diff --git a/src/Components/Components/ref/Microsoft.AspNetCore.Components.netcoreapp.cs b/src/Components/Components/ref/Microsoft.AspNetCore.Components.netcoreapp.cs
index 1ee9bf558a..b6c4f834e2 100644
--- a/src/Components/Components/ref/Microsoft.AspNetCore.Components.netcoreapp.cs
+++ b/src/Components/Components/ref/Microsoft.AspNetCore.Components.netcoreapp.cs
@@ -407,6 +407,7 @@ namespace Microsoft.AspNetCore.Components.Rendering
     {
         public RenderTreeBuilder() { }
         public void AddAttribute(int sequence, in Microsoft.AspNetCore.Components.RenderTree.RenderTreeFrame frame) { }
+        public void AddAttribute(int sequence, string name) { }
         public void AddAttribute(int sequence, string name, Microsoft.AspNetCore.Components.EventCallback value) { }
         public void AddAttribute(int sequence, string name, bool value) { }
         public void AddAttribute(int sequence, string name, System.MulticastDelegate? value) { }
diff --git a/src/Components/Components/src/Rendering/RenderTreeBuilder.cs b/src/Components/Components/src/Rendering/RenderTreeBuilder.cs
index 224fc55ff9..4e9280c70f 100644
--- a/src/Components/Components/src/Rendering/RenderTreeBuilder.cs
+++ b/src/Components/Components/src/Rendering/RenderTreeBuilder.cs
@@ -157,6 +157,29 @@ namespace Microsoft.AspNetCore.Components.Rendering
         public void AddContent(int sequence, object? textContent)
             => AddContent(sequence, textContent?.ToString());
 
+        /// <summary>
+        /// <para>
+        /// Appends a frame representing a bool-valued attribute with value 'true'.
+        /// </para>
+        /// <para>
+        /// The attribute is associated with the most recently added element.
+        /// </para>
+        /// </summary>
+        /// <param name="sequence">An integer that represents the position of the instruction in the source code.</param>
+        /// <param name="name">The name of the attribute.</param>
+        public void AddAttribute(int sequence, string name)
+        {
+            ProfilingStart();
+
+            if (_lastNonAttributeFrameType != RenderTreeFrameType.Element)
+            {
+                throw new InvalidOperationException($"Valueless attributes may only be added immediately after frames of type {RenderTreeFrameType.Element}");
+            }
+
+            Append(RenderTreeFrame.Attribute(sequence, name, BoxedTrue));
+            ProfilingEnd();
+        }
+
         /// <summary>
         /// <para>
         /// Appends a frame representing a bool-valued attribute.
diff --git a/src/Razor/Microsoft.AspNetCore.Razor.Language/src/Components/ComponentCssScopePass.cs b/src/Razor/Microsoft.AspNetCore.Razor.Language/src/Components/ComponentCssScopePass.cs
new file mode 100644
index 0000000000..9192f23e69
--- /dev/null
+++ b/src/Razor/Microsoft.AspNetCore.Razor.Language/src/Components/ComponentCssScopePass.cs
@@ -0,0 +1,46 @@
+// 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.Components
+{
+    internal class ComponentCssScopePass : ComponentIntermediateNodePassBase, IRazorOptimizationPass
+    {
+        // Runs after components/bind, since it's preferable for the auto-generated attribute to appear later
+        // in the DOM than developer-written ones
+        public override int Order => 110;
+
+        protected override void ExecuteCore(RazorCodeDocument codeDocument, DocumentIntermediateNode documentNode)
+        {
+            if (!IsComponentDocument(documentNode))
+            {
+                return;
+            }
+
+            var cssScope = codeDocument.GetCssScope();
+            if (string.IsNullOrEmpty(cssScope))
+            {
+                return;
+            }
+
+            var nodes = documentNode.FindDescendantNodes<MarkupElementIntermediateNode>();
+            for (var i = 0; i < nodes.Count; i++)
+            {
+                ProcessElement(nodes[i], cssScope);
+            }
+        }
+
+        private void ProcessElement(MarkupElementIntermediateNode node, string cssScope)
+        {
+            // Add a minimized attribute whose name is simply the CSS scope
+            node.Children.Add(new HtmlAttributeIntermediateNode
+            {
+                AttributeName = cssScope,
+                Prefix = cssScope,
+                Suffix = string.Empty,
+            });
+        }
+    }
+}
diff --git a/src/Razor/Microsoft.AspNetCore.Razor.Language/src/Components/ComponentDesignTimeNodeWriter.cs b/src/Razor/Microsoft.AspNetCore.Razor.Language/src/Components/ComponentDesignTimeNodeWriter.cs
index c1e0c625f6..4e2cd831ef 100644
--- a/src/Razor/Microsoft.AspNetCore.Razor.Language/src/Components/ComponentDesignTimeNodeWriter.cs
+++ b/src/Razor/Microsoft.AspNetCore.Razor.Language/src/Components/ComponentDesignTimeNodeWriter.cs
@@ -316,8 +316,7 @@ namespace Microsoft.AspNetCore.Razor.Language.Components
                 .WriteStartMethodInvocation($"{_scopeStack.BuilderVarName}.{nameof(ComponentsApi.RenderTreeBuilder.AddAttribute)}")
                 .Write("-1")
                 .WriteParameterSeparator()
-                .WriteStringLiteral(key)
-                .WriteParameterSeparator();
+                .WriteStringLiteral(key);
         }
 
         protected override void BeginWriteAttribute(CodeRenderingContext context, IntermediateNode expression)
@@ -341,8 +340,6 @@ namespace Microsoft.AspNetCore.Razor.Language.Components
             {
                 context.CodeWriter.Write(tokens[i].Content);
             }
-
-            context.CodeWriter.WriteParameterSeparator();
         }
 
         public override void WriteComponent(CodeRenderingContext context, ComponentIntermediateNode node)
@@ -731,6 +728,7 @@ namespace Microsoft.AspNetCore.Razor.Language.Components
             // OR
             // __builder.AddAttribute(1, "ChildContent", (RenderFragment<Person>)((person) => (__builder73) => { ... }));
             BeginWriteAttribute(context, node.AttributeName);
+            context.CodeWriter.WriteParameterSeparator();
             context.CodeWriter.Write($"({node.TypeName})(");
 
             WriteComponentChildContentInnards(context, node);
diff --git a/src/Razor/Microsoft.AspNetCore.Razor.Language/src/Components/ComponentRuntimeNodeWriter.cs b/src/Razor/Microsoft.AspNetCore.Razor.Language/src/Components/ComponentRuntimeNodeWriter.cs
index b57552e5e6..93df99a41e 100644
--- a/src/Razor/Microsoft.AspNetCore.Razor.Language/src/Components/ComponentRuntimeNodeWriter.cs
+++ b/src/Razor/Microsoft.AspNetCore.Razor.Language/src/Components/ComponentRuntimeNodeWriter.cs
@@ -673,6 +673,7 @@ namespace Microsoft.AspNetCore.Razor.Language.Components
             // OR
             // _builder.AddAttribute(1, "ChildContent", (RenderFragment<Person>)((person) => (__builder73) => { ... }));
             BeginWriteAttribute(context, node.AttributeName);
+            context.CodeWriter.WriteParameterSeparator();
             context.CodeWriter.Write($"({node.TypeName})(");
 
             WriteComponentChildContentInnards(context, node);
@@ -851,14 +852,22 @@ namespace Microsoft.AspNetCore.Razor.Language.Components
         private void WriteAttribute(CodeRenderingContext context, string key, IList<IntermediateToken> value)
         {
             BeginWriteAttribute(context, key);
-            WriteAttributeValue(context, value);
+            if (value.Count > 0)
+            {
+                context.CodeWriter.WriteParameterSeparator();
+                WriteAttributeValue(context, value);
+            }
             context.CodeWriter.WriteEndMethodInvocation();
         }
 
         private void WriteAttribute(CodeRenderingContext context, IntermediateNode nameExpression, IList<IntermediateToken> value)
         {
             BeginWriteAttribute(context, nameExpression);
-            WriteAttributeValue(context, value);
+            if (value.Count > 0)
+            {
+                context.CodeWriter.WriteParameterSeparator();
+                WriteAttributeValue(context, value);
+            }
             context.CodeWriter.WriteEndMethodInvocation();
         }
 
@@ -868,8 +877,7 @@ namespace Microsoft.AspNetCore.Razor.Language.Components
                 .WriteStartMethodInvocation($"{_scopeStack.BuilderVarName}.{ComponentsApi.RenderTreeBuilder.AddAttribute}")
                 .Write((_sourceSequence++).ToString())
                 .WriteParameterSeparator()
-                .WriteStringLiteral(key)
-                .WriteParameterSeparator();
+                .WriteStringLiteral(key);
         }
 
         protected override void BeginWriteAttribute(CodeRenderingContext context, IntermediateNode nameExpression)
@@ -883,8 +891,6 @@ namespace Microsoft.AspNetCore.Razor.Language.Components
             {
                 WriteCSharpToken(context, tokens[i]);
             }
-
-            context.CodeWriter.WriteParameterSeparator();
         }
 
         private static string GetHtmlContent(HtmlContentIntermediateNode node)
@@ -988,8 +994,7 @@ namespace Microsoft.AspNetCore.Razor.Language.Components
             }
             else
             {
-                // Minimized attributes always map to 'true'
-                writer.Write("true");
+                throw new InvalidOperationException("Found attribute whose value is neither HTML nor CSharp");
             }
         }
 
diff --git a/src/Razor/Microsoft.AspNetCore.Razor.Language/src/DefaultRazorProjectEngine.cs b/src/Razor/Microsoft.AspNetCore.Razor.Language/src/DefaultRazorProjectEngine.cs
index c8fc4f6f9b..a11e63cc90 100644
--- a/src/Razor/Microsoft.AspNetCore.Razor.Language/src/DefaultRazorProjectEngine.cs
+++ b/src/Razor/Microsoft.AspNetCore.Razor.Language/src/DefaultRazorProjectEngine.cs
@@ -85,7 +85,7 @@ namespace Microsoft.AspNetCore.Razor.Language
             }
 
             var importSourceDocuments = GetImportSourceDocuments(importItems);
-            return CreateCodeDocumentCore(sourceDocument, projectItem.FileKind, importSourceDocuments, tagHelpers: null, configureParser, configureCodeGeneration);
+            return CreateCodeDocumentCore(sourceDocument, projectItem.FileKind, importSourceDocuments, tagHelpers: null, configureParser, configureCodeGeneration, cssScope: projectItem.CssScope);
         }
 
         protected internal RazorCodeDocument CreateCodeDocumentCore(
@@ -94,7 +94,8 @@ namespace Microsoft.AspNetCore.Razor.Language
             IReadOnlyList<RazorSourceDocument> importSourceDocuments = null, 
             IReadOnlyList<TagHelperDescriptor> tagHelpers = null,
             Action<RazorParserOptionsBuilder> configureParser = null,
-            Action<RazorCodeGenerationOptionsBuilder> configureCodeGeneration = null)
+            Action<RazorCodeGenerationOptionsBuilder> configureCodeGeneration = null,
+            string cssScope = null)
         {
             if (sourceDocument == null)
             {
@@ -122,6 +123,11 @@ namespace Microsoft.AspNetCore.Razor.Language
                 codeDocument.SetFileKind(fileKind);
             }
 
