAttributeValue -  - __tagHelperAttribute_1 - type - text - HtmlAttributeValueStyle.SingleQuotes
-            PreallocatedTagHelperHtmlAttributeValue -  - __tagHelperAttribute_2 - unbound - foo - HtmlAttributeValueStyle.DoubleQuotes
-            DefaultTagHelperRuntime - 
-            FieldDeclaration -  - private - global::FormTagHelper - __FormTagHelper
-            FieldDeclaration -  - private - global::InputTagHelper - __InputTagHelper
-            MethodDeclaration -  - public async override - global::System.Threading.Tasks.Task - ExecuteAsync
-                CSharpCode - 
-                    IntermediateToken -  - CSharp - BeginContext(31, 28, true);
-                HtmlContent - (31:1,0 [28] BasicTest.cshtml)
-                    IntermediateToken - (31:1,0 [5] BasicTest.cshtml) - Html - <span
-                    IntermediateToken - (36:1,5 [9] BasicTest.cshtml) - Html -  someattr
-                    IntermediateToken - (45:1,14 [1] BasicTest.cshtml) - Html - >
-                    IntermediateToken - (46:1,15 [4] BasicTest.cshtml) - Html - Hola
-                    IntermediateToken - (50:1,19 [7] BasicTest.cshtml) - Html - </span>
-                    IntermediateToken - (57:1,26 [2] BasicTest.cshtml) - Html - \n
-                CSharpCode - 
-                    IntermediateToken -  - CSharp - EndContext();
-                CSharpCode - 
-                    IntermediateToken -  - CSharp - BeginContext(61, 7, false);
-                CSharpExpression - (61:2,2 [7] BasicTest.cshtml)
-                    IntermediateToken - (61:2,2 [7] BasicTest.cshtml) - CSharp - "Hello"
-                CSharpCode - 
-                    IntermediateToken -  - CSharp - EndContext();
-                CSharpCode - 
-                    IntermediateToken -  - CSharp - BeginContext(69, 2, true);
-                HtmlContent - (69:2,10 [2] BasicTest.cshtml)
-                    IntermediateToken - (69:2,10 [2] BasicTest.cshtml) - Html - \n
-                CSharpCode - 
-                    IntermediateToken -  - CSharp - EndContext();
-                CSharpCode - 
-                    IntermediateToken -  - CSharp - BeginContext(71, 87, false);
-                TagHelper - (71:3,0 [87] BasicTest.cshtml) - form - TagMode.StartTagAndEndTag
-                    DefaultTagHelperBody - 
-                        CSharpCode - 
-                            IntermediateToken -  - CSharp - BeginContext(91, 6, true);
-                        HtmlContent - (91:3,20 [6] BasicTest.cshtml)
-                            IntermediateToken - (91:3,20 [6] BasicTest.cshtml) - Html - \n    
-                        CSharpCode - 
-                            IntermediateToken -  - CSharp - EndContext();
-                        CSharpCode - 
-                            IntermediateToken -  - CSharp - BeginContext(97, 52, false);
-                        TagHelper - (97:4,4 [52] BasicTest.cshtml) - input - TagMode.SelfClosing
-                            DefaultTagHelperBody - 
-                            DefaultTagHelperCreate -  - InputTagHelper
-                            PreallocatedTagHelperProperty - (110:4,17 [5] BasicTest.cshtml) - __tagHelperAttribute_0 - value - FooProp
-                            DefaultTagHelperProperty - (121:4,28 [13] BasicTest.cshtml) - date - System.DateTime InputTagHelper.BarProp - HtmlAttributeValueStyle.DoubleQuotes
-                                CSharpExpression - (122:4,29 [12] BasicTest.cshtml)
-                                    IntermediateToken - (122:4,29 [12] BasicTest.cshtml) - CSharp - DateTime.Now
-                            PreallocatedTagHelperHtmlAttribute -  - __tagHelperAttribute_1
-                            DefaultTagHelperExecute - 
-                        CSharpCode - 
-                            IntermediateToken -  - CSharp - EndContext();
-                        CSharpCode - 
-                            IntermediateToken -  - CSharp - BeginContext(149, 2, true);
-                        HtmlContent - (149:4,56 [2] BasicTest.cshtml)
-                            IntermediateToken - (149:4,56 [2] BasicTest.cshtml) - Html - \n
-                        CSharpCode - 
-                            IntermediateToken -  - CSharp - EndContext();
-                    DefaultTagHelperCreate -  - FormTagHelper
-                    PreallocatedTagHelperHtmlAttribute -  - __tagHelperAttribute_2
-                    DefaultTagHelperExecute - 
-                CSharpCode - 
-                    IntermediateToken -  - CSharp - EndContext();
-                CSharpCode - 
-                    IntermediateToken -  - CSharp - BeginContext(158, 31, true);
-                HtmlContent - (158:5,7 [31] BasicTest.cshtml)
-                    IntermediateToken - (158:5,7 [4] BasicTest.cshtml) - Html - \n\n
-                    IntermediateToken - (162:7,0 [6] BasicTest.cshtml) - Html - <span>
-                    IntermediateToken - (168:7,6 [21] BasicTest.cshtml) - Html - Here is some content 
-                CSharpCode - 
-                    IntermediateToken -  - CSharp - EndContext();
-                CSharpCode - 
-                    IntermediateToken -  - CSharp - BeginContext(207, 9, true);
-                HtmlContent - (207:7,45 [9] BasicTest.cshtml)
-                    IntermediateToken - (207:7,45 [7] BasicTest.cshtml) - Html - </span>
-                    IntermediateToken - (214:7,52 [2] BasicTest.cshtml) - Html - \n
-                CSharpCode - 
-                    IntermediateToken -  - CSharp - EndContext();
-                CSharpCode - 
-                    IntermediateToken -  - CSharp - BeginContext(217, 29, false);
-                CSharpExpression - (217:8,1 [29] BasicTest.cshtml)
-                    IntermediateToken - (217:8,1 [4] BasicTest.cshtml) - CSharp - Foo(
-                    Template - (222:8,6 [24] BasicTest.cshtml)
-                        CSharpCode - 
-                            IntermediateToken -  - CSharp - BeginContext(222, 24, true);
-                        HtmlContent - (222:8,6 [24] BasicTest.cshtml)
-                            IntermediateToken - (222:8,6 [6] BasicTest.cshtml) - Html - <span>
-                            IntermediateToken - (228:8,12 [11] BasicTest.cshtml) - Html - Hello world
-                            IntermediateToken - (239:8,23 [7] BasicTest.cshtml) - Html - </span>
-                        CSharpCode - 
-                            IntermediateToken -  - CSharp - EndContext();
-                    IntermediateToken - (246:8,30 [1] BasicTest.cshtml) - CSharp - )
-                CSharpCode - 
-                    IntermediateToken -  - CSharp - EndContext();

test/Microsoft.AspNetCore.Razor.Language.Test/Components/ComponentDocumentClassifierPassTest.cs

