Merge remote-tracking branch 'origin/release/2.2'

src/Microsoft.AspNetCore.Mvc.Analyzers/CodeAnalysisExtensions.cs

@@ -123,7 +123,7 @@ namespace Microsoft.CodeAnalysis
             return false;
         }
 
-        private static bool HasAttribute(this ISymbol symbol, ITypeSymbol attribute)
+        public static bool HasAttribute(this ISymbol symbol, ITypeSymbol attribute)
         {
             foreach (var declaredAttribute in symbol.GetAttributes())
             {

src/Microsoft.AspNetCore.Mvc.Analyzers/MvcFacts.cs

@@ -116,6 +116,11 @@ namespace Microsoft.AspNetCore.Mvc.Analyzers
                 return false;
             }
 
+            if (!method.ReturnsVoid)
+            {
+                return false;
+            }
+
             if (method.Parameters.Length != disposableDispose.Parameters.Length)
             {
                 return false;

src/Microsoft.AspNetCore.Mvc.Api.Analyzers/ApiControllerSymbolCache.cs

@@ -2,6 +2,7 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
+using System.Diagnostics;
 using Microsoft.CodeAnalysis;
 
 namespace Microsoft.AspNetCore.Mvc.Api.Analyzers
@@ -24,6 +25,11 @@ namespace Microsoft.AspNetCore.Mvc.Api.Analyzers
             ProducesDefaultResponseTypeAttribute = compilation.GetTypeByMetadataName(ApiSymbolNames.ProducesDefaultResponseTypeAttribute);
             ProducesResponseTypeAttribute = compilation.GetTypeByMetadataName(ApiSymbolNames.ProducesResponseTypeAttribute);
 
+            StatusCodeValueAttribute = compilation.GetTypeByMetadataName(ApiSymbolNames.StatusCodeValueAttribute);
+
+            var statusCodeActionResult = compilation.GetTypeByMetadataName(ApiSymbolNames.IStatusCodeActionResult);
+            StatusCodeActionResultStatusProperty = (IPropertySymbol)statusCodeActionResult?.GetMembers("StatusCode")[0];
+
             var disposable = compilation.GetSpecialType(SpecialType.System_IDisposable);
             var members = disposable.GetMembers(nameof(IDisposable.Dispose));
             IDisposableDispose = members.Length == 1 ? (IMethodSymbol)members[0] : null;
@@ -47,6 +53,8 @@ namespace Microsoft.AspNetCore.Mvc.Api.Analyzers
 
         public IMethodSymbol IDisposableDispose { get; }
 
+        public IPropertySymbol StatusCodeActionResultStatusProperty { get; }
+
         public ITypeSymbol ModelStateDictionary { get; }
 
         public INamedTypeSymbol NonActionAttribute { get; }
@@ -56,5 +64,7 @@ namespace Microsoft.AspNetCore.Mvc.Api.Analyzers
         public INamedTypeSymbol ProducesDefaultResponseTypeAttribute { get; }
 
         public INamedTypeSymbol ProducesResponseTypeAttribute { get; }
+
+        public INamedTypeSymbol StatusCodeValueAttribute { get; }
     }
 }

src/Microsoft.AspNetCore.Mvc.Api.Analyzers/ApiSymbolNames.cs

@@ -23,6 +23,8 @@ namespace Microsoft.AspNetCore.Mvc.Api.Analyzers
 
         public const string IActionResult = "Microsoft.AspNetCore.Mvc.IActionResult";
 
+        public const string IStatusCodeActionResult = "Microsoft.AspNetCore.Mvc.Infrastructure.IStatusCodeActionResult";
+
         public const string ModelStateDictionary = "Microsoft.AspNetCore.Mvc.ModelBinding.ModelStateDictionary";
 
         public const string NonActionAttribute = "Microsoft.AspNetCore.Mvc.NonActionAttribute";
@@ -34,5 +36,7 @@ namespace Microsoft.AspNetCore.Mvc.Api.Analyzers
         public const string ProducesResponseTypeAttribute = "Microsoft.AspNetCore.Mvc.ProducesResponseTypeAttribute";
 
         public const string HttpStatusCodes = "Microsoft.AspNetCore.Http.StatusCodes";
+
+        public const string StatusCodeValueAttribute = "Microsoft.AspNetCore.Mvc.Infrastructure.StatusCodeValueAttribute";
     }
 }

src/Microsoft.AspNetCore.Mvc.Api.Analyzers/SymbolApiResponseMetadataProvider.cs

@@ -61,7 +61,8 @@ namespace Microsoft.AspNetCore.Mvc.Api.Analyzers
             }
 
             return Array.Empty<DeclaredApiResponseMetadata>();
-       }
+        }
+
         private static IMethodSymbol GetMethodFromConventionMethodAttribute(ApiControllerSymbolCache symbolCache, IMethodSymbol method)
         {
             var attribute = method.GetAttributes(symbolCache.ApiConventionMethodAttribute, inherit: true)
@@ -222,6 +223,12 @@ namespace Microsoft.AspNetCore.Mvc.Api.Analyzers
 
             foreach (var returnStatementSyntax in methodSyntax.DescendantNodes(_shouldDescendIntoChildren).OfType<ReturnStatementSyntax>())
             {
+                if (returnStatementSyntax.IsMissing || returnStatementSyntax.Expression.IsMissing)
+                {
+                    // Ignore malformed return statements.
+                    continue;
+                }
+
                 var responseMetadata = InspectReturnStatementSyntax(
                     symbolCache,
                     semanticModel,
@@ -248,11 +255,6 @@ namespace Microsoft.AspNetCore.Mvc.Api.Analyzers
             CancellationToken cancellationToken)
         {
             var returnExpression = returnStatementSyntax.Expression;
-            if (returnExpression.IsMissing)
-            {
-                return null;
-            }
-
             var typeInfo = semanticModel.GetTypeInfo(returnExpression, cancellationToken);
             if (typeInfo.Type.TypeKind == TypeKind.Error)
             {
@@ -267,25 +269,176 @@ namespace Microsoft.AspNetCore.Mvc.Api.Analyzers
 
             if (defaultStatusCodeAttribute != null)
             {
-                var statusCode = GetDefaultStatusCode(defaultStatusCodeAttribute);
+                var defaultStatusCode = GetDefaultStatusCode(defaultStatusCodeAttribute);
-                if (statusCode == null)
+                if (defaultStatusCode == null)
                 {
                     // Unable to read the status code even though the attribute exists.
                     return null;
                 }
 
-                return new ActualApiResponseMetadata(returnStatementSyntax, statusCode.Value);
+                return new ActualApiResponseMetadata(returnStatementSyntax, defaultStatusCode.Value);
             }
-            else if (!symbolCache.IActionResult.IsAssignableFrom(statementReturnType))
+
+            if (!symbolCache.IActionResult.IsAssignableFrom(statementReturnType))
             {
                 // Return expression does not have a DefaultStatusCodeAttribute and it is not
                 // an instance of IActionResult. Must be returning the "model".
                 return new ActualApiResponseMetadata(returnStatementSyntax);
             }
 
+            int statusCode;
+            switch (returnExpression)
+            {
+                case InvocationExpressionSyntax invocation:
+                    // Covers the 'return StatusCode(200)' case.
+                    if (TryGetParameterStatusCode(symbolCache, semanticModel, invocation.Expression, invocation.ArgumentList, cancellationToken, out statusCode))
+                    {
+                        return new ActualApiResponseMetadata(returnStatementSyntax, statusCode);
+                    }
+                    break;
+
+                case ObjectCreationExpressionSyntax creation:
+                    // Covers the 'return new ObjectResult(...) { StatusCode = 200 }' case.
+                    if (TryGetInitializerStatusCode(symbolCache, semanticModel, creation.Initializer, cancellationToken, out statusCode))
+                    {
+                        return new ActualApiResponseMetadata(returnStatementSyntax, statusCode);
+                    }
+
+                    // Covers the 'return new StatusCodeResult(200) case.
+                    if (TryGetParameterStatusCode(symbolCache, semanticModel, creation, creation.ArgumentList, cancellationToken, out statusCode))
+                    {
+                        return new ActualApiResponseMetadata(returnStatementSyntax, statusCode);
+                    }
+                    break;
+            }
+
             return null;
         }
 
+        private static bool TryGetInitializerStatusCode(
+            in ApiControllerSymbolCache symbolCache,
+            SemanticModel semanticModel,
+            InitializerExpressionSyntax initializer,
+            CancellationToken cancellationToken,
+            out int statusCode)
+        {
+            if (initializer == null)
+            {
+                statusCode = default;
+                return false;
+            }
+
+            for (var i = 0; i < initializer.Expressions.Count; i++)
+            {
+                if (!(initializer.Expressions[i] is AssignmentExpressionSyntax assignment))
+                {
+                    continue;
+                }
+
+                if (assignment.Left is IdentifierNameSyntax identifier)
+                {
+                    var symbolInfo = semanticModel.GetSymbolInfo(identifier, cancellationToken);
+
+                    if (symbolInfo.Symbol is IPropertySymbol property && IsInterfaceImplementation(property, symbolCache.StatusCodeActionResultStatusProperty))
+                    {
+                        return TryGetExpressionStatusCode(semanticModel, assignment.Right, cancellationToken, out statusCode);
+                    }
+                }
+            }
+
+            statusCode = default;
+            return false;
+        }
+
+        private static bool IsInterfaceImplementation(IPropertySymbol property, IPropertySymbol statusCodeActionResultStatusProperty)
+        {
+            if (property.Name != statusCodeActionResultStatusProperty.Name)
+            {
+                return false;
+            }
+
+            for (var i = 0; i < property.ExplicitInterfaceImplementations.Length; i++)
+            {
+                if (property.ExplicitInterfaceImplementations[i] == statusCodeActionResultStatusProperty)
+                {
+                    return true;
+                }
+            }
+
+            var implementedProperty = property.ContainingType.FindImplementationForInterfaceMember(statusCodeActionResultStatusProperty);
+            return implementedProperty == property;
+        }
+
+        private static bool TryGetParameterStatusCode(
+            in ApiControllerSymbolCache symbolCache,
+            SemanticModel semanticModel,
+            ExpressionSyntax expression,
+            BaseArgumentListSyntax argumentList,
+            CancellationToken cancellationToken,
+            out int statusCode)
+        {
+            var symbolInfo = semanticModel.GetSymbolInfo(expression, cancellationToken);
+
+            if (!(symbolInfo.Symbol is IMethodSymbol method))
+            {
+                statusCode = default;
+                return false;
+            }
+
+            for (var i = 0; i < method.Parameters.Length; i++)
+            {
+                var parameter = method.Parameters[i];
+                if (!parameter.HasAttribute(symbolCache.StatusCodeValueAttribute))
+                {
+                    continue;
+                }
+
+
+                var argument = argumentList.Arguments[parameter.Ordinal];
+                return TryGetExpressionStatusCode(semanticModel, argument.Expression, cancellationToken, out statusCode);
+            }
+
+            statusCode = default;
+            return false;
+        }
+
+        private static bool TryGetExpressionStatusCode(
+            SemanticModel semanticModel,
+            ExpressionSyntax expression,
+            CancellationToken cancellationToken,
+            out int statusCode)
+        {
+            if (expression is LiteralExpressionSyntax literal && literal.Token.Value is int literalStatusCode)
+            {
+                // Covers the 'return StatusCode(200)' case.
+                statusCode = literalStatusCode;
+                return true;
+            }
+
+            if (expression is IdentifierNameSyntax || expression is MemberAccessExpressionSyntax)
+            {
+                var symbolInfo = semanticModel.GetSymbolInfo(expression, cancellationToken);
+
+                if (symbolInfo.Symbol is IFieldSymbol field && field.HasConstantValue && field.ConstantValue is int constantStatusCode)
+                {
+                    // Covers the 'return StatusCode(StatusCodes.Status200OK)' case.
+                    // It also covers the 'return StatusCode(StatusCode)' case, where 'StatusCode' is a constant field.
+                    statusCode = constantStatusCode;
+                    return true;
+                }
+
+                if (symbolInfo.Symbol is ILocalSymbol local && local.HasConstantValue && local.ConstantValue is int localStatusCode)
+                {
+                    // Covers the 'return StatusCode(statusCode)' case, where 'statusCode' is a local constant.
+                    statusCode = localStatusCode;
+                    return true;
+                }
+            }
+
+            statusCode = default;
+            return false;
+        }
+
         private static bool ShouldDescendIntoChildren(SyntaxNode syntaxNode)
         {
             return !syntaxNode.IsKind(SyntaxKind.LocalFunctionStatement) &&

src/Microsoft.AspNetCore.Mvc.ApiExplorer/ApiResponseTypeProvider.cs

@@ -46,7 +46,13 @@ namespace Microsoft.AspNetCore.Mvc.ApiExplorer
                 responseMetadataAttributes = apiConventionResult.ResponseMetadataProviders;
             }
 
-            var apiResponseTypes = GetApiResponseTypes(responseMetadataAttributes, runtimeReturnType);
+            var defaultErrorType = typeof(void);
+            if (action.Properties.TryGetValue(typeof(ProducesErrorResponseTypeAttribute), out result))
+            {
+                defaultErrorType = ((ProducesErrorResponseTypeAttribute)result).Type;
+            }
+
+            var apiResponseTypes = GetApiResponseTypes(responseMetadataAttributes, runtimeReturnType, defaultErrorType);
             return apiResponseTypes;
         }
 
@@ -69,7 +75,8 @@ namespace Microsoft.AspNetCore.Mvc.ApiExplorer
 
         private ICollection<ApiResponseType> GetApiResponseTypes(
            IReadOnlyList<IApiResponseMetadataProvider> responseMetadataAttributes,
-           Type type)
+           Type type,
+           Type defaultErrorType)
         {
             var results = new Dictionary<int, ApiResponseType>();
 
@@ -83,48 +90,39 @@ namespace Microsoft.AspNetCore.Mvc.ApiExplorer
                 {
                     metadataAttribute.SetContentTypes(contentTypes);
 
-                    ApiResponseType apiResponseType;
+                    var statusCode = metadataAttribute.StatusCode;
 
-                    if (metadataAttribute is IApiDefaultResponseMetadataProvider)
+                    var apiResponseType = new ApiResponseType
                     {
-                        apiResponseType = new ApiResponseType
+                        Type = metadataAttribute.Type,
+                        StatusCode = statusCode,
+                        IsDefaultResponse = metadataAttribute is IApiDefaultResponseMetadataProvider,
+                    };
+
+                    if (apiResponseType.Type == typeof(void))
+                    {
+                        if (type != null && (statusCode == StatusCodes.Status200OK || statusCode == StatusCodes.Status201Created))
                         {
-                            IsDefaultResponse = true,
+                            // ProducesResponseTypeAttribute's constructor defaults to setting "Type" to void when no value is specified.
-                            Type = metadataAttribute.Type,
+                            // In this event, use the action's return type for 200 or 201 status codes. This lets you decorate an action with a
-                        };
+                            // [ProducesResponseType(201)] instead of [ProducesResponseType(201, typeof(Person)] when typeof(Person) can be inferred
-                    }
+                            // from the return type.
-                    else if (metadataAttribute.Type == typeof(void) &&
+                            apiResponseType.Type = type;
-                        type != null &&
+                        }
-                        (metadataAttribute.StatusCode == StatusCodes.Status200OK || metadataAttribute.StatusCode == StatusCodes.Status201Created))
+                        else if (IsClientError(statusCode) || apiResponseType.IsDefaultResponse)
-                    {
-                        // ProducesResponseTypeAttribute's constructor defaults to setting "Type" to void when no value is specified.
-                        // In this event, use the action's return type for 200 or 201 status codes. This lets you decorate an action with a
-                        // [ProducesResponseType(201)] instead of [ProducesResponseType(201, typeof(Person)] when typeof(Person) can be inferred
-                        // from the return type.
-                        apiResponseType = new ApiResponseType
                         {
-                            StatusCode = metadataAttribute.StatusCode,
+                            // Use the default error type for "default" responses or 4xx client errors if no response type is specified.
-                            Type = type,
+                            apiResponseType.Type = defaultErrorType;
-                        };
+                        }
-                    }
-                    else if (metadataAttribute.Type != null)
-                    {
-                        apiResponseType = new ApiResponseType
-                        {
-                            StatusCode = metadataAttribute.StatusCode,
-                            Type = metadataAttribute.Type,
-                        };
-                    }
-                    else
-                    {
-                        continue;
                     }
 