+            if (cssScope != null)
+            {
+                codeDocument.SetCssScope(cssScope);
+            }
+
             return codeDocument;
         }
 
diff --git a/src/Razor/Microsoft.AspNetCore.Razor.Language/src/DefaultRazorProjectFileSystem.cs b/src/Razor/Microsoft.AspNetCore.Razor.Language/src/DefaultRazorProjectFileSystem.cs
index c80f43307b..de7f34f5cd 100644
--- a/src/Razor/Microsoft.AspNetCore.Razor.Language/src/DefaultRazorProjectFileSystem.cs
+++ b/src/Razor/Microsoft.AspNetCore.Razor.Language/src/DefaultRazorProjectFileSystem.cs
@@ -40,7 +40,7 @@ namespace Microsoft.AspNetCore.Razor.Language
                     var relativePhysicalPath = file.FullName.Substring(absoluteBasePath.Length + 1); // Include leading separator
                     var filePath = "/" + relativePhysicalPath.Replace(Path.DirectorySeparatorChar, '/');
 
-                    return new DefaultRazorProjectItem(basePath, filePath, relativePhysicalPath, fileKind: null, file);
+                    return new DefaultRazorProjectItem(basePath, filePath, relativePhysicalPath, fileKind: null, file, cssScope: null);
                 });
         }
 
@@ -58,7 +58,7 @@ namespace Microsoft.AspNetCore.Razor.Language
             var relativePhysicalPath = file.FullName.Substring(absoluteBasePath.Length + 1); // Include leading separator
             var filePath = "/" + relativePhysicalPath.Replace(Path.DirectorySeparatorChar, '/');
 
-            return new DefaultRazorProjectItem("/", filePath, relativePhysicalPath, fileKind, new FileInfo(absolutePath));
+            return new DefaultRazorProjectItem("/", filePath, relativePhysicalPath, fileKind, new FileInfo(absolutePath), cssScope: null);
         }
 
         [Obsolete("Use GetItem(string path, string fileKind) instead.")]
diff --git a/src/Razor/Microsoft.AspNetCore.Razor.Language/src/DefaultRazorProjectItem.cs b/src/Razor/Microsoft.AspNetCore.Razor.Language/src/DefaultRazorProjectItem.cs
index 082ed4666a..5dc5100238 100644
--- a/src/Razor/Microsoft.AspNetCore.Razor.Language/src/DefaultRazorProjectItem.cs
+++ b/src/Razor/Microsoft.AspNetCore.Razor.Language/src/DefaultRazorProjectItem.cs
@@ -17,13 +17,15 @@ namespace Microsoft.AspNetCore.Razor.Language
         /// <param name="filePath">The path.</param>
         /// <param name="fileKind">The file kind. If null, the document kind will be inferred from the file extension.</param>
         /// <param name="file">The <see cref="FileInfo"/>.</param>
-        public DefaultRazorProjectItem(string basePath, string filePath, string relativePhysicalPath, string fileKind, FileInfo file)
+        /// <param name="cssScope">A scope identifier that will be used on elements in the generated class, or null.</param>
+        public DefaultRazorProjectItem(string basePath, string filePath, string relativePhysicalPath, string fileKind, FileInfo file, string cssScope)
         {
             BasePath = basePath;
             FilePath = filePath;
             RelativePhysicalPath = relativePhysicalPath;
             _fileKind = fileKind;
             File = file;
+            CssScope = cssScope;
         }
 
         public FileInfo File { get; }
@@ -40,6 +42,8 @@ namespace Microsoft.AspNetCore.Razor.Language
 
         public override string FileKind => _fileKind ?? base.FileKind;
 
+        public override string CssScope { get; }
+
         public override Stream Read() => new FileStream(PhysicalPath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite | FileShare.Delete);
     }
 }
\ No newline at end of file
diff --git a/src/Razor/Microsoft.AspNetCore.Razor.Language/src/RazorCodeDocumentExtensions.cs b/src/Razor/Microsoft.AspNetCore.Razor.Language/src/RazorCodeDocumentExtensions.cs
index 6d22aa5f27..df6240e2e5 100644
--- a/src/Razor/Microsoft.AspNetCore.Razor.Language/src/RazorCodeDocumentExtensions.cs
+++ b/src/Razor/Microsoft.AspNetCore.Razor.Language/src/RazorCodeDocumentExtensions.cs
@@ -14,6 +14,7 @@ namespace Microsoft.AspNetCore.Razor.Language
     {
         private static readonly char[] PathSeparators = new char[] { '/', '\\' };
         private static readonly char[] NamespaceSeparators = new char[] { '.' };
+        private static object CssScopeKey = new object();
 
         public static TagHelperDocumentContext GetTagHelperContext(this RazorCodeDocument document)
         {
@@ -216,6 +217,26 @@ namespace Microsoft.AspNetCore.Razor.Language
             document.Items[typeof(FileKinds)] = fileKind;
         }
 
+        public static string GetCssScope(this RazorCodeDocument document)
+        {
+            if (document == null)
+            {
+                throw new ArgumentNullException(nameof(document));
+            }
+
+            return (string)document.Items[CssScopeKey];
+        }
+
+        public static void SetCssScope(this RazorCodeDocument document, string cssScope)
+        {
+            if (document == null)
+            {
+                throw new ArgumentNullException(nameof(document));
+            }
+
+            document.Items[CssScopeKey] = cssScope;
+        }
+
         // In general documents will have a relative path (relative to the project root).
         // We can only really compute a nice namespace when we know a relative path.
         //
diff --git a/src/Razor/Microsoft.AspNetCore.Razor.Language/src/RazorProjectEngine.cs b/src/Razor/Microsoft.AspNetCore.Razor.Language/src/RazorProjectEngine.cs
index ac75eac6d1..1d664e8028 100644
--- a/src/Razor/Microsoft.AspNetCore.Razor.Language/src/RazorProjectEngine.cs
+++ b/src/Razor/Microsoft.AspNetCore.Razor.Language/src/RazorProjectEngine.cs
@@ -238,6 +238,7 @@ namespace Microsoft.AspNetCore.Razor.Language
             builder.Features.Add(new ComponentReferenceCaptureLoweringPass());
             builder.Features.Add(new ComponentSplatLoweringPass());
             builder.Features.Add(new ComponentBindLoweringPass());
+            builder.Features.Add(new ComponentCssScopePass());
             builder.Features.Add(new ComponentTemplateDiagnosticPass());
             builder.Features.Add(new ComponentGenericTypePass());
             builder.Features.Add(new ComponentChildContentDiagnosticPass());
diff --git a/src/Razor/Microsoft.AspNetCore.Razor.Language/src/RazorProjectItem.cs b/src/Razor/Microsoft.AspNetCore.Razor.Language/src/RazorProjectItem.cs
index 5ee33824d5..6c245de893 100644
--- a/src/Razor/Microsoft.AspNetCore.Razor.Language/src/RazorProjectItem.cs
+++ b/src/Razor/Microsoft.AspNetCore.Razor.Language/src/RazorProjectItem.cs
@@ -35,6 +35,11 @@ namespace Microsoft.AspNetCore.Razor.Language
         /// </summary>
         public virtual string RelativePhysicalPath => null;
 
+        /// <summary>
+        /// A scope identifier that will be used on elements in the generated class, or null.
+        /// </summary>
+        public virtual string CssScope { get; }
+
         /// <summary>
         /// Gets the document kind that should be used for the generated document. If possible this will be inferred from the file path. May be null.
         /// </summary>
diff --git a/src/Razor/Microsoft.AspNetCore.Razor.Language/test/DefaultRazorProjectItemTest.cs b/src/Razor/Microsoft.AspNetCore.Razor.Language/test/DefaultRazorProjectItemTest.cs
index f903b16f63..f302becbea 100644
--- a/src/Razor/Microsoft.AspNetCore.Razor.Language/test/DefaultRazorProjectItemTest.cs
+++ b/src/Razor/Microsoft.AspNetCore.Razor.Language/test/DefaultRazorProjectItemTest.cs
@@ -20,7 +20,7 @@ namespace Microsoft.AspNetCore.Razor.Language
             var fileInfo = new FileInfo(Path.Combine(TestFolder, "Home.cshtml"));
 
             // Act
-            var projectItem = new DefaultRazorProjectItem("/", "/Home.cshtml", "Home.cshtml", "test", fileInfo);
+            var projectItem = new DefaultRazorProjectItem("/", "/Home.cshtml", "Home.cshtml", "test", fileInfo, "MyCssScope");
 
             // Assert
             Assert.Equal("/Home.cshtml", projectItem.FilePath);
@@ -30,6 +30,7 @@ namespace Microsoft.AspNetCore.Razor.Language
             Assert.Equal("test", projectItem.FileKind);
             Assert.Equal(fileInfo.FullName, projectItem.PhysicalPath);
             Assert.Equal("Home.cshtml", projectItem.RelativePhysicalPath);
+            Assert.Equal("MyCssScope", projectItem.CssScope);
         }
 
         [Fact]
@@ -39,7 +40,7 @@ namespace Microsoft.AspNetCore.Razor.Language
             var fileInfo = new FileInfo(Path.Combine(TestFolder, "Home.cshtml"));
 
             // Act
-            var projectItem = new DefaultRazorProjectItem("/", "/Home.razor", "Home.cshtml", fileKind: null, fileInfo);
+            var projectItem = new DefaultRazorProjectItem("/", "/Home.razor", "Home.cshtml", fileKind: null, fileInfo, cssScope: null);
 
             // Assert
             Assert.Equal(FileKinds.Component, projectItem.FileKind);
@@ -52,7 +53,7 @@ namespace Microsoft.AspNetCore.Razor.Language
             var fileInfo = new FileInfo(Path.Combine(TestFolder, "Home.cshtml"));
 
