From 60d600dd5c458365631049240dda22f49907c438 Mon Sep 17 00:00:00 2001
From: cjrosa <crosa@snet.net>
Date: Fri, 30 Sep 2016 12:40:53 -0400
Subject: [PATCH] Issue #5310 (#5334)

* Issue #5310
---
 .../MvcRazorParser.cs                         | 27 +-----
 .../TagHelpersWebSite.Home.Index.html         |  5 +
 .../DictionaryPrefixTestTagHelper.cs          | 20 ++++
 .../ViewComponentTagHelperChunkVisitorTest.cs |  2 +-
 .../MvcRazorHostTest.cs                       | 52 ++++++++--
 .../Input/ModelExpressionTagHelper.cshtml     |  6 +-
 .../DesignTime/ModelExpressionTagHelper.cs    | 23 ++++-
 .../Runtime/ModelExpressionTagHelper.cs       | 97 ++++++++++++++-----
 .../DictionaryPrefixTestTagHelper.cs          | 33 +++++++
 .../TagHelpersWebSite/Views/Home/Index.cshtml |  5 +
 10 files changed, 208 insertions(+), 62 deletions(-)
 create mode 100644 test/Microsoft.AspNetCore.Mvc.Razor.Host.Test/DictionaryPrefixTestTagHelper.cs
 create mode 100644 test/WebSites/TagHelpersWebSite/TagHelpers/DictionaryPrefixTestTagHelper.cs

diff --git a/src/Microsoft.AspNetCore.Mvc.Razor.Host/MvcRazorParser.cs b/src/Microsoft.AspNetCore.Mvc.Razor.Host/MvcRazorParser.cs
index 086f4ba2c1..b0b0fa53b7 100644
--- a/src/Microsoft.AspNetCore.Mvc.Razor.Host/MvcRazorParser.cs
+++ b/src/Microsoft.AspNetCore.Mvc.Razor.Host/MvcRazorParser.cs
@@ -21,7 +21,6 @@ namespace Microsoft.AspNetCore.Mvc.Razor
     public class MvcRazorParser : RazorParser
     {
         private readonly IEnumerable<TagHelperDirectiveDescriptor> _viewImportsDirectiveDescriptors;
-        private readonly string _modelExpressionTypeName;
 
         /// <summary>
         /// Initializes a new instance of <see cref="MvcRazorParser"/>.
@@ -63,8 +62,6 @@ namespace Microsoft.AspNetCore.Mvc.Razor
             _viewImportsDirectiveDescriptors = GetTagHelperDirectiveDescriptors(
                 inheritedChunkTrees,
                 defaultInheritedChunks);
-
-            _modelExpressionTypeName = modelExpressionTypeName;
         }
 
         /// <inheritdoc />
@@ -87,29 +84,7 @@ namespace Microsoft.AspNetCore.Mvc.Razor
                 _viewImportsDirectiveDescriptors,
                 errorSink);
 
-            var descriptors = visitor.GetDescriptors(documentRoot);
-            foreach (var descriptor in descriptors)
-            {
-                foreach (var attributeDescriptor in descriptor.Attributes)
-                {
-                    if (attributeDescriptor.IsIndexer &&
-                        string.Equals(
-                            attributeDescriptor.TypeName,
-                            _modelExpressionTypeName,
-                            StringComparison.Ordinal))
-                    {
-                        errorSink.OnError(
-                            SourceLocation.Undefined,
-                            Resources.FormatMvcRazorParser_InvalidPropertyType(
-                                descriptor.TypeName,
-                                attributeDescriptor.Name,
-                                _modelExpressionTypeName),
-                            length: 0);
-                    }
-                }
-            }
-
-            return descriptors;
+            return visitor.GetDescriptors(documentRoot);
         }
 