@@ -0,0 +1,207 @@
+// 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.AspNetCore.Razor.Language.Intermediate;
+using Xunit;
+
+namespace Microsoft.AspNetCore.Razor.Language.Components
+{
+    public class ComponentDocumentClassifierPassTest
+    {
+        [Fact]
+        public void Execute_SetsDocumentKind()
+        {
+            // Arrange
+            var codeDocument = RazorCodeDocument.Create(RazorSourceDocument.Create("some-content", "Test.razor"));
+            codeDocument.SetInputDocumentKind(InputDocumentKind.Component);
+
+            var projectEngine = CreateProjectEngine();
+            var irDocument = CreateIRDocument(projectEngine, codeDocument);
+            var pass = new ComponentDocumentClassifierPass
+            {
+                Engine = projectEngine.Engine
+            };
+
+            // Act
+            pass.Execute(codeDocument, irDocument);
+
+            // Assert
+            Assert.Equal(ComponentDocumentClassifierPass.ComponentDocumentKind, irDocument.DocumentKind);
+        }
+
+        [Fact]
+        public void ComponentDocumentClassifierPass_SetsNamespace()
+        {
+            // Arrange
+            var properties = new RazorSourceDocumentProperties(filePath: "/MyApp/Test.razor", relativePath: "Test.razor");
+            var codeDocument = RazorCodeDocument.Create(RazorSourceDocument.Create("some-content", properties));
+            codeDocument.SetInputDocumentKind(InputDocumentKind.Component);
+
+            var projectEngine = CreateProjectEngine();
+            var irDocument = CreateIRDocument(projectEngine, codeDocument);
+            var pass = new ComponentDocumentClassifierPass
+            {
+                Engine = projectEngine.Engine
+            };
+
+            // Act
+            pass.Execute(codeDocument, irDocument);
+            var visitor = new Visitor();
+            visitor.Visit(irDocument);
+
+            // Assert
+            Assert.Equal("MyApp", visitor.Namespace.Content);
+        }
+
+        [Fact]
+        public void ComponentDocumentClassifierPass_SetsClass()
+        {
+            // Arrange
+            var properties = new RazorSourceDocumentProperties(filePath: "/MyApp/Test.razor", relativePath: "Test.razor");
+            var codeDocument = RazorCodeDocument.Create(RazorSourceDocument.Create("some-content", properties));
+            codeDocument.SetInputDocumentKind(InputDocumentKind.Component);
+
+            var projectEngine = CreateProjectEngine();
+            var irDocument = CreateIRDocument(projectEngine, codeDocument);
+            var pass = new ComponentDocumentClassifierPass
+            {
+                Engine = projectEngine.Engine
+            };
+
+            // Act
+            pass.Execute(codeDocument, irDocument);
+            var visitor = new Visitor();
+            visitor.Visit(irDocument);
+
+            // Assert
+            Assert.Equal($"global::{CodeGenerationConstants.RazorComponent.FullTypeName}", visitor.Class.BaseType);
+            Assert.Equal(new[] { "public", "sealed" }, visitor.Class.Modifiers);
+            Assert.Equal("Test", visitor.Class.ClassName);
+        }
+
+        [Fact]
+        public void ComponentDocumentClassifierPass_UsesRelativePathToGenerateTypeNameAndNamespace()
+        {
+            // Arrange
+            var relativePath = "/Pages/Announcements/Banner.razor";
+            var properties = new RazorSourceDocumentProperties(filePath: $"/MyApp{relativePath}", relativePath: relativePath);
+            var codeDocument = RazorCodeDocument.Create(RazorSourceDocument.Create("some-content", properties));
+            codeDocument.SetInputDocumentKind(InputDocumentKind.Component);
+
+            var projectEngine = CreateProjectEngine();
+            var irDocument = CreateIRDocument(projectEngine, codeDocument);
+            var pass = new ComponentDocumentClassifierPass
+            {
+                Engine = projectEngine.Engine
+            };
+
+            // Act
+            pass.Execute(codeDocument, irDocument);
+            var visitor = new Visitor();
+            visitor.Visit(irDocument);
+
+            // Assert
+            Assert.Equal("Banner", visitor.Class.ClassName);
+            Assert.Equal("MyApp.Pages.Announcements", visitor.Namespace.Content);
+        }
+
+        [Fact]
+        public void ComponentDocumentClassifierPass_SanitizesClassName()
+        {
+            // Arrange
+            var properties = new RazorSourceDocumentProperties(filePath: @"x:\path.with+invalid-chars.razor", relativePath: "path.with+invalid-chars.razor");
+            var codeDocument = RazorCodeDocument.Create(RazorSourceDocument.Create("some-content", properties));
+            codeDocument.SetInputDocumentKind(InputDocumentKind.Component);
+
+            var projectEngine = CreateProjectEngine();
+            var irDocument = CreateIRDocument(projectEngine, codeDocument);
+            var pass = new ComponentDocumentClassifierPass
+            {
+                Engine = projectEngine.Engine
+            };
+
+            // Act
+            pass.Execute(codeDocument, irDocument);
+            var visitor = new Visitor();
+            visitor.Visit(irDocument);
+
+            // Assert
+            Assert.Equal("path_with_invalid_chars", visitor.Class.ClassName);
+        }
+
+        [Fact]
+        public void ComponentDocumentClassifierPass_SetsUpMainMethod()
+        {
+            // Arrange
+            var codeDocument = RazorCodeDocument.Create(RazorSourceDocument.Create("some-content", "Test.razor"));
+            codeDocument.SetInputDocumentKind(InputDocumentKind.Component);
+
+            var projectEngine = CreateProjectEngine();
+            var irDocument = CreateIRDocument(projectEngine, codeDocument);
+            var pass = new ComponentDocumentClassifierPass
+            {
+                Engine = projectEngine.Engine
+            };
+
+            // Act
+            pass.Execute(codeDocument, irDocument);
+            var visitor = new Visitor();
+            visitor.Visit(irDocument);
+
+            // Assert
+            Assert.Equal(CodeGenerationConstants.RazorComponent.BuildRenderTree, visitor.Method.MethodName);
+            Assert.Equal("void", visitor.Method.ReturnType);
+            Assert.Equal(new[] { "public", "override" }, visitor.Method.Modifiers);
+        }
+
+        private static RazorProjectEngine CreateProjectEngine() => RazorProjectEngine.Create();
+
+        private static DocumentIntermediateNode CreateIRDocument(RazorProjectEngine projectEngine, RazorCodeDocument codeDocument)
+        {
+            for (var i = 0; i < projectEngine.Phases.Count; i++)
+            {
+                var phase = projectEngine.Phases[i];
+                phase.Execute(codeDocument);
+
+                if (phase is IRazorIntermediateNodeLoweringPhase)
+                {
+                    break;
+                }
+            }
+
+            return codeDocument.GetDocumentIntermediateNode();
+        }
+
+        private class Visitor : IntermediateNodeWalker
+        {
+            public NamespaceDeclarationIntermediateNode Namespace { get; private set; }
+
+            public ClassDeclarationIntermediateNode Class { get; private set; }
+
+            public MethodDeclarationIntermediateNode Method { get; private set; }
+
+            public override void VisitMethodDeclaration(MethodDeclarationIntermediateNode node)
+            {
+                Method = node;
+            }
+
+            public override void VisitNamespaceDeclaration(NamespaceDeclarationIntermediateNode node)
+            {
+                Namespace = node;
+                base.VisitNamespaceDeclaration(node);
+            }
+
+            public override void VisitClassDeclaration(ClassDeclarationIntermediateNode node)
+            {
+                Class = node;
+                base.VisitClassDeclaration(node);
+            }
+        }
+
+        private class TestComponentDocumentClassifierPass : ComponentDocumentClassifierPass
+        {
+            public new bool IsMatch(RazorCodeDocument codeDocument, DocumentIntermediateNode documentNode)
+                => base.IsMatch(codeDocument, documentNode);
+        }
+    }
+}

test/Microsoft.AspNetCore.Razor.Language.Test/DefaultRazorIntermediateNodeLoweringPhaseIntegrationTest.cs

@@ -465,7 +465,6 @@ namespace Microsoft.AspNetCore.Razor.Language
             {
                 builder?.Invoke(b);
 
-                FunctionsDirective.Register(b);
                 SectionDirective.Register(b);
                 b.AddTagHelpers(tagHelpers);
 

test/Microsoft.AspNetCore.Razor.Language.Test/Extensions/FunctionsDirectivePassTest.cs

@@ -76,10 +76,7 @@ namespace Microsoft.AspNetCore.Razor.Language.Extensions
 
         private static RazorProjectEngine CreateProjectEngine()
         {
-            return RazorProjectEngine.Create(b =>
+            return RazorProjectEngine.Create();
-            {
-                FunctionsDirective.Register(b);
-            });
         }
 
         private static DocumentIntermediateNode Lower(RazorCodeDocument codeDocument, RazorProjectEngine projectEngine)

test/Microsoft.AspNetCore.Razor.Language.Test/IntegrationTests/CodeGenerationIntegrationTest.cs

@@ -884,7 +884,6 @@ namespace Microsoft.AspNetCore.Razor.Language.IntegrationTests
                 // Some of these tests use templates
                 builder.AddTargetExtension(new TemplateTargetExtension());
 
-                FunctionsDirective.Register(builder);
                 InheritsDirective.Register(builder);
                 SectionDirective.Register(builder);
             });
@@ -910,7 +909,6 @@ namespace Microsoft.AspNetCore.Razor.Language.IntegrationTests
                 // Some of these tests use templates
                 builder.AddTargetExtension(new TemplateTargetExtension());
                 
-                FunctionsDirective.Register(builder);
                 InheritsDirective.Register(builder);
                 SectionDirective.Register(builder);
             });
@@ -935,7 +933,6 @@ namespace Microsoft.AspNetCore.Razor.Language.IntegrationTests
                 // Some of these tests use templates
                 builder.AddTargetExtension(new TemplateTargetExtension());
 
-                FunctionsDirective.Register(builder);
                 InheritsDirective.Register(builder);
                 SectionDirective.Register(builder);
             });
@@ -961,7 +958,6 @@ namespace Microsoft.AspNetCore.Razor.Language.IntegrationTests
                 // Some of these tests use templates
                 builder.AddTargetExtension(new TemplateTargetExtension());
 
-                FunctionsDirective.Register(builder);
                 InheritsDirective.Register(builder);
                 SectionDirective.Register(builder);
             });

test/Microsoft.AspNetCore.Razor.Language.Test/IntegrationTests/ComponentIntegrationTest.cs

@@ -0,0 +1,50 @@
+// 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.AspNetCore.Razor.Language.Components;
+using Microsoft.AspNetCore.Razor.Language.Intermediate;
+using Xunit;
+
+namespace Microsoft.AspNetCore.Razor.Language.IntegrationTests
+{
+    public class ComponentIntegrationTest : IntegrationTestBase
+    {
+        public ComponentIntegrationTest()
+            : base(generateBaselines: null)
+        {
+            Configuration = RazorConfiguration.Default;
+            FileExtension = ".razor";
+        }
+
+        protected override RazorConfiguration Configuration { get; }
+
+        [Fact]
+        public void BasicTest()
+        {
+            var projectEngine = CreateProjectEngine(engine =>
+            {
+                engine.Features.Add(new InputDocumentKindClassifierPass());
+            });
+
+            var projectItem = CreateProjectItemFromFile();
+
+            // Act
+            var codeDocument = projectEngine.Process(projectItem);
+
+            // Assert
+            AssertDocumentNodeMatchesBaseline(codeDocument.GetDocumentIntermediateNode());
+            AssertCSharpDocumentMatchesBaseline(codeDocument.GetCSharpDocument());
+        }
+
+        private class InputDocumentKindClassifierPass : RazorEngineFeatureBase, IRazorDocumentClassifierPass
+        {
+            // Run before other document classifiers
+            public int Order => -1000;
+
+            public void Execute(RazorCodeDocument codeDocument, DocumentIntermediateNode documentNode)
+            {
+                codeDocument.SetInputDocumentKind(InputDocumentKind.Component);
+            }
+        }
+    }
+}

test/Microsoft.AspNetCore.Razor.Language.Test/IntegrationTests/SuppressPrimaryMethodBodyntegrationTest.cs