             // Act
-            var projectItem = new DefaultRazorProjectItem("/", "/Home.cshtml", "Home.cshtml", fileKind: null, fileInfo);
+            var projectItem = new DefaultRazorProjectItem("/", "/Home.cshtml", "Home.cshtml", fileKind: null, fileInfo, cssScope: null);
 
             // Assert
             Assert.Equal(FileKinds.Legacy, projectItem.FileKind);
@@ -65,7 +66,7 @@ namespace Microsoft.AspNetCore.Razor.Language
             var fileInfo = new FileInfo(Path.Combine(TestFolder, "Home.cshtml"));
 
             // Act
-            var projectItem = new DefaultRazorProjectItem("/", filePath: null, "Home.cshtml", fileKind: null, fileInfo);
+            var projectItem = new DefaultRazorProjectItem("/", filePath: null, "Home.cshtml", fileKind: null, fileInfo, cssScope: null);
 
             // Assert
             Assert.Null(projectItem.FileKind);
@@ -78,7 +79,7 @@ namespace Microsoft.AspNetCore.Razor.Language
             var fileInfo = new FileInfo(Path.Combine(TestFolder, "Views", "FileDoesNotExist.cshtml"));
 
             // Act
-            var projectItem = new DefaultRazorProjectItem("/Views", "/FileDoesNotExist.cshtml", Path.Combine("Views", "FileDoesNotExist.cshtml"), "test", fileInfo);
+            var projectItem = new DefaultRazorProjectItem("/Views", "/FileDoesNotExist.cshtml", Path.Combine("Views", "FileDoesNotExist.cshtml"), "test", fileInfo, cssScope: null);
 
             // Assert
             Assert.False(projectItem.Exists);
@@ -89,7 +90,7 @@ namespace Microsoft.AspNetCore.Razor.Language
         {
             // Arrange
             var fileInfo = new FileInfo(Path.Combine(TestFolder, "Home.cshtml"));
-            var projectItem = new DefaultRazorProjectItem("/", "/Home.cshtml", "Home.cshtml", "test", fileInfo);
+            var projectItem = new DefaultRazorProjectItem("/", "/Home.cshtml", "Home.cshtml", "test", fileInfo, cssScope: null);
 
             // Act
             var stream = projectItem.Read();
diff --git a/src/Razor/Microsoft.AspNetCore.Razor.Language/test/IntegrationTests/ComponentCodeGenerationTestBase.cs b/src/Razor/Microsoft.AspNetCore.Razor.Language/test/IntegrationTests/ComponentCodeGenerationTestBase.cs
index d7d135b9b1..0308fe46c4 100644
--- a/src/Razor/Microsoft.AspNetCore.Razor.Language/test/IntegrationTests/ComponentCodeGenerationTestBase.cs
+++ b/src/Razor/Microsoft.AspNetCore.Razor.Language/test/IntegrationTests/ComponentCodeGenerationTestBase.cs
@@ -4929,6 +4929,69 @@ namespace New.Test
 
         #endregion
 
+        #region "CSS scoping"
+        [Fact]
+        public void Component_WithCssScope()
+        {
+            // Arrange
+            AdditionalSyntaxTrees.Add(Parse(@"
+using Microsoft.AspNetCore.Components;
+
+namespace Test
+{
+    public class TemplatedComponent : ComponentBase
+    {
+        [Parameter]
+        public RenderFragment ChildContent { get; set; }
+    }
+}
+"));
+
+            // Act
+            // This test case attempts to use all syntaxes that might interact with auto-generated attributes
+            var generated = CompileToCSharp(@"
+@using Microsoft.AspNetCore.Components.Web
+@using Microsoft.AspNetCore.Components.Rendering
+<h1>Element with no attributes</h1>
+<parent with-attributes=""yes"" with-csharp-attribute-value=""@(123)"">
+    <child />
+    <child has multiple attributes=""some with values"">With text</child>
+    <TemplatedComponent @ref=""myComponentReference"">
+        <span id=""hello"">This is in child content</span>
+    </TemplatedComponent>
+</parent>
+@if (DateTime.Now.Year > 1950)
+{
+    <with-ref-capture some-attr @ref=""myElementReference"">Content</with-ref-capture>
+    <input id=""myElem"" @bind=""myVariable"" another-attr=""Another attr value"" />
+}
+
+@code {
+    ElementReference myElementReference;
+    TemplatedComponent myComponentReference;
+    string myVariable;
+
+    void MethodRenderingMarkup(RenderTreeBuilder __builder)
+    {
+        for (var i = 0; i < 10; i++)
+        {
+            <li data-index=@i>Something @i</li>
+        }
+
+        System.GC.KeepAlive(myElementReference);
+        System.GC.KeepAlive(myComponentReference);
+        System.GC.KeepAlive(myVariable);
+    }
+}
+", cssScope: "TestCssScope");
+
+            // Assert
+            AssertDocumentNodeMatchesBaseline(generated.CodeDocument);
+            AssertCSharpDocumentMatchesBaseline(generated.CodeDocument);
+            CompileToAssembly(generated);
+        }
+        #endregion
+
         #region Misc
 