-                    results[apiResponseType.StatusCode] = apiResponseType;
+                    if (apiResponseType.Type != null)
+                    {
+                        results[apiResponseType.StatusCode] = apiResponseType;
+                    }
                 }
             }
 
-
             // Set the default status only when no status has already been set explicitly
             if (results.Count == 0 && type != null)
             {
@@ -225,5 +223,10 @@ namespace Microsoft.AspNetCore.Mvc.ApiExplorer
 
             return declaredReturnType;
         }
+
+        private static bool IsClientError(int statusCode)
+        {
+            return statusCode >= 400 && statusCode < 500;
+        }
     }
 }

src/Microsoft.AspNetCore.Mvc.Core/ApiBehaviorOptions.cs

@@ -15,7 +15,7 @@ namespace Microsoft.AspNetCore.Mvc
     /// </summary>
     public class ApiBehaviorOptions : IEnumerable<ICompatibilitySwitch>
     {
-        private readonly CompatibilitySwitch<bool> _suppressUseClientErrorFactory;
+        private readonly CompatibilitySwitch<bool> _suppressMapClientErrors;
         private readonly CompatibilitySwitch<bool> _suppressUseValidationProblemDetailsForInvalidModelStateResponses;
         private readonly ICompatibilitySwitch[] _switches;
 
@@ -26,11 +26,11 @@ namespace Microsoft.AspNetCore.Mvc
         /// </summary>
         public ApiBehaviorOptions()
         {
-            _suppressUseClientErrorFactory = new CompatibilitySwitch<bool>(nameof(SuppressUseClientErrorFactory));
+            _suppressMapClientErrors = new CompatibilitySwitch<bool>(nameof(SuppressMapClientErrors));
             _suppressUseValidationProblemDetailsForInvalidModelStateResponses = new CompatibilitySwitch<bool>(nameof(SuppressUseValidationProblemDetailsForInvalidModelStateResponses));
             _switches = new[]
             {
-                _suppressUseClientErrorFactory,
+                _suppressMapClientErrors,
                 _suppressUseValidationProblemDetailsForInvalidModelStateResponses,
             };
         }
@@ -71,12 +71,16 @@ namespace Microsoft.AspNetCore.Mvc
         public bool SuppressConsumesConstraintForFormFileParameters { get; set; }
 
         /// <summary>
-        /// Gets or sets a value that determines if controllers with <see cref="ApiControllerAttribute"/> use <see cref="ClientErrorFactory"/>
+        /// Gets or sets a value that determines if controllers with <see cref="ApiControllerAttribute"/>
-        /// to transform certain certain client errors.
+        /// transform certain certain client errors.
         /// <para>
-        /// When <c>false</c>, <see cref="ClientErrorFactory"/> is used to transform <see cref="IClientErrorActionResult"/> to the value
+        /// When <c>false</c>, a result filter is added to API controller actions that transforms <see cref="IClientErrorActionResult"/>.
-        /// specified by the factory. In the default case, this converts <see cref="StatusCodeResult"/> instances to an <see cref="ObjectResult"/>
+        /// By default, <see cref="ClientErrorMapping"/> is used to map <see cref="IClientErrorActionResult"/> to a
-        /// with <see cref="ProblemDetails"/>.
+        /// <see cref="ProblemDetails"/> instance (returned as the value for <see cref="ObjectResult"/>).
+        /// </para>
+        /// <para>
+        /// To customize the output of the filter (for e.g. to return a different error type), register a custom
+        /// implementation of of <see cref="IClientErrorFactory"/> in the service collection.
         /// </para>
         /// </summary>
         /// <value>
@@ -102,11 +106,11 @@ namespace Microsoft.AspNetCore.Mvc
         /// higher then this setting will have the value <see langword="true"/> unless explicitly configured.
         /// </para>
         /// </remarks>
-        public bool SuppressUseClientErrorFactory
+        public bool SuppressMapClientErrors
         {
             // Note: When compatibility switches are removed in 3.0, this property should be retained as a regular boolean property.
-            get => _suppressUseClientErrorFactory.Value;
+            get => _suppressMapClientErrors.Value;
-            set => _suppressUseClientErrorFactory.Value = value;
+            set => _suppressMapClientErrors.Value = value;
         }
 
         /// <summary>
@@ -148,11 +152,15 @@ namespace Microsoft.AspNetCore.Mvc
         }
 
         /// <summary>
-        /// Gets a map of HTTP status codes to <see cref="IActionResult"/> factories.
+        /// Gets a map of HTTP status codes to <see cref="ClientErrorData"/>. Configured values
-        /// Configured factories are used when <see cref="SuppressUseClientErrorFactory"/> is <see langword="false"/>.
+        /// are used to transform <see cref="IClientErrorActionResult"/> to an <see cref="ObjectResult"/>
+        /// instance where the <see cref="ObjectResult.Value"/> is <see cref="ProblemDetails"/>.
+        /// <para>
+        /// Use of this feature can be disabled by resetting <see cref="SuppressMapClientErrors"/>.
+        /// </para>
         /// </summary>
-        public IDictionary<int, Func<ActionContext, IActionResult>> ClientErrorFactory { get; } =
+        public IDictionary<int, ClientErrorData> ClientErrorMapping { get; } =
-            new Dictionary<int, Func<ActionContext, IActionResult>>();
+            new Dictionary<int, ClientErrorData>();
 
         IEnumerator<ICompatibilitySwitch> IEnumerable<ICompatibilitySwitch>.GetEnumerator()
         {

src/Microsoft.AspNetCore.Mvc.Core/ClientErrorData.cs

@@ -0,0 +1,29 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+namespace Microsoft.AspNetCore.Mvc
+{
+    /// <summary>
+    /// Information for producing client errors. This type is used to configure client errors
+    /// produced by consumers of <see cref="ApiBehaviorOptions.ClientErrorMapping"/>.
+    /// </summary>
+    public class ClientErrorData
+    {
+        /// <summary>
+        /// Gets or sets a link (URI) that describes the client error.
+        /// </summary>
+        /// <remarks>
+        /// By default, this maps to <see cref="ProblemDetails.Type"/>.
+        /// </remarks>
+        public string Link { get; set; }
+
+        /// <summary>
+        /// Gets or sets the summary of the client error.
+        /// </summary>
+        /// <remarks>
+        /// By default, this maps to <see cref="ProblemDetails.Title"/> and should not change
+        /// between multiple occurences of the same error.
+        /// </remarks>
+        public string Title { get; set; }
+    }
+}

src/Microsoft.AspNetCore.Mvc.Core/ControllerBase.cs

@@ -10,6 +10,7 @@ using System.Threading.Tasks;
 using Microsoft.AspNetCore.Authentication;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Mvc.Core;
+using Microsoft.AspNetCore.Mvc.Infrastructure;
 using Microsoft.AspNetCore.Mvc.ModelBinding;
 using Microsoft.AspNetCore.Mvc.ModelBinding.Internal;
 using Microsoft.AspNetCore.Mvc.ModelBinding.Validation;
@@ -200,7 +201,7 @@ namespace Microsoft.AspNetCore.Mvc
         /// <param name="statusCode">The status code to set on the response.</param>
         /// <returns>The created <see cref="StatusCodeResult"/> object for the response.</returns>
         [NonAction]
-        public virtual StatusCodeResult StatusCode(int statusCode)
+        public virtual StatusCodeResult StatusCode([StatusCodeValue] int statusCode)
             => new StatusCodeResult(statusCode);
 
         /// <summary>
@@ -210,10 +211,12 @@ namespace Microsoft.AspNetCore.Mvc
         /// <param name="value">The value to set on the <see cref="ObjectResult"/>.</param>
         /// <returns>The created <see cref="ObjectResult"/> object for the response.</returns>
         [NonAction]
-        public virtual ObjectResult StatusCode(int statusCode, object value)
+        public virtual ObjectResult StatusCode([StatusCodeValue] int statusCode, object value)
         {
-            var result = new ObjectResult(value);
+            var result = new ObjectResult(value)
-            result.StatusCode = statusCode;
+            {
+                StatusCode = statusCode
+            };
 
             return result;
         }

src/Microsoft.AspNetCore.Mvc.Core/DependencyInjection/MvcCoreServiceCollectionExtensions.cs

@@ -257,6 +257,7 @@ namespace Microsoft.Extensions.DependencyInjection
             services.TryAddSingleton<IActionResultExecutor<RedirectToRouteResult>, RedirectToRouteResultExecutor>();
             services.TryAddSingleton<IActionResultExecutor<RedirectToPageResult>, RedirectToPageResultExecutor>();
             services.TryAddSingleton<IActionResultExecutor<ContentResult>, ContentResultExecutor>();
+            services.TryAddSingleton<IClientErrorFactory, ProblemDetailsClientErrorFactory>();
 
             //
             // Route Handlers

src/Microsoft.AspNetCore.Mvc.Core/Infrastructure/ClientErrorResultFilter.cs

@@ -2,7 +2,6 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
-using System.Collections.Generic;
 using Microsoft.AspNetCore.Mvc.Filters;
 using Microsoft.AspNetCore.Mvc.Internal;
 using Microsoft.Extensions.Logging;
@@ -11,7 +10,7 @@ namespace Microsoft.AspNetCore.Mvc.Infrastructure
 {
     internal class ClientErrorResultFilter : IAlwaysRunResultFilter, IOrderedFilter
     {
-        private readonly IDictionary<int, Func<ActionContext, IActionResult>> _clientErrorFactory;
+        private readonly IClientErrorFactory _clientErrorFactory;
         private readonly ILogger<ClientErrorResultFilter> _logger;
 
         /// <summary>
@@ -20,10 +19,10 @@ namespace Microsoft.AspNetCore.Mvc.Infrastructure
         public int Order => -2000;
 
         public ClientErrorResultFilter(
-            ApiBehaviorOptions apiBehaviorOptions,
+            IClientErrorFactory clientErrorFactory,
             ILogger<ClientErrorResultFilter> logger)
         {
-            _clientErrorFactory = apiBehaviorOptions?.ClientErrorFactory ?? throw new ArgumentNullException(nameof(apiBehaviorOptions));
+            _clientErrorFactory = clientErrorFactory ?? throw new ArgumentNullException(nameof(clientErrorFactory));
             _logger = logger ?? throw new ArgumentNullException(nameof(logger));
         }
 
@@ -38,16 +37,19 @@ namespace Microsoft.AspNetCore.Mvc.Infrastructure
                 throw new ArgumentNullException(nameof(context));
             }
 
-            if (context.Result is IClientErrorActionResult clientErrorActionResult &&
+            if (!(context.Result is IClientErrorActionResult clientError))
-                clientErrorActionResult.StatusCode is int statusCode &&
-                _clientErrorFactory.TryGetValue(statusCode, out var factory))
             {
-                var result = factory(context);
+                return;
-
-                _logger.TransformingClientError(context.Result.GetType(), result?.GetType(), statusCode);
-
-                context.Result = factory(context);
             }
+
+            var result = _clientErrorFactory.GetClientError(context, clientError);
+            if (result == null)
+            {
+                return;
+            }
+
+            _logger.TransformingClientError(context.Result.GetType(), result?.GetType(), clientError.StatusCode);
+            context.Result = result;
         }
     }
 }

src/Microsoft.AspNetCore.Mvc.Core/Infrastructure/IClientErrorFactory.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.
+
+namespace Microsoft.AspNetCore.Mvc.Infrastructure
+{
+    /// <summary>
+    /// A factory for producing client errors. This contract is used by controllers annotated
+    /// with <see cref="ApiControllerAttribute"/> to transform <see cref="IClientErrorActionResult"/>.
+    /// </summary>
+    public interface IClientErrorFactory
+    {
+        /// <summary>
+        /// Transforms <paramref name="clientError"/> for the specified <paramref name="actionContext"/>.
+        /// </summary>
+        /// <param name="actionContext">The <see cref="ActionContext"/>.</param>
+        /// <param name="clientError">The <see cref="IClientErrorActionResult"/>.</param>
+        /// <returns>THe <see cref="IActionResult"/> that would be returned to the client.</returns>
+        IActionResult GetClientError(ActionContext actionContext, IClientErrorActionResult clientError);
+    }
+}

src/Microsoft.AspNetCore.Mvc.Core/Infrastructure/ProblemDetailsClientErrorFactory.cs

@@ -0,0 +1,54 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Diagnostics;
+using Microsoft.Extensions.Options;
+
+namespace Microsoft.AspNetCore.Mvc.Infrastructure
+{
+    internal class ProblemDetailsClientErrorFactory : IClientErrorFactory
+    {
+        private static readonly string TraceIdentifierKey = "traceId";
+        private readonly ApiBehaviorOptions _options;
+
+        public ProblemDetailsClientErrorFactory(IOptions<ApiBehaviorOptions> options)
+        {
+            _options = options?.Value ?? throw new ArgumentNullException(nameof(options));
+        }
+
+        public IActionResult GetClientError(ActionContext actionContext, IClientErrorActionResult clientError)
+        {
+            var problemDetails = new ProblemDetails
+            {
+                Status = clientError.StatusCode,
+                Type = "about:blank",
+            };
+
+            if (clientError.StatusCode is int statusCode &&
+                _options.ClientErrorMapping.TryGetValue(statusCode, out var errorData))
+            {
+                problemDetails.Title = errorData.Title;
+                problemDetails.Type = errorData.Link;
+
+                SetTraceId(actionContext, problemDetails);
+            }
+
+            return new ObjectResult(problemDetails)
+            {
+                StatusCode = problemDetails.Status,
+                ContentTypes =
+                {
+                    "application/problem+json",
+                    "application/problem+xml",
+                },
+            };
+        }
+
+        internal static void SetTraceId(ActionContext actionContext, ProblemDetails problemDetails)
+        {
+            var traceId = Activity.Current?.Id ?? actionContext.HttpContext.TraceIdentifier;
+            problemDetails.Extensions[TraceIdentifierKey] = traceId;
+        }
+    }
+}

src/Microsoft.AspNetCore.Mvc.Core/Infrastructure/StatusCodeValueAttribute.cs

@@ -0,0 +1,12 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+
+namespace Microsoft.AspNetCore.Mvc.Infrastructure
+{
+    [AttributeUsage(AttributeTargets.Parameter, AllowMultiple = false, Inherited = false)]
+    internal sealed class StatusCodeValueAttribute : Attribute
+    {
+    }
+}

src/Microsoft.AspNetCore.Mvc.Core/Internal/ApiBehaviorApplicationModelProvider.cs