@@ -0,0 +1,65 @@
+// 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.AspNetCore.Razor.Language.Components;
+using Microsoft.AspNetCore.Razor.Language.IntegrationTests;
+using Microsoft.AspNetCore.Razor.Language.Intermediate;
+using Xunit;
+
+namespace Microsoft.AspNetCore.Razor.Language
+{
+    public class SuppressPrimaryMethodBodyIntegrationTest : IntegrationTestBase
+    {
+        public SuppressPrimaryMethodBodyIntegrationTest()
+            : base(generateBaselines: null)
+        {
+            Configuration = RazorConfiguration.Default;
+            FileExtension = ".razor";
+        }
+
+        protected override RazorConfiguration Configuration { get; }
+
+        [Fact]
+        public void BasicTest()
+        {
+            var engine = CreateProjectEngine(e =>
+            {
+                e.Features.Add(new SetSuppressPrimaryMethodBodyFeature());
+                e.Features.Add(new InputDocumentKindClassifierPass());
+            });
+
+            var projectItem = CreateProjectItemFromFile();
+
+            // Act
+            var codeDocument = engine.Process(projectItem);
+
+            // Assert
+            AssertDocumentNodeMatchesBaseline(codeDocument.GetDocumentIntermediateNode());
+
+            var csharpDocument = codeDocument.GetCSharpDocument();
+            AssertCSharpDocumentMatchesBaseline(csharpDocument);
+            Assert.Empty(csharpDocument.Diagnostics);
+        }
+
+        private class SetSuppressPrimaryMethodBodyFeature : RazorEngineFeatureBase, IConfigureRazorCodeGenerationOptionsFeature
+        {
+            public int Order { get; set; }
+
+            public void Configure(RazorCodeGenerationOptionsBuilder options)
+            {
+                options.SuppressPrimaryMethodBody = true;
+            }
+        }
+
+        private class InputDocumentKindClassifierPass : RazorEngineFeatureBase, IRazorDocumentClassifierPass
+        {
+            // Run before other document classifiers
+            public int Order => -1000;
+
+            public void Execute(RazorCodeDocument codeDocument, DocumentIntermediateNode documentNode)
+            {
+                codeDocument.SetInputDocumentKind(InputDocumentKind.Component);
+            }
+        }
+    }
+}

test/Microsoft.AspNetCore.Razor.Language.Test/RazorProjectEngineTest.cs

@@ -1,8 +1,8 @@
 // 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.Collections.Generic;
 using System.Linq;
+using Microsoft.AspNetCore.Razor.Language.Components;
 using Microsoft.AspNetCore.Razor.Language.Extensions;
 using Moq;
 using Xunit;
@@ -45,6 +45,7 @@ namespace Microsoft.AspNetCore.Razor.Language.Test
             var features = engine.EngineFeatures.OrderBy(f => f.GetType().Name).ToArray();
             Assert.Collection(
                 features,
+                feature => Assert.IsType<ComponentDocumentClassifierPass>(feature),
                 feature => Assert.IsType<DefaultDirectiveSyntaxTreePass>(feature),
                 feature => Assert.IsType<DefaultDocumentClassifierPass>(feature),
                 feature => Assert.IsType<DefaultDocumentClassifierPassFeature>(feature),
@@ -56,6 +57,8 @@ namespace Microsoft.AspNetCore.Razor.Language.Test
                 feature => Assert.IsType<DefaultTagHelperOptimizationPass>(feature),
                 feature => Assert.IsType<DesignTimeDirectivePass>(feature),
                 feature => Assert.IsType<DirectiveRemovalOptimizationPass>(feature),
+                feature => Assert.IsType<EliminateMethodBodyPass>(feature),
+                feature => Assert.IsType<FunctionsDirectivePass>(feature),
                 feature => Assert.IsType<HtmlNodeOptimizationPass>(feature),
                 feature => Assert.IsType<MetadataAttributePass>(feature),
                 feature => Assert.IsType<PreallocatedTagHelperAttributeOptimizationPass>(feature));
@@ -65,7 +68,9 @@ namespace Microsoft.AspNetCore.Razor.Language.Test
         {
             var feature = engine.EngineFeatures.OfType<IRazorDirectiveFeature>().FirstOrDefault();
             Assert.NotNull(feature);
-            Assert.Empty(feature.Directives);
+            Assert.Collection(
+                feature.Directives,
+                directive => Assert.Same(FunctionsDirective.Directive, directive));
         }
 
         private static void AssertDefaultTargetExtensions(RazorProjectEngine engine)

test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/ComponentIntegrationTest/BasicTest.codegen.cs

@@ -0,0 +1,26 @@
+#pragma checksum "TestFiles/IntegrationTests/ComponentIntegrationTest/BasicTest.razor" "{ff1816ec-aa5e-4d10-87f7-6f4963833460}" "47f616cdc7ec75674c74246619b0e6118ef227e4"
+// <auto-generated/>
+#pragma warning disable 1591
+[assembly: global::Microsoft.AspNetCore.Razor.Hosting.RazorCompiledItemAttribute(typeof(AspNetCore.BasicTest), @"component.1.0", @"/TestFiles/IntegrationTests/ComponentIntegrationTest/BasicTest.razor")]
+namespace AspNetCore
+{
+    #line hidden
+    [global::Microsoft.AspNetCore.Razor.Hosting.RazorSourceChecksumAttribute(@"SHA1", @"47f616cdc7ec75674c74246619b0e6118ef227e4", @"/TestFiles/IntegrationTests/ComponentIntegrationTest/BasicTest.razor")]
+    public sealed class BasicTest : global::Microsoft.AspNetCore.Components.Component
+    {
+        #pragma warning disable 1998
+        public override void BuildRenderTree(Microsoft.AspNetCore.Components.RenderTree.RenderTreeBuilder builder)
+        {
+            base.BuildRenderTree(builder);
+            WriteLiteral("Hello world\r\n<span class=\"content\"></span>\r\n\r\n");
+        }
+        #pragma warning restore 1998
+#line 4 "TestFiles/IntegrationTests/ComponentIntegrationTest/BasicTest.razor"
+            
+    string SomeProperty { get; set; }
+
+#line default
+#line hidden
+    }
+}
+#pragma warning restore 1591

test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/ComponentIntegrationTest/BasicTest.ir.txt

@@ -0,0 +1,17 @@
+Document - 
+    RazorCompiledItemAttribute - 
+    NamespaceDeclaration -  - AspNetCore
+        RazorSourceChecksumAttribute - 
+        ClassDeclaration -  - public sealed - BasicTest - global::Microsoft.AspNetCore.Components.Component - 
+            MethodDeclaration -  - public override - void - BuildRenderTree
+                CSharpCode - 
+                    IntermediateToken -  - CSharp - base.BuildRenderTree(builder);
+                HtmlContent - (0:0,0 [46] BasicTest.razor)
+                    IntermediateToken - (0:0,0 [13] BasicTest.razor) - Html - Hello world\n
+                    IntermediateToken - (13:1,0 [5] BasicTest.razor) - Html - <span
+                    IntermediateToken - (18:1,5 [16] BasicTest.razor) - Html -  class="content"
+                    IntermediateToken - (34:1,21 [1] BasicTest.razor) - Html - >
+                    IntermediateToken - (35:1,22 [7] BasicTest.razor) - Html - </span>
+                    IntermediateToken - (42:1,29 [4] BasicTest.razor) - Html - \n\n
+            CSharpCode - (58:3,12 [41] BasicTest.razor)
+                IntermediateToken - (58:3,12 [41] BasicTest.razor) - CSharp - \n    string SomeProperty { get; set; }\n

test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/ComponentIntegrationTest/BasicTest.razor

@@ -0,0 +1,6 @@
+Hello world
+<span class="content"></span>
+
+@functions {
+    string SomeProperty { get; set; }
+}

test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/SuppressPrimaryMethodBodyIntegrationTest/BasicTest.codegen.cs

@@ -0,0 +1,28 @@
+#pragma checksum "TestFiles/IntegrationTests/SuppressPrimaryMethodBodyIntegrationTest/BasicTest.razor" "{ff1816ec-aa5e-4d10-87f7-6f4963833460}" "47f616cdc7ec75674c74246619b0e6118ef227e4"
+// <auto-generated/>
+#pragma warning disable 1591
+[assembly: global::Microsoft.AspNetCore.Razor.Hosting.RazorCompiledItemAttribute(typeof(AspNetCore.BasicTest), @"component.1.0", @"/TestFiles/IntegrationTests/SuppressPrimaryMethodBodyIntegrationTest/BasicTest.razor")]
+#pragma warning disable 0414
+#pragma warning disable 0649
+#pragma warning disable 0169
+
+namespace AspNetCore
+{
+    #line hidden
+    [global::Microsoft.AspNetCore.Razor.Hosting.RazorSourceChecksumAttribute(@"SHA1", @"47f616cdc7ec75674c74246619b0e6118ef227e4", @"/TestFiles/IntegrationTests/SuppressPrimaryMethodBodyIntegrationTest/BasicTest.razor")]
+    public sealed class BasicTest : global::Microsoft.AspNetCore.Components.Component
+    {
+        #pragma warning disable 1998
+        public override void BuildRenderTree(Microsoft.AspNetCore.Components.RenderTree.RenderTreeBuilder builder)
+        {
+        }
+        #pragma warning restore 1998
+#line 4 "TestFiles/IntegrationTests/SuppressPrimaryMethodBodyIntegrationTest/BasicTest.razor"
+            
+    string SomeProperty { get; set; }
+
+#line default
+#line hidden
+    }
+}
+#pragma warning restore 1591

test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/SuppressPrimaryMethodBodyIntegrationTest/BasicTest.ir.txt