         [Fact] // We don't process <!DOCTYPE ...> - we just skip them
diff --git a/src/Razor/Microsoft.AspNetCore.Razor.Language/test/RazorProjectEngineTest.cs b/src/Razor/Microsoft.AspNetCore.Razor.Language/test/RazorProjectEngineTest.cs
index c9fa4504cd..d483472fa4 100644
--- a/src/Razor/Microsoft.AspNetCore.Razor.Language/test/RazorProjectEngineTest.cs
+++ b/src/Razor/Microsoft.AspNetCore.Razor.Language/test/RazorProjectEngineTest.cs
@@ -49,6 +49,7 @@ namespace Microsoft.AspNetCore.Razor.Language
                 feature => Assert.IsType<ComponentBindLoweringPass>(feature),
                 feature => Assert.IsType<ComponentChildContentDiagnosticPass>(feature),
                 feature => Assert.IsType<ComponentComplexAttributeContentPass>(feature),
+                feature => Assert.IsType<ComponentCssScopePass>(feature),
                 feature => Assert.IsType<ComponentDocumentClassifierPass>(feature),
                 feature => Assert.IsType<ComponentEventHandlerLoweringPass>(feature),
                 feature => Assert.IsType<ComponentGenericTypePass>(feature),
diff --git a/src/Razor/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/Component_WithCssScope/TestComponent.codegen.cs b/src/Razor/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/Component_WithCssScope/TestComponent.codegen.cs
new file mode 100644
index 0000000000..95b48f43d9
--- /dev/null
+++ b/src/Razor/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/Component_WithCssScope/TestComponent.codegen.cs
@@ -0,0 +1,148 @@
+// <auto-generated/>
+#pragma warning disable 1591
+namespace Test
+{
+    #line hidden
+    using System;
+    using System.Collections.Generic;
+    using System.Linq;
+    using System.Threading.Tasks;
+    using Microsoft.AspNetCore.Components;
+#nullable restore
+#line 1 "x:\dir\subdir\Test\TestComponent.cshtml"
+using Microsoft.AspNetCore.Components.Web;
+
+#line default
+#line hidden
+#nullable disable
+#nullable restore
+#line 2 "x:\dir\subdir\Test\TestComponent.cshtml"
+using Microsoft.AspNetCore.Components.Rendering;
+
+#line default
+#line hidden
+#nullable disable
+    public partial class TestComponent : Microsoft.AspNetCore.Components.ComponentBase
+    {
+        #pragma warning disable 219
+        private void __RazorDirectiveTokenHelpers__() {
+        }
+        #pragma warning restore 219
+        #pragma warning disable 0414
+        private static System.Object __o = null;
+        #pragma warning restore 0414
+        #pragma warning disable 1998
+        protected override void BuildRenderTree(Microsoft.AspNetCore.Components.Rendering.RenderTreeBuilder __builder)
+        {
+            __o = 
+#nullable restore
+#line 4 "x:\dir\subdir\Test\TestComponent.cshtml"
+                                                             123
+
+#line default
+#line hidden
+#nullable disable
+            ;
+            __builder.AddAttribute(-1, "ChildContent", (Microsoft.AspNetCore.Components.RenderFragment)((__builder2) => {
+            }
+            ));
+#nullable restore
+#line 7 "x:\dir\subdir\Test\TestComponent.cshtml"
+                              myComponentReference = default(Test.TemplatedComponent);
+
+#line default
+#line hidden
+#nullable disable
+#nullable restore
+#line 7 "x:\dir\subdir\Test\TestComponent.cshtml"
+__o = typeof(TemplatedComponent);
+
+#line default
+#line hidden
+#nullable disable
+#nullable restore
+#line 11 "x:\dir\subdir\Test\TestComponent.cshtml"
+ if (DateTime.Now.Year > 1950)
+{
+    
+
+#line default
+#line hidden
+#nullable disable
+#nullable restore
+#line 13 "x:\dir\subdir\Test\TestComponent.cshtml"
+                                      myElementReference = default(Microsoft.AspNetCore.Components.ElementReference);
+
+#line default
+#line hidden
+#nullable disable
+                                                                                                
+    
+            __o = Microsoft.AspNetCore.Components.BindConverter.FormatValue(
+#nullable restore
+#line 14 "x:\dir\subdir\Test\TestComponent.cshtml"
+                              myVariable
+
+#line default
+#line hidden
+#nullable disable
+            );
+            __o = Microsoft.AspNetCore.Components.EventCallback.Factory.CreateBinder(this, __value => myVariable = __value, myVariable);
+#nullable restore
+#line 14 "x:\dir\subdir\Test\TestComponent.cshtml"
+                                                                              
+}
+
+#line default
+#line hidden
+#nullable disable
+        }
+        #pragma warning restore 1998
+#nullable restore
+#line 17 "x:\dir\subdir\Test\TestComponent.cshtml"
+       
+    ElementReference myElementReference;
+    TemplatedComponent myComponentReference;
+    string myVariable;
+
+    void MethodRenderingMarkup(RenderTreeBuilder __builder)
+    {
+        for (var i = 0; i < 10; i++)
+        {
+            
+
+#line default
+#line hidden
+#nullable disable
+        __o = 
+#nullable restore
+#line 26 "x:\dir\subdir\Test\TestComponent.cshtml"
+                            i
+
+#line default
+#line hidden
+#nullable disable
+        ;
+#nullable restore
+#line 26 "x:\dir\subdir\Test\TestComponent.cshtml"
+                                   __o = i;
+
+#line default
+#line hidden
+#nullable disable
+#nullable restore
+#line 26 "x:\dir\subdir\Test\TestComponent.cshtml"
+                                               
+        }
+
+        System.GC.KeepAlive(myElementReference);
+        System.GC.KeepAlive(myComponentReference);
+        System.GC.KeepAlive(myVariable);
+    }
+
+#line default
+#line hidden
+#nullable disable
+    }
+}
+#pragma warning restore 1591
diff --git a/src/Razor/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/Component_WithCssScope/TestComponent.ir.txt b/src/Razor/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/Component_WithCssScope/TestComponent.ir.txt
new file mode 100644
index 0000000000..0d679be1f3
--- /dev/null
+++ b/src/Razor/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/Component_WithCssScope/TestComponent.ir.txt
@@ -0,0 +1,114 @@
+Document - 
+    NamespaceDeclaration -  - Test
+        UsingDirective - (3:1,1 [12] ) - System
+        UsingDirective - (18:2,1 [32] ) - System.Collections.Generic
+        UsingDirective - (53:3,1 [17] ) - System.Linq
+        UsingDirective - (73:4,1 [28] ) - System.Threading.Tasks
+        UsingDirective - (104:5,1 [37] ) - Microsoft.AspNetCore.Components
+        UsingDirective - (1:0,1 [41] x:\dir\subdir\Test\TestComponent.cshtml) - Microsoft.AspNetCore.Components.Web
+        UsingDirective - (45:1,1 [47] x:\dir\subdir\Test\TestComponent.cshtml) - Microsoft.AspNetCore.Components.Rendering
+        ClassDeclaration -  - public partial - TestComponent - Microsoft.AspNetCore.Components.ComponentBase - 
+            DesignTimeDirective - 
+            CSharpCode - 
+                IntermediateToken -  - CSharp - #pragma warning disable 0414
+            CSharpCode - 
+                IntermediateToken -  - CSharp - private static System.Object __o = null;
+            CSharpCode - 
+                IntermediateToken -  - CSharp - #pragma warning restore 0414
+            MethodDeclaration -  - protected override - void - BuildRenderTree
+                HtmlContent - (42:0,42 [2] x:\dir\subdir\Test\TestComponent.cshtml)
+                    LazyIntermediateToken - (42:0,42 [2] x:\dir\subdir\Test\TestComponent.cshtml) - Html - \n
+                HtmlContent - (92:1,48 [2] x:\dir\subdir\Test\TestComponent.cshtml)
+                    LazyIntermediateToken - (92:1,48 [2] x:\dir\subdir\Test\TestComponent.cshtml) - Html - \n
+                MarkupElement - (94:2,0 [35] x:\dir\subdir\Test\TestComponent.cshtml) - h1
+                    HtmlContent - (98:2,4 [26] x:\dir\subdir\Test\TestComponent.cshtml)
+                        LazyIntermediateToken - (98:2,4 [26] x:\dir\subdir\Test\TestComponent.cshtml) - Html - Element with no attributes
+                HtmlContent - (129:2,35 [2] x:\dir\subdir\Test\TestComponent.cshtml)
+                    LazyIntermediateToken - (129:2,35 [2] x:\dir\subdir\Test\TestComponent.cshtml) - Html - \n
+                MarkupElement - (131:3,0 [305] x:\dir\subdir\Test\TestComponent.cshtml) - parent
+                    HtmlAttribute - (138:3,7 [22] x:\dir\subdir\Test\TestComponent.cshtml) -  with-attributes=" - "
+                        HtmlAttributeValue - (156:3,25 [3] x:\dir\subdir\Test\TestComponent.cshtml) - 
+                            LazyIntermediateToken - (156:3,25 [3] x:\dir\subdir\Test\TestComponent.cshtml) - Html - yes
+                    HtmlAttribute - (160:3,29 [37] x:\dir\subdir\Test\TestComponent.cshtml) -  with-csharp-attribute-value=" - "
+                        CSharpExpressionAttributeValue - (190:3,59 [6] x:\dir\subdir\Test\TestComponent.cshtml) - 
+                            LazyIntermediateToken - (192:3,61 [3] x:\dir\subdir\Test\TestComponent.cshtml) - CSharp - 123
+                    HtmlContent - (198:3,67 [6] x:\dir\subdir\Test\TestComponent.cshtml)
+                        LazyIntermediateToken - (198:3,67 [6] x:\dir\subdir\Test\TestComponent.cshtml) - Html - \n    
+                    MarkupElement - (204:4,4 [9] x:\dir\subdir\Test\TestComponent.cshtml) - child
+                    HtmlContent - (213:4,13 [6] x:\dir\subdir\Test\TestComponent.cshtml)
+                        LazyIntermediateToken - (213:4,13 [6] x:\dir\subdir\Test\TestComponent.cshtml) - Html - \n    
+                    MarkupElement - (219:5,4 [67] x:\dir\subdir\Test\TestComponent.cshtml) - child
+                        HtmlAttribute - (225:5,10 [4] x:\dir\subdir\Test\TestComponent.cshtml) -  has - 
+                        HtmlAttribute - (229:5,14 [9] x:\dir\subdir\Test\TestComponent.cshtml) -  multiple - 
+                        HtmlAttribute - (238:5,23 [30] x:\dir\subdir\Test\TestComponent.cshtml) -  attributes=" - "
+                            HtmlAttributeValue - (251:5,36 [4] x:\dir\subdir\Test\TestComponent.cshtml) - 
+                                LazyIntermediateToken - (251:5,36 [4] x:\dir\subdir\Test\TestComponent.cshtml) - Html - some
+                            HtmlAttributeValue - (255:5,40 [5] x:\dir\subdir\Test\TestComponent.cshtml) -  
+                                LazyIntermediateToken - (256:5,41 [4] x:\dir\subdir\Test\TestComponent.cshtml) - Html - with
+                            HtmlAttributeValue - (260:5,45 [7] x:\dir\subdir\Test\TestComponent.cshtml) -  
+                                LazyIntermediateToken - (261:5,46 [6] x:\dir\subdir\Test\TestComponent.cshtml) - Html - values
+                        HtmlContent - (269:5,54 [9] x:\dir\subdir\Test\TestComponent.cshtml)
+                            LazyIntermediateToken - (269:5,54 [9] x:\dir\subdir\Test\TestComponent.cshtml) - Html - With text
+                    HtmlContent - (286:5,71 [6] x:\dir\subdir\Test\TestComponent.cshtml)
+                        LazyIntermediateToken - (286:5,71 [6] x:\dir\subdir\Test\TestComponent.cshtml) - Html - \n    
+                    Component - (292:6,4 [133] x:\dir\subdir\Test\TestComponent.cshtml) - TemplatedComponent
+                        ComponentChildContent -  - ChildContent - context
+                            HtmlContent - (340:6,52 [10] x:\dir\subdir\Test\TestComponent.cshtml)
+                                LazyIntermediateToken - (340:6,52 [10] x:\dir\subdir\Test\TestComponent.cshtml) - Html - \n        
+                            MarkupElement - (350:7,8 [48] x:\dir\subdir\Test\TestComponent.cshtml) - span
+                                HtmlAttribute - (355:7,13 [11] x:\dir\subdir\Test\TestComponent.cshtml) -  id=" - "
+                                    HtmlAttributeValue - (360:7,18 [5] x:\dir\subdir\Test\TestComponent.cshtml) - 
+                                        LazyIntermediateToken - (360:7,18 [5] x:\dir\subdir\Test\TestComponent.cshtml) - Html - hello
+                                HtmlContent - (367:7,25 [24] x:\dir\subdir\Test\TestComponent.cshtml)
+                                    LazyIntermediateToken - (367:7,25 [24] x:\dir\subdir\Test\TestComponent.cshtml) - Html - This is in child content
+                            HtmlContent - (398:7,56 [6] x:\dir\subdir\Test\TestComponent.cshtml)
+                                LazyIntermediateToken - (398:7,56 [6] x:\dir\subdir\Test\TestComponent.cshtml) - Html - \n    
+                        ReferenceCapture - (318:6,30 [20] x:\dir\subdir\Test\TestComponent.cshtml) - myComponentReference
+                    HtmlContent - (425:8,25 [2] x:\dir\subdir\Test\TestComponent.cshtml)
+                        LazyIntermediateToken - (425:8,25 [2] x:\dir\subdir\Test\TestComponent.cshtml) - Html - \n
+                HtmlContent - (436:9,9 [2] x:\dir\subdir\Test\TestComponent.cshtml)
+                    LazyIntermediateToken - (436:9,9 [2] x:\dir\subdir\Test\TestComponent.cshtml) - Html - \n
+                CSharpCode - (439:10,1 [38] x:\dir\subdir\Test\TestComponent.cshtml)
+                    LazyIntermediateToken - (439:10,1 [38] x:\dir\subdir\Test\TestComponent.cshtml) - CSharp - if (DateTime.Now.Year > 1950)\n{\n    
+                MarkupElement - (477:12,4 [80] x:\dir\subdir\Test\TestComponent.cshtml) - with-ref-capture
+                    HtmlContent - (531:12,58 [7] x:\dir\subdir\Test\TestComponent.cshtml)
+                        LazyIntermediateToken - (531:12,58 [7] x:\dir\subdir\Test\TestComponent.cshtml) - Html - Content
+                    HtmlAttribute -  - some-attr - 
+                    ReferenceCapture - (511:12,38 [18] x:\dir\subdir\Test\TestComponent.cshtml) - myElementReference
+                CSharpCode - (557:12,84 [6] x:\dir\subdir\Test\TestComponent.cshtml)
+                    LazyIntermediateToken - (557:12,84 [6] x:\dir\subdir\Test\TestComponent.cshtml) - CSharp - \n    
+                MarkupElement - (563:13,4 [74] x:\dir\subdir\Test\TestComponent.cshtml) - input
+                    HtmlAttribute -  - id=" - "