         private static IEnumerable<TagHelperDirectiveDescriptor> GetTagHelperDirectiveDescriptors(
diff --git a/test/Microsoft.AspNetCore.Mvc.FunctionalTests/compiler/resources/TagHelpersWebSite.Home.Index.html b/test/Microsoft.AspNetCore.Mvc.FunctionalTests/compiler/resources/TagHelpersWebSite.Home.Index.html
index dcf5fd12da..27bc4cf95a 100644
--- a/test/Microsoft.AspNetCore.Mvc.FunctionalTests/compiler/resources/TagHelpersWebSite.Home.Index.html
+++ b/test/Microsoft.AspNetCore.Mvc.FunctionalTests/compiler/resources/TagHelpersWebSite.Home.Index.html
@@ -39,6 +39,11 @@
 <br /><p><em>Rendering Template:</em></p>
 <div><h3 style="font-family: cursive;">Tag Cloud from Template: </h3>Lorem,ipsum,dolor,sit,amet,consectetur,adipisicing,elit,sed,do,eiusmod,tempor,incididunt,ut,labore,et,dolore,magna,aliquaUt,enim</div></div>
 
+<div>
+    <h3 style="font-family: cursive;">Dictionary Valued Model Expression</h3>
+    <div><ul><li>TagsToShow</li><li>Version.Build</li></ul></div>
+</div>
+
 
         <hr />
         <footer>
diff --git a/test/Microsoft.AspNetCore.Mvc.Razor.Host.Test/DictionaryPrefixTestTagHelper.cs b/test/Microsoft.AspNetCore.Mvc.Razor.Host.Test/DictionaryPrefixTestTagHelper.cs
new file mode 100644
index 0000000000..d64e8d8d19
--- /dev/null
+++ b/test/Microsoft.AspNetCore.Mvc.Razor.Host.Test/DictionaryPrefixTestTagHelper.cs
@@ -0,0 +1,20 @@
+// 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 Microsoft.AspNetCore.Mvc.ViewFeatures;
+using Microsoft.AspNetCore.Razor.TagHelpers;
+
+namespace Microsoft.AspNetCore.Mvc.Razor
+{
+    [HtmlTargetElement(Attributes = "prefix-*")]
+    public class DictionaryPrefixTestTagHelper : TagHelper
+    {
+        [HtmlAttributeName(DictionaryAttributePrefix = "prefix-")]
+        public IDictionary<string, ModelExpression> PrefixValues { get; set; } = new Dictionary<string, ModelExpression>();
+
+        public override void Process(TagHelperContext context, TagHelperOutput output)
+        {
+        }
+    }
+}
diff --git a/test/Microsoft.AspNetCore.Mvc.Razor.Host.Test/Internal/ViewComponentTagHelperChunkVisitorTest.cs b/test/Microsoft.AspNetCore.Mvc.Razor.Host.Test/Internal/ViewComponentTagHelperChunkVisitorTest.cs
index b3dc7fb59c..39a13605e4 100644
--- a/test/Microsoft.AspNetCore.Mvc.Razor.Host.Test/Internal/ViewComponentTagHelperChunkVisitorTest.cs
+++ b/test/Microsoft.AspNetCore.Mvc.Razor.Host.Test/Internal/ViewComponentTagHelperChunkVisitorTest.cs
@@ -46,7 +46,7 @@ namespace Microsoft.AspNetCore.Mvc.Razor.Host.Test.Internal
             var resultOutput = writer.GenerateCode();
 