@@ -0,0 +1,12 @@
+Document - 
+    RazorCompiledItemAttribute - 
+    CSharpCode - 
+        IntermediateToken -  - CSharp - #pragma warning disable 0414\n
+        IntermediateToken -  - CSharp - #pragma warning disable 0649\n
+        IntermediateToken -  - CSharp - #pragma warning disable 0169\n
+    NamespaceDeclaration -  - AspNetCore
+        RazorSourceChecksumAttribute - 
+        ClassDeclaration -  - public sealed - BasicTest - global::Microsoft.AspNetCore.Components.Component - 
+            MethodDeclaration -  - public override - void - BuildRenderTree
+            CSharpCode - (58:3,12 [41] BasicTest.razor)
+                IntermediateToken - (58:3,12 [41] BasicTest.razor) - CSharp - \n    string SomeProperty { get; set; }\n

test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/SuppressPrimaryMethodBodyIntegrationTest/BasicTest.razor

@@ -0,0 +1,6 @@
+Hello world
+<span class="content"></span>
+
+@functions {
+    string SomeProperty { get; set; }
+}

test/Microsoft.AspNetCore.Razor.Test.Common/Language/IntegrationTests/IntegrationTestBase.cs

@@ -132,6 +132,8 @@ namespace Microsoft.AspNetCore.Razor.Language.IntegrationTests
 #endif
         }
 
+        public string FileExtension { get; set; } = ".cshtml";
+
         protected virtual void ConfigureProjectEngine(RazorProjectEngineBuilder builder)
         {
         }
@@ -193,7 +195,7 @@ namespace Microsoft.AspNetCore.Razor.Language.IntegrationTests
 
             var suffixIndex = FileName.LastIndexOf("_");
             var normalizedFileName = suffixIndex == -1 ? FileName : FileName.Substring(0, suffixIndex);
-            var sourceFileName = Path.ChangeExtension(normalizedFileName, ".cshtml");
+            var sourceFileName = Path.ChangeExtension(normalizedFileName, FileExtension);
             var testFile = TestFile.Create(sourceFileName, GetType().GetTypeInfo().Assembly);
             if (!testFile.Exists())
             {

test/Microsoft.AspNetCore.Razor.Test.MvcShim.ClassLib/Microsoft.AspNetCore.Razor.Test.MvcShim.ClassLib.csproj

@@ -13,7 +13,7 @@
   </ItemGroup>
 
   <ItemGroup>
-    <Compile Include="..\Microsoft.AspNetCore.Razor.Test.MvcShim\Microsoft.AspNetCore.Mvc*\**\*.cs" />
+    <Compile Include="..\Microsoft.AspNetCore.Razor.Test.MvcShim\Microsoft.*\**\*.cs" />
   </ItemGroup>
 
 </Project>

test/Microsoft.AspNetCore.Razor.Test.MvcShim/Microsoft.AspNetCore.Components/Component.cs

@@ -0,0 +1,16 @@
+// 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.AspNetCore.Components.RenderTree;
+
+namespace Microsoft.AspNetCore.Components
+{
+    public abstract class Component : IComponent
+    {
+        public virtual void BuildRenderTree(RenderTreeBuilder builder)
+        {
+        }
+
+        protected void WriteLiteral(string literal) { }
+    }
+}

test/Microsoft.AspNetCore.Razor.Test.MvcShim/Microsoft.AspNetCore.Components/IComponent.cs

@@ -0,0 +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.
+
+namespace Microsoft.AspNetCore.Components
+{
+    public interface IComponent
+    {
+    }
+}

test/Microsoft.AspNetCore.Razor.Test.MvcShim/Microsoft.AspNetCore.Components/RenderTree/RenderTreeBuilder.cs

@@ -0,0 +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.
+
+namespace Microsoft.AspNetCore.Components.RenderTree
+{
+    public abstract class RenderTreeBuilder
+    {
+    }
+}

test/Microsoft.AspNetCore.Razor.Tools.Test/Microsoft.AspNetCore.Razor.Tools.Test.csproj

@@ -1,7 +1,8 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
     <TargetFramework>netcoreapp3.0</TargetFramework>
+    <DefaultItemExcludes>$(DefaultItemExcludes);TestFiles\**</DefaultItemExcludes>
   </PropertyGroup>
 
   <ItemGroup>

test/Microsoft.AspNetCore.Razor.Tools.Test/MvcShim.cs

@@ -0,0 +1,45 @@
+// 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.IO;
+using System.Reflection;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp;
+
+namespace Microsoft.AspNetCore.Razor.Tools
+{
+    internal static class MvcShim
+    {
+        public static readonly string AssemblyName = "Microsoft.AspNetCore.Razor.Test.MvcShim";
+
+        private static Assembly _assembly;
+        private static CSharpCompilation _baseCompilation;
+
+        public static Assembly Assembly
+        {
+            get
+            {
+                if (_assembly == null)
+                {
+                    var filePath = Path.Combine(Directory.GetCurrentDirectory(), AssemblyName + ".dll");
+                    _assembly = Assembly.LoadFrom(filePath);
+                }
+
+                return _assembly;
+            }
+        }
+
+        public static CSharpCompilation BaseCompilation
+        {
+            get
+            {
+                if (_baseCompilation == null)
+                {
+                    _baseCompilation = TestCompilation.Create(Assembly);
+                }
+
+                return _baseCompilation;
+            }
+        }
+    }
+}

test/Microsoft.NET.Sdk.Razor.Test/IntegrationTests/Assert.cs

@@ -4,6 +4,9 @@
 using System;
 using System.IO;
 using System.IO.Compression;
+using System.Linq;
+using System.Reflection.Metadata;
+using System.Reflection.PortableExecutable;
 using System.Text;
 using System.Text.RegularExpressions;
 
@@ -373,6 +376,28 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
             }
         }
 
+        public static void AssemblyContainsType(MSBuildResult result, string assemblyPath, string fullTypeName)
+        {
+            if (result == null)
+            {
+                throw new ArgumentNullException(nameof(result));
+            }
+
+            assemblyPath = Path.Combine(result.Project.DirectoryPath, Path.Combine(assemblyPath));
+            using (var file = File.OpenRead(assemblyPath))
+            {
+                var peReader = new PEReader(file);
+                var metadataReader = peReader.GetMetadataReader();
+                var typeNames = metadataReader.TypeDefinitions.Where(t => !t.IsNil).Select(t =>
+                {
+                    var type = metadataReader.GetTypeDefinition(t);
+                    return metadataReader.GetString(type.Namespace) + "." + metadataReader.GetString(type.Name);
+                });
+
+                Assert.Contains(fullTypeName, typeNames);
+            }
+        }
+
         private abstract class MSBuildXunitException : Xunit.Sdk.XunitException
         {
             protected MSBuildXunitException(MSBuildResult result)

test/Microsoft.NET.Sdk.Razor.Test/IntegrationTests/BuildIncrementalismTest.cs

@@ -75,7 +75,7 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
             var result = await DotnetMSBuild("Build");
             var file = Path.Combine(Project.DirectoryPath, "SimpleTagHelper.cs");
             var tagHelperOutputCache = Path.Combine(IntermediateOutputPath, "SimpleMvc.TagHelpers.output.cache");
-            var generatedFile = Path.Combine(RazorIntermediateOutputPath, "Views", "Home", "Index.g.cshtml.cs");
+            var generatedFile = Path.Combine(RazorIntermediateOutputPath, "Views", "Home", "Index.cshtml.g.cs");
 
             // Assert - 1
             Assert.BuildPassed(result);
@@ -133,6 +133,152 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
             }
         }
 