+                        HtmlAttributeValue - (574:13,15 [6] x:\dir\subdir\Test\TestComponent.cshtml) - 
+                            LazyIntermediateToken - (574:13,15 [6] x:\dir\subdir\Test\TestComponent.cshtml) - Html - myElem
+                    HtmlAttribute -  - another-attr=" - "
+                        HtmlAttributeValue - (615:13,56 [18] x:\dir\subdir\Test\TestComponent.cshtml) - 
+                            LazyIntermediateToken - (615:13,56 [18] x:\dir\subdir\Test\TestComponent.cshtml) - Html - Another attr value
+                    HtmlAttribute - (589:13,30 [10] x:\dir\subdir\Test\TestComponent.cshtml) - value=" - "
+                        CSharpExpressionAttributeValue -  - 
+                            IntermediateToken -  - CSharp - Microsoft.AspNetCore.Components.BindConverter.FormatValue(
+                            LazyIntermediateToken - (589:13,30 [10] x:\dir\subdir\Test\TestComponent.cshtml) - CSharp - myVariable
+                            IntermediateToken -  - CSharp - )
+                    HtmlAttribute - (589:13,30 [10] x:\dir\subdir\Test\TestComponent.cshtml) - onchange=" - "
+                        CSharpExpressionAttributeValue -  - 
+                            IntermediateToken -  - CSharp - Microsoft.AspNetCore.Components.EventCallback.Factory.CreateBinder(this, __value => myVariable = __value, 
+                            IntermediateToken -  - CSharp - myVariable
+                            IntermediateToken -  - CSharp - )
+                CSharpCode - (637:13,78 [3] x:\dir\subdir\Test\TestComponent.cshtml)
+                    LazyIntermediateToken - (637:13,78 [3] x:\dir\subdir\Test\TestComponent.cshtml) - CSharp - \n}
+                HtmlContent - (640:14,1 [4] x:\dir\subdir\Test\TestComponent.cshtml)
+                    LazyIntermediateToken - (640:14,1 [4] x:\dir\subdir\Test\TestComponent.cshtml) - Html - \n\n
+                HtmlContent - (1098:32,1 [2] x:\dir\subdir\Test\TestComponent.cshtml)
+                    LazyIntermediateToken - (1098:32,1 [2] x:\dir\subdir\Test\TestComponent.cshtml) - Html - \n
+            CSharpCode - (651:16,7 [245] x:\dir\subdir\Test\TestComponent.cshtml)
+                LazyIntermediateToken - (651:16,7 [245] x:\dir\subdir\Test\TestComponent.cshtml) - CSharp - \n    ElementReference myElementReference;\n    TemplatedComponent myComponentReference;\n    string myVariable;\n\n    void MethodRenderingMarkup(RenderTreeBuilder __builder)\n    {\n        for (var i = 0; i < 10; i++)\n        {\n            
+            MarkupElement - (896:25,12 [35] x:\dir\subdir\Test\TestComponent.cshtml) - li
+                HtmlAttribute - (899:25,15 [14] x:\dir\subdir\Test\TestComponent.cshtml) -  data-index= - 
+                    CSharpExpressionAttributeValue - (911:25,27 [2] x:\dir\subdir\Test\TestComponent.cshtml) - 
+                        LazyIntermediateToken - (912:25,28 [1] x:\dir\subdir\Test\TestComponent.cshtml) - CSharp - i
+                HtmlContent - (914:25,30 [10] x:\dir\subdir\Test\TestComponent.cshtml)
+                    LazyIntermediateToken - (914:25,30 [10] x:\dir\subdir\Test\TestComponent.cshtml) - Html - Something 
+                CSharpExpression - (925:25,41 [1] x:\dir\subdir\Test\TestComponent.cshtml)
+                    LazyIntermediateToken - (925:25,41 [1] x:\dir\subdir\Test\TestComponent.cshtml) - CSharp - i
+            CSharpCode - (931:25,47 [166] x:\dir\subdir\Test\TestComponent.cshtml)
+                LazyIntermediateToken - (931:25,47 [166] x:\dir\subdir\Test\TestComponent.cshtml) - CSharp - \n        }\n\n        System.GC.KeepAlive(myElementReference);\n        System.GC.KeepAlive(myComponentReference);\n        System.GC.KeepAlive(myVariable);\n    }\n
diff --git a/src/Razor/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/Component_WithCssScope/TestComponent.mappings.txt b/src/Razor/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/Component_WithCssScope/TestComponent.mappings.txt
new file mode 100644
index 0000000000..f3d9de1293
--- /dev/null
+++ b/src/Razor/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/Component_WithCssScope/TestComponent.mappings.txt
@@ -0,0 +1,105 @@
+Source Location: (1:0,1 [41] x:\dir\subdir\Test\TestComponent.cshtml)
+|using Microsoft.AspNetCore.Components.Web|
+Generated Location: (320:12,0 [41] )
+|using Microsoft.AspNetCore.Components.Web|
+
+Source Location: (45:1,1 [47] x:\dir\subdir\Test\TestComponent.cshtml)
+|using Microsoft.AspNetCore.Components.Rendering|
+Generated Location: (484:19,0 [47] )
+|using Microsoft.AspNetCore.Components.Rendering|
+
+Source Location: (192:3,61 [3] x:\dir\subdir\Test\TestComponent.cshtml)
+|123|
+Generated Location: (1267:39,61 [3] )
+|123|
+
+Source Location: (318:6,30 [20] x:\dir\subdir\Test\TestComponent.cshtml)
+|myComponentReference|
+Generated Location: (1592:50,30 [20] )
+|myComponentReference|
+
+Source Location: (439:10,1 [38] x:\dir\subdir\Test\TestComponent.cshtml)
+|if (DateTime.Now.Year > 1950)
+{
+    |
+Generated Location: (1927:64,1 [38] )
+|if (DateTime.Now.Year > 1950)
+{
+    |
+
+Source Location: (511:12,38 [18] x:\dir\subdir\Test\TestComponent.cshtml)
+|myElementReference|
+Generated Location: (2126:73,38 [18] )
+|myElementReference|
+
+Source Location: (557:12,84 [6] x:\dir\subdir\Test\TestComponent.cshtml)
+|
+    |
+Generated Location: (2353:78,96 [6] )
+|
+    |
+
+Source Location: (589:13,30 [10] x:\dir\subdir\Test\TestComponent.cshtml)
+|myVariable|
+Generated Location: (2540:83,30 [10] )
+|myVariable|
+
+Source Location: (637:13,78 [3] x:\dir\subdir\Test\TestComponent.cshtml)
+|
+}|
+Generated Location: (2905:92,78 [3] )
+|
+}|
+
+Source Location: (651:16,7 [245] x:\dir\subdir\Test\TestComponent.cshtml)
+|
+    ElementReference myElementReference;
+    TemplatedComponent myComponentReference;
+    string myVariable;
+
+    void MethodRenderingMarkup(RenderTreeBuilder __builder)
+    {
+        for (var i = 0; i < 10; i++)
+        {
+            |
+Generated Location: (3087:102,7 [245] )
+|
+    ElementReference myElementReference;
+    TemplatedComponent myComponentReference;
+    string myVariable;
+
+    void MethodRenderingMarkup(RenderTreeBuilder __builder)
+    {
+        for (var i = 0; i < 10; i++)
+        {
+            |
+
+Source Location: (912:25,28 [1] x:\dir\subdir\Test\TestComponent.cshtml)
+|i|
+Generated Location: (3499:119,28 [1] )
+|i|
+
+Source Location: (925:25,41 [1] x:\dir\subdir\Test\TestComponent.cshtml)
+|i|
+Generated Location: (3675:127,41 [1] )
+|i|
+
+Source Location: (931:25,47 [166] x:\dir\subdir\Test\TestComponent.cshtml)
+|
+        }
+
+        System.GC.KeepAlive(myElementReference);
+        System.GC.KeepAlive(myComponentReference);
+        System.GC.KeepAlive(myVariable);
+    }
+|
+Generated Location: (3847:134,47 [166] )
+|
+        }
+
+        System.GC.KeepAlive(myElementReference);
+        System.GC.KeepAlive(myComponentReference);
+        System.GC.KeepAlive(myVariable);
+    }
+|
+
diff --git a/src/Razor/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/Component_WithCssScope/TestComponent.codegen.cs b/src/Razor/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/Component_WithCssScope/TestComponent.codegen.cs
new file mode 100644
index 0000000000..6e2c5dbff4
--- /dev/null
+++ b/src/Razor/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/Component_WithCssScope/TestComponent.codegen.cs
@@ -0,0 +1,162 @@
+// <auto-generated/>
+#pragma warning disable 1591
+namespace Test
+{
+    #line hidden
+    using System;
+    using System.Collections.Generic;
+    using System.Linq;
+    using System.Threading.Tasks;
+    using Microsoft.AspNetCore.Components;
+#nullable restore
+#line 1 "x:\dir\subdir\Test\TestComponent.cshtml"
+using Microsoft.AspNetCore.Components.Web;
+
+#line default
+#line hidden
+#nullable disable
+#nullable restore
+#line 2 "x:\dir\subdir\Test\TestComponent.cshtml"
+using Microsoft.AspNetCore.Components.Rendering;
+
+#line default
+#line hidden
+#nullable disable
+    public partial class TestComponent : Microsoft.AspNetCore.Components.ComponentBase
+    {
+        #pragma warning disable 1998
+        protected override void BuildRenderTree(Microsoft.AspNetCore.Components.Rendering.RenderTreeBuilder __builder)
+        {
+            __builder.AddMarkupContent(0, "<h1 TestCssScope>Element with no attributes</h1>\r\n");
+            __builder.OpenElement(1, "parent");
+            __builder.AddAttribute(2, "with-attributes", "yes");
+            __builder.AddAttribute(3, "with-csharp-attribute-value", 
+#nullable restore
+#line 4 "x:\dir\subdir\Test\TestComponent.cshtml"
+                                                             123
+
+#line default
+#line hidden
+#nullable disable
+            );
+            __builder.AddAttribute(4, "TestCssScope");
+            __builder.AddMarkupContent(5, "<child TestCssScope></child>\r\n    ");
+            __builder.AddMarkupContent(6, "<child has multiple attributes=\"some with values\" TestCssScope>With text</child>\r\n    ");
+            __builder.OpenComponent<Test.TemplatedComponent>(7);
+            __builder.AddAttribute(8, "ChildContent", (Microsoft.AspNetCore.Components.RenderFragment)((__builder2) => {
+                __builder2.AddMarkupContent(9, "<span id=\"hello\" TestCssScope>This is in child content</span>");
+            }
+            ));
+            __builder.AddComponentReferenceCapture(10, (__value) => {
+#nullable restore
+#line 7 "x:\dir\subdir\Test\TestComponent.cshtml"
+                              myComponentReference = (Test.TemplatedComponent)__value;
+
+#line default
+#line hidden
+#nullable disable
+            }
+            );
+            __builder.CloseComponent();
+            __builder.CloseElement();
+#nullable restore
+#line 11 "x:\dir\subdir\Test\TestComponent.cshtml"
+ if (DateTime.Now.Year > 1950)
+{
+
+#line default
+#line hidden
+#nullable disable
+            __builder.OpenElement(11, "with-ref-capture");
+            __builder.AddAttribute(12, "some-attr");
+            __builder.AddAttribute(13, "TestCssScope");
+            __builder.AddElementReferenceCapture(14, (__value) => {
+#nullable restore
+#line 13 "x:\dir\subdir\Test\TestComponent.cshtml"
+                                      myElementReference = __value;
+
+#line default
+#line hidden
+#nullable disable
+            }
+            );
+            __builder.AddContent(15, "Content");
+            __builder.CloseElement();
+            __builder.AddMarkupContent(16, "\r\n    ");
+            __builder.OpenElement(17, "input");
+            __builder.AddAttribute(18, "id", "myElem");
+            __builder.AddAttribute(19, "another-attr", "Another attr value");
+            __builder.AddAttribute(20, "value", Microsoft.AspNetCore.Components.BindConverter.FormatValue(
+#nullable restore
+#line 14 "x:\dir\subdir\Test\TestComponent.cshtml"
+                              myVariable
+
+#line default
+#line hidden
+#nullable disable
+            ));
+            __builder.AddAttribute(21, "onchange", Microsoft.AspNetCore.Components.EventCallback.Factory.CreateBinder(this, __value => myVariable = __value, myVariable));
+            __builder.SetUpdatesAttributeName("value");
+            __builder.AddAttribute(22, "TestCssScope");
+            __builder.CloseElement();
+#nullable restore
+#line 15 "x:\dir\subdir\Test\TestComponent.cshtml"
+}
+
+#line default
+#line hidden
+#nullable disable
+        }
+        #pragma warning restore 1998
+#nullable restore
+#line 17 "x:\dir\subdir\Test\TestComponent.cshtml"
+       
+    ElementReference myElementReference;
+    TemplatedComponent myComponentReference;
+    string myVariable;
+
+    void MethodRenderingMarkup(RenderTreeBuilder __builder)
+    {
+        for (var i = 0; i < 10; i++)
+        {
+
+#line default
+#line hidden
+#nullable disable
+        __builder.OpenElement(23, "li");
+        __builder.AddAttribute(24, "data-index", 
+#nullable restore
+#line 26 "x:\dir\subdir\Test\TestComponent.cshtml"
+                            i
+
+#line default
+#line hidden
+#nullable disable
+        );
+        __builder.AddAttribute(25, "TestCssScope");
+        __builder.AddContent(26, "Something ");
+        __builder.AddContent(27, 
+#nullable restore
+#line 26 "x:\dir\subdir\Test\TestComponent.cshtml"
+                                         i
+
+#line default
+#line hidden
+#nullable disable
+        );
+        __builder.CloseElement();
+#nullable restore
+#line 27 "x:\dir\subdir\Test\TestComponent.cshtml"
+        }
+
+        System.GC.KeepAlive(myElementReference);
+        System.GC.KeepAlive(myComponentReference);
+        System.GC.KeepAlive(myVariable);
+    }
+
+#line default
+#line hidden
+#nullable disable
+    }
+}
+#pragma warning restore 1591
diff --git a/src/Razor/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/Component_WithCssScope/TestComponent.ir.txt b/src/Razor/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/Component_WithCssScope/TestComponent.ir.txt
new file mode 100644
index 0000000000..e0f558f3cb
--- /dev/null
+++ b/src/Razor/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/Component_WithCssScope/TestComponent.ir.txt
@@ -0,0 +1,70 @@
+Document - 
+    NamespaceDeclaration -  - Test
+        UsingDirective - (3:1,1 [14] ) - System
+        UsingDirective - (18:2,1 [34] ) - System.Collections.Generic
+        UsingDirective - (53:3,1 [19] ) - System.Linq
+        UsingDirective - (73:4,1 [30] ) - System.Threading.Tasks
+        UsingDirective - (104:5,1 [39] ) - Microsoft.AspNetCore.Components
+        UsingDirective - (1:0,1 [43] x:\dir\subdir\Test\TestComponent.cshtml) - Microsoft.AspNetCore.Components.Web
+        UsingDirective - (45:1,1 [49] x:\dir\subdir\Test\TestComponent.cshtml) - Microsoft.AspNetCore.Components.Rendering
+        ClassDeclaration -  - public partial - TestComponent - Microsoft.AspNetCore.Components.ComponentBase - 