 #if GENERATE_BASELINES
-            if (!string.Equals(expectedOutput, resultOutput, StringComparison.Ordinal))
+            if (!string.Equals(expectedOutput, resultOutput, System.StringComparison.Ordinal))
             {
                 ResourceFile.UpdateFile(assembly, path, expectedOutput, resultOutput);
             }
diff --git a/test/Microsoft.AspNetCore.Mvc.Razor.Host.Test/MvcRazorHostTest.cs b/test/Microsoft.AspNetCore.Mvc.Razor.Host.Test/MvcRazorHostTest.cs
index 74402918dd..7749ebe427 100644
--- a/test/Microsoft.AspNetCore.Mvc.Razor.Host.Test/MvcRazorHostTest.cs
+++ b/test/Microsoft.AspNetCore.Mvc.Razor.Host.Test/MvcRazorHostTest.cs
@@ -142,30 +142,62 @@ namespace Microsoft.AspNetCore.Mvc.Razor
                     generatedLineIndex: 17,
                     generatedCharacterIndex: 48,
                     contentLength: 91),
+                BuildLineMapping(
+                    documentAbsoluteIndex: 140,
+                    documentLineIndex: 3,
+                    documentCharacterIndex: 14,
+                    generatedAbsoluteIndex: 797,
+                    generatedLineIndex: 18,
+                    generatedCharacterIndex: 48,
+                    contentLength: 102),
                 BuildLineMapping(
                     documentAbsoluteIndex: 7,
                     documentLineIndex: 0,
                     documentCharacterIndex: 7,
-                    generatedAbsoluteIndex: 836,
-                    generatedLineIndex: 19,
+                    generatedAbsoluteIndex: 990,
+                    generatedLineIndex: 20,
                     generatedCharacterIndex: 28,
                     contentLength: 8),
                 BuildLineMapping(
-                    documentAbsoluteIndex: 145,
-                    documentLineIndex: 4,
+                    documentAbsoluteIndex: 263,
+                    documentLineIndex: 5,
                     documentCharacterIndex: 17,
-                    generatedAbsoluteIndex: 2530,
-                    generatedLineIndex: 50,
+                    generatedAbsoluteIndex: 2841,
+                    generatedLineIndex: 52,
                     generatedCharacterIndex: 133,
                     contentLength: 3),
                 BuildLineMapping(
-                    documentAbsoluteIndex: 172,
-                    documentLineIndex: 5,
+                    documentAbsoluteIndex: 290,
+                    documentLineIndex: 6,
                     documentCharacterIndex: 18,
-                    generatedAbsoluteIndex: 2897,
-                    generatedLineIndex: 56,
+                    generatedAbsoluteIndex: 3208,
+                    generatedLineIndex: 58,
                     generatedCharacterIndex: 125,
                     contentLength: 5),
+                BuildLineMapping(
+                    documentAbsoluteIndex: 322,
+                    documentLineIndex: 8,
+                    documentCharacterIndex: 19,
+                    generatedAbsoluteIndex: 3627,
+                    generatedLineIndex: 64,
+                    generatedCharacterIndex: 153,
+                    contentLength: 5),
+                BuildLineMapping(
+                    documentAbsoluteIndex: 357,
+                    documentLineIndex: 9,
+                    documentCharacterIndex: 19,
+                    generatedAbsoluteIndex: 4055,
+                    generatedLineIndex: 70,
+                    generatedCharacterIndex: 161,
+                    contentLength: 4),
+                BuildLineMapping(
+                    documentAbsoluteIndex: 378,
+                    documentLineIndex: 9,
+                    documentCharacterIndex: 40,
+                    generatedAbsoluteIndex: 4317,
+                    generatedLineIndex: 75,
+                    generatedCharacterIndex: 163,
+                    contentLength: 6),
             };
 
             // Act and Assert
diff --git a/test/Microsoft.AspNetCore.Mvc.Razor.Host.Test/TestFiles/Input/ModelExpressionTagHelper.cshtml b/test/Microsoft.AspNetCore.Mvc.Razor.Host.Test/TestFiles/Input/ModelExpressionTagHelper.cshtml
index fc408467f0..e0505d4001 100644
--- a/test/Microsoft.AspNetCore.Mvc.Razor.Host.Test/TestFiles/Input/ModelExpressionTagHelper.cshtml
+++ b/test/Microsoft.AspNetCore.Mvc.Razor.Host.Test/TestFiles/Input/ModelExpressionTagHelper.cshtml
@@ -1,6 +1,10 @@
 @model DateTime
 