+        [Fact]
+        [InitializeTestProject("MvcWithComponents")]
+        public async Task BuildComponents_ErrorInGeneratedCode_ReportsMSBuildError_OnIncrementalBuild()
+        {
+            // Introducing a Razor semantic error
+            ReplaceContent("@{ // Unterminated code block", "Views", "Shared", "NavMenu.razor");
+
+            // Regular build
+            await VerifyError();
+
+            // Incremental build
+            await VerifyError();
+
+            async Task VerifyError()
+            {
+                var result = await DotnetMSBuild("Build");
+
+                Assert.BuildFailed(result);
+
+                // This needs to be relative path. Tracked by https://github.com/aspnet/Razor/issues/2187.
+                var filePath = Path.Combine(Project.DirectoryPath, "Views", "Shared", "NavMenu.razor");
+                var location = filePath + "(1,2)";
+                if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
+                {
+                    // Absolute paths on OSX don't work well.
+                    location = null;
+                }
+
+                Assert.BuildError(result, "RZ1006", location: location);
+
+                // Compilation failed without creating the views assembly
+                Assert.FileDoesNotExist(result, IntermediateOutputPath, "MvcWithComponents.dll");
+                Assert.FileDoesNotExist(result, IntermediateOutputPath, "MvcWithComponents.Views.dll");
+
+                // File with error does not get written to disk.
+                Assert.FileDoesNotExist(result, IntermediateOutputPath, "RazorComponents", "Views", "Shared", "NavMenu.razor.g.cs");
+            }
+        }
+
+        [Fact]
+        [InitializeTestProject("MvcWithComponents")]
+        public async Task BuildComponents_RegeneratesComponentDefinition_WhenFilesChange()
+        {
+            // Act - 1
+            var tagHelperOutputCache = Path.Combine(IntermediateOutputPath, "MvcWithComponents.TagHelpers.output.cache");
+
+            var generatedFile = Path.Combine(RazorIntermediateOutputPath, "Views", "Shared", "NavMenu.razor.g.cs");
+            var generatedDefinitionFile = Path.Combine(RazorComponentIntermediateOutputPath, "Views", "Shared", "NavMenu.razor.g.cs");
+
+            // Assert - 1
+            var result = await DotnetMSBuild("Build");
+
+            Assert.BuildPassed(result);
+            var outputFile = Path.Combine(OutputPath, "MvcWithComponents.dll");
+            Assert.FileExists(result, OutputPath, "MvcWithComponents.dll");
+            var outputAssemblyThumbprint = GetThumbPrint(outputFile);
+
+            Assert.FileExists(result, generatedDefinitionFile);
+            var generatedDefinitionThumbprint = GetThumbPrint(generatedDefinitionFile);
+            Assert.FileExists(result, generatedFile);
+            var generatedFileThumbprint = GetThumbPrint(generatedFile);
+
+            Assert.FileExists(result, tagHelperOutputCache);
+            Assert.FileContains(
+                result,
+                tagHelperOutputCache,
+                @"""Name"":""MvcWithComponents.Views.Shared.NavMenu""");
+
+            var definitionThumbprint = GetThumbPrint(tagHelperOutputCache);
+
+            // Act - 2
+            ReplaceContent("Different things", "Views", "Shared", "NavMenu.razor");
+            result = await DotnetMSBuild("Build");
+
+            // Assert - 2
+            Assert.FileExists(result, OutputPath, "MvcWithComponents.dll");
+            Assert.NotEqual(outputAssemblyThumbprint, GetThumbPrint(outputFile));
+
+            Assert.FileExists(result, generatedDefinitionFile);
+            Assert.NotEqual(generatedDefinitionThumbprint, GetThumbPrint(generatedDefinitionFile));
+            Assert.FileExists(result, generatedFile);
+            Assert.NotEqual(generatedFileThumbprint, GetThumbPrint(generatedFile));
+
+            Assert.FileExists(result, tagHelperOutputCache);
+            Assert.FileContains(
+                result,
+                tagHelperOutputCache,
+                @"""Name"":""MvcWithComponents.Views.Shared.NavMenu""");
+
+            // TODO:
+            Assert.Equal(definitionThumbprint, GetThumbPrint(tagHelperOutputCache));
+        }
+
+        [Fact]
+        [InitializeTestProject("MvcWithComponents")]
+        public async Task BuildComponents_DoesNotModifyFiles_IfFilesDoNotChange()
+        {
+            // Act - 1
+            var tagHelperOutputCache = Path.Combine(IntermediateOutputPath, "MvcWithComponents.TagHelpers.output.cache");
+
+            var file = Path.Combine(Project.DirectoryPath, "Views", "Shared", "NavMenu.razor.g.cs");
+            var generatedFile = Path.Combine(RazorIntermediateOutputPath, "Views", "Shared", "NavMenu.razor.g.cs");
+            var generatedDefinitionFile = Path.Combine(RazorComponentIntermediateOutputPath, "Views", "Shared", "NavMenu.razor.g.cs");
+
+            // Assert - 1
+            var result = await DotnetMSBuild("Build");
+
+            Assert.BuildPassed(result);
+            var outputFile = Path.Combine(OutputPath, "MvcWithComponents.dll");
+            Assert.FileExists(result, OutputPath, "MvcWithComponents.dll");
+            var outputAssemblyThumbprint = GetThumbPrint(outputFile);
+
+            Assert.FileExists(result, generatedDefinitionFile);
+            var generatedDefinitionThumbprint = GetThumbPrint(generatedDefinitionFile);
+            Assert.FileExists(result, generatedFile);
+            var generatedFileThumbprint = GetThumbPrint(generatedFile);
+
+            Assert.FileExists(result, tagHelperOutputCache);
+            Assert.FileContains(
+                result,
+                tagHelperOutputCache,
+                @"""Name"":""MvcWithComponents.Views.Shared.NavMenu""");
+
+            var definitionThumbprint = GetThumbPrint(tagHelperOutputCache);
+
+            // Act - 2
+            result = await DotnetMSBuild("Build");
+
+            // Assert - 2
+            Assert.FileExists(result, OutputPath, "MvcWithComponents.dll");
+            Assert.Equal(outputAssemblyThumbprint, GetThumbPrint(outputFile));
+
+            Assert.FileExists(result, generatedDefinitionFile);
+            Assert.Equal(generatedDefinitionThumbprint, GetThumbPrint(generatedDefinitionFile));
+            Assert.FileExists(result, generatedFile);
+            Assert.Equal(generatedFileThumbprint, GetThumbPrint(generatedFile));
+
+            Assert.FileExists(result, tagHelperOutputCache);
+            Assert.FileContains(
+                result,
+                tagHelperOutputCache,
+                @"""Name"":""MvcWithComponents.Views.Shared.NavMenu""");
+
+            Assert.Equal(definitionThumbprint, GetThumbPrint(tagHelperOutputCache));
+        }
+
         [Fact]
         [InitializeTestProject("AppWithP2PReference", additionalProjects: "ClassLibrary")]
         public async Task IncrementalBuild_WithP2P_WorksWhenBuildProjectReferencesIsDisabled()

test/Microsoft.NET.Sdk.Razor.Test/IntegrationTests/BuildIntrospectionTest.cs

@@ -33,7 +33,7 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
             var result = await DotnetMSBuild("Build", "/t:_IntrospectRazorCompileItems");
 
             Assert.BuildPassed(result);
-            Assert.BuildOutputContainsLine(result, $"RazorCompile: {Path.Combine(IntermediateOutputPath, "Razor", "Views", "Home", "Index.g.cshtml.cs")}");
+            Assert.BuildOutputContainsLine(result, $"RazorCompile: {Path.Combine(IntermediateOutputPath, "Razor", "Views", "Home", "Index.cshtml.g.cs")}");
             Assert.BuildOutputContainsLine(result, $"RazorCompile: {Path.Combine(IntermediateOutputPath, "SimpleMvc.RazorTargetAssemblyInfo.cs")}");
         }
 

test/Microsoft.NET.Sdk.Razor.Test/IntegrationTests/BuildPerformanceTest.cs

@@ -0,0 +1,109 @@
+// 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.Linq;
+using System.Text.RegularExpressions;
+using System.Threading.Tasks;
+using Xunit;
+
+namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
+{
+    public class BuildPerformanceTest : MSBuildIntegrationTestBase, IClassFixture<BuildServerTestFixture>
+    {
+        public BuildPerformanceTest(BuildServerTestFixture buildServer)
+            : base(buildServer)
+        {
+        }
+
+        [Fact]
+        [InitializeTestProject("SimpleMvc")]
+        public async Task BuildMvcApp()
+        {
+            var result = await DotnetMSBuild(target: default, args: "/clp:PerformanceSummary");
+
+            Assert.BuildPassed(result);
+            var summary = ParseTaskPerformanceSummary(result.Output);
+
+            Assert.Equal(1, summary.First(f => f.Name == "RazorGenerate").Calls);
+            Assert.Equal(1, summary.First(f => f.Name == "RazorTagHelper").Calls);
+
+            // Incremental builds
+            for (var i = 0; i < 2; i++)
+            {
+                result = await DotnetMSBuild(target: default, args: "/clp:PerformanceSummary");
+
+                Assert.BuildPassed(result);
+                summary = ParseTaskPerformanceSummary(result.Output);
+
+                Assert.DoesNotContain(summary, item => item.Name == "RazorGenerate");
+                Assert.DoesNotContain(summary, item => item.Name == "RazorTagHelper");
+            }
+        }
+
+        [Fact]
+        [InitializeTestProject("MvcWithComponents")]
+        public async Task BuildMvcAppWithComponents()
+        {
+            var result = await DotnetMSBuild(target: default, args: "/clp:PerformanceSummary");
+
+            Assert.BuildPassed(result);
+            var summary = ParseTaskPerformanceSummary(result.Output);
+
+            // One for declaration build, one for the "real" code gen
+            Assert.Equal(2, summary.First(f => f.Name == "RazorGenerate").Calls);
+            Assert.Equal(1, summary.First(f => f.Name == "RazorTagHelper").Calls);
+
+            // Incremental builds
+            for (var i = 0; i < 2; i++)
+            {
+                result = await DotnetMSBuild(target: default, args: "/clp:PerformanceSummary");
+
+                Assert.BuildPassed(result);
+                summary = ParseTaskPerformanceSummary(result.Output);
+
+                Assert.DoesNotContain(summary, item => item.Name == "RazorGenerate");
+                Assert.DoesNotContain(summary, item => item.Name == "RazorTagHelper");
+            }
+        }
+
+        private List<PerformanceSummaryEntry> ParseTaskPerformanceSummary(string output)
+        {
+            const string Header = "Task Performance Summary:";
+            var lines = output.Split(Environment.NewLine);
+            var taskSection = Array.LastIndexOf(lines, Header);
+            Assert.True(taskSection != -1, $"Could not find line ${Header} in {output}");
+
+            var entries = new List<PerformanceSummaryEntry>();
+            // 6 ms  FindAppConfigFile                          4 calls
+            var matcher = new Regex(@"\s+(?<time>\w+) ms\s+(?<name>\w+)\s+(?<calls>\d+) calls");
+            for (var i = taskSection + 1; i < lines.Length; i++)
+            {
+                if (string.IsNullOrWhiteSpace(lines[i]))
+                {
+                    continue;
+                }
+
+                var match = matcher.Match(lines[i]);
+                Assert.True(match.Success, $"Line {lines[i]} did not match.");
+
+                var entry = new PerformanceSummaryEntry
+                {
+                    Name = match.Groups["name"].Value,
+                    Calls = int.Parse(match.Groups["calls"].Value),
+                };
+                entries.Add(entry);
+            }
+
+            return entries;
+        }
+
+        private class PerformanceSummaryEntry
+        {
+            public string Name { get; set; }
+
+            public int Calls { get; set; }
+        }
+    }
+}

test/Microsoft.NET.Sdk.Razor.Test/IntegrationTests/BuildServerIntegrationTest.cs

@@ -3,14 +3,10 @@
 
 using System.Diagnostics;
 using System.IO;
-using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Razor.Language;
-using Microsoft.AspNetCore.Razor.Tools;
 using Microsoft.AspNetCore.Testing;
 using Microsoft.AspNetCore.Testing.xunit;
-using Microsoft.CodeAnalysis;
-using Moq;
 using Xunit;
 
 namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
@@ -92,7 +88,7 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
 