+            MethodDeclaration -  - protected override - void - BuildRenderTree
+                MarkupBlock -  - <h1 TestCssScope>Element with no attributes</h1>\n
+                MarkupElement - (131:3,0 [305] x:\dir\subdir\Test\TestComponent.cshtml) - parent
+                    HtmlAttribute - (138:3,7 [22] x:\dir\subdir\Test\TestComponent.cshtml) -  with-attributes=" - "
+                        HtmlAttributeValue - (156:3,25 [3] x:\dir\subdir\Test\TestComponent.cshtml) - 
+                            LazyIntermediateToken - (156:3,25 [3] x:\dir\subdir\Test\TestComponent.cshtml) - Html - yes
+                    HtmlAttribute - (160:3,29 [37] x:\dir\subdir\Test\TestComponent.cshtml) -  with-csharp-attribute-value=" - "
+                        CSharpExpressionAttributeValue - (190:3,59 [6] x:\dir\subdir\Test\TestComponent.cshtml) - 
+                            LazyIntermediateToken - (192:3,61 [3] x:\dir\subdir\Test\TestComponent.cshtml) - CSharp - 123
+                    MarkupBlock -  - <child TestCssScope></child>\n    
+                    MarkupBlock -  - <child has multiple attributes="some with values" TestCssScope>With text</child>\n    
+                    Component - (292:6,4 [133] x:\dir\subdir\Test\TestComponent.cshtml) - TemplatedComponent
+                        ComponentChildContent -  - ChildContent - context
+                            MarkupBlock -  - <span id="hello" TestCssScope>This is in child content</span>
+                        ReferenceCapture - (318:6,30 [20] x:\dir\subdir\Test\TestComponent.cshtml) - myComponentReference
+                    HtmlAttribute -  - TestCssScope - 
+                CSharpCode - (439:10,1 [34] x:\dir\subdir\Test\TestComponent.cshtml)
+                    LazyIntermediateToken - (439:10,1 [34] x:\dir\subdir\Test\TestComponent.cshtml) - CSharp - if (DateTime.Now.Year > 1950)\n{\n
+                MarkupElement - (477:12,4 [80] x:\dir\subdir\Test\TestComponent.cshtml) - with-ref-capture
+                    HtmlContent - (531:12,58 [7] x:\dir\subdir\Test\TestComponent.cshtml)
+                        LazyIntermediateToken - (531:12,58 [7] x:\dir\subdir\Test\TestComponent.cshtml) - Html - Content
+                    HtmlAttribute -  - some-attr - 
+                    ReferenceCapture - (511:12,38 [18] x:\dir\subdir\Test\TestComponent.cshtml) - myElementReference
+                    HtmlAttribute -  - TestCssScope - 
+                HtmlContent - (557:12,84 [6] x:\dir\subdir\Test\TestComponent.cshtml)
+                    LazyIntermediateToken - (557:12,84 [2] x:\dir\subdir\Test\TestComponent.cshtml) - Html - \n
+                    LazyIntermediateToken - (559:13,0 [4] x:\dir\subdir\Test\TestComponent.cshtml) - Html -     
+                MarkupElement - (563:13,4 [74] x:\dir\subdir\Test\TestComponent.cshtml) - input
+                    HtmlAttribute -  - id=" - "
+                        HtmlAttributeValue - (574:13,15 [6] x:\dir\subdir\Test\TestComponent.cshtml) - 
+                            LazyIntermediateToken - (574:13,15 [6] x:\dir\subdir\Test\TestComponent.cshtml) - Html - myElem
+                    HtmlAttribute -  - another-attr=" - "
+                        HtmlAttributeValue - (615:13,56 [18] x:\dir\subdir\Test\TestComponent.cshtml) - 
+                            LazyIntermediateToken - (615:13,56 [18] x:\dir\subdir\Test\TestComponent.cshtml) - Html - Another attr value
+                    HtmlAttribute - (589:13,30 [10] x:\dir\subdir\Test\TestComponent.cshtml) - value=" - "
+                        CSharpExpressionAttributeValue -  - 
+                            IntermediateToken -  - CSharp - Microsoft.AspNetCore.Components.BindConverter.FormatValue(
+                            LazyIntermediateToken - (589:13,30 [10] x:\dir\subdir\Test\TestComponent.cshtml) - CSharp - myVariable
+                            IntermediateToken -  - CSharp - )
+                    HtmlAttribute - (589:13,30 [10] x:\dir\subdir\Test\TestComponent.cshtml) - onchange=" - "
+                        CSharpExpressionAttributeValue -  - 
+                            IntermediateToken -  - CSharp - Microsoft.AspNetCore.Components.EventCallback.Factory.CreateBinder(this, __value => myVariable = __value, 
+                            IntermediateToken -  - CSharp - myVariable
+                            IntermediateToken -  - CSharp - )
+                    HtmlAttribute -  - TestCssScope - 
+                CSharpCode - (639:14,0 [3] x:\dir\subdir\Test\TestComponent.cshtml)
+                    LazyIntermediateToken - (639:14,0 [3] x:\dir\subdir\Test\TestComponent.cshtml) - CSharp - }\n
+            CSharpCode - (651:16,7 [233] x:\dir\subdir\Test\TestComponent.cshtml)
+                LazyIntermediateToken - (651:16,7 [233] x:\dir\subdir\Test\TestComponent.cshtml) - CSharp - \n    ElementReference myElementReference;\n    TemplatedComponent myComponentReference;\n    string myVariable;\n\n    void MethodRenderingMarkup(RenderTreeBuilder __builder)\n    {\n        for (var i = 0; i < 10; i++)\n        {\n
+            MarkupElement - (896:25,12 [35] x:\dir\subdir\Test\TestComponent.cshtml) - li
+                HtmlAttribute - (899:25,15 [14] x:\dir\subdir\Test\TestComponent.cshtml) -  data-index= - 
+                    CSharpExpressionAttributeValue - (911:25,27 [2] x:\dir\subdir\Test\TestComponent.cshtml) - 
+                        LazyIntermediateToken - (912:25,28 [1] x:\dir\subdir\Test\TestComponent.cshtml) - CSharp - i
+                HtmlContent - (914:25,30 [10] x:\dir\subdir\Test\TestComponent.cshtml)
+                    LazyIntermediateToken - (914:25,30 [10] x:\dir\subdir\Test\TestComponent.cshtml) - Html - Something 
+                CSharpExpression - (925:25,41 [1] x:\dir\subdir\Test\TestComponent.cshtml)
+                    LazyIntermediateToken - (925:25,41 [1] x:\dir\subdir\Test\TestComponent.cshtml) - CSharp - i
+                HtmlAttribute -  - TestCssScope - 
+            CSharpCode - (933:26,0 [164] x:\dir\subdir\Test\TestComponent.cshtml)
+                LazyIntermediateToken - (933:26,0 [164] x:\dir\subdir\Test\TestComponent.cshtml) - CSharp -         }\n\n        System.GC.KeepAlive(myElementReference);\n        System.GC.KeepAlive(myComponentReference);\n        System.GC.KeepAlive(myVariable);\n    }\n
diff --git a/src/Razor/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/Component_WithCssScope/TestComponent.mappings.txt b/src/Razor/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/Component_WithCssScope/TestComponent.mappings.txt
new file mode 100644
index 0000000000..1dd0bdefa2
--- /dev/null
+++ b/src/Razor/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/Component_WithCssScope/TestComponent.mappings.txt
@@ -0,0 +1,66 @@
+Source Location: (318:6,30 [20] x:\dir\subdir\Test\TestComponent.cshtml)
+|myComponentReference|
+Generated Location: (2121:62,30 [20] )
+|myComponentReference|
+
+Source Location: (439:10,1 [34] x:\dir\subdir\Test\TestComponent.cshtml)
+|if (DateTime.Now.Year > 1950)
+{
+|
+Generated Location: (2412:73,1 [34] )
+|if (DateTime.Now.Year > 1950)
+{
+|
+
+Source Location: (511:12,38 [18] x:\dir\subdir\Test\TestComponent.cshtml)
+|myElementReference|
+Generated Location: (2845:85,38 [18] )
+|myElementReference|
+
+Source Location: (639:14,0 [3] x:\dir\subdir\Test\TestComponent.cshtml)
+|}
+|
+Generated Location: (3972:113,0 [3] )
+|}
+|
+
+Source Location: (651:16,7 [233] x:\dir\subdir\Test\TestComponent.cshtml)
+|
+    ElementReference myElementReference;
+    TemplatedComponent myComponentReference;
+    string myVariable;
+
+    void MethodRenderingMarkup(RenderTreeBuilder __builder)
+    {
+        for (var i = 0; i < 10; i++)
+        {
+|
+Generated Location: (4152:122,7 [233] )
+|
+    ElementReference myElementReference;
+    TemplatedComponent myComponentReference;
+    string myVariable;
+
+    void MethodRenderingMarkup(RenderTreeBuilder __builder)
+    {
+        for (var i = 0; i < 10; i++)
+        {
+|
+
+Source Location: (933:26,0 [164] x:\dir\subdir\Test\TestComponent.cshtml)
+|        }
+
+        System.GC.KeepAlive(myElementReference);
+        System.GC.KeepAlive(myComponentReference);
+        System.GC.KeepAlive(myVariable);
+    }
+|
+Generated Location: (5112:159,0 [164] )
+|        }
+
+        System.GC.KeepAlive(myElementReference);
+        System.GC.KeepAlive(myComponentReference);
+        System.GC.KeepAlive(myVariable);
+    }
+|
+
diff --git a/src/Razor/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/DuplicateMarkupAttributes_IsAnError/TestComponent.codegen.cs b/src/Razor/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/DuplicateMarkupAttributes_IsAnError/TestComponent.codegen.cs
index af3808fed1..69f1edaf96 100644
--- a/src/Razor/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/DuplicateMarkupAttributes_IsAnError/TestComponent.codegen.cs
+++ b/src/Razor/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/DuplicateMarkupAttributes_IsAnError/TestComponent.codegen.cs
@@ -16,8 +16,8 @@ namespace Test
             __builder.OpenElement(0, "div");
             __builder.OpenElement(1, "a");
             __builder.AddAttribute(2, "href", "/cool-url");
-            __builder.AddAttribute(3, "style", true);
-            __builder.AddAttribute(4, "disabled", true);
+            __builder.AddAttribute(3, "style");
+            __builder.AddAttribute(4, "disabled");
             __builder.AddAttribute(5, "href", "/even-cooler-url");
             __builder.AddContent(6, "Learn the ten cool tricks your compiler author will hate!");
             __builder.CloseElement();
diff --git a/src/Razor/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/DuplicateMarkupAttributes_Multiple_IsAnError/TestComponent.codegen.cs b/src/Razor/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/DuplicateMarkupAttributes_Multiple_IsAnError/TestComponent.codegen.cs
index 4ee5c736c6..3e1eac8fe2 100644
--- a/src/Razor/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/DuplicateMarkupAttributes_Multiple_IsAnError/TestComponent.codegen.cs
+++ b/src/Razor/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/DuplicateMarkupAttributes_Multiple_IsAnError/TestComponent.codegen.cs
@@ -16,10 +16,10 @@ namespace Test
             __builder.OpenElement(0, "div");
             __builder.OpenElement(1, "a");
             __builder.AddAttribute(2, "href", "/cool-url");
-            __builder.AddAttribute(3, "style", true);
-            __builder.AddAttribute(4, "disabled", true);
+            __builder.AddAttribute(3, "style");
+            __builder.AddAttribute(4, "disabled");
             __builder.AddAttribute(5, "href", "/even-cooler-url");
-            __builder.AddAttribute(6, "href", true);
+            __builder.AddAttribute(6, "href");
             __builder.AddContent(7, "Learn the ten cool tricks your compiler author will hate!");
             __builder.CloseElement();
             __builder.CloseElement();
diff --git a/src/Razor/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/EventHandler_PreventDefault_Duplicates/TestComponent.codegen.cs b/src/Razor/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/EventHandler_PreventDefault_Duplicates/TestComponent.codegen.cs
index 42db467644..c234bb73ba 100644
--- a/src/Razor/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/EventHandler_PreventDefault_Duplicates/TestComponent.codegen.cs
+++ b/src/Razor/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/EventHandler_PreventDefault_Duplicates/TestComponent.codegen.cs
@@ -30,7 +30,7 @@ using Microsoft.AspNetCore.Components.Web;
 #line hidden
 #nullable disable
             );
-            __builder.AddAttribute(2, "@onclick:preventDefault", true);
+            __builder.AddAttribute(2, "@onclick:preventDefault");
             __builder.CloseElement();
         }
         #pragma warning restore 1998
diff --git a/src/Razor/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/ScriptTag_WithErrorSuppressed/TestComponent.codegen.cs b/src/Razor/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/ScriptTag_WithErrorSuppressed/TestComponent.codegen.cs
index a4085edb4a..3f0e7d9727 100644
--- a/src/Razor/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/ScriptTag_WithErrorSuppressed/TestComponent.codegen.cs
+++ b/src/Razor/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/ScriptTag_WithErrorSuppressed/TestComponent.codegen.cs
@@ -16,7 +16,7 @@ namespace Test
             __builder.OpenElement(0, "div");
             __builder.OpenElement(1, "script");
             __builder.AddAttribute(2, "src", "some/url.js");
-            __builder.AddAttribute(3, "anotherattribute", true);
+            __builder.AddAttribute(3, "anotherattribute");
             __builder.AddMarkupContent(4, "\r\n        some text\r\n        some more text\r\n    ");
             __builder.CloseElement();
             __builder.CloseElement();
diff --git a/src/Razor/Microsoft.AspNetCore.Razor.Tools/src/GenerateCommand.cs b/src/Razor/Microsoft.AspNetCore.Razor.Tools/src/GenerateCommand.cs
index 0406225fc8..6bcf622d1d 100644
--- a/src/Razor/Microsoft.AspNetCore.Razor.Tools/src/GenerateCommand.cs
+++ b/src/Razor/Microsoft.AspNetCore.Razor.Tools/src/GenerateCommand.cs
@@ -5,6 +5,7 @@ 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.CodeAnalysis.CSharp;
@@ -25,6 +26,8 @@ namespace Microsoft.AspNetCore.Razor.Tools
             Outputs = Option("-o", "Generated output file path", CommandOptionType.MultipleValue);
             RelativePaths = Option("-r", "Relative path", CommandOptionType.MultipleValue);
             FileKinds = Option("-k", "File kind", CommandOptionType.MultipleValue);
+            CssScopeSources = Option("-cssscopedinput", ".razor file with scoped CSS", CommandOptionType.MultipleValue);
+            CssScopeValues = Option("-cssscopevalue", "CSS scope value for .razor file with scoped CSS", 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);
@@ -44,6 +47,10 @@ namespace Microsoft.AspNetCore.Razor.Tools
 