 @addTagHelper Microsoft.AspNetCore.Mvc.Razor.InputTestTagHelper, Microsoft.AspNetCore.Mvc.Razor.Host.Test
+@addTagHelper Microsoft.AspNetCore.Mvc.Razor.DictionaryPrefixTestTagHelper, Microsoft.AspNetCore.Mvc.Razor.Host.Test
 
 <input-test for="Now" />
-<input-test for="@Model" />
\ No newline at end of file
+<input-test for="@Model" />
+
+<div prefix-test="@Model" ></div>
+<span prefix-hour="Hour" prefix-minute="Minute"></span>
\ No newline at end of file
diff --git a/test/Microsoft.AspNetCore.Mvc.Razor.Host.Test/TestFiles/Output/DesignTime/ModelExpressionTagHelper.cs b/test/Microsoft.AspNetCore.Mvc.Razor.Host.Test/TestFiles/Output/DesignTime/ModelExpressionTagHelper.cs
index 47be6e965e..20017fff61 100644
--- a/test/Microsoft.AspNetCore.Mvc.Razor.Host.Test/TestFiles/Output/DesignTime/ModelExpressionTagHelper.cs
+++ b/test/Microsoft.AspNetCore.Mvc.Razor.Host.Test/TestFiles/Output/DesignTime/ModelExpressionTagHelper.cs
@@ -16,6 +16,7 @@ namespace AspNetCore
             #pragma warning disable 219
             string __tagHelperDirectiveSyntaxHelper = null;
             __tagHelperDirectiveSyntaxHelper = "Microsoft.AspNetCore.Mvc.Razor.InputTestTagHelper, Microsoft.AspNetCore.Mvc.Razor.Host.Test";
+            __tagHelperDirectiveSyntaxHelper = "Microsoft.AspNetCore.Mvc.Razor.DictionaryPrefixTestTagHelper, Microsoft.AspNetCore.Mvc.Razor.Host.Test";
 #line 1 "testfiles/input/modelexpressiontaghelper.cshtml"
 var __modelHelper = default(DateTime);
 
@@ -25,6 +26,7 @@ var __modelHelper = default(DateTime);
         }
         #line hidden
         private global::Microsoft.AspNetCore.Mvc.Razor.InputTestTagHelper __Microsoft_AspNetCore_Mvc_Razor_InputTestTagHelper = null;
+        private global::Microsoft.AspNetCore.Mvc.Razor.DictionaryPrefixTestTagHelper __Microsoft_AspNetCore_Mvc_Razor_DictionaryPrefixTestTagHelper = null;
         #line hidden
         public testfiles_input_modelexpressiontaghelper_cshtml()
         {
@@ -47,15 +49,32 @@ var __modelHelper = default(DateTime);
         public override async Task ExecuteAsync()
         {
             __Microsoft_AspNetCore_Mvc_Razor_InputTestTagHelper = CreateTagHelper<global::Microsoft.AspNetCore.Mvc.Razor.InputTestTagHelper>();
-#line 5 "testfiles/input/modelexpressiontaghelper.cshtml"
+#line 6 "testfiles/input/modelexpressiontaghelper.cshtml"
 __Microsoft_AspNetCore_Mvc_Razor_InputTestTagHelper.For = ModelExpressionProvider.CreateModelExpression(ViewData, __model => __model.Now);
 
 #line default
 #line hidden
             __Microsoft_AspNetCore_Mvc_Razor_InputTestTagHelper = CreateTagHelper<global::Microsoft.AspNetCore.Mvc.Razor.InputTestTagHelper>();
-#line 6 "testfiles/input/modelexpressiontaghelper.cshtml"
+#line 7 "testfiles/input/modelexpressiontaghelper.cshtml"
 __Microsoft_AspNetCore_Mvc_Razor_InputTestTagHelper.For = ModelExpressionProvider.CreateModelExpression(ViewData, __model => Model);
 