@@ -18,6 +18,7 @@ namespace Microsoft.AspNetCore.Mvc.Internal
 {
     public class ApiBehaviorApplicationModelProvider : IApplicationModelProvider
     {
+        private readonly ProducesErrorResponseTypeAttribute DefaultErrorType = new ProducesErrorResponseTypeAttribute(typeof(ProblemDetails));
         private readonly ApiBehaviorOptions _apiBehaviorOptions;
         private readonly IModelMetadataProvider _modelMetadataProvider;
         private readonly ModelStateInvalidFilter _modelStateInvalidFilter;
@@ -27,6 +28,7 @@ namespace Microsoft.AspNetCore.Mvc.Internal
         public ApiBehaviorApplicationModelProvider(
             IOptions<ApiBehaviorOptions> apiBehaviorOptions,
             IModelMetadataProvider modelMetadataProvider,
+            IClientErrorFactory clientErrorFactory,
             ILoggerFactory loggerFactory)
         {
             _apiBehaviorOptions = apiBehaviorOptions.Value;
@@ -45,7 +47,7 @@ namespace Microsoft.AspNetCore.Mvc.Internal
                 loggerFactory.CreateLogger<ModelStateInvalidFilter>());
 
             _clientErrorResultFilter = new ClientErrorResultFilter(
-                _apiBehaviorOptions,
+                clientErrorFactory,
                 loggerFactory.CreateLogger<ClientErrorResultFilter>());
         }
 
@@ -104,6 +106,8 @@ namespace Microsoft.AspNetCore.Mvc.Internal
                     AddMultipartFormDataConsumesAttribute(actionModel);
 
                     DiscoverApiConvention(actionModel, conventions);
+
+                    DiscoverErrorResponseType(actionModel);
                 }
             }
         }
@@ -158,7 +162,7 @@ namespace Microsoft.AspNetCore.Mvc.Internal
 
         private void AddClientErrorFilter(ActionModel actionModel)
         {
-            if (_apiBehaviorOptions.SuppressUseClientErrorFactory)
+            if (_apiBehaviorOptions.SuppressMapClientErrors)
             {
                 return;
             }
@@ -273,6 +277,25 @@ namespace Microsoft.AspNetCore.Mvc.Internal
             }
         }
 
+        internal void DiscoverErrorResponseType(ActionModel actionModel)
+        {
+            var errorTypeAttribute =
+                actionModel.Attributes.OfType<ProducesErrorResponseTypeAttribute>().FirstOrDefault() ??
+                actionModel.Controller.Attributes.OfType<ProducesErrorResponseTypeAttribute>().FirstOrDefault() ??
+                actionModel.Controller.ControllerType.Assembly.GetCustomAttribute<ProducesErrorResponseTypeAttribute>();
+
+            if (!_apiBehaviorOptions.SuppressMapClientErrors)
+            {
+                // If ClientErrorFactory is being used and the application does not supply a error response type, assume ProblemDetails.
+                errorTypeAttribute = errorTypeAttribute ?? DefaultErrorType;
+            }
+
+            if (errorTypeAttribute != null)
+            {
+                actionModel.Properties[typeof(ProducesErrorResponseTypeAttribute)] = errorTypeAttribute;
+            }
+        }
+
         private bool ParameterExistsInAnyRoute(ActionModel actionModel, string parameterName)
         {
             foreach (var (route, _, _) in ActionAttributeRouteModel.GetAttributeRoutes(actionModel))

src/Microsoft.AspNetCore.Mvc.Core/Internal/ApiBehaviorOptionsSetup.cs

@@ -3,6 +3,7 @@
 
 using System;
 using System.Collections.Generic;
+using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Mvc.Core;
 using Microsoft.AspNetCore.Mvc.Infrastructure;
 using Microsoft.Extensions.Logging;
@@ -32,7 +33,7 @@ namespace Microsoft.AspNetCore.Mvc.Internal
 
                 if (Version < CompatibilityVersion.Version_2_2)
                 {
-                    dictionary[nameof(ApiBehaviorOptions.SuppressUseClientErrorFactory)] = true;
+                    dictionary[nameof(ApiBehaviorOptions.SuppressMapClientErrors)] = true;
                     dictionary[nameof(ApiBehaviorOptions.SuppressUseValidationProblemDetailsForInvalidModelStateResponses)] = true;
                 }
 
@@ -48,7 +49,7 @@ namespace Microsoft.AspNetCore.Mvc.Internal
             }
 
             options.InvalidModelStateResponseFactory = DefaultFactory;
-            ConfigureClientErrorFactories(options);
+            ConfigureClientErrorMapping(options);
         }
 
         public override void PostConfigure(string name, ApiBehaviorOptions options)
@@ -57,9 +58,9 @@ namespace Microsoft.AspNetCore.Mvc.Internal
             base.PostConfigure(name, options);
 
             // We want to use problem details factory only if
-            // (a) it has not been opted out of (SuppressUseClientErrorFactory = true)
+            // (a) it has not been opted out of (SuppressMapClientErrors = true)
             // (b) a different factory was configured
-            if (!options.SuppressUseClientErrorFactory &&
+            if (!options.SuppressMapClientErrors &&
                 object.ReferenceEquals(options.InvalidModelStateResponseFactory, DefaultFactory))
             {
                 options.InvalidModelStateResponseFactory = ProblemDetailsFactory;
@@ -67,77 +68,55 @@ namespace Microsoft.AspNetCore.Mvc.Internal
         }
 
         // Internal for unit testing
-        internal static void ConfigureClientErrorFactories(ApiBehaviorOptions options)
+        internal static void ConfigureClientErrorMapping(ApiBehaviorOptions options)
         {
-            AddClientErrorFactory(new ProblemDetails
+            options.ClientErrorMapping[400] = new ClientErrorData
             {
-                Status = 400,
+                Link = "https://tools.ietf.org/html/rfc7231#section-6.5.1",
-                Type = "https://tools.ietf.org/html/rfc7231#section-6.5.1",
                 Title = Resources.ApiConventions_Title_400,
-            });
+            };
 
-            AddClientErrorFactory(new ProblemDetails
+            options.ClientErrorMapping[401] = new ClientErrorData
             {
-                Status = 401,
+                Link = "https://tools.ietf.org/html/rfc7235#section-3.1",
-                Type = "https://tools.ietf.org/html/rfc7235#section-3.1",
                 Title = Resources.ApiConventions_Title_401,
-            });
+            };
 
-            AddClientErrorFactory(new ProblemDetails
+            options.ClientErrorMapping[403] = new ClientErrorData
             {
-                Status = 403,
+                Link = "https://tools.ietf.org/html/rfc7231#section-6.5.3",
-                Type = "https://tools.ietf.org/html/rfc7231#section-6.5.3",
                 Title = Resources.ApiConventions_Title_403,
-            });
+            };
 
-            AddClientErrorFactory(new ProblemDetails
+            options.ClientErrorMapping[404] = new ClientErrorData
             {
-                Status = 404,
+                Link = "https://tools.ietf.org/html/rfc7231#section-6.5.4",
-                Type = "https://tools.ietf.org/html/rfc7231#section-6.5.4",
                 Title = Resources.ApiConventions_Title_404,
-            });
+            };
 
-            AddClientErrorFactory(new ProblemDetails
+            options.ClientErrorMapping[406] = new ClientErrorData
             {
-                Status = 406,
+                Link = "https://tools.ietf.org/html/rfc7231#section-6.5.6",
-                Type = "https://tools.ietf.org/html/rfc7231#section-6.5.6",
                 Title = Resources.ApiConventions_Title_406,
-            });
+            };
 
-            AddClientErrorFactory(new ProblemDetails
+            options.ClientErrorMapping[409] = new ClientErrorData
             {
-                Status = 409,
+                Link = "https://tools.ietf.org/html/rfc7231#section-6.5.8",
-                Type = "https://tools.ietf.org/html/rfc7231#section-6.5.8",
                 Title = Resources.ApiConventions_Title_409,
-            });
+            };
 
-            AddClientErrorFactory(new ProblemDetails
+            options.ClientErrorMapping[415] = new ClientErrorData
             {
-                Status = 415,
+                Link = "https://tools.ietf.org/html/rfc7231#section-6.5.13",
-                Type = "https://tools.ietf.org/html/rfc7231#section-6.5.13",
                 Title = Resources.ApiConventions_Title_415,
-            });
+            };
 
-            AddClientErrorFactory(new ProblemDetails
+            options.ClientErrorMapping[422] = new ClientErrorData
             {
-                Status = 422,
+                Link = "https://tools.ietf.org/html/rfc4918#section-11.2",
-                Type = "https://tools.ietf.org/html/rfc4918#section-11.2",
                 Title = Resources.ApiConventions_Title_422,
-            });
+            };
-
-            void AddClientErrorFactory(ProblemDetails problemDetails)
-            {
-                var statusCode = problemDetails.Status.Value;
-                options.ClientErrorFactory[statusCode] = _ => new ObjectResult(problemDetails)
-                {
-                    StatusCode = statusCode,
-                    ContentTypes =
-                    {
-                        "application/problem+json",
-                        "application/problem+xml",
-                    },
-                };
-            }
         }
 
         private static IActionResult DefaultInvalidModelStateResponse(ActionContext context)
@@ -150,9 +129,16 @@ namespace Microsoft.AspNetCore.Mvc.Internal
             return result;
         }
 
-        private static IActionResult ProblemDetailsInvalidModelStateResponse(ActionContext context)
+        internal static IActionResult ProblemDetailsInvalidModelStateResponse(ActionContext context)
         {
-            var result = new BadRequestObjectResult(new ValidationProblemDetails(context.ModelState));
+            var problemDetails = new ValidationProblemDetails(context.ModelState)
+            {
+                Status = StatusCodes.Status400BadRequest,
+            };
+
+            ProblemDetailsClientErrorFactory.SetTraceId(context, problemDetails);
+
+            var result = new BadRequestObjectResult(problemDetails);
 
             result.ContentTypes.Add("application/problem+json");
             result.ContentTypes.Add("application/problem+xml");

src/Microsoft.AspNetCore.Mvc.Core/Internal/MvcCoreLoggerExtensions.cs

@@ -151,7 +151,7 @@ namespace Microsoft.AspNetCore.Mvc.Internal
         private static readonly Action<ILogger, Type, Type, Type, Exception> _notMostEffectiveFilter;
         private static readonly Action<ILogger, IEnumerable<IOutputFormatter>, Exception> _registeredOutputFormatters;
 
-        private static readonly Action<ILogger, Type, Type, int, Exception> _transformingClientError;
+        private static readonly Action<ILogger, Type, int?, Type, Exception> _transformingClientError;
 
         static MvcCoreLoggerExtensions()
         {
@@ -651,10 +651,10 @@ namespace Microsoft.AspNetCore.Mvc.Internal
                48,
                "Skipped binding parameter '{ParameterName}' since its binding information disallowed it for the current request.");
 
-            _transformingClientError = LoggerMessage.Define<Type, Type, int>(
+            _transformingClientError = LoggerMessage.Define<Type, int?, Type>(
                 LogLevel.Trace,
                 new EventId(49, nameof(Infrastructure.ClientErrorResultFilter)),
-                "Replacing {InitialActionResultType} with status code {StatusCode} with {ReplacedActionResultType} produced from ClientErrorFactory'.");
+                "Replacing {InitialActionResultType} with status code {StatusCode} with {ReplacedActionResultType}.");
         }
 
         public static void RegisteredOutputFormatters(this ILogger logger, IEnumerable<IOutputFormatter> outputFormatters)
@@ -1585,9 +1585,9 @@ namespace Microsoft.AspNetCore.Mvc.Internal
             }
         }
 
-        public static void TransformingClientError(this ILogger logger, Type initialType, Type replacedType, int statusCode)
+        public static void TransformingClientError(this ILogger logger, Type initialType, Type replacedType, int? statusCode)
         {
-            _transformingClientError(logger, initialType, replacedType, statusCode, null);
+            _transformingClientError(logger, initialType, statusCode, replacedType, null);
         }
 
         private static void LogFilterExecutionPlan(

src/Microsoft.AspNetCore.Mvc.Core/Internal/MvcEndpointDataSource.cs

@@ -174,7 +174,9 @@ namespace Microsoft.AspNetCore.Mvc.Internal
                                         endpointInfo.Defaults,
                                         ++conventionalRouteOrder,
                                         endpointInfo,
-                                        suppressLinkGeneration: false);
+                                        endpointInfo.DataTokens,
+                                        suppressLinkGeneration: false,
+                                        suppressPathMatching: false);
                                     endpoints.Add(subEndpoint);
                                 }
 
@@ -213,7 +215,9 @@ namespace Microsoft.AspNetCore.Mvc.Internal
                                 endpointInfo.Defaults,
                                 ++conventionalRouteOrder,
                                 endpointInfo,
-                                suppressLinkGeneration: false);
+                                endpointInfo.DataTokens,
+                                suppressLinkGeneration: false,
+                                suppressPathMatching: false);
                             endpoints.Add(endpoint);
                         }
                     }
@@ -227,7 +231,9 @@ namespace Microsoft.AspNetCore.Mvc.Internal
                             nonInlineDefaults: null,
                             action.AttributeRouteInfo.Order,
                             action.AttributeRouteInfo,
-                            suppressLinkGeneration: action.AttributeRouteInfo.SuppressLinkGeneration);
+                            dataTokens: null,
+                            suppressLinkGeneration: action.AttributeRouteInfo.SuppressLinkGeneration,
+                            suppressPathMatching: action.AttributeRouteInfo.SuppressPathMatching);
                         endpoints.Add(endpoint);
                     }
                 }
@@ -375,19 +381,13 @@ namespace Microsoft.AspNetCore.Mvc.Internal
             object nonInlineDefaults,
             int order,
             object source,
-            bool suppressLinkGeneration)
+            RouteValueDictionary dataTokens,
+            bool suppressLinkGeneration,
+            bool suppressPathMatching)
         {
             RequestDelegate requestDelegate = (context) =>
             {
-                var values = context.Features.Get<IRouteValuesFeature>().RouteValues;
+                var routeData = context.GetRouteData();
-                var routeData = new RouteData();
-                foreach (var kvp in values)
-                {
-                    if (kvp.Value != null)
-                    {
-                        routeData.Values.Add(kvp.Key, kvp.Value);
-                    }
-                }
 
                 var actionContext = new ActionContext(context, routeData, action);
 
@@ -403,7 +403,9 @@ namespace Microsoft.AspNetCore.Mvc.Internal
                 routeName,
                 new RouteValueDictionary(action.RouteValues),
                 source,
-                suppressLinkGeneration);
+                dataTokens,
+                suppressLinkGeneration,
+                suppressPathMatching);
 
             var endpoint = new RouteEndpoint(
                 requestDelegate,
@@ -420,12 +422,12 @@ namespace Microsoft.AspNetCore.Mvc.Internal
             string routeName,
             RouteValueDictionary requiredValues,
             object source,
-            bool suppressLinkGeneration)
+            RouteValueDictionary dataTokens,
+            bool suppressLinkGeneration,
+            bool suppressPathMatching)
         {
             var metadata = new List<object>
             {
-                // REVIEW: Used for debugging. Consider removing before release
-                source,
                 action
             };
 