             Assert.FileExists(result, IntermediateOutputPath, "Whitespace in name.Views.dll");
             Assert.FileExists(result, IntermediateOutputPath, "Whitespace in name.RazorCoreGenerate.cache");
-            Assert.FileExists(result, RazorIntermediateOutputPath, "Views", "Home", "Index.g.cshtml.cs");
+            Assert.FileExists(result, RazorIntermediateOutputPath, "Views", "Home", "Index.cshtml.g.cs");
         }
 
         [Fact]
@@ -230,6 +226,35 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
             }
         }
 
+        [Fact]
+        [InitializeTestProject("MvcWithComponents")]
+        public async Task Build_MvcWithComponents()
+        {
+            var tagHelperOutputCacheFile = Path.Combine(IntermediateOutputPath, "MvcWithComponents.TagHelpers.output.cache");
+
+            var result = await DotnetMSBuild(
+                "Build",
+                "/p:_RazorForceBuildServer=true");
+
+            Assert.BuildPassed(result);
+            Assert.FileExists(result, OutputPath, "MvcWithComponents.dll");
+            Assert.FileExists(result, OutputPath, "MvcWithComponents.pdb");
+            Assert.FileExists(result, OutputPath, "MvcWithComponents.Views.dll");
+            Assert.FileExists(result, OutputPath, "MvcWithComponents.Views.pdb");
+
+            // Verify tag helper discovery from components work
+            Assert.FileExists(result, tagHelperOutputCacheFile);
+            Assert.FileContains(
+                result,
+                tagHelperOutputCacheFile,
+                @"""Name"":""MvcWithComponents.TestComponent""");
+
+            Assert.FileContains(
+                result,
+                tagHelperOutputCacheFile,
+                @"""Name"":""MvcWithComponents.Views.Shared.NavMenu""");
+        }
+
         private class TestProjectDirectory : ProjectDirectory
         {
             public TestProjectDirectory(string solutionPath, string directoryPath, string projectFilePath)

test/Microsoft.NET.Sdk.Razor.Test/IntegrationTests/BuildWithComponentsIntegrationTest.cs

@@ -0,0 +1,41 @@
+// 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.IO;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Testing.xunit;
+using Xunit;
+
+namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
+{
+    public class BuildWithComponentsIntegrationTest : MSBuildIntegrationTestBase, IClassFixture<BuildServerTestFixture>
+    {
+        public BuildWithComponentsIntegrationTest(BuildServerTestFixture buildServer)
+            : base(buildServer)
+        {
+        }
+
+        [Fact]
+        [InitializeTestProject("MvcWithComponents")]
+        public Task Build_Components_WithDotNetCoreMSBuild_Works() => Build_ComponentsWorks(MSBuildProcessKind.Dotnet);
+
+        [ConditionalFact]
+        [OSSkipCondition(OperatingSystems.Linux | OperatingSystems.MacOSX)]
+        [InitializeTestProject("MvcWithComponents")]
+        public Task Build_Components_WithDesktopMSBuild_Works() => Build_ComponentsWorks(MSBuildProcessKind.Desktop);
+
+        private async Task Build_ComponentsWorks(MSBuildProcessKind msBuildProcessKind)
+        {
+            var result = await DotnetMSBuild("Build", msBuildProcessKind: msBuildProcessKind);
+
+            Assert.BuildPassed(result);
+            Assert.FileExists(result, OutputPath, "MvcWithComponents.dll");
+            Assert.FileExists(result, OutputPath, "MvcWithComponents.pdb");
+            Assert.FileExists(result, OutputPath, "MvcWithComponents.Views.dll");
+            Assert.FileExists(result, OutputPath, "MvcWithComponents.Views.pdb");
+
+            Assert.AssemblyContainsType(result, Path.Combine(OutputPath, "MvcWithComponents.dll"), "MvcWithComponents.TestComponent");
+            Assert.AssemblyContainsType(result, Path.Combine(OutputPath, "MvcWithComponents.dll"), "MvcWithComponents.Views.Shared.NavMenu");
+        }
+    }
+}

test/Microsoft.NET.Sdk.Razor.Test/IntegrationTests/DesignTimeBuildIntegrationTest.cs

@@ -61,7 +61,7 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
             {
                 Assert.BuildOutputContainsLine(
                     result,
-                    $@"RazorGenerateWithTargetPath: {filePath} {filePath} {Path.Combine(RazorIntermediateOutputPath, Path.ChangeExtension(filePath, ".g.cshtml.cs"))}");
+                    $@"RazorGenerateWithTargetPath: {filePath} {filePath} {Path.Combine(RazorIntermediateOutputPath, filePath + ".g.cs")}");
             }
         }
     }

test/Microsoft.NET.Sdk.Razor.Test/IntegrationTests/MSBuildIntegrationTestBase.cs

@@ -44,6 +44,8 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
 
         protected string RazorIntermediateOutputPath => Path.Combine(IntermediateOutputPath, "Razor");
 
+        protected string RazorComponentIntermediateOutputPath => Path.Combine(IntermediateOutputPath, "RazorDeclaration");
+
         internal static string TargetFramework
         {
             get => _projectTfm.Value;

test/Microsoft.NET.Sdk.Razor.Test/IntegrationTests/RazorGenerateIntegrationTest.cs

@@ -38,15 +38,15 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
                 Path.Combine(IntermediateOutputPath, "SimpleMvc.TagHelpers.output.cache"),
                 @"""Name"":""SimpleMvc.SimpleTagHelper""");
 
-            Assert.FileExists(result, RazorIntermediateOutputPath, "Views", "_ViewImports.g.cshtml.cs");
+            Assert.FileExists(result, RazorIntermediateOutputPath, "Views", "_ViewImports.cshtml.g.cs");
-            Assert.FileExists(result, RazorIntermediateOutputPath, "Views", "_ViewStart.g.cshtml.cs");
+            Assert.FileExists(result, RazorIntermediateOutputPath, "Views", "_ViewStart.cshtml.g.cs");
-            Assert.FileExists(result, RazorIntermediateOutputPath, "Views", "Home", "About.g.cshtml.cs");
+            Assert.FileExists(result, RazorIntermediateOutputPath, "Views", "Home", "About.cshtml.g.cs");
-            Assert.FileExists(result, RazorIntermediateOutputPath, "Views", "Home", "Contact.g.cshtml.cs");
+            Assert.FileExists(result, RazorIntermediateOutputPath, "Views", "Home", "Contact.cshtml.g.cs");
-            Assert.FileExists(result, RazorIntermediateOutputPath, "Views", "Home", "Index.g.cshtml.cs");
+            Assert.FileExists(result, RazorIntermediateOutputPath, "Views", "Home", "Index.cshtml.g.cs");
-            Assert.FileExists(result, RazorIntermediateOutputPath, "Views", "Shared", "_Layout.g.cshtml.cs");
+            Assert.FileExists(result, RazorIntermediateOutputPath, "Views", "Shared", "_Layout.cshtml.g.cs");
-            Assert.FileExists(result, RazorIntermediateOutputPath, "Views", "Shared", "_ValidationScriptsPartial.g.cshtml.cs");
+            Assert.FileExists(result, RazorIntermediateOutputPath, "Views", "Shared", "_ValidationScriptsPartial.cshtml.g.cs");
-            Assert.FileExists(result, RazorIntermediateOutputPath, "Views", "Shared", "Error.g.cshtml.cs");
+            Assert.FileExists(result, RazorIntermediateOutputPath, "Views", "Shared", "Error.cshtml.g.cs");
-            Assert.FileCountEquals(result, 8, RazorIntermediateOutputPath, "*.g.cshtml.cs");
+            Assert.FileCountEquals(result, 8, RazorIntermediateOutputPath, "*.cshtml.g.cs");
         }
 
         [Fact]
@@ -68,7 +68,7 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
             Assert.FileDoesNotExist(result, IntermediateOutputPath, "SimpleMvc.Views.dll");
 
             // If there's a parser error, the generated file contents is likely incorrect. The file should not be written to disk.
-            Assert.FileDoesNotExist(result, RazorIntermediateOutputPath, "Views", "Home", "Index.g.cshtml.cs");
+            Assert.FileDoesNotExist(result, RazorIntermediateOutputPath, "Views", "Home", "Index.cshtml.g.cs");
         }
 
         [Fact]
@@ -96,7 +96,7 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
         {
             // Act - 1
             var result = await DotnetMSBuild(RazorGenerateTarget);
-            var generatedFile = Path.Combine(Project.DirectoryPath, RazorIntermediateOutputPath, "Views", "Home", "About.g.cshtml.cs");
+            var generatedFile = Path.Combine(Project.DirectoryPath, RazorIntermediateOutputPath, "Views", "Home", "About.cshtml.g.cs");
 
             // Assert - 1
             Assert.BuildPassed(result);
@@ -123,7 +123,7 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
             // Act - 1
             var result = await DotnetMSBuild(RazorGenerateTarget);
             var file = Path.Combine(Project.DirectoryPath, "Views", "Home", "Contact.cshtml");
-            var generatedFile = Path.Combine(RazorIntermediateOutputPath, "Views", "Home", "Contact.g.cshtml.cs");
+            var generatedFile = Path.Combine(RazorIntermediateOutputPath, "Views", "Home", "Contact.cshtml.g.cs");
 