+#line default
+#line hidden
+            __Microsoft_AspNetCore_Mvc_Razor_DictionaryPrefixTestTagHelper = CreateTagHelper<global::Microsoft.AspNetCore.Mvc.Razor.DictionaryPrefixTestTagHelper>();
+#line 9 "testfiles/input/modelexpressiontaghelper.cshtml"
+__Microsoft_AspNetCore_Mvc_Razor_DictionaryPrefixTestTagHelper.PrefixValues["test"] = ModelExpressionProvider.CreateModelExpression(ViewData, __model => Model);
+
+#line default
+#line hidden
+            __Microsoft_AspNetCore_Mvc_Razor_DictionaryPrefixTestTagHelper = CreateTagHelper<global::Microsoft.AspNetCore.Mvc.Razor.DictionaryPrefixTestTagHelper>();
+#line 10 "testfiles/input/modelexpressiontaghelper.cshtml"
+__Microsoft_AspNetCore_Mvc_Razor_DictionaryPrefixTestTagHelper.PrefixValues["hour"] = ModelExpressionProvider.CreateModelExpression(ViewData, __model => __model.Hour);
+
+#line default
+#line hidden
+#line 10 "testfiles/input/modelexpressiontaghelper.cshtml"
+__Microsoft_AspNetCore_Mvc_Razor_DictionaryPrefixTestTagHelper.PrefixValues["minute"] = ModelExpressionProvider.CreateModelExpression(ViewData, __model => __model.Minute);
+
 #line default
 #line hidden
         }
diff --git a/test/Microsoft.AspNetCore.Mvc.Razor.Host.Test/TestFiles/Output/Runtime/ModelExpressionTagHelper.cs b/test/Microsoft.AspNetCore.Mvc.Razor.Host.Test/TestFiles/Output/Runtime/ModelExpressionTagHelper.cs
index 30e09a89bd..65981e63c3 100644
--- a/test/Microsoft.AspNetCore.Mvc.Razor.Host.Test/TestFiles/Output/Runtime/ModelExpressionTagHelper.cs
+++ b/test/Microsoft.AspNetCore.Mvc.Razor.Host.Test/TestFiles/Output/Runtime/ModelExpressionTagHelper.cs
@@ -1,4 +1,4 @@
-#pragma checksum "TestFiles/Input/ModelExpressionTagHelper.cshtml" "{ff1816ec-aa5e-4d10-87f7-6f4963833460}" "bb128a8b2ca348e77a9b5481e541b5a8bf82de0b"
+#pragma checksum "TestFiles/Input/ModelExpressionTagHelper.cshtml" "{ff1816ec-aa5e-4d10-87f7-6f4963833460}" "faaab08eebb321aea098bd40df018e89cd247b6f"
 namespace AspNetCore
 {
     using System;
@@ -19,6 +19,7 @@ namespace AspNetCore
         private global::Microsoft.AspNetCore.Razor.Runtime.TagHelpers.TagHelperRunner __tagHelperRunner = null;
         private global::Microsoft.AspNetCore.Razor.Runtime.TagHelpers.TagHelperScopeManager __tagHelperScopeManager = null;
         private global::Microsoft.AspNetCore.Mvc.Razor.InputTestTagHelper __Microsoft_AspNetCore_Mvc_Razor_InputTestTagHelper = null;
+        private global::Microsoft.AspNetCore.Mvc.Razor.DictionaryPrefixTestTagHelper __Microsoft_AspNetCore_Mvc_Razor_DictionaryPrefixTestTagHelper = null;
         #line hidden
         public TestFiles_Input_ModelExpressionTagHelper_cshtml()
         {
@@ -42,26 +43,7 @@ namespace AspNetCore
         {
             __tagHelperRunner = __tagHelperRunner ?? new global::Microsoft.AspNetCore.Razor.Runtime.TagHelpers.TagHelperRunner();
             __tagHelperScopeManager = __tagHelperScopeManager ?? new global::Microsoft.AspNetCore.Razor.Runtime.TagHelpers.TagHelperScopeManager(StartTagHelperWritingScope, EndTagHelperWritingScope);
-            BeginContext(126, 2, true);
-            WriteLiteral("\r\n");
-            EndContext();