@@ -434,6 +436,11 @@ namespace Microsoft.AspNetCore.Mvc.Internal
                 metadata.AddRange(action.EndpointMetadata);
             }
 
+            if (dataTokens != null)
+            {
+                metadata.Add(new DataTokensMetadata(dataTokens));
+            }
+
             metadata.Add(new RouteValuesAddressMetadata(routeName, requiredValues));
 
             // Add filter descriptors to endpoint metadata
@@ -475,6 +482,11 @@ namespace Microsoft.AspNetCore.Mvc.Internal
                 metadata.Add(new SuppressLinkGenerationMetadata());
             }
 
+            if (suppressPathMatching)
+            {
+                metadata.Add(new SuppressMatchingMetadata());
+            }
+
             var metadataCollection = new EndpointMetadataCollection(metadata);
             return metadataCollection;
         }
@@ -497,10 +509,11 @@ namespace Microsoft.AspNetCore.Mvc.Internal
         {
             foreach (var kvp in requiredValues)
             {
-                defaults[kvp.Key] = kvp.Value;
+                if (kvp.Value != null)
+                {
+                    defaults[kvp.Key] = kvp.Value;
+                }
             }
         }
-
-        private class SuppressLinkGenerationMetadata : ISuppressLinkGenerationMetadata { }
     }
 }

src/Microsoft.AspNetCore.Mvc.Core/ProblemDetails.cs

@@ -3,6 +3,7 @@
 
 using System;
 using System.Collections.Generic;
+using Newtonsoft.Json;
 
 namespace Microsoft.AspNetCore.Mvc
 {
@@ -17,6 +18,7 @@ namespace Microsoft.AspNetCore.Mvc
         /// (e.g., using HTML [W3C.REC-html5-20141028]).  When this member is not present, its value is assumed to be
         /// "about:blank".
         /// </summary>
+        [JsonProperty(NullValueHandling = NullValueHandling.Ignore)]
         public string Type { get; set; }
 
         /// <summary>
@@ -24,21 +26,39 @@ namespace Microsoft.AspNetCore.Mvc
         /// of the problem, except for purposes of localization(e.g., using proactive content negotiation;
         /// see[RFC7231], Section 3.4).
         /// </summary>
+        [JsonProperty(NullValueHandling = NullValueHandling.Ignore)]
         public string Title { get; set; }
 
         /// <summary>
         /// The HTTP status code([RFC7231], Section 6) generated by the origin server for this occurrence of the problem.
         /// </summary>
+        [JsonProperty(NullValueHandling = NullValueHandling.Ignore)]
         public int? Status { get; set; }
 
         /// <summary>
         /// A human-readable explanation specific to this occurrence of the problem.
         /// </summary>
+        [JsonProperty(NullValueHandling = NullValueHandling.Ignore)]
         public string Detail { get; set; }
 
         /// <summary>
         /// A URI reference that identifies the specific occurrence of the problem.It may or may not yield further information if dereferenced.
         /// </summary>
+        [JsonProperty(NullValueHandling = NullValueHandling.Ignore)]
         public string Instance { get; set; }
+
+        /// <summary>
+        /// Gets the <see cref="IDictionary{TKey, TValue}"/> for extension members.
+        /// <para>
+        /// Problem type definitions MAY extend the problem details object with additional members. Extension members appear in the same namespace as
+        /// other members of a problem type.
+        /// </para>
+        /// </summary>
+        /// <remarks>
+        /// The round-tripping behavior for <see cref="Extensions"/> is determined by the implementation of the Input \ Output formatters.
+        /// In particular, complex types or collection types may not round-trip to the original type when using the built-in JSON or XML formatters.
+        /// </remarks>
+        [JsonExtensionData]
+        public IDictionary<string, object> Extensions { get; } = new Dictionary<string, object>(StringComparer.Ordinal);
     }
 }

src/Microsoft.AspNetCore.Mvc.Core/ProducesErrorResponseTypeAttribute.cs

@@ -0,0 +1,38 @@
+// 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.Mvc.Infrastructure;
+
+namespace Microsoft.AspNetCore.Mvc
+{
+    /// <summary>
+    /// Specifies the type returned by default by controllers annotated with <see cref="ApiControllerAttribute"/>.
+    /// <para>
+    /// <see cref="Type"/> specifies the error model type associated with a <see cref="ProducesResponseTypeAttribute"/>
+    /// for a client error (HTTP Status Code 4xx) when no value is provided. When no value is specified, MVC assumes the
+    /// client error type to be <see cref="ProblemDetails"/>, if mapping client errors (<see cref="ApiBehaviorOptions.ClientErrorMapping"/>)
+    /// is used.
+    /// </para>
+    /// <para>
+    /// Use this <see cref="Attribute"/> to configure the default error type if your application uses a custom error type to respond.
+    /// </para>
+    /// </summary>
+    [AttributeUsage(AttributeTargets.Assembly | AttributeTargets.Class | AttributeTargets.Method, AllowMultiple = false, Inherited = true)]
+    public sealed class ProducesErrorResponseTypeAttribute : Attribute
+    {
+        /// <summary>
+        /// Initializes a new instance of <see cref="ProducesErrorResponseTypeAttribute"/>.
+        /// </summary>
+        /// <param name="type">The error type.</param>
+        public ProducesErrorResponseTypeAttribute(Type type)
+        {
+            Type = type ?? throw new ArgumentNullException(nameof(type));
+        }
+
+        /// <summary>
+        /// Gets the default error type.
+        /// </summary>
+        public Type Type { get; }
+    }
+}

src/Microsoft.AspNetCore.Mvc.Core/Routing/KnownRouteValueConstraint.cs

@@ -14,8 +14,26 @@ namespace Microsoft.AspNetCore.Mvc.Routing
 {
     public class KnownRouteValueConstraint : IRouteConstraint
     {
+        private readonly IActionDescriptorCollectionProvider _actionDescriptorCollectionProvider;
         private RouteValuesCollection _cachedValuesCollection;
 
+        [Obsolete("This constructor is obsolete. Use KnownRouteValueConstraint.ctor(IActionDescriptorCollectionProvider) instead.")]
+        public KnownRouteValueConstraint()
+        {
+            // Empty constructor for backwards compatibility
+            // Services will need to be resolved from HttpContext when this ctor is used
+        }
+
+        public KnownRouteValueConstraint(IActionDescriptorCollectionProvider actionDescriptorCollectionProvider)
+        {
+            if (actionDescriptorCollectionProvider == null)
+            {
+                throw new ArgumentNullException(nameof(actionDescriptorCollectionProvider));
+            }
+
+            _actionDescriptorCollectionProvider = actionDescriptorCollectionProvider;
+        }
+
         public bool Match(
             HttpContext httpContext,
             IRouter route,
@@ -23,16 +41,6 @@ namespace Microsoft.AspNetCore.Mvc.Routing
             RouteValueDictionary values,
             RouteDirection routeDirection)
         {
-            if (httpContext == null)
-            {
-                throw new ArgumentNullException(nameof(httpContext));
-            }
-
-            if (route == null)
-            {
-                throw new ArgumentNullException(nameof(route));
-            }
-
             if (routeKey == null)
             {
                 throw new ArgumentNullException(nameof(routeKey));
@@ -49,7 +57,9 @@ namespace Microsoft.AspNetCore.Mvc.Routing
                 var value = obj as string;
                 if (value != null)
                 {
-                    var allValues = GetAndCacheAllMatchingValues(routeKey, httpContext);
+                    var actionDescriptors = GetAndValidateActionDescriptors(httpContext);
+
+                    var allValues = GetAndCacheAllMatchingValues(routeKey, actionDescriptors);
                     foreach (var existingValue in allValues)
                     {
                         if (string.Equals(value, existingValue, StringComparison.OrdinalIgnoreCase))
@@ -63,9 +73,36 @@ namespace Microsoft.AspNetCore.Mvc.Routing
             return false;
         }
 
-        private string[] GetAndCacheAllMatchingValues(string routeKey, HttpContext httpContext)
+        private ActionDescriptorCollection GetAndValidateActionDescriptors(HttpContext httpContext)
+        {
+            var actionDescriptorsProvider = _actionDescriptorCollectionProvider;
+
+            if (actionDescriptorsProvider == null)
+            {
+                // Only validate that HttpContext was passed to constraint if it is needed
+                if (httpContext == null)
+                {
+                    throw new ArgumentNullException(nameof(httpContext));
+                }
+
+                var services = httpContext.RequestServices;
+                actionDescriptorsProvider = services.GetRequiredService<IActionDescriptorCollectionProvider>();
+            }
+
+            var actionDescriptors = actionDescriptorsProvider.ActionDescriptors;
+            if (actionDescriptors == null)
+            {
+                throw new InvalidOperationException(
+                    Resources.FormatPropertyOfTypeCannotBeNull(
+                        nameof(IActionDescriptorCollectionProvider.ActionDescriptors),
+                        actionDescriptorsProvider.GetType()));
+            }
+
+            return actionDescriptors;
+        }
+
+        private string[] GetAndCacheAllMatchingValues(string routeKey, ActionDescriptorCollection actionDescriptors)
         {
-            var actionDescriptors = GetAndValidateActionDescriptorCollection(httpContext);
             var version = actionDescriptors.Version;
             var valuesCollection = _cachedValuesCollection;
 
@@ -77,8 +114,7 @@ namespace Microsoft.AspNetCore.Mvc.Routing
                 {
                     var action = actionDescriptors.Items[i];
 
-                    string value;
+                    if (action.RouteValues.TryGetValue(routeKey, out var value) &&
-                    if (action.RouteValues.TryGetValue(routeKey, out value) &&
                         !string.IsNullOrEmpty(value))
                     {
                         values.Add(value);
@@ -92,22 +128,6 @@ namespace Microsoft.AspNetCore.Mvc.Routing
             return _cachedValuesCollection.Items;
         }
 
-        private static ActionDescriptorCollection GetAndValidateActionDescriptorCollection(HttpContext httpContext)
-        {
-            var services = httpContext.RequestServices;
-            var provider = services.GetRequiredService<IActionDescriptorCollectionProvider>();
-            var descriptors = provider.ActionDescriptors;
-
-            if (descriptors == null)
-            {
-                throw new InvalidOperationException(
-                    Resources.FormatPropertyOfTypeCannotBeNull("ActionDescriptors",
-                                                               provider.GetType()));
-            }
-
-            return descriptors;
-        }
-
         private class RouteValuesCollection
         {
             public RouteValuesCollection(int version, string[] items)

src/Microsoft.AspNetCore.Mvc.Core/StatusCodeResult.cs

@@ -20,7 +20,7 @@ namespace Microsoft.AspNetCore.Mvc
         /// with the given <paramref name="statusCode"/>.
         /// </summary>
         /// <param name="statusCode">The HTTP status code of the response.</param>
-        public StatusCodeResult(int statusCode)
+        public StatusCodeResult([StatusCodeValue] int statusCode)
         {
             StatusCode = statusCode;
         }

src/Microsoft.AspNetCore.Mvc.Formatters.Xml/ProblemDetailsWrapper.cs

@@ -0,0 +1,187 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Globalization;
+using System.Xml;
+using System.Xml.Schema;
+using System.Xml.Serialization;
+
+namespace Microsoft.AspNetCore.Mvc.Formatters.Xml
+{
+    /// <summary>
+    /// Wrapper class for <see cref="Mvc.ProblemDetails"/> to enable it to be serialized by the xml formatters.
+    /// </summary>
+    [XmlRoot(nameof(ProblemDetails))]
+    public class ProblemDetailsWrapper : IXmlSerializable, IUnwrappable
+    {
+        /// <summary>
+        /// Key used to represent dictionary elements with empty keys
+        /// </summary>
+        protected static readonly string EmptyKey = SerializableErrorWrapper.EmptyKey;
+
+        /// <summary>
+        /// Initializes a new instance of <see cref="ProblemDetailsWrapper"/>.
+        /// </summary>
+        public ProblemDetailsWrapper()
+            : this(new ProblemDetails())
+        {
+        }
+
+        /// <summary>
+        /// Initializes a new instance of <see cref="ProblemDetailsWrapper"/>.
+        /// </summary>
+        public ProblemDetailsWrapper(ProblemDetails problemDetails)
+        {
+            ProblemDetails = problemDetails;
+        }
+
+        internal ProblemDetails ProblemDetails { get; }
+
+        /// <inheritdoc />
+        public XmlSchema GetSchema() => null;
+
+        /// <inheritdoc />
+        public virtual void ReadXml(XmlReader reader)
+        {
+            if (reader == null)
+            {
+                throw new ArgumentNullException(nameof(reader));
+            }
+
+            if (reader.IsEmptyElement)
+            {
+                reader.Read();
+                return;
+            }
+
+            reader.ReadStartElement();
+            while (reader.NodeType != XmlNodeType.EndElement)
+            {
+                var key = XmlConvert.DecodeName(reader.LocalName);
+                ReadValue(reader, key);
+
+                reader.MoveToContent();
+            }
+
+            reader.ReadEndElement();
+        }
+
+        /// <summary>
+        /// Reads the value for the specified <paramref name="name"/> from the <paramref name="reader"/>.
+        /// </summary>
+        /// <param name="reader">The <see cref="XmlReader"/>.</param>
+        /// <param name="name">The name of the node.</param>
+        protected virtual void ReadValue(XmlReader reader, string name)
+        {
+            if (reader == null)
+            {
+                throw new ArgumentNullException(nameof(reader));
+            }
+
+            var value = reader.ReadInnerXml();
+
+            switch (name)
+            {
+                case nameof(ProblemDetails.Detail):
+                    ProblemDetails.Detail = value;
+                    break;
+
+                case nameof(ProblemDetails.Instance):
+                    ProblemDetails.Instance = value;
+                    break;
+
+                case nameof(ProblemDetails.Status):
+                    ProblemDetails.Status = string.IsNullOrEmpty(value) ?
+                        (int?)null :
+                        int.Parse(value, CultureInfo.InvariantCulture);
+                    break;
+
+                case nameof(ProblemDetails.Title):
+                    ProblemDetails.Title = value;
+                    break;
+
+                case nameof(ProblemDetails.Type):
+                    ProblemDetails.Type = value;
+                    break;
+
+                default:
+                    if (string.Equals(name, EmptyKey, StringComparison.Ordinal))
+                    {
+                        name = string.Empty;
+                    }
+
+                    ProblemDetails.Extensions.Add(name, value);
+                    break;
+            }
+        }
+
+        /// <inheritdoc />
+        public virtual void WriteXml(XmlWriter writer)
+        {
+            if (!string.IsNullOrEmpty(ProblemDetails.Detail))
+            {
+                writer.WriteElementString(
+                    XmlConvert.EncodeLocalName(nameof(ProblemDetails.Detail)),
+                    ProblemDetails.Detail);
+            }
+
+            if (!string.IsNullOrEmpty(ProblemDetails.Instance))
+            {
+                writer.WriteElementString(
+                    XmlConvert.EncodeLocalName(nameof(ProblemDetails.Instance)),
+                    ProblemDetails.Instance);
+            }
+
+            if (ProblemDetails.Status.HasValue)
+            {
+                writer.WriteStartElement(XmlConvert.EncodeLocalName(nameof(ProblemDetails.Status)));
+                writer.WriteValue(ProblemDetails.Status.Value);
+                writer.WriteEndElement();
+            }
+
+            if (!string.IsNullOrEmpty(ProblemDetails.Title))
+            {
+                writer.WriteElementString(
+                    XmlConvert.EncodeLocalName(nameof(ProblemDetails.Title)),
+                    ProblemDetails.Title);
+            }
+
+            if (!string.IsNullOrEmpty(ProblemDetails.Type))
+            {
+                writer.WriteElementString(
+                    XmlConvert.EncodeLocalName(nameof(ProblemDetails.Type)),
+                    ProblemDetails.Type);
+            }
+
+            foreach (var keyValuePair in ProblemDetails.Extensions)
+            {
+                var key = keyValuePair.Key;
+                var value = keyValuePair.Value;
+
+                if (string.IsNullOrEmpty(key))
+                {
+                    key = EmptyKey;
+                }
+
+                writer.WriteStartElement(XmlConvert.EncodeLocalName(key));
+                if (value != null)
+                {
+                    writer.WriteValue(value);
+                }
+
+                writer.WriteEndElement();
+            }
+        }
+
+        object IUnwrappable.Unwrap(Type declaredType)
+        {
+            if (declaredType == null)
+            {
+                throw new ArgumentNullException(nameof(declaredType));
+            }
+
+            return ProblemDetails;
+        }
+    }
+}