             // Assert - 1
             Assert.BuildPassed(result);
@@ -146,7 +146,7 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
         {
             // Act - 1
             var result = await DotnetMSBuild(RazorGenerateTarget);
-            var file = Path.Combine(Project.DirectoryPath, RazorIntermediateOutputPath, "Views", "Home", "About.g.cshtml.cs");
+            var file = Path.Combine(Project.DirectoryPath, RazorIntermediateOutputPath, "Views", "Home", "About.cshtml.g.cs");
 
             // Assert - 1
             Assert.BuildPassed(result);
@@ -169,7 +169,7 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
             var result = await DotnetMSBuild(RazorGenerateTarget);
             var file = Path.Combine(Project.DirectoryPath, "Views", "Home", "Index.cshtml");
             var renamed = Path.Combine(Project.DirectoryPath, "Views", "Home", "NewIndex.cshtml");
-            var generated = Path.Combine(RazorIntermediateOutputPath, "Views", "Home", "Index.g.cshtml.cs");
+            var generated = Path.Combine(RazorIntermediateOutputPath, "Views", "Home", "Index.cshtml.g.cs");
 
             // Assert - 1
             Assert.BuildPassed(result);
@@ -182,7 +182,7 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
 
             // Assert - 2
             Assert.BuildPassed(result);
-            Assert.FileExists(result, RazorIntermediateOutputPath, "Views", "Home", "NewIndex.g.cshtml.cs");
+            Assert.FileExists(result, RazorIntermediateOutputPath, "Views", "Home", "NewIndex.cshtml.g.cs");
             Assert.FileDoesNotExist(result, generated);
         }
 
@@ -193,7 +193,7 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
             // Act - 1
             var result = await DotnetMSBuild(RazorGenerateTarget);
             var file = Path.Combine(Project.DirectoryPath, "Views", "Home", "Index.cshtml");
-            var generatedFile = Path.Combine(RazorIntermediateOutputPath, "Views", "Home", "Index.g.cshtml.cs");
+            var generatedFile = Path.Combine(RazorIntermediateOutputPath, "Views", "Home", "Index.cshtml.g.cs");
 
             // Assert - 1
             Assert.BuildPassed(result);
@@ -225,7 +225,7 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
             // We shouldn't need to hash the files
             Assert.FileDoesNotExist(result, Path.Combine(IntermediateOutputPath, "SimpleMvc.RazorCoreGenerate.cache"));
 
-            Assert.FileCountEquals(result, 0, RazorIntermediateOutputPath, "*.g.cshtml.cs");
+            Assert.FileCountEquals(result, 0, RazorIntermediateOutputPath, "*.cshtml.g.cs");
         }
 
         [Fact]
@@ -243,8 +243,8 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
 
             Assert.BuildPassed(result);
 
-            Assert.FileExists(result, RazorIntermediateOutputPath, "Views", "Home", "About.g.cshtml.cs");
+            Assert.FileExists(result, RazorIntermediateOutputPath, "Views", "Home", "About.cshtml.g.cs");
-            Assert.FileCountEquals(result, 1, RazorIntermediateOutputPath, "*.g.cshtml.cs");
+            Assert.FileCountEquals(result, 1, RazorIntermediateOutputPath, "*.cshtml.g.cs");
         }
 
         [Fact]
@@ -265,8 +265,8 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
 
             Assert.BuildPassed(result);
 
-            Assert.FileExists(result, RazorIntermediateOutputPath, "Views", "Home", "About.g.cshtml.cs");
+            Assert.FileExists(result, RazorIntermediateOutputPath, "Views", "Home", "About.cshtml.g.cs");
-            Assert.FileCountEquals(result, 1, RazorIntermediateOutputPath, "*.g.cshtml.cs");
+            Assert.FileCountEquals(result, 1, RazorIntermediateOutputPath, "*.cshtml.g.cs");
         }
 
         [Fact]
@@ -287,13 +287,13 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
 
             Assert.BuildPassed(result);
 
-            Assert.FileExists(result, RazorIntermediateOutputPath, "LinkedFile.g.cshtml.cs");
+            Assert.FileExists(result, RazorIntermediateOutputPath, "LinkedFile.cshtml.g.cs");
-            Assert.FileExists(result, RazorIntermediateOutputPath, "LinkedFileOut", "LinkedFile2.g.cshtml.cs");
+            Assert.FileExists(result, RazorIntermediateOutputPath, "LinkedFileOut", "LinkedFile2.cshtml.g.cs");
-            Assert.FileExists(result, RazorIntermediateOutputPath, "LinkedFileOut", "LinkedFileWithRename.g.cshtml.cs");
+            Assert.FileExists(result, RazorIntermediateOutputPath, "LinkedFileOut", "LinkedFileWithRename.cshtml.g.cs");
 
-            Assert.BuildOutputContainsLine(result, $@"RazorGenerateWithTargetPath: {Path.Combine("..", "LinkedDir", "LinkedFile.cshtml")} LinkedFile.cshtml {Path.Combine(RazorIntermediateOutputPath, "LinkedFile.g.cshtml.cs")}");
+            Assert.BuildOutputContainsLine(result, $@"RazorGenerateWithTargetPath: {Path.Combine("..", "LinkedDir", "LinkedFile.cshtml")} LinkedFile.cshtml {Path.Combine(RazorIntermediateOutputPath, "LinkedFile.cshtml.g.cs")}");
-            Assert.BuildOutputContainsLine(result, $@"RazorGenerateWithTargetPath: {Path.Combine("..", "LinkedDir", "LinkedFile2.cshtml")} LinkedFileOut\LinkedFile2.cshtml {Path.Combine(RazorIntermediateOutputPath, "LinkedFileOut", "LinkedFile2.g.cshtml.cs")}");
+            Assert.BuildOutputContainsLine(result, $@"RazorGenerateWithTargetPath: {Path.Combine("..", "LinkedDir", "LinkedFile2.cshtml")} LinkedFileOut\LinkedFile2.cshtml {Path.Combine(RazorIntermediateOutputPath, "LinkedFileOut", "LinkedFile2.cshtml.g.cs")}");
-            Assert.BuildOutputContainsLine(result, $@"RazorGenerateWithTargetPath: {Path.Combine("..", "LinkedDir", "LinkedFile3.cshtml")} LinkedFileOut\LinkedFileWithRename.cshtml {Path.Combine(RazorIntermediateOutputPath, "LinkedFileOut", "LinkedFileWithRename.g.cshtml.cs")}");
+            Assert.BuildOutputContainsLine(result, $@"RazorGenerateWithTargetPath: {Path.Combine("..", "LinkedDir", "LinkedFile3.cshtml")} LinkedFileOut\LinkedFileWithRename.cshtml {Path.Combine(RazorIntermediateOutputPath, "LinkedFileOut", "LinkedFileWithRename.cshtml.g.cs")}");
         }
 
         [Fact]
@@ -342,17 +342,17 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
             Assert.FileExists(result, IntermediateOutputPath, "SimpleMvc.dll");
             Assert.FileDoesNotExist(result, IntermediateOutputPath, "SimpleMvc.Views.dll");
 
-            Assert.FileExists(result, RazorIntermediateOutputPath, "Views", "_ViewImports.g.cshtml.cs");
+            Assert.FileExists(result, RazorIntermediateOutputPath, "Views", "_ViewImports.cshtml.g.cs");
-            Assert.FileExists(result, RazorIntermediateOutputPath, "Views", "_ViewStart.g.cshtml.cs");
+            Assert.FileExists(result, RazorIntermediateOutputPath, "Views", "_ViewStart.cshtml.g.cs");
-            Assert.FileExists(result, RazorIntermediateOutputPath, "Views", "Home", "About.g.cshtml.cs");
+            Assert.FileExists(result, RazorIntermediateOutputPath, "Views", "Home", "About.cshtml.g.cs");
-            Assert.FileExists(result, RazorIntermediateOutputPath, "Views", "Home", "Contact.g.cshtml.cs");
+            Assert.FileExists(result, RazorIntermediateOutputPath, "Views", "Home", "Contact.cshtml.g.cs");
-            Assert.FileExists(result, RazorIntermediateOutputPath, "Views", "Home", "Index.g.cshtml.cs");
+            Assert.FileExists(result, RazorIntermediateOutputPath, "Views", "Home", "Index.cshtml.g.cs");
-            Assert.FileExists(result, RazorIntermediateOutputPath, "Views", "Shared", "_Layout.g.cshtml.cs");
+            Assert.FileExists(result, RazorIntermediateOutputPath, "Views", "Shared", "_Layout.cshtml.g.cs");
-            Assert.FileExists(result, RazorIntermediateOutputPath, "Views", "Shared", "_ValidationScriptsPartial.g.cshtml.cs");
+            Assert.FileExists(result, RazorIntermediateOutputPath, "Views", "Shared", "_ValidationScriptsPartial.cshtml.g.cs");
-            Assert.FileExists(result, RazorIntermediateOutputPath, "Views", "Shared", "Error.g.cshtml.cs");
+            Assert.FileExists(result, RazorIntermediateOutputPath, "Views", "Shared", "Error.cshtml.g.cs");
-            Assert.FileExists(result, RazorIntermediateOutputPath, "temp.g.cshtml.cs");
+            Assert.FileExists(result, RazorIntermediateOutputPath, "temp.cshtml.g.cs");
-            Assert.FileCountEquals(result, 9, RazorIntermediateOutputPath, "*.g.cshtml.cs");
+            Assert.FileCountEquals(result, 9, RazorIntermediateOutputPath, "*.cshtml.g.cs");
-            Assert.BuildOutputContainsLine(result, $@"RazorGenerateWithTargetPath: {filePath} temp.cshtml {Path.Combine(RazorIntermediateOutputPath, "temp.g.cshtml.cs")}");
+            Assert.BuildOutputContainsLine(result, $@"RazorGenerateWithTargetPath: {filePath} temp.cshtml {Path.Combine(RazorIntermediateOutputPath, "temp.cshtml.g.cs")}");
         }
     }
 }

test/testapps/AppWithP2PReference/AppWithP2PReference.csproj

@@ -23,7 +23,6 @@
     <!-- In test scenarios $(BinariesRoot) is defined in a generated Directory.Build.props file -->
     <ProjectReference Include="..\..\Microsoft.AspNetCore.Razor.Test.MvcShim.ClassLib\Microsoft.AspNetCore.Razor.Test.MvcShim.ClassLib.csproj"/>
     <ProjectReference Include="..\..\..\src\Microsoft.AspNetCore.Razor.Runtime\Microsoft.AspNetCore.Razor.Runtime.csproj"/>
-    <ProjectReference Include="..\..\..\src\Microsoft.AspNetCore.Razor.Design\Microsoft.AspNetCore.Razor.Design.csproj" ReferenceOutputAssembly="false" />
   </ItemGroup>
 