-            __tagHelperExecutionContext = __tagHelperScopeManager.Begin("input-test", global::Microsoft.AspNetCore.Razor.TagHelpers.TagMode.SelfClosing, "test", async() => {
-            }
-            );
-            __Microsoft_AspNetCore_Mvc_Razor_InputTestTagHelper = CreateTagHelper<global::Microsoft.AspNetCore.Mvc.Razor.InputTestTagHelper>();
-            __tagHelperExecutionContext.Add(__Microsoft_AspNetCore_Mvc_Razor_InputTestTagHelper);
-#line 5 "TestFiles/Input/ModelExpressionTagHelper.cshtml"
-__Microsoft_AspNetCore_Mvc_Razor_InputTestTagHelper.For = ModelExpressionProvider.CreateModelExpression(ViewData, __model => __model.Now);
-
-#line default
-#line hidden
-            __tagHelperExecutionContext.AddTagHelperAttribute("for", __Microsoft_AspNetCore_Mvc_Razor_InputTestTagHelper.For, global::Microsoft.AspNetCore.Razor.TagHelpers.HtmlAttributeValueStyle.DoubleQuotes);
-            await __tagHelperRunner.RunAsync(__tagHelperExecutionContext);
-            BeginContext(128, 24, false);
-            Write(__tagHelperExecutionContext.Output);
-            EndContext();
-            __tagHelperExecutionContext = __tagHelperScopeManager.End();
-            BeginContext(152, 2, true);
+            BeginContext(244, 2, true);
             WriteLiteral("\r\n");
             EndContext();
             __tagHelperExecutionContext = __tagHelperScopeManager.Begin("input-test", global::Microsoft.AspNetCore.Razor.TagHelpers.TagMode.SelfClosing, "test", async() => {
@@ -70,13 +52,84 @@ __Microsoft_AspNetCore_Mvc_Razor_InputTestTagHelper.For = ModelExpressionProvide
             __Microsoft_AspNetCore_Mvc_Razor_InputTestTagHelper = CreateTagHelper<global::Microsoft.AspNetCore.Mvc.Razor.InputTestTagHelper>();
             __tagHelperExecutionContext.Add(__Microsoft_AspNetCore_Mvc_Razor_InputTestTagHelper);
 #line 6 "TestFiles/Input/ModelExpressionTagHelper.cshtml"
+__Microsoft_AspNetCore_Mvc_Razor_InputTestTagHelper.For = ModelExpressionProvider.CreateModelExpression(ViewData, __model => __model.Now);
+
+#line default
+#line hidden
+            __tagHelperExecutionContext.AddTagHelperAttribute("for", __Microsoft_AspNetCore_Mvc_Razor_InputTestTagHelper.For, global::Microsoft.AspNetCore.Razor.TagHelpers.HtmlAttributeValueStyle.DoubleQuotes);
+            await __tagHelperRunner.RunAsync(__tagHelperExecutionContext);
+            BeginContext(246, 24, false);
+            Write(__tagHelperExecutionContext.Output);
+            EndContext();
+            __tagHelperExecutionContext = __tagHelperScopeManager.End();
+            BeginContext(270, 2, true);
+            WriteLiteral("\r\n");
+            EndContext();
+            __tagHelperExecutionContext = __tagHelperScopeManager.Begin("input-test", global::Microsoft.AspNetCore.Razor.TagHelpers.TagMode.SelfClosing, "test", async() => {
+            }
+            );
+            __Microsoft_AspNetCore_Mvc_Razor_InputTestTagHelper = CreateTagHelper<global::Microsoft.AspNetCore.Mvc.Razor.InputTestTagHelper>();
+            __tagHelperExecutionContext.Add(__Microsoft_AspNetCore_Mvc_Razor_InputTestTagHelper);
+#line 7 "TestFiles/Input/ModelExpressionTagHelper.cshtml"
 __Microsoft_AspNetCore_Mvc_Razor_InputTestTagHelper.For = ModelExpressionProvider.CreateModelExpression(ViewData, __model => Model);
 