src/Microsoft.AspNetCore.Mvc.Formatters.Xml/Properties/AssemblyInfo.cs

@@ -0,0 +1,6 @@
+// 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.Runtime.CompilerServices;
+
+[assembly: InternalsVisibleTo("Microsoft.AspNetCore.Mvc.Formatters.Xml.Test, PublicKey=0024000004800000940000000602000000240000525341310004000001000100f33a29044fa9d740c9b3213a93e57c84b472c84e0b8a0e1ae48e67a9f8f6de9d5f7f3d52ac23e48ac51801f1dc950abe901da34d2a9e3baadb141a17c77ef3c565dd5ee5054b91cf63bb3c6ab83f72ab3aafe93d0fc3c2348b764fafb0b1c0733de51459aeab46580384bf9d74c4e28164b7cde247f891ba07891c9d872ad2bb")]

src/Microsoft.AspNetCore.Mvc.Formatters.Xml/SerializableErrorWrapper.cs

@@ -16,7 +16,7 @@ namespace Microsoft.AspNetCore.Mvc.Formatters.Xml
     {
         // Element name used when ModelStateEntry's Key is empty. Dash in element name should avoid collisions with
         // other ModelState entries because the character is not legal in an expression name.
-        private static readonly string EmptyKey = "MVC-Empty";
+        internal static readonly string EmptyKey = "MVC-Empty";
 
         // Note: XmlSerializer requires to have default constructor
         public SerializableErrorWrapper()

src/Microsoft.AspNetCore.Mvc.Formatters.Xml/ValidationProblemDetailsWrapper.cs

@@ -0,0 +1,126 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Xml;
+using System.Xml.Serialization;
+
+namespace Microsoft.AspNetCore.Mvc.Formatters.Xml
+{
+    /// <summary>
+    /// Wrapper class for <see cref="ValidationProblemDetails"/> to enable it to be serialized by the xml formatters.
+    /// </summary>
+    [XmlRoot(nameof(ValidationProblemDetails))]
+    public class ValidationProblemDetailsWrapper : ProblemDetailsWrapper, IUnwrappable
+    {
+        private static readonly string ErrorKey = "MVC-Errors";
+
+        /// <summary>
+        /// Initializes a new instance of <see cref="ValidationProblemDetailsWrapper"/>.
+        /// </summary>
+        public ValidationProblemDetailsWrapper()
+            : this(new ValidationProblemDetails())
+        {
+        }
+
+        /// <summary>
+        /// Initializes a new instance of <see cref="ValidationProblemDetailsWrapper"/> for the specified
+        /// <paramref name="problemDetails"/>.
+        /// </summary>
+        /// <param name="problemDetails">The <see cref="ProblemDetails"/>.</param>
+        public ValidationProblemDetailsWrapper(ValidationProblemDetails problemDetails)
+            : base(problemDetails)
+        {
+            ProblemDetails = problemDetails;
+        }
+
+        internal new ValidationProblemDetails ProblemDetails { get; }
+
+        /// <inheritdoc />
+        protected override void ReadValue(XmlReader reader, string name)
+        {
+            if (reader == null)
+            {
+                throw new ArgumentNullException(nameof(reader));
+            }
+
+            if (string.Equals(name, ErrorKey, StringComparison.Ordinal))
+            {
+                reader.Read();
+                ReadErrorProperty(reader);
+            }
+            else
+            {
+                base.ReadValue(reader, name);
+            }
+        }
+
+        private void ReadErrorProperty(XmlReader reader)
+        {
+            if (reader.IsEmptyElement)
+            {
+                return;
+            }
+
+            while (reader.NodeType != XmlNodeType.EndElement)
+            {
+                var key = XmlConvert.DecodeName(reader.LocalName);
+                var value = reader.ReadInnerXml();
+                if (string.Equals(EmptyKey, key, StringComparison.Ordinal))
+                {
+                    key = string.Empty;
+                }
+
+                ProblemDetails.Errors.Add(key, new[] { value });
+                reader.MoveToContent();
+            }
+        }
+
+        /// <inheritdoc />
+        public override void WriteXml(XmlWriter writer)
+        {
+            if (writer == null)
+            {
+                throw new ArgumentNullException(nameof(writer));
+            }
+
+            base.WriteXml(writer);
+
+            if (ProblemDetails.Errors.Count == 0)
+            {
+                return;
+            }
+
+            writer.WriteStartElement(XmlConvert.EncodeLocalName(ErrorKey));
+
+            foreach (var keyValuePair in ProblemDetails.Errors)
+            {
+                var key = keyValuePair.Key;
+                var value = keyValuePair.Value;
+                if (string.IsNullOrEmpty(key))
+                {
+                    key = EmptyKey;
+                }
+
+                writer.WriteStartElement(XmlConvert.EncodeLocalName(key));
+                if (value != null)
+                {
+                    writer.WriteValue(value);
+                }
+
+                writer.WriteEndElement();
+            }
+            writer.WriteEndElement();
+        }
+
+        object IUnwrappable.Unwrap(Type declaredType)
+        {
+            if (declaredType == null)
+            {
+                throw new ArgumentNullException(nameof(declaredType));
+            }
+
+            return ProblemDetails;
+        }
+    }
+}

src/Microsoft.AspNetCore.Mvc.Formatters.Xml/WrapperProviderFactoriesExtensions.cs

@@ -44,5 +44,24 @@ namespace Microsoft.AspNetCore.Mvc.Formatters.Xml
 
             return null;
         }
+
+        internal static IList<IWrapperProviderFactory> GetDefaultProviderFactories()
+        {
+            var wrapperProviderFactories = new List<IWrapperProviderFactory>();
+
+            wrapperProviderFactories.Add(new SerializableErrorWrapperProviderFactory());
+
+            wrapperProviderFactories.Add(new WrapperProviderFactory(
+                typeof(ProblemDetails),
+                typeof(ProblemDetailsWrapper),
+                value => new ProblemDetailsWrapper((ProblemDetails)value)));
+
+            wrapperProviderFactories.Add(new WrapperProviderFactory(
+                typeof(ValidationProblemDetails),
+                typeof(ValidationProblemDetailsWrapper),
+                value => new ValidationProblemDetailsWrapper((ValidationProblemDetails)value)));
+
+            return wrapperProviderFactories;
+        }
     }
 }

src/Microsoft.AspNetCore.Mvc.Formatters.Xml/WrapperProviderFactory.cs

@@ -0,0 +1,50 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+
+namespace Microsoft.AspNetCore.Mvc.Formatters.Xml
+{
+    internal class WrapperProviderFactory : IWrapperProviderFactory
+    {
+        public WrapperProviderFactory(Type declaredType, Type wrappingType, Func<object, object> wrapper)
+        {
+            DeclaredType = declaredType;
+            WrappingType = wrappingType;
+            Wrapper = wrapper;
+        }
+
+        public Type DeclaredType { get; }
+
+        public Type WrappingType { get; }
+
+        public Func<object, object> Wrapper { get; }
+
+        public IWrapperProvider GetProvider(WrapperProviderContext context)
+        {
+            if (context.DeclaredType == DeclaredType)
+            {
+                return new WrapperProvider(this);
+            }
+
+            return null;
+        }
+
+        private class WrapperProvider : IWrapperProvider
+        {
+            private readonly WrapperProviderFactory _wrapperFactory;
+
+            public WrapperProvider(WrapperProviderFactory wrapperFactory)
+            {
+                _wrapperFactory = wrapperFactory;
+            }
+
+            public Type WrappingType => _wrapperFactory.WrappingType;
+
+            public object Wrap(object original)
+            {
+                return _wrapperFactory.Wrapper(original);
+            }
+        }
+    }
+}

src/Microsoft.AspNetCore.Mvc.Formatters.Xml/XmlDataContractSerializerInputFormatter.cs

@@ -46,8 +46,7 @@ namespace Microsoft.AspNetCore.Mvc.Formatters
 
             _serializerSettings = new DataContractSerializerSettings();
 
-            WrapperProviderFactories = new List<IWrapperProviderFactory>();
+            WrapperProviderFactories = WrapperProviderFactoriesExtensions.GetDefaultProviderFactories();
-            WrapperProviderFactories.Add(new SerializableErrorWrapperProviderFactory());
         }
 
         /// <summary>

src/Microsoft.AspNetCore.Mvc.Formatters.Xml/XmlDataContractSerializerOutputFormatter.cs

@@ -76,9 +76,8 @@ namespace Microsoft.AspNetCore.Mvc.Formatters
 
             _serializerSettings = new DataContractSerializerSettings();
 
-            WrapperProviderFactories = new List<IWrapperProviderFactory>();
+            WrapperProviderFactories = WrapperProviderFactoriesExtensions.GetDefaultProviderFactories();
             WrapperProviderFactories.Add(new EnumerableWrapperProviderFactory(WrapperProviderFactories));
-            WrapperProviderFactories.Add(new SerializableErrorWrapperProviderFactory());
 
             _logger = loggerFactory?.CreateLogger(GetType());
         }

src/Microsoft.AspNetCore.Mvc.Formatters.Xml/XmlSerializerInputFormatter.cs

@@ -43,8 +43,7 @@ namespace Microsoft.AspNetCore.Mvc.Formatters
             SupportedMediaTypes.Add(MediaTypeHeaderValues.TextXml);
             SupportedMediaTypes.Add(MediaTypeHeaderValues.ApplicationAnyXmlSyntax);
 
-            WrapperProviderFactories = new List<IWrapperProviderFactory>();
+            WrapperProviderFactories = WrapperProviderFactoriesExtensions.GetDefaultProviderFactories();
-            WrapperProviderFactories.Add(new SerializableErrorWrapperProviderFactory());
         }
 
         /// <summary>

src/Microsoft.AspNetCore.Mvc.Formatters.Xml/XmlSerializerOutputFormatter.cs

@@ -73,9 +73,8 @@ namespace Microsoft.AspNetCore.Mvc.Formatters
 
             WriterSettings = writerSettings;
 
-            WrapperProviderFactories = new List<IWrapperProviderFactory>();
+            WrapperProviderFactories = WrapperProviderFactoriesExtensions.GetDefaultProviderFactories();
             WrapperProviderFactories.Add(new EnumerableWrapperProviderFactory(WrapperProviderFactories));
-            WrapperProviderFactories.Add(new SerializableErrorWrapperProviderFactory());
 
             _logger = loggerFactory?.CreateLogger(GetType());
         }

src/Microsoft.AspNetCore.Mvc.Razor/RazorPage.cs

@@ -196,11 +196,12 @@ namespace Microsoft.AspNetCore.Mvc.Razor
             else if (required)
             {
                 // If the section is not found, and it is not optional, throw an error.
-                var message = Resources.FormatSectionNotDefined(
+                var viewContext = ViewContext;
-                    ViewContext.ExecutingFilePath,
+                throw new InvalidOperationException(
-                    sectionName,
+                    Resources.FormatSectionNotDefined(
-                    ViewContext.View.Path);
+                        viewContext.ExecutingFilePath,
-                throw new InvalidOperationException(message);
+                        sectionName,
+                        viewContext.View.Path));
             }
             else
             {

src/Microsoft.AspNetCore.Mvc.Razor/RazorPageBase.cs

@@ -51,13 +51,13 @@ namespace Microsoft.AspNetCore.Mvc.Razor
         {
             get
             {
-                if (ViewContext == null)
+                var viewContext = ViewContext;
+                if (viewContext == null)
                 {
-                    var message = Resources.FormatViewContextMustBeSet("ViewContext", "Output");
+                    throw new InvalidOperationException(Resources.FormatViewContextMustBeSet(nameof(ViewContext), nameof(Output)));
-                    throw new InvalidOperationException(message);
                 }
 
-                return ViewContext.Writer;
+                return viewContext.Writer;
             }
         }
 
@@ -183,8 +183,9 @@ namespace Microsoft.AspNetCore.Mvc.Razor
         /// </remarks>
         public void StartTagHelperWritingScope(HtmlEncoder encoder)
         {
+            var viewContext = ViewContext;
             var buffer = new ViewBuffer(BufferScope, Path, ViewBuffer.TagHelperPageSize);
-            TagHelperScopes.Push(new TagHelperScopeInfo(buffer, HtmlEncoder, ViewContext.Writer));
+            TagHelperScopes.Push(new TagHelperScopeInfo(buffer, HtmlEncoder, viewContext.Writer));
 
             // If passed an HtmlEncoder, override the property.
             if (encoder != null)
@@ -194,7 +195,7 @@ namespace Microsoft.AspNetCore.Mvc.Razor
 
             // We need to replace the ViewContext's Writer to ensure that all content (including content written
             // from HTML helpers) is redirected.
-            ViewContext.Writer = new ViewBufferTextWriter(buffer, ViewContext.Writer.Encoding);
+            viewContext.Writer = new ViewBufferTextWriter(buffer, viewContext.Writer.Encoding);
         }
 
         /// <summary>
@@ -238,7 +239,8 @@ namespace Microsoft.AspNetCore.Mvc.Razor
                 throw new InvalidOperationException(Resources.RazorPage_NestingAttributeWritingScopesNotSupported);
             }
 
-            _pageWriter = ViewContext.Writer;
+            var viewContext = ViewContext;
+            _pageWriter = viewContext.Writer;
 
             if (_valueBuffer == null)
             {
@@ -247,7 +249,7 @@ namespace Microsoft.AspNetCore.Mvc.Razor
 
             // We need to replace the ViewContext's Writer to ensure that all content (including content written
             // from HTML helpers) is redirected.
-            ViewContext.Writer = _valueBuffer;
+            viewContext.Writer = _valueBuffer;
 
         }
 
@@ -284,15 +286,18 @@ namespace Microsoft.AspNetCore.Mvc.Razor
                 throw new ArgumentNullException(nameof(writer));
             }
 
-            _textWriterStack.Push(ViewContext.Writer);
+            var viewContext = ViewContext;
-            ViewContext.Writer = writer;
+            _textWriterStack.Push(viewContext.Writer);
+            viewContext.Writer = writer;
         }
 