         public CommandOption FileKinds { get; }
 
+        public CommandOption CssScopeSources { get; }
+
+        public CommandOption CssScopeValues { get; }
+
         public CommandOption ProjectDirectory { get; }
 
         public CommandOption TagHelperManifest { get; }
@@ -81,7 +88,9 @@ 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, FileKinds.Values);
+            var sourceItems = GetSourceItems(
+                Sources.Values, Outputs.Values, RelativePaths.Values,
+                FileKinds.Values, CssScopeSources.Values, CssScopeValues.Values);
 
             var result = ExecuteCore(
                 configuration: configuration,
@@ -120,6 +129,13 @@ namespace Microsoft.AspNetCore.Razor.Tools
                 return false;
             }
 
+            if (CssScopeSources.Values.Count != CssScopeValues.Values.Count)
+            {
+                // CssScopeSources and CssScopeValues arguments must appear as matched pairs
+                Error.WriteLine($"{CssScopeSources.Description} has {CssScopeSources.Values.Count}, but {CssScopeValues.Description} has {CssScopeValues.Values.Count} values.");
+                return false;
+            }
+
             if (string.IsNullOrEmpty(ProjectDirectory.Value()))
             {
                 ProjectDirectory.Values.Add(Environment.CurrentDirectory);
@@ -256,7 +272,8 @@ namespace Microsoft.AspNetCore.Razor.Tools
                     filePath: item.FilePath,
                     relativePhysicalPath: item.RelativePhysicalPath,
                     fileKind: item.FileKind,
-                    file: new FileInfo(item.SourcePath));
+                    file: new FileInfo(item.SourcePath),
+                    cssScope: item.CssScope);
 
                 project.Add(projectItem);
             }
@@ -284,19 +301,28 @@ namespace Microsoft.AspNetCore.Razor.Tools
             }
         }
 