 #line default
 #line hidden
             __tagHelperExecutionContext.AddTagHelperAttribute("for", __Microsoft_AspNetCore_Mvc_Razor_InputTestTagHelper.For, global::Microsoft.AspNetCore.Razor.TagHelpers.HtmlAttributeValueStyle.DoubleQuotes);
             await __tagHelperRunner.RunAsync(__tagHelperExecutionContext);
-            BeginContext(154, 27, false);
+            BeginContext(272, 27, false);
+            Write(__tagHelperExecutionContext.Output);
+            EndContext();
+            __tagHelperExecutionContext = __tagHelperScopeManager.End();
+            BeginContext(299, 4, true);
+            WriteLiteral("\r\n\r\n");
+            EndContext();
+            __tagHelperExecutionContext = __tagHelperScopeManager.Begin("div", global::Microsoft.AspNetCore.Razor.TagHelpers.TagMode.StartTagAndEndTag, "test", async() => {
+            }
+            );
+            __Microsoft_AspNetCore_Mvc_Razor_DictionaryPrefixTestTagHelper = CreateTagHelper<global::Microsoft.AspNetCore.Mvc.Razor.DictionaryPrefixTestTagHelper>();
+            __tagHelperExecutionContext.Add(__Microsoft_AspNetCore_Mvc_Razor_DictionaryPrefixTestTagHelper);
+            if (__Microsoft_AspNetCore_Mvc_Razor_DictionaryPrefixTestTagHelper.PrefixValues == null)
+            {
+                throw new InvalidOperationException(InvalidTagHelperIndexerAssignment("prefix-test", "Microsoft.AspNetCore.Mvc.Razor.DictionaryPrefixTestTagHelper", "PrefixValues"));
+            }
+#line 9 "TestFiles/Input/ModelExpressionTagHelper.cshtml"
+__Microsoft_AspNetCore_Mvc_Razor_DictionaryPrefixTestTagHelper.PrefixValues["test"] = ModelExpressionProvider.CreateModelExpression(ViewData, __model => Model);
+
+#line default
+#line hidden
+            __tagHelperExecutionContext.AddTagHelperAttribute("prefix-test", __Microsoft_AspNetCore_Mvc_Razor_DictionaryPrefixTestTagHelper.PrefixValues["test"], global::Microsoft.AspNetCore.Razor.TagHelpers.HtmlAttributeValueStyle.DoubleQuotes);
+            await __tagHelperRunner.RunAsync(__tagHelperExecutionContext);
+            BeginContext(303, 33, false);
+            Write(__tagHelperExecutionContext.Output);
+            EndContext();
+            __tagHelperExecutionContext = __tagHelperScopeManager.End();
+            BeginContext(336, 2, true);
+            WriteLiteral("\r\n");
+            EndContext();
+            __tagHelperExecutionContext = __tagHelperScopeManager.Begin("span", global::Microsoft.AspNetCore.Razor.TagHelpers.TagMode.StartTagAndEndTag, "test", async() => {
+            }
+            );
+            __Microsoft_AspNetCore_Mvc_Razor_DictionaryPrefixTestTagHelper = CreateTagHelper<global::Microsoft.AspNetCore.Mvc.Razor.DictionaryPrefixTestTagHelper>();
+            __tagHelperExecutionContext.Add(__Microsoft_AspNetCore_Mvc_Razor_DictionaryPrefixTestTagHelper);
+            if (__Microsoft_AspNetCore_Mvc_Razor_DictionaryPrefixTestTagHelper.PrefixValues == null)
+            {
+                throw new InvalidOperationException(InvalidTagHelperIndexerAssignment("prefix-hour", "Microsoft.AspNetCore.Mvc.Razor.DictionaryPrefixTestTagHelper", "PrefixValues"));
+            }
+#line 10 "TestFiles/Input/ModelExpressionTagHelper.cshtml"