         // Internal for unit testing.
         protected internal virtual TextWriter PopWriter()
         {
-            ViewContext.Writer = _textWriterStack.Pop();
+            var viewContext = ViewContext;
-            return ViewContext.Writer;
+            var writer = _textWriterStack.Pop();
+            viewContext.Writer = writer;
+            return writer;
         }
 
         public virtual string Href(string contentPath)
@@ -304,9 +309,10 @@ namespace Microsoft.AspNetCore.Mvc.Razor
 
             if (_urlHelper == null)
             {
-                var services = ViewContext?.HttpContext.RequestServices;
+                var viewContext = ViewContext;
+                var services = viewContext?.HttpContext.RequestServices;
                 var factory = services.GetRequiredService<IUrlHelperFactory>();
-                _urlHelper = factory.GetUrlHelper(ViewContext);
+                _urlHelper = factory.GetUrlHelper(viewContext);
             }
 
             return _urlHelper.Content(contentPath);
@@ -637,8 +643,9 @@ namespace Microsoft.AspNetCore.Mvc.Razor
         /// before <see cref="RazorPageBase.FlushAsync"/> flushes the headers. </remarks>
         public virtual HtmlString SetAntiforgeryCookieAndHeader()
         {
-            var antiforgery = ViewContext?.HttpContext.RequestServices.GetRequiredService<IAntiforgery>();
+            var viewContext = ViewContext;
-            antiforgery.SetCookieTokenAndHeader(ViewContext?.HttpContext);
+            var antiforgery = viewContext?.HttpContext.RequestServices.GetRequiredService<IAntiforgery>();
+            antiforgery.SetCookieTokenAndHeader(viewContext?.HttpContext);
 
             return HtmlString.Empty;
         }

src/Microsoft.AspNetCore.Mvc.Testing/build/netstandard2.0/Microsoft.AspNetCore.Mvc.Testing.targets

@@ -53,7 +53,7 @@
         Include="$([System.IO.Path]::ChangeExtension('%(_ContentRootProjectReferences.ResolvedFrom)', '.deps.json'))" />
     </ItemGroup>
 
-    <Copy SourceFiles="%(DepsFilePaths.FullPath)" DestinationFolder="$(OutputPath)" Condition="Exists('%(DepsFilePaths.FullPath)')" />
+    <Copy SourceFiles="%(DepsFilePaths.FullPath)" DestinationFolder="$(OutDir)" Condition="Exists('%(DepsFilePaths.FullPath)')" />
   </Target>
     
 </Project>

src/Microsoft.AspNetCore.Mvc.ViewFeatures/Internal/PagedBufferedTextWriter.cs

@@ -37,7 +37,8 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures.Internal
             }
 
             var pages = _charBuffer.Pages;
-            for (var i = 0; i < pages.Count; i++)
+            var count = pages.Count;
+            for (var i = 0; i < count; i++)
             {
                 var page = pages[i];
                 var pageLength = Math.Min(length, page.Length);

src/Microsoft.AspNetCore.Mvc.ViewFeatures/Internal/PagedCharBuffer.cs

@@ -19,16 +19,19 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures.Internal
 
         public ICharBufferSource BufferSource { get; }
 
-        public IList<char[]> Pages { get; } = new List<char[]>();
+        // Strongly typed rather than IList for performance
+        public List<char[]> Pages { get; } = new List<char[]>(); 
 
         public int Length
         {
             get
             {
                 var length = _charIndex;
-                for (var i = 0; i < Pages.Count - 1; i++)
+                var pages = Pages;
+                var fullPages = pages.Count - 1;
+                for (var i = 0; i < fullPages; i++)
                 {
-                    length += Pages[i].Length;
+                    length += pages[i].Length;
                 }
 
                 return length;
@@ -100,13 +103,14 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures.Internal
         /// </summary>
         public void Clear()
         {
-            for (var i = Pages.Count - 1; i > 0; i--)
+            var pages = Pages;
+            for (var i = pages.Count - 1; i > 0; i--)
             {
-                var page = Pages[i];
+                var page = pages[i];
 
                 try
                 {
-                    Pages.RemoveAt(i);
+                    pages.RemoveAt(i);
                 }
                 finally
                 {
@@ -115,7 +119,7 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures.Internal
             }
 
             _charIndex = 0;
-            CurrentPage = Pages.Count > 0 ? Pages[0] : null;
+            CurrentPage = pages.Count > 0 ? pages[0] : null;
         }
 
         private char[] GetCurrentPage()
@@ -148,12 +152,14 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures.Internal
 
         public void Dispose()
         {
-            for (var i = 0; i < Pages.Count; i++)
+            var pages = Pages;
+            var count = pages.Count;
+            for (var i = 0; i < count; i++)
             {
-                BufferSource.Return(Pages[i]);
+                BufferSource.Return(pages[i]);
             }
 
-            Pages.Clear();
+            pages.Clear();
         }
     }
 }

src/Microsoft.AspNetCore.Mvc.ViewFeatures/Internal/ViewBuffer.cs

@@ -5,6 +5,7 @@ using System;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.IO;
+using System.Runtime.CompilerServices;
 using System.Text.Encodings.Web;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Html;
@@ -90,55 +91,73 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures.Internal
         }
 
         /// <inheritdoc />
+        // Very common trival method; nudge it to inline https://github.com/aspnet/Mvc/pull/8339
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public IHtmlContentBuilder Append(string unencoded)
         {
-            if (unencoded == null)
+            if (unencoded != null)
             {
-                return this;
+                // Text that needs encoding is the uncommon case in views, which is why it
+                // creates a wrapper and pre-encoded text does not.
+                AppendValue(new ViewBufferValue(new EncodingWrapper(unencoded)));
             }
 
-            // Text that needs encoding is the uncommon case in views, which is why it
-            // creates a wrapper and pre-encoded text does not.
-            AppendValue(new ViewBufferValue(new EncodingWrapper(unencoded)));
             return this;
         }
 
         /// <inheritdoc />
+        // Very common trival method; nudge it to inline https://github.com/aspnet/Mvc/pull/8339
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public IHtmlContentBuilder AppendHtml(IHtmlContent content)
         {
-            if (content == null)
+            if (content != null)
             {
-                return this;
+                AppendValue(new ViewBufferValue(content));
             }
 
-            AppendValue(new ViewBufferValue(content));
             return this;
         }
 
         /// <inheritdoc />
+        // Very common trival method; nudge it to inline https://github.com/aspnet/Mvc/pull/8339
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public IHtmlContentBuilder AppendHtml(string encoded)
         {
-            if (encoded == null)
+            if (encoded != null)
             {
-                return this;
+                AppendValue(new ViewBufferValue(encoded));
             }
 
-            AppendValue(new ViewBufferValue(encoded));
             return this;
         }
 
+        // Very common trival method; nudge it to inline https://github.com/aspnet/Mvc/pull/8339
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
         private void AppendValue(ViewBufferValue value)
         {
             var page = GetCurrentPage();
             page.Append(value);
         }
 
+        // Very common trival method; nudge it to inline https://github.com/aspnet/Mvc/pull/8339
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
         private ViewBufferPage GetCurrentPage()
         {
-            if (_currentPage == null || _currentPage.IsFull)
+            var currentPage = _currentPage;
+            if (currentPage == null || currentPage.IsFull)
             {
-                AddPage(new ViewBufferPage(_bufferScope.GetPage(_pageSize)));
+                // Uncommon slow-path
+                return AppendNewPage();
             }
+
+            return currentPage;
+        }
+
+        // Slow path for above, don't inline
+        [MethodImpl(MethodImplOptions.NoInlining)]
+        private ViewBufferPage AppendNewPage()
+        {
+            AddPage(new ViewBufferPage(_bufferScope.GetPage(_pageSize)));
             return _currentPage;
         }
 

src/Microsoft.AspNetCore.Mvc.ViewFeatures/Internal/ViewBufferPage.cs

@@ -1,6 +1,8 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
+using System.Runtime.CompilerServices;
+
 namespace Microsoft.AspNetCore.Mvc.ViewFeatures.Internal
 {
     public class ViewBufferPage
@@ -18,6 +20,8 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures.Internal
 
         public bool IsFull => Count == Capacity;
 
+        // Very common trival method; nudge it to inline https://github.com/aspnet/Mvc/pull/8339
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public void Append(ViewBufferValue value) => Buffer[Count++] = value;
     }
 }

test/Microsoft.AspNetCore.Mvc.ApiExplorer.Test/ApiResponseTypeProviderTest.cs

@@ -309,6 +309,247 @@ namespace Microsoft.AspNetCore.Mvc.ApiExplorer
                 });
         }
 
+        [Fact]
+        public void GetApiResponseTypes_UsesErrorType_ForClientErrors()
+        {
+            // Arrange
+            var errorType = typeof(InvalidTimeZoneException);
+            var actionDescriptor = GetControllerActionDescriptor(
+                 typeof(GetApiResponseTypes_ReturnsResponseTypesFromDefaultConventionsController),
+                 nameof(GetApiResponseTypes_ReturnsResponseTypesFromDefaultConventionsController.DeleteBase));
+            actionDescriptor.Properties[typeof(ApiConventionResult)] = new ApiConventionResult(new IApiResponseMetadataProvider[]
+            {
+                new ProducesResponseTypeAttribute(200),
+                new ProducesResponseTypeAttribute(404),
+                new ProducesResponseTypeAttribute(415),
+            });
+
+            actionDescriptor.Properties[typeof(ProducesErrorResponseTypeAttribute)] = new ProducesErrorResponseTypeAttribute(errorType);
+
+            var provider = GetProvider();
+
+            // Act
+            var result = provider.GetApiResponseTypes(actionDescriptor);
+
+            // Assert
+            Assert.Collection(
+                result.OrderBy(r => r.StatusCode),
+                responseType =>
+                {
+                    Assert.Equal(200, responseType.StatusCode);
+                    Assert.Equal(typeof(BaseModel), responseType.Type);
+                    Assert.Collection(
+                        responseType.ApiResponseFormats,
+                        format => Assert.Equal("application/json", format.MediaType));
+                },
+                responseType =>
+                {
+                    Assert.Equal(404, responseType.StatusCode);
+                    Assert.Equal(errorType, responseType.Type);
+                    Assert.False(responseType.IsDefaultResponse);
+                    Assert.Collection(
+                        responseType.ApiResponseFormats,
+                        format => Assert.Equal("application/json", format.MediaType));
+                },
+                responseType =>
+                {
+                    Assert.Equal(415, responseType.StatusCode);
+                    Assert.Equal(errorType, responseType.Type);
+                    Assert.False(responseType.IsDefaultResponse);
+                    Assert.Collection(
+                        responseType.ApiResponseFormats,
+                        format => Assert.Equal("application/json", format.MediaType));
+                });
+        }
+
+        [Fact]
+        public void GetApiResponseTypes_UsesErrorType_ForDefaultResponse()
+        {
+            // Arrange
+            var errorType = typeof(ProblemDetails);
+            var actionDescriptor = GetControllerActionDescriptor(
+                 typeof(GetApiResponseTypes_ReturnsResponseTypesFromDefaultConventionsController),
+                 nameof(GetApiResponseTypes_ReturnsResponseTypesFromDefaultConventionsController.DeleteBase));
+            actionDescriptor.Properties[typeof(ApiConventionResult)] = new ApiConventionResult(new IApiResponseMetadataProvider[]
+            {
+                new ProducesResponseTypeAttribute(200),
+                new ProducesDefaultResponseTypeAttribute(),
+            });
+
+            actionDescriptor.Properties[typeof(ProducesErrorResponseTypeAttribute)] = new ProducesErrorResponseTypeAttribute(errorType);
+
+            var provider = GetProvider();
+
+            // Act
+            var result = provider.GetApiResponseTypes(actionDescriptor);
+
+            // Assert
+            Assert.Collection(
+                result.OrderBy(r => r.StatusCode),
+                responseType =>
+                {
+                    Assert.Equal(errorType, responseType.Type);
+                    Assert.True(responseType.IsDefaultResponse);
+                    Assert.Collection(
+                        responseType.ApiResponseFormats,
+                        format => Assert.Equal("application/json", format.MediaType));
+                },
+                responseType =>
+                {
+                    Assert.Equal(200, responseType.StatusCode);
+                    Assert.Equal(typeof(BaseModel), responseType.Type);
+                    Assert.Collection(
+                        responseType.ApiResponseFormats,
+                        format => Assert.Equal("application/json", format.MediaType));
+                });
+        }
+
+        [Fact]
+        public void GetApiResponseTypes_DoesNotUseErrorType_IfSpecified()
+        {
+            // Arrange
+            var errorType = typeof(InvalidTimeZoneException);
+            var actionDescriptor = GetControllerActionDescriptor(
+                 typeof(GetApiResponseTypes_ReturnsResponseTypesFromDefaultConventionsController),
+                 nameof(GetApiResponseTypes_ReturnsResponseTypesFromDefaultConventionsController.DeleteBase));
+            actionDescriptor.Properties[typeof(ApiConventionResult)] = new ApiConventionResult(new IApiResponseMetadataProvider[]
+            {
+                new ProducesResponseTypeAttribute(200),
+                new ProducesResponseTypeAttribute(typeof(DivideByZeroException), 415),
+                new ProducesDefaultResponseTypeAttribute(typeof(DivideByZeroException)),
+            });
+
+            actionDescriptor.Properties[typeof(ProducesErrorResponseTypeAttribute)] = new ProducesErrorResponseTypeAttribute(errorType);
+
+            var provider = GetProvider();
+
+            // Act
+            var result = provider.GetApiResponseTypes(actionDescriptor);
+
+            // Assert
+            Assert.Collection(
+                result.OrderBy(r => r.StatusCode),
+                responseType =>
+                {
+                    Assert.Equal(typeof(DivideByZeroException), responseType.Type);
+                    Assert.True(responseType.IsDefaultResponse);
+                    Assert.Collection(
+                        responseType.ApiResponseFormats,
+                        format => Assert.Equal("application/json", format.MediaType));
+                },
+                responseType =>
+                {
+                    Assert.Equal(200, responseType.StatusCode);
+                    Assert.Equal(typeof(BaseModel), responseType.Type);
+                    Assert.Collection(
+                        responseType.ApiResponseFormats,
+                        format => Assert.Equal("application/json", format.MediaType));
+                },
+                responseType =>
+                {
+                    Assert.Equal(415, responseType.StatusCode);
+                    Assert.Equal(typeof(DivideByZeroException), responseType.Type);
+                    Assert.False(responseType.IsDefaultResponse);
+                    Assert.Collection(
+                        responseType.ApiResponseFormats,
+                        format => Assert.Equal("application/json", format.MediaType));
+                });
+        }
+
+        [Fact]
+        public void GetApiResponseTypes_DoesNotUseErrorType_ForNonClientErrors()
+        {
+            // Arrange
+            var actionDescriptor = GetControllerActionDescriptor(
+                 typeof(GetApiResponseTypes_ReturnsResponseTypesFromDefaultConventionsController),
+                 nameof(GetApiResponseTypes_ReturnsResponseTypesFromDefaultConventionsController.DeleteBase));
+            actionDescriptor.Properties[typeof(ApiConventionResult)] = new ApiConventionResult(new IApiResponseMetadataProvider[]
+            {
+                new ProducesResponseTypeAttribute(201),
+                new ProducesResponseTypeAttribute(300),
+                new ProducesResponseTypeAttribute(500),
+            });
+
+            actionDescriptor.Properties[typeof(ProducesErrorResponseTypeAttribute)] = new ProducesErrorResponseTypeAttribute(typeof(InvalidTimeZoneException));
+
+            var provider = GetProvider();
+
+            // Act
+            var result = provider.GetApiResponseTypes(actionDescriptor);
+
+            // Assert
+            Assert.Collection(
+                result.OrderBy(r => r.StatusCode),
+                responseType =>
+                {
+                    Assert.Equal(201, responseType.StatusCode);
+                    Assert.Equal(typeof(BaseModel), responseType.Type);
+                    Assert.Collection(
+                        responseType.ApiResponseFormats,
+                        format => Assert.Equal("application/json", format.MediaType));
+                },
+                responseType =>
+                {
+                    Assert.Equal(300, responseType.StatusCode);
+                    Assert.Equal(typeof(void), responseType.Type);
+                    Assert.Empty(responseType.ApiResponseFormats);
+                },
+                responseType =>
+                {
+                    Assert.Equal(500, responseType.StatusCode);
+                    Assert.Equal(typeof(void), responseType.Type);
+                    Assert.Empty(responseType.ApiResponseFormats);
+                });
+        }
+
+        [Fact]
+        public void GetApiResponseTypes_AllowsUsingVoid()
+        {
+            // Arrange
+            var actionDescriptor = GetControllerActionDescriptor(
+                 typeof(GetApiResponseTypes_ReturnsResponseTypesFromDefaultConventionsController),
+                 nameof(GetApiResponseTypes_ReturnsResponseTypesFromDefaultConventionsController.DeleteBase));
+            actionDescriptor.Properties[typeof(ApiConventionResult)] = new ApiConventionResult(new IApiResponseMetadataProvider[]
+            {
+                new ProducesResponseTypeAttribute(typeof(InvalidCastException), 400),
+                new ProducesResponseTypeAttribute(415),
+                new ProducesDefaultResponseTypeAttribute(),
+            });
+
+            actionDescriptor.Properties[typeof(ProducesErrorResponseTypeAttribute)] = new ProducesErrorResponseTypeAttribute(typeof(void));
+
+            var provider = GetProvider();
+
+            // Act
+            var result = provider.GetApiResponseTypes(actionDescriptor);
+
+            // Assert
+            Assert.Collection(
+                result.OrderBy(r => r.StatusCode),
+                responseType =>
+                {
+                    Assert.True(responseType.IsDefaultResponse);
+                    Assert.Equal(typeof(void), responseType.Type);
+                    Assert.Empty(responseType.ApiResponseFormats);
+                },
+                responseType =>
+                {
+                    Assert.Equal(400, responseType.StatusCode);
+                    Assert.Equal(typeof(InvalidCastException), responseType.Type);
+                    Assert.False(responseType.IsDefaultResponse);
+                    Assert.Collection(
+                        responseType.ApiResponseFormats,
+                        format => Assert.Equal("application/json", format.MediaType));
+                },
+                responseType =>
+                {
+                    Assert.Equal(415, responseType.StatusCode);
+                    Assert.Equal(typeof(void), responseType.Type);
+                    Assert.False(responseType.IsDefaultResponse);
+                    Assert.Empty(responseType.ApiResponseFormats);
+                });
+        }
+
         private static ApiResponseTypeProvider GetProvider()
         {
             var mvcOptions = new MvcOptions

