Fix up error message when compilation references are missing

src/Microsoft.AspNetCore.Mvc.Razor/Internal/CompilationFailedExceptionFactory.cs

@@ -77,9 +77,8 @@ namespace Microsoft.AspNetCore.Mvc.Razor.Internal
                     string.Equals(CS0234, g.Id, StringComparison.OrdinalIgnoreCase) ||
                     string.Equals(CS0246, g.Id, StringComparison.OrdinalIgnoreCase)))
                 {
-                    additionalMessage = Resources.FormatCompilation_DependencyContextIsNotSpecified(
+                    additionalMessage = Resources.FormatCompilation_MissingReferences(
-                        "Microsoft.NET.Sdk.Web",
+                        "CopyRefAssembliesToPublishDirectory");
-                        "PreserveCompilationContext");
                 }
 
                 var compilationFailure = new CompilationFailure(

src/Microsoft.AspNetCore.Mvc.Razor/Properties/Resources.Designer.cs

@@ -267,18 +267,18 @@ namespace Microsoft.AspNetCore.Mvc.Razor
             => string.Format(CultureInfo.CurrentCulture, GetString("LayoutHasCircularReference"), p0, p1);
 
         /// <summary>
-        /// One or more compilation references are missing. Ensure that your project is referencing '{0}' and the '{1}' property is not set to false.
+        /// One or more compilation references may be missing. If you're seeing this in a published application, set '{0}' to true in your project file to ensure files in the refs directory are published.
         /// </summary>
-        internal static string Compilation_DependencyContextIsNotSpecified
+        internal static string Compilation_MissingReferences
         {
-            get => GetString("Compilation_DependencyContextIsNotSpecified");
+            get => GetString("Compilation_MissingReferences");
         }
 
         /// <summary>
-        /// One or more compilation references are missing. Ensure that your project is referencing '{0}' and the '{1}' property is not set to false.
+        /// One or more compilation references may be missing. If you're seeing this in a published application, set '{0}' to true in your project file to ensure files in the refs directory are published.
         /// </summary>
-        internal static string FormatCompilation_DependencyContextIsNotSpecified(object p0, object p1)
+        internal static string FormatCompilation_MissingReferences(object p0)
-            => string.Format(CultureInfo.CurrentCulture, GetString("Compilation_DependencyContextIsNotSpecified"), p0, p1);
+            => string.Format(CultureInfo.CurrentCulture, GetString("Compilation_MissingReferences"), p0);
 
         /// <summary>
         /// '{0}' cannot be empty. These locations are required to locate a view for rendering.

src/Microsoft.AspNetCore.Mvc.Razor/Resources.resx

@@ -173,8 +173,8 @@
   <data name="LayoutHasCircularReference" xml:space="preserve">
     <value>A circular layout reference was detected when rendering '{0}'. The layout page '{1}' has already been rendered.</value>
   </data>
-  <data name="Compilation_DependencyContextIsNotSpecified" xml:space="preserve">
+  <data name="Compilation_MissingReferences" xml:space="preserve">
-    <value>One or more compilation references are missing. Ensure that your project is referencing '{0}' and the '{1}' property is not set to false.</value>
+    <value>One or more compilation references may be missing. If you're seeing this in a published application, set '{0}' to true in your project file to ensure files in the refs directory are published.</value>
   </data>
   <data name="ViewLocationFormatsIsRequired" xml:space="preserve">
     <value>'{0}' cannot be empty. These locations are required to locate a view for rendering.</value>

test/Microsoft.AspNetCore.Mvc.FunctionalTests/AntiforgeryTestHelper.cs

@@ -39,7 +39,7 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
                 }
             }
 
-            throw new Exception($"Antiforgery token could not be located in {htmlDocument.TextContent}.");
+            throw new Exception($"Antiforgery token could not be located in {htmlDocument.Source.Text}.");
         }
 
         public static CookieMetadata RetrieveAntiforgeryCookie(HttpResponseMessage response)

test/Microsoft.AspNetCore.Mvc.FunctionalTests/ErrorPageTests.cs

@@ -6,7 +6,6 @@ using System.Net.Http;
 using System.Net.Http.Headers;
 using System.Text.Encodings.Web;
 using System.Threading.Tasks;
-using Microsoft.AspNetCore.Mvc.Razor.Internal;
 using Xunit;
 
 namespace Microsoft.AspNetCore.Mvc.FunctionalTests
@@ -17,8 +16,8 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
     public class ErrorPageTests : IClassFixture<MvcTestFixture<ErrorPageMiddlewareWebSite.Startup>>
     {
         private static readonly string PreserveCompilationContextMessage = HtmlEncoder.Default.Encode(
-            "One or more compilation references are missing. Ensure that your project is referencing " +
+            "One or more compilation references may be missing. " +
-            "'Microsoft.NET.Sdk.Web' and the 'PreserveCompilationContext' property is not set to false.");
+            "If you're seeing this in a published application, set 'CopyRefAssembliesToPublishDirectory' to true in your project file to ensure files in the refs directory are published.");
         public ErrorPageTests(MvcTestFixture<ErrorPageMiddlewareWebSite.Startup> fixture)
         {
             Client = fixture.CreateDefaultClient();

test/Microsoft.AspNetCore.Mvc.Razor.Test/Internal/CompilerFailedExceptionFactoryTest.cs

@@ -2,10 +2,12 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System.IO;
+using System.Linq;
 using System.Text;
 using Microsoft.AspNetCore.Mvc.Razor.Extensions;
 using Microsoft.AspNetCore.Razor.Language;
 using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp;
 using Microsoft.CodeAnalysis.Text;
 using Xunit;
 
@@ -43,6 +45,29 @@ namespace Microsoft.AspNetCore.Mvc.Razor.Internal
                     message.Message));
         }
 
+        [Fact]
+        public void GetCompilationFailedResult_WithMissingReferences()
+        {
+            // Arrange
+            var expected = "One or more compilation references may be missing. If you're seeing this in a published application, set 'CopyRefAssembliesToPublishDirectory' to true in your project file to ensure files in the refs directory are published.";
+            var compilation = CSharpCompilation.Create("Test", options: new CSharpCompilationOptions(OutputKind.DynamicallyLinkedLibrary));
+            var syntaxTree = CSharpSyntaxTree.ParseText("@class Test { public string Test { get; set; } }");
+            compilation = compilation.AddSyntaxTrees(syntaxTree);
+            var emitResult = compilation.Emit(new MemoryStream());
+
+            // Act
+            var exception = CompilationFailedExceptionFactory.Create(
+                RazorCodeDocument.Create(RazorSourceDocument.Create("Test", "Index.cshtml"), Enumerable.Empty<RazorSourceDocument>()),
+                syntaxTree.ToString(),
+                "Test",
+                emitResult.Diagnostics);
+
+            // Assert
+            Assert.Collection(
+                exception.CompilationFailures,
+                failure => Assert.Equal(expected, failure.FailureSummary));
+        }
+
         [Fact]
         public void GetCompilationFailedResult_UsesPhysicalPath()
         {