+__Microsoft_AspNetCore_Mvc_Razor_DictionaryPrefixTestTagHelper.PrefixValues["hour"] = ModelExpressionProvider.CreateModelExpression(ViewData, __model => __model.Hour);
+
+#line default
+#line hidden
+            __tagHelperExecutionContext.AddTagHelperAttribute("prefix-hour", __Microsoft_AspNetCore_Mvc_Razor_DictionaryPrefixTestTagHelper.PrefixValues["hour"], global::Microsoft.AspNetCore.Razor.TagHelpers.HtmlAttributeValueStyle.DoubleQuotes);
+#line 10 "TestFiles/Input/ModelExpressionTagHelper.cshtml"
+__Microsoft_AspNetCore_Mvc_Razor_DictionaryPrefixTestTagHelper.PrefixValues["minute"] = ModelExpressionProvider.CreateModelExpression(ViewData, __model => __model.Minute);
+
+#line default
+#line hidden
+            __tagHelperExecutionContext.AddTagHelperAttribute("prefix-minute", __Microsoft_AspNetCore_Mvc_Razor_DictionaryPrefixTestTagHelper.PrefixValues["minute"], global::Microsoft.AspNetCore.Razor.TagHelpers.HtmlAttributeValueStyle.DoubleQuotes);
+            await __tagHelperRunner.RunAsync(__tagHelperExecutionContext);
+            BeginContext(338, 55, false);
             Write(__tagHelperExecutionContext.Output);
             EndContext();
             __tagHelperExecutionContext = __tagHelperScopeManager.End();
diff --git a/test/WebSites/TagHelpersWebSite/TagHelpers/DictionaryPrefixTestTagHelper.cs b/test/WebSites/TagHelpersWebSite/TagHelpers/DictionaryPrefixTestTagHelper.cs
new file mode 100644
index 0000000000..08b015a4fe
--- /dev/null
+++ b/test/WebSites/TagHelpersWebSite/TagHelpers/DictionaryPrefixTestTagHelper.cs
@@ -0,0 +1,33 @@
+// 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 Microsoft.AspNetCore.Mvc.Rendering;
+using Microsoft.AspNetCore.Mvc.ViewFeatures;
+using Microsoft.AspNetCore.Razor.TagHelpers;
+
+namespace TagHelpersWebSite.TagHelpers
+{
+    [HtmlTargetElement(Attributes = "prefix-*")]
+    public class DictionaryPrefixTestTagHelper : TagHelper
+    {
+        [HtmlAttributeName(DictionaryAttributePrefix = "prefix-")]
+        public IDictionary<string, ModelExpression> PrefixValues { get; set; } = new Dictionary<string, ModelExpression>();
+
+        public override void Process(TagHelperContext context, TagHelperOutput output)
+        {
+            var ulTag = new TagBuilder("ul");
+
+            foreach (var item in PrefixValues)
+            {
+                var liTag = new TagBuilder("li");
+                
+                liTag.InnerHtml.Append(item.Value.Name);
+
+                ulTag.InnerHtml.AppendHtml(liTag);
+            }
+
+            output.Content.SetHtmlContent(ulTag);
+        }
+    }
+}
diff --git a/test/WebSites/TagHelpersWebSite/Views/Home/Index.cshtml b/test/WebSites/TagHelpersWebSite/Views/Home/Index.cshtml
index ca2c33b94e..2af1cd0a61 100644
--- a/test/WebSites/TagHelpersWebSite/Views/Home/Index.cshtml
+++ b/test/WebSites/TagHelpersWebSite/Views/Home/Index.cshtml
@@ -43,6 +43,11 @@
     }
 </div>
 
+<div>
+    <h3>Dictionary Valued Model Expression</h3>
+    <div prefix-test1="@Model.TagsToShow" prefix-test2="@Model.Version.Build"></div>
+</div>
+
 @section footerContent {
     <p condition="Model.Approved" bold surround="section">&copy; @Model.CopyrightYear - My ASP.NET Application</p>
 }
\ No newline at end of file