test/Microsoft.AspNetCore.Mvc.Core.Test/Infrastructure/ClientErrorResultFilterTest.cs

@@ -32,35 +32,25 @@ namespace Microsoft.AspNetCore.Mvc.Infrastructure
         }
 
         [Fact]
-        public void OnResultExecuting_DoesNothing_IfStatusCodeDoesNotExistInApiBehaviorOptions()
+        public void OnResultExecuting_DoesNothing_IfTransformedValueIsNull()
         {
             // Arrange
             var actionResult = new NotFoundResult();
             var context = GetContext(actionResult);
-            var filter = GetFilter(new ApiBehaviorOptions());
+            var factory = new Mock<IClientErrorFactory>();
-
+            factory
-            // Act
+                .Setup(f => f.GetClientError(It.IsAny<ActionContext>(), It.IsAny<IClientErrorActionResult>()))
-            filter.OnResultExecuting(context);
+                .Returns((IActionResult)null)
-
+                .Verifiable();
-            // Assert
+
-            Assert.Same(actionResult, context.Result);
+            var filter = new ClientErrorResultFilter(factory.Object, NullLogger<ClientErrorResultFilter>.Instance);
-        }
-
-        [Fact]
-        public void OnResultExecuting_DoesNothing_IfResultDoesNotHaveStatusCode()
-        {
-            // Arrange
-            var actionResult = new Mock<IActionResult>()
-                .As<IClientErrorActionResult>()
-                .Object;
-            var context = GetContext(actionResult);
-            var filter = GetFilter(new ApiBehaviorOptions());
 
             // Act
             filter.OnResultExecuting(context);
 
             // Assert
             Assert.Same(actionResult, context.Result);
+            factory.Verify();
         }
 
         [Fact]
@@ -78,18 +68,12 @@ namespace Microsoft.AspNetCore.Mvc.Infrastructure
             Assert.Same(Result, context.Result);
         }
 
-        private static ClientErrorResultFilter GetFilter(ApiBehaviorOptions options = null)
+        private static ClientErrorResultFilter GetFilter()
         {
-            var apiBehaviorOptions = options ?? GetOptions();
+            var factory = Mock.Of<IClientErrorFactory>(
-            var filter = new ClientErrorResultFilter(apiBehaviorOptions, NullLogger<ClientErrorResultFilter>.Instance);
+                f => f.GetClientError(It.IsAny<ActionContext>(), It.IsAny<IClientErrorActionResult>()) == Result);
-            return filter;
-        }
 
-        private static ApiBehaviorOptions GetOptions()
+            return new ClientErrorResultFilter(factory, NullLogger<ClientErrorResultFilter>.Instance);
-        {
-            var apiBehaviorOptions = new ApiBehaviorOptions();
-            apiBehaviorOptions.ClientErrorFactory[404] = _ => Result;
-            return apiBehaviorOptions;
         }
 
         private static ResultExecutingContext GetContext(IActionResult actionResult)

test/Microsoft.AspNetCore.Mvc.Core.Test/Infrastructure/ProblemDetalsClientErrorFactoryTest.cs

@@ -0,0 +1,129 @@
+// 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.Diagnostics;
+using Microsoft.AspNetCore.Http;
+using Microsoft.Extensions.Options;
+using Xunit;
+
+namespace Microsoft.AspNetCore.Mvc.Infrastructure
+{
+    public class ProblemDetalsClientErrorFactoryTest
+    {
+        [Fact]
+        public void GetClientError_ReturnsProblemDetails_IfNoMappingWasFound()
+        {
+            // Arrange
+            var clientError = new UnsupportedMediaTypeResult();
+            var factory = new ProblemDetailsClientErrorFactory(Options.Create(new ApiBehaviorOptions
+            {
+                ClientErrorMapping =
+                {
+                    [405] = new ClientErrorData { Link = "Some link", Title = "Summary" },
+                },
+            }));
+
+            // Act
+            var result = factory.GetClientError(GetActionContext(), clientError);
+
+            // Assert
+            var objectResult = Assert.IsType<ObjectResult>(result);
+            Assert.Equal(new[] { "application/problem+json", "application/problem+xml" }, objectResult.ContentTypes);
+            var problemDetails = Assert.IsType<ProblemDetails>(objectResult.Value);
+            Assert.Equal(415, problemDetails.Status);
+            Assert.Equal("about:blank", problemDetails.Type);
+            Assert.Null(problemDetails.Title);
+            Assert.Null(problemDetails.Detail);
+            Assert.Null(problemDetails.Instance);
+        }
+
+        [Fact]
+        public void GetClientError_ReturnsProblemDetails()
+        {
+            // Arrange
+            var clientError = new UnsupportedMediaTypeResult();
+            var factory = new ProblemDetailsClientErrorFactory(Options.Create(new ApiBehaviorOptions
+            {
+                ClientErrorMapping =
+                {
+                    [415] = new ClientErrorData { Link = "Some link", Title = "Summary" },
+                },
+            }));
+
+            // Act
+            var result = factory.GetClientError(GetActionContext(), clientError);
+
+            // Assert
+            var objectResult = Assert.IsType<ObjectResult>(result);
+            Assert.Equal(new[] { "application/problem+json", "application/problem+xml" }, objectResult.ContentTypes);
+            var problemDetails = Assert.IsType<ProblemDetails>(objectResult.Value);
+            Assert.Equal(415, problemDetails.Status);
+            Assert.Equal("Some link", problemDetails.Type);
+            Assert.Equal("Summary", problemDetails.Title);
+            Assert.Null(problemDetails.Detail);
+            Assert.Null(problemDetails.Instance);
+        }
+
+        [Fact]
+        public void GetClientError_UsesActivityId_ToSetTraceId()
+        {
+            // Arrange
+            using (new ActivityReplacer())
+            {
+                var clientError = new UnsupportedMediaTypeResult();
+                var factory = new ProblemDetailsClientErrorFactory(Options.Create(new ApiBehaviorOptions
+                {
+                    ClientErrorMapping =
+                {
+                    [415] = new ClientErrorData { Link = "Some link", Title = "Summary" },
+                },
+                }));
+
+                // Act
+                var result = factory.GetClientError(GetActionContext(), clientError);
+
+                // Assert
+                var objectResult = Assert.IsType<ObjectResult>(result);
+                Assert.Equal(new[] { "application/problem+json", "application/problem+xml" }, objectResult.ContentTypes);
+                var problemDetails = Assert.IsType<ProblemDetails>(objectResult.Value);
+
+                Assert.Equal(Activity.Current.Id, problemDetails.Extensions["traceId"]);
+            }
+        }
+
+        [Fact]
+        public void GetClientError_UsesHttpContext_ToSetTraceIdIfActivityIdIsNotSet()
+        {
+            // Arrange
+            var clientError = new UnsupportedMediaTypeResult();
+            var factory = new ProblemDetailsClientErrorFactory(Options.Create(new ApiBehaviorOptions
+            {
+                ClientErrorMapping =
+                {
+                    [415] = new ClientErrorData { Link = "Some link", Title = "Summary" },
+                },
+            }));
+
+            // Act
+            var result = factory.GetClientError(GetActionContext(), clientError);
+
+            // Assert
+            var objectResult = Assert.IsType<ObjectResult>(result);
+            Assert.Equal(new[] { "application/problem+json", "application/problem+xml" }, objectResult.ContentTypes);
+            var problemDetails = Assert.IsType<ProblemDetails>(objectResult.Value);
+
+            Assert.Equal("42", problemDetails.Extensions["traceId"]);
+        }
+
+        private static ActionContext GetActionContext()
+        {
+            return new ActionContext
+            {
+                HttpContext = new DefaultHttpContext
+                {
+                    TraceIdentifier = "42",
+                }
+            };
+        }
+    }
+}

test/Microsoft.AspNetCore.Mvc.Core.Test/Internal/ApiBehaviorApplicationModelProviderTest.cs

@@ -12,13 +12,15 @@ using System.Threading.Tasks;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Mvc.ApiExplorer;
 using Microsoft.AspNetCore.Mvc.ApplicationModels;
-using Microsoft.AspNetCore.Mvc.Authorization;
 using Microsoft.AspNetCore.Mvc.Infrastructure;
 using Microsoft.AspNetCore.Mvc.ModelBinding;
 using Microsoft.Extensions.Logging.Abstractions;
 using Microsoft.Extensions.Options;
+using Moq;
 using Xunit;
 
+[assembly: Microsoft.AspNetCore.Mvc.ProducesErrorResponseType(typeof(InvalidEnumArgumentException))]
+
 namespace Microsoft.AspNetCore.Mvc.Internal
 {
     public class ApiBehaviorApplicationModelProviderTest
@@ -1041,9 +1043,6 @@ Environment.NewLine + "int b";
             var actionModel = new ActionModel(
                 typeof(TestApiConventionController).GetMethod(nameof(TestApiConventionController.Delete)),
                 Array.Empty<object>());
-            actionModel.Filters.Add(new AuthorizeFilter());
-            actionModel.Filters.Add(new ServiceFilterAttribute(typeof(object)));
-            actionModel.Filters.Add(new ConsumesAttribute("application/xml"));
             var attributes = new[] { new ApiConventionTypeAttribute(typeof(DefaultApiConventions)) };
 
             // Act
@@ -1059,6 +1058,167 @@ Environment.NewLine + "int b";
                 });
         }
 