   <ItemGroup Condition="'$(BinariesRoot)'!=''">

test/testapps/ClassLibrary/ClassLibrary.csproj

@@ -26,7 +26,6 @@
     <!-- In test scenarios $(BinariesRoot) is defined in a generated Directory.Build.props file -->
     <ProjectReference Include="..\..\Microsoft.AspNetCore.Razor.Test.MvcShim.ClassLib\Microsoft.AspNetCore.Razor.Test.MvcShim.ClassLib.csproj"/>
     <ProjectReference Include="..\..\..\src\Microsoft.AspNetCore.Razor.Runtime\Microsoft.AspNetCore.Razor.Runtime.csproj"/>
-    <ProjectReference Include="..\..\..\src\Microsoft.AspNetCore.Razor.Design\Microsoft.AspNetCore.Razor.Design.csproj" ReferenceOutputAssembly="false" />
   </ItemGroup>
 
   <ItemGroup Condition="'$(BinariesRoot)'!=''">

test/testapps/ClassLibrary2/ClassLibrary2.csproj

@@ -25,7 +25,6 @@
     <!-- In test scenarios $(BinariesRoot) is defined in a generated Directory.Build.props file -->
     <ProjectReference Include="..\..\Microsoft.AspNetCore.Razor.Test.MvcShim.ClassLib\Microsoft.AspNetCore.Razor.Test.MvcShim.ClassLib.csproj"/>
     <ProjectReference Include="..\..\..\src\Microsoft.AspNetCore.Razor.Runtime\Microsoft.AspNetCore.Razor.Runtime.csproj"/>
-    <ProjectReference Include="..\..\..\src\Microsoft.AspNetCore.Razor.Design\Microsoft.AspNetCore.Razor.Design.csproj" ReferenceOutputAssembly="false" />
   </ItemGroup>
 
   <ItemGroup Condition="'$(BinariesRoot)'!=''">

test/testapps/LargeProject/LargeProject.csproj

@@ -17,7 +17,6 @@
     <!-- In test scenarios $(BinariesRoot) is defined in a generated Directory.Build.props file -->
     <ProjectReference Include="..\..\Microsoft.AspNetCore.Razor.Test.MvcShim.ClassLib\Microsoft.AspNetCore.Razor.Test.MvcShim.ClassLib.csproj"/>
     <ProjectReference Include="..\..\..\src\Microsoft.AspNetCore.Razor.Runtime\Microsoft.AspNetCore.Razor.Runtime.csproj"/>
-    <ProjectReference Include="..\..\..\src\Microsoft.AspNetCore.Razor.Design\Microsoft.AspNetCore.Razor.Design.csproj" ReferenceOutputAssembly="false" />
   </ItemGroup>
 
   <ItemGroup Condition="'$(BinariesRoot)'!=''">

test/testapps/MvcWithComponents/Models/ErrorViewModel.cs

@@ -0,0 +1,11 @@
+using System;
+
+namespace MvcWithComponents.Models
+{
+    public class ErrorViewModel
+    {
+        public string RequestId { get; set; }
+
+        public bool ShowRequestId => !string.IsNullOrEmpty(RequestId);
+    }
+}

test/testapps/MvcWithComponents/MvcWithComponents.csproj

@@ -0,0 +1,31 @@
+<Project Sdk="Microsoft.NET.Sdk.Web">
+
+  <PropertyGroup>
+    <RazorSdkDirectoryRoot>$(RazorSdkProjectDirectory)bin\$(Configuration)\sdk-output\</RazorSdkDirectoryRoot>
+  </PropertyGroup>
+
+  <PropertyGroup>
+    <TargetFramework>netcoreapp3.0</TargetFramework>
+  </PropertyGroup>
+
+  <PropertyGroup Condition="'$(RunningAsTest)' == ''">
+    <!-- We don't want to run build server when not running as tests. -->
+    <UseRazorBuildServer>false</UseRazorBuildServer>
+  </PropertyGroup>
+
+  <ItemGroup Condition="'$(BinariesRoot)'==''">
+    <!-- In test scenarios $(BinariesRoot) is defined in a generated Directory.Build.props file -->
+    <ProjectReference Include="..\..\Microsoft.AspNetCore.Razor.Test.MvcShim.ClassLib\Microsoft.AspNetCore.Razor.Test.MvcShim.ClassLib.csproj"/>
+    <ProjectReference Include="..\..\..\src\Microsoft.AspNetCore.Razor.Runtime\Microsoft.AspNetCore.Razor.Runtime.csproj"/>
+  </ItemGroup>
+
+  <ItemGroup Condition="'$(BinariesRoot)'!=''">
+    <Reference Include="$(BinariesRoot)\Microsoft.AspNetCore.Html.Abstractions.dll"/>
+    <Reference Include="$(BinariesRoot)\Microsoft.AspNetCore.Razor.dll"/>
+    <Reference Include="$(BinariesRoot)\Microsoft.AspNetCore.Razor.Runtime.dll"/>
+    <Reference Include="$(BinariesRoot)\Microsoft.AspNetCore.Razor.Test.MvcShim.ClassLib.dll"/>
+  </ItemGroup>
+
+  <!-- Test Placeholder -->
+
+</Project>

test/testapps/MvcWithComponents/Program.cs

@@ -0,0 +1,13 @@
+
+namespace MvcWithComponents
+{
+    public class Program
+    {
+        public static void Main(string[] args)
+        {
+            // Just make sure we have a reference to the MvcShim
+            var t = typeof(Microsoft.AspNetCore.Mvc.IActionResult);
+            System.Console.WriteLine(t.FullName);
+        }
+    }
+}

test/testapps/MvcWithComponents/TestComponent.razor

@@ -0,0 +1 @@
+Hello from component

test/testapps/MvcWithComponents/Views/Home/Index.cshtml

@@ -0,0 +1,5 @@
+@{
+    ViewData["Title"] = "Home Page";
+}
+
+Hello world!

test/testapps/MvcWithComponents/Views/Shared/NavMenu.razor

@@ -0,0 +1,2 @@
+NavMenu content
+

test/testapps/MvcWithComponents/Views/_ViewImports.cshtml

@@ -0,0 +1,3 @@
+@using MvcWithComponents
+@using MvcWithComponents.Models
+@addTagHelper *, Microsoft.AspNetCore.Mvc.TagHelpers

test/testapps/MvcWithComponents/Views/_ViewStart.cshtml

@@ -0,0 +1,3 @@
+@{
+    Layout = "_Layout";
+}

test/testapps/SimpleMvcFSharp/SimpleMvcFSharp.fsproj

@@ -22,7 +22,6 @@
     <!-- In test scenarios $(BinariesRoot) is defined in a generated Directory.Build.props file -->
     <ProjectReference Include="..\..\Microsoft.AspNetCore.Razor.Test.MvcShim.ClassLib\Microsoft.AspNetCore.Razor.Test.MvcShim.ClassLib.csproj"/>
     <ProjectReference Include="..\..\..\src\Microsoft.AspNetCore.Razor.Runtime\Microsoft.AspNetCore.Razor.Runtime.csproj"/>
-    <ProjectReference Include="..\..\..\src\Microsoft.AspNetCore.Razor.Design\Microsoft.AspNetCore.Razor.Design.csproj" ReferenceOutputAssembly="false" />
   </ItemGroup>
 
   <ItemGroup Condition="'$(BinariesRoot)'!=''">

test/testapps/SimplePages/SimplePages.csproj

@@ -17,7 +17,6 @@
     <!-- In test scenarios $(BinariesRoot) is defined in a generated Directory.Build.props file -->
     <ProjectReference Include="..\..\Microsoft.AspNetCore.Razor.Test.MvcShim.ClassLib\Microsoft.AspNetCore.Razor.Test.MvcShim.ClassLib.csproj"/>
     <ProjectReference Include="..\..\..\src\Microsoft.AspNetCore.Razor.Runtime\Microsoft.AspNetCore.Razor.Runtime.csproj"/>
-    <ProjectReference Include="..\..\..\src\Microsoft.AspNetCore.Razor.Design\Microsoft.AspNetCore.Razor.Design.csproj" ReferenceOutputAssembly="false" />
   </ItemGroup>
 
   <ItemGroup Condition="'$(BinariesRoot)'!=''">