-        private SourceItem[] GetSourceItems(string projectDirectory, List<string> sources, List<string> outputs, List<string> relativePath, List<string> fileKinds)
+        private static SourceItem[] GetSourceItems(List<string> sources, List<string> outputs, List<string> relativePath, List<string> fileKinds, List<string> cssScopeSources, List<string> cssScopeValues)
         {
+            var cssScopeAssociations = new Dictionary<string, int>(StringComparer.OrdinalIgnoreCase);
+            for (var cssScopeSourceIndex = 0; cssScopeSourceIndex < cssScopeSources.Count; cssScopeSourceIndex++)
+            {
+                cssScopeAssociations.Add(cssScopeSources[cssScopeSourceIndex], cssScopeSourceIndex);
+            }
+
             var items = new SourceItem[sources.Count];
             for (var i = 0; i < items.Length; i++)
             {
-                var outputPath = Path.Combine(projectDirectory, outputs[i]);
                 var fileKind = fileKinds.Count > 0 ? fileKinds[i] : "mvc";
                 if (Language.FileKinds.IsComponent(fileKind))
                 {
                     fileKind = Language.FileKinds.GetComponentFileKindFromFilePath(sources[i]);
                 }
 
-                items[i] = new SourceItem(sources[i], outputs[i], relativePath[i], fileKind);
+                var cssScopeValue = cssScopeAssociations.TryGetValue(sources[i], out var cssScopeIndex)
+                    ? cssScopeValues[cssScopeIndex]
+                    : null;
+
+                items[i] = new SourceItem(sources[i], outputs[i], relativePath[i], fileKind, cssScopeValue);
             }
 
             return items;
@@ -334,7 +360,7 @@ namespace Microsoft.AspNetCore.Razor.Tools
 
         private readonly struct SourceItem
         {
-            public SourceItem(string sourcePath, string outputPath, string physicalRelativePath, string fileKind)
+            public SourceItem(string sourcePath, string outputPath, string physicalRelativePath, string fileKind, string cssScope)
             {
                 SourcePath = sourcePath;
                 OutputPath = outputPath;
@@ -343,6 +369,7 @@ namespace Microsoft.AspNetCore.Razor.Tools
                     .Replace(Path.DirectorySeparatorChar, '/')
                     .Replace("//", "/");
                 FileKind = fileKind;
+                CssScope = cssScope;
             }
 
             public string SourcePath { get; }
@@ -354,6 +381,8 @@ namespace Microsoft.AspNetCore.Razor.Tools
             public string FilePath { get; }
 
             public string FileKind { get; }
+
+            public string CssScope { get; }
         }
 
         private class StaticTagHelperFeature : ITagHelperFeature
diff --git a/src/Razor/Microsoft.NET.Sdk.Razor/src/RazorGenerate.cs b/src/Razor/Microsoft.NET.Sdk.Razor/src/RazorGenerate.cs
index bee0df6816..36875942b0 100644
--- a/src/Razor/Microsoft.NET.Sdk.Razor/src/RazorGenerate.cs
+++ b/src/Razor/Microsoft.NET.Sdk.Razor/src/RazorGenerate.cs
@@ -23,6 +23,7 @@ namespace Microsoft.AspNetCore.Razor.Tasks
         private const string Identity = "Identity";
         private const string AssemblyName = "AssemblyName";
         private const string AssemblyFilePath = "AssemblyFilePath";
+        private const string CssScope = "CssScope";
 
         public string RootNamespace { get; set; }
 
@@ -127,6 +128,26 @@ namespace Microsoft.AspNetCore.Razor.Tasks
                 }
             }
 
+            // Added in 5.0: CSS scopes
+            if (parsedVersion.Major >= 5)
+            {
+                for (var i = 0; i < Sources.Length; i++)
+                {
+                    // Most inputs won't have an associated CSS scope, so we only want to generate
+                    // a scope parameter for those that do. Hence we need to specify in the parameter
+                    // which one we're talking about.
+                    var input = Sources[i];
+                    var cssScope = input.GetMetadata(CssScope);
+                    if (!string.IsNullOrEmpty(cssScope))
+                    {
+                        builder.AppendLine("-cssscopedinput");
+                        builder.AppendLine(input.GetMetadata(FullPath));
+                        builder.AppendLine("-cssscopevalue");
+                        builder.AppendLine(cssScope);
+                    }
+                }
+            }
+
             builder.AppendLine("-p");
             builder.AppendLine(ProjectRoot);
 
diff --git a/src/Razor/test/Microsoft.AspNetCore.Razor.Test.Common/Language/IntegrationTests/RazorIntegrationTestBase.cs b/src/Razor/test/Microsoft.AspNetCore.Razor.Test.Common/Language/IntegrationTests/RazorIntegrationTestBase.cs
index 5266adac10..ddd1b5dbd1 100644
--- a/src/Razor/test/Microsoft.AspNetCore.Razor.Test.Common/Language/IntegrationTests/RazorIntegrationTestBase.cs
+++ b/src/Razor/test/Microsoft.AspNetCore.Razor.Test.Common/Language/IntegrationTests/RazorIntegrationTestBase.cs
@@ -140,7 +140,7 @@ namespace Microsoft.AspNetCore.Razor.Language.IntegrationTests
             });
         }
 
-        internal RazorProjectItem CreateProjectItem(string cshtmlRelativePath, string cshtmlContent, string fileKind = null)
+        internal RazorProjectItem CreateProjectItem(string cshtmlRelativePath, string cshtmlContent, string fileKind = null, string cssScope = null)
         {
             var fullPath = WorkingDirectory + PathSeparator + cshtmlRelativePath;
 
@@ -161,18 +161,19 @@ namespace Microsoft.AspNetCore.Razor.Language.IntegrationTests
                 physicalPath: fullPath,
                 relativePhysicalPath: cshtmlRelativePath,
                 basePath: WorkingDirectory,
-                fileKind: fileKind ?? FileKind)
+                fileKind: fileKind ?? FileKind,
+                cssScope: cssScope)
             {
                 Content = cshtmlContent.TrimStart(),
             };
         }
 
-        protected CompileToCSharpResult CompileToCSharp(string cshtmlContent, bool throwOnFailure=true)
+        protected CompileToCSharpResult CompileToCSharp(string cshtmlContent, bool throwOnFailure=true, string cssScope = null)
         {
-            return CompileToCSharp(DefaultFileName, cshtmlContent, throwOnFailure);
+            return CompileToCSharp(DefaultFileName, cshtmlContent, throwOnFailure, cssScope: cssScope);
         }
 
-        protected CompileToCSharpResult CompileToCSharp(string cshtmlRelativePath, string cshtmlContent, bool throwOnFailure = true, string fileKind = null)
+        protected CompileToCSharpResult CompileToCSharp(string cshtmlRelativePath, string cshtmlContent, bool throwOnFailure = true, string fileKind = null, string cssScope = null)
         {
             if (DeclarationOnly && DesignTime)
             {
@@ -202,7 +203,7 @@ namespace Microsoft.AspNetCore.Razor.Language.IntegrationTests
                 }
 
                 // Result of generating declarations
-                var projectItem = CreateProjectItem(cshtmlRelativePath, cshtmlContent, fileKind);
+                var projectItem = CreateProjectItem(cshtmlRelativePath, cshtmlContent, fileKind, cssScope);
                 codeDocument = projectEngine.ProcessDeclarationOnly(projectItem);
                 var declaration = new CompileToCSharpResult
                 {
@@ -248,7 +249,7 @@ namespace Microsoft.AspNetCore.Razor.Language.IntegrationTests
                 // This will include the built-in components.
                 var projectEngine = CreateProjectEngine(Configuration, BaseCompilation.References.ToArray());
 
-                var projectItem = CreateProjectItem(cshtmlRelativePath, cshtmlContent, fileKind);
+                var projectItem = CreateProjectItem(cshtmlRelativePath, cshtmlContent, fileKind, cssScope);
 
                 RazorCodeDocument codeDocument;
                 if (DeclarationOnly)
diff --git a/src/Razor/test/Microsoft.AspNetCore.Razor.Test.Common/Language/TestRazorProjectItem.cs b/src/Razor/test/Microsoft.AspNetCore.Razor.Test.Common/Language/TestRazorProjectItem.cs
index e811043206..407169e646 100644
--- a/src/Razor/test/Microsoft.AspNetCore.Razor.Test.Common/Language/TestRazorProjectItem.cs
+++ b/src/Razor/test/Microsoft.AspNetCore.Razor.Test.Common/Language/TestRazorProjectItem.cs
@@ -15,12 +15,14 @@ namespace Microsoft.AspNetCore.Razor.Language
             string physicalPath = null,
             string relativePhysicalPath = null,
             string basePath = "/",
-            string fileKind = null)
+            string fileKind = null,
+            string cssScope = null)
         {
             FilePath = filePath;
             PhysicalPath = physicalPath;
             RelativePhysicalPath = relativePhysicalPath;
             BasePath = basePath;
+            CssScope = cssScope;
             _fileKind = fileKind;
         }
 
@@ -34,6 +36,8 @@ namespace Microsoft.AspNetCore.Razor.Language
 
         public override string RelativePhysicalPath { get; }
 
+        public override string CssScope { get; }
+
         public override bool Exists { get; } = true;
 
         public string Content { get; set; } = "Default content";
diff --git a/src/Razor/test/Microsoft.AspNetCore.Razor.Test.ComponentShim/Microsoft.AspNetCore.Components.netstandard2.0.cs b/src/Razor/test/Microsoft.AspNetCore.Razor.Test.ComponentShim/Microsoft.AspNetCore.Components.netstandard2.0.cs
index c244065999..6a5ff2c2e3 100644
--- a/src/Razor/test/Microsoft.AspNetCore.Razor.Test.ComponentShim/Microsoft.AspNetCore.Components.netstandard2.0.cs
+++ b/src/Razor/test/Microsoft.AspNetCore.Razor.Test.ComponentShim/Microsoft.AspNetCore.Components.netstandard2.0.cs
@@ -385,6 +385,7 @@ namespace Microsoft.AspNetCore.Components.Rendering
     {
         public RenderTreeBuilder() { }
         public void AddAttribute(int sequence, in Microsoft.AspNetCore.Components.RenderTree.RenderTreeFrame frame) { }
+        public void AddAttribute(int sequence, string name) { }
         public void AddAttribute(int sequence, string name, Microsoft.AspNetCore.Components.EventCallback value) { }
         public void AddAttribute(int sequence, string name, bool value) { }
         public void AddAttribute(int sequence, string name, System.MulticastDelegate value) { }