+        [Fact]
+        public void DiscoverErrorResponseType_SetsProblemDetails_IfActionHasNoAttributes()
+        {
+            // Arrange
+            var expected = typeof(ProblemDetails);
+            var controllerModel = new ControllerModel(typeof(object).GetTypeInfo(), new[] { new object() });
+            var actionModel = new ActionModel(
+                typeof(TestApiConventionController).GetMethod(nameof(TestApiConventionController.Delete)),
+                Array.Empty<object>())
+            {
+                Controller = controllerModel,
+            };
+            var provider = GetProvider();
+
+            // Act
+            provider.DiscoverErrorResponseType(actionModel);
+
+            // Assert
+            Assert.Collection(
+                actionModel.Properties,
+                kvp =>
+                {
+                    Assert.Equal(typeof(ProducesErrorResponseTypeAttribute), kvp.Key);
+                    var value = Assert.IsType<ProducesErrorResponseTypeAttribute>(kvp.Value);
+                    Assert.Equal(expected, value.Type);
+                });
+        }
+
+        [Fact]
+        public void DiscoverErrorResponseType_DoesNotSetDefaultProblemDetailsResponse_IfSuppressMapClientErrorsIsSet()
+        {
+            // Arrange
+            var expected = typeof(ProblemDetails);
+            var controllerModel = new ControllerModel(typeof(object).GetTypeInfo(), new[] { new object() });
+            var actionModel = new ActionModel(
+                typeof(TestApiConventionController).GetMethod(nameof(TestApiConventionController.Delete)),
+                Array.Empty<object>())
+            {
+                Controller = controllerModel,
+            };
+            var provider = GetProvider(new ApiBehaviorOptions
+            {
+                InvalidModelStateResponseFactory = _ => null,
+                SuppressMapClientErrors = true,
+            });
+
+            // Act
+            provider.DiscoverErrorResponseType(actionModel);
+
+            // Assert
+            Assert.Empty(actionModel.Properties);
+        }
+
+        [Fact]
+        public void DiscoverErrorResponseType_UsesValueFromApiErrorTypeAttribute_SpecifiedOnControllerAsssembly()
+        {
+            // Arrange
+            var expected = typeof(InvalidEnumArgumentException);
+            var controllerModel = new ControllerModel(typeof(TestApiConventionController).GetTypeInfo(), new[] { new object() });
+            var actionModel = new ActionModel(
+                typeof(TestApiConventionController).GetMethod(nameof(TestApiConventionController.Delete)),
+                Array.Empty<object>())
+            {
+                Controller = controllerModel,
+            };
+            var provider = GetProvider();
+
+            // Act
+            provider.DiscoverErrorResponseType(actionModel);
+
+            // Assert
+            Assert.Collection(
+                actionModel.Properties,
+                kvp =>
+                {
+                    Assert.Equal(typeof(ProducesErrorResponseTypeAttribute), kvp.Key);
+                    var value = Assert.IsType<ProducesErrorResponseTypeAttribute>(kvp.Value);
+                    Assert.Equal(expected, value.Type);
+                });
+        }
+
+        [Fact]
+        public void DiscoverErrorResponseType_UsesValueFromApiErrorTypeAttribute_SpecifiedOnController()
+        {
+            // Arrange
+            var expected = typeof(InvalidTimeZoneException);
+            var controllerModel = new ControllerModel(typeof(TestApiConventionController).GetTypeInfo(), new[] { new ProducesErrorResponseTypeAttribute(expected) });
+            var actionModel = new ActionModel(
+                typeof(TestApiConventionController).GetMethod(nameof(TestApiConventionController.Delete)),
+                Array.Empty<object>())
+            {
+                Controller = controllerModel,
+            };
+            var provider = GetProvider();
+
+            // Act
+            provider.DiscoverErrorResponseType(actionModel);
+
+            // Assert
+            Assert.Collection(
+                actionModel.Properties,
+                kvp =>
+                {
+                    Assert.Equal(typeof(ProducesErrorResponseTypeAttribute), kvp.Key);
+                    var value = Assert.IsType<ProducesErrorResponseTypeAttribute>(kvp.Value);
+                    Assert.Equal(expected, value.Type);
+                });
+        }
+
+        [Fact]
+        public void DiscoverErrorResponseType_UsesValueFromApiErrorTypeAttribute_SpecifiedOnAction()
+        {
+            // Arrange
+            var expected = typeof(InvalidTimeZoneException);
+            var controllerModel = new ControllerModel(typeof(TestApiConventionController).GetTypeInfo(), new[] { new ProducesErrorResponseTypeAttribute(typeof(Guid)) });
+            var actionModel = new ActionModel(
+                typeof(TestApiConventionController).GetMethod(nameof(TestApiConventionController.Delete)),
+                new[] { new ProducesErrorResponseTypeAttribute(expected) })
+            {
+                Controller = controllerModel,
+            };
+            var provider = GetProvider();
+
+            // Act
+            provider.DiscoverErrorResponseType(actionModel);
+
+            // Assert
+            Assert.Collection(
+                actionModel.Properties,
+                kvp =>
+                {
+                    Assert.Equal(typeof(ProducesErrorResponseTypeAttribute), kvp.Key);
+                    var value = Assert.IsType<ProducesErrorResponseTypeAttribute>(kvp.Value);
+                    Assert.Equal(expected, value.Type);
+                });
+        }
+
+        [Fact]
+        public void DiscoverErrorResponseType_AllowsVoidsType()
+        {
+            // Arrange
+            var expected = typeof(void);
+            var actionModel = new ActionModel(
+                typeof(TestApiConventionController).GetMethod(nameof(TestApiConventionController.Delete)),
+                new[] { new ProducesErrorResponseTypeAttribute(expected) });
+            var provider = GetProvider();
+
+            // Act
+            provider.DiscoverErrorResponseType(actionModel);
+
+            // Assert
+            Assert.Collection(
+                actionModel.Properties,
+                kvp =>
+                {
+                    Assert.Equal(typeof(ProducesErrorResponseTypeAttribute), kvp.Key);
+                    var value = Assert.IsType<ProducesErrorResponseTypeAttribute>(kvp.Value);
+                    Assert.Equal(expected, value.Type);
+                });
+        }
+
         [Fact]
         public void OnProvidersExecuting_AddsClientErrorResultFilter()
         {
@@ -1081,7 +1241,7 @@ Environment.NewLine + "int b";
             var context = GetContext(typeof(TestApiController));
             var options = new ApiBehaviorOptions
             {
-                SuppressUseClientErrorFactory = true,
+                SuppressMapClientErrors = true,
                 InvalidModelStateResponseFactory = _ => null,
             };
             var provider = GetProvider(options);
@@ -1122,7 +1282,11 @@ Environment.NewLine + "int b";
 
             var loggerFactory = NullLoggerFactory.Instance;
             modelMetadataProvider = modelMetadataProvider ?? new EmptyModelMetadataProvider();
-            return new ApiBehaviorApplicationModelProvider(optionsAccessor, modelMetadataProvider, loggerFactory);
+            return new ApiBehaviorApplicationModelProvider(
+                optionsAccessor,
+                modelMetadataProvider,
+                Mock.Of<IClientErrorFactory>(),
+                loggerFactory);
         }
 
         private static ApplicationModelProviderContext GetContext(

test/Microsoft.AspNetCore.Mvc.Core.Test/Internal/ApiBehaviorOptionsSetupTest.cs

@@ -2,6 +2,9 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
+using System.Diagnostics;
+using System.Linq;
+using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Mvc.Infrastructure;
 using Microsoft.Extensions.Logging.Abstractions;
 using Microsoft.Extensions.Options;
@@ -28,7 +31,7 @@ namespace Microsoft.AspNetCore.Mvc.Internal
         }
 
         [Fact]
-        public void Configure_AddsClientErrorFactories()
+        public void Configure_AddsClientErrorMappings()
         {
             // Arrange
             var expected = new[] { 400, 401, 403, 404, 406, 409, 415, 422, };
@@ -41,7 +44,7 @@ namespace Microsoft.AspNetCore.Mvc.Internal
             optionsSetup.Configure(options);
 
             // Assert
-            Assert.Equal(expected, options.ClientErrorFactory.Keys);
+            Assert.Equal(expected, options.ClientErrorMapping.Keys);
         }
 
         [Fact]
@@ -97,5 +100,64 @@ namespace Microsoft.AspNetCore.Mvc.Internal
             // Assert
             Assert.Same(expected, options.InvalidModelStateResponseFactory);
         }
+
+        [Fact]
+        public void ProblemDetailsInvalidModelStateResponse_ReturnsBadRequestWithProblemDetails()
+        {
+            // Arrange
+            var actionContext = new ActionContext
+            {
+                HttpContext = new DefaultHttpContext { TraceIdentifier = "42" },
+            };
+
+            // Act
+            var result = ApiBehaviorOptionsSetup.ProblemDetailsInvalidModelStateResponse(actionContext);
+
+            // Assert
+            var badRequest = Assert.IsType<BadRequestObjectResult>(result);
+            Assert.Equal(new[] { "application/problem+json", "application/problem+xml" }, badRequest.ContentTypes.OrderBy(c => c));
+
+            var problemDetails = Assert.IsType<ValidationProblemDetails>(badRequest.Value);
+            Assert.Equal(400, problemDetails.Status);
+        }
+
+        [Fact]
+        public void ProblemDetailsInvalidModelStateResponse_SetsTraceId()
+        {
+            // Arrange
+            using (new ActivityReplacer())
+            {
+                var actionContext = new ActionContext
+                {
+                    HttpContext = new DefaultHttpContext { TraceIdentifier = "42" },
+                };
+
+                // Act
+                var result = ApiBehaviorOptionsSetup.ProblemDetailsInvalidModelStateResponse(actionContext);
+
+                // Assert
+                var badRequest = Assert.IsType<BadRequestObjectResult>(result);
+                var problemDetails = Assert.IsType<ValidationProblemDetails>(badRequest.Value);
+                Assert.Equal(Activity.Current.Id, problemDetails.Extensions["traceId"]);
+            }
+        }
+
+        [Fact]
+        public void ProblemDetailsInvalidModelStateResponse_SetsTraceIdFromRequest_IfActivityIsNull()
+        {
+            // Arrange
+            var actionContext = new ActionContext
+            {
+                HttpContext = new DefaultHttpContext { TraceIdentifier = "42" },
+            };
+
+            // Act
+            var result = ApiBehaviorOptionsSetup.ProblemDetailsInvalidModelStateResponse(actionContext);
+
+            // Assert
+            var badRequest = Assert.IsType<BadRequestObjectResult>(result);
+            var problemDetails = Assert.IsType<ValidationProblemDetails>(badRequest.Value);
+            Assert.Equal("42", problemDetails.Extensions["traceId"]);
+        }
     }
 }

test/Microsoft.AspNetCore.Mvc.Core.Test/Internal/AttributeRoutingTest.cs

@@ -175,8 +175,12 @@ namespace Microsoft.AspNetCore.Mvc.Internal
                 .SetupGet(o => o.Value)
                 .Returns(new RouteOptions());
 
+#pragma warning disable CS0618 // Type or member is obsolete
+            var inlineConstraintResolver = new DefaultInlineConstraintResolver(routeOptions.Object);
+#pragma warning restore CS0618 // Type or member is obsolete
+
             var services = new ServiceCollection()
-                .AddSingleton<IInlineConstraintResolver>(new DefaultInlineConstraintResolver(routeOptions.Object))
+                .AddSingleton<IInlineConstraintResolver>(inlineConstraintResolver)
                 .AddSingleton<ObjectPoolProvider, DefaultObjectPoolProvider>();
 
             services.AddSingleton<ObjectPoolProvider, DefaultObjectPoolProvider>();

test/Microsoft.AspNetCore.Mvc.Core.Test/Internal/MvcEndpointDataSourceTests.cs

@@ -89,6 +89,7 @@ namespace Microsoft.AspNetCore.Mvc.Internal
             var featureCollection = new FeatureCollection();
             featureCollection.Set<IEndpointFeature>(endpointFeature);
             featureCollection.Set<IRouteValuesFeature>(endpointFeature);
+            featureCollection.Set<IRoutingFeature>(endpointFeature);
 
             var httpContextMock = new Mock<HttpContext>();
             httpContextMock.Setup(m => m.Features).Returns(featureCollection);
@@ -180,7 +181,15 @@ namespace Microsoft.AspNetCore.Mvc.Internal
             var actionDescriptorCollection = GetActionDescriptorCollection(
                 new { controller = "TestController", action = "TestAction", area = "TestArea" });
             var dataSource = CreateMvcEndpointDataSource(actionDescriptorCollection);
-            dataSource.ConventionalEndpointInfos.Add(CreateEndpointInfo(string.Empty, endpointInfoRoute));
+
+            var services = new ServiceCollection();
+            services.AddRouting();
+            services.AddSingleton(actionDescriptorCollection);
+
+            var routeOptionsSetup = new MvcCoreRouteOptionsSetup();
+            services.Configure<RouteOptions>(routeOptionsSetup.Configure);
+
+            dataSource.ConventionalEndpointInfos.Add(CreateEndpointInfo(string.Empty, endpointInfoRoute, serviceProvider: services.BuildServiceProvider()));
 
             // Act
             var endpoints = dataSource.Endpoints;
@@ -686,28 +695,6 @@ namespace Microsoft.AspNetCore.Mvc.Internal
             AssertIsSubset(expectedDefaults, matcherEndpoint.RoutePattern.Defaults);
         }
 
-        [Fact]
-        public void RequiredValues_HavingNull_AndNotPresentInDefaultValues_IsAddedToDefaultValues()
-        {
-            // Arrange
-            var requiredValues = new RouteValueDictionary(
-                new { area = (string)null, controller = "Foo", action = "Bar", page = (string)null });
-            var expectedDefaults = requiredValues;
-            var actionDescriptorCollection = GetActionDescriptorCollection(requiredValues: requiredValues);
-            var dataSource = CreateMvcEndpointDataSource(actionDescriptorCollection);
-            dataSource.ConventionalEndpointInfos.Add(
-                CreateEndpointInfo(string.Empty, "{controller=Home}/{action=Index}"));
-
-            // Act
-            var endpoints = dataSource.Endpoints;
-
-            // Assert
-            var endpoint = Assert.Single(endpoints);
-            var matcherEndpoint = Assert.IsType<RouteEndpoint>(endpoint);
-            Assert.Equal("Foo/Bar", matcherEndpoint.RoutePattern.RawText);
-            AssertIsSubset(expectedDefaults, matcherEndpoint.RoutePattern.Defaults);
-        }
-
         private MvcEndpointDataSource CreateMvcEndpointDataSource(
             IActionDescriptorCollectionProvider actionDescriptorCollectionProvider = null,
             MvcEndpointInvokerFactory mvcEndpointInvokerFactory = null)
@@ -719,13 +706,13 @@ namespace Microsoft.AspNetCore.Mvc.Internal
                     Array.Empty<IActionDescriptorChangeProvider>());
             }
 
-            var serviceProviderMock = new Mock<IServiceProvider>();
+            var services = new ServiceCollection();
-            serviceProviderMock.Setup(m => m.GetService(typeof(IActionDescriptorCollectionProvider))).Returns(actionDescriptorCollectionProvider);
+            services.AddSingleton(actionDescriptorCollectionProvider);
 
             var dataSource = new MvcEndpointDataSource(
                 actionDescriptorCollectionProvider,
                 mvcEndpointInvokerFactory ?? new MvcEndpointInvokerFactory(new ActionInvokerFactory(Array.Empty<IActionInvokerProvider>())),
-                serviceProviderMock.Object);
+                services.BuildServiceProvider());
 
             return dataSource;
         }
@@ -735,15 +722,19 @@ namespace Microsoft.AspNetCore.Mvc.Internal
             string template,
             RouteValueDictionary defaults = null,
             IDictionary<string, object> constraints = null,
-            RouteValueDictionary dataTokens = null)
+            RouteValueDictionary dataTokens = null,
+            IServiceProvider serviceProvider = null)
         {
-            var serviceCollection = new ServiceCollection();
+            if (serviceProvider == null)
-            serviceCollection.AddRouting();
+            {
+                var serviceCollection = new ServiceCollection();
+                serviceCollection.AddRouting();
 
-            var routeOptionsSetup = new MvcCoreRouteOptionsSetup();
+                var routeOptionsSetup = new MvcCoreRouteOptionsSetup();
-            serviceCollection.Configure<RouteOptions>(routeOptionsSetup.Configure);
+                serviceCollection.Configure<RouteOptions>(routeOptionsSetup.Configure);
 
-            var serviceProvider = serviceCollection.BuildServiceProvider();
+                serviceProvider = serviceCollection.BuildServiceProvider();
+            }
 
             var parameterPolicyFactory = serviceProvider.GetRequiredService<ParameterPolicyFactory>();
             return new MvcEndpointInfo(name, template, defaults, constraints, dataTokens, parameterPolicyFactory);

test/Microsoft.AspNetCore.Mvc.Core.Test/Routing/KnownRouteValueConstraintTests.cs

@@ -2,7 +2,6 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
-using System.Collections.Generic;
 using System.Linq;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Mvc.Abstractions;
@@ -10,6 +9,7 @@ using Microsoft.AspNetCore.Mvc.Controllers;
 using Microsoft.AspNetCore.Mvc.Infrastructure;
 using Microsoft.AspNetCore.Mvc.Internal;
 using Microsoft.AspNetCore.Routing;
+using Microsoft.Extensions.DependencyInjection;
 using Moq;
 using Xunit;
 
@@ -17,7 +17,47 @@ namespace Microsoft.AspNetCore.Mvc.Routing
 {
     public class KnownRouteValueConstraintTests
     {
+#pragma warning disable CS0618 // Type or member is obsolete
         private readonly IRouteConstraint _constraint = new KnownRouteValueConstraint();
+#pragma warning restore CS0618 // Type or member is obsolete
+
+        [Fact]
+        public void ResolveFromServices_InjectsServiceProvider_HttpContextNotNeeded()
+        {
+            // Arrange
+            var actionDescriptor = CreateActionDescriptor("testArea",
+                "testController",
+                "testAction");
+            actionDescriptor.RouteValues.Add("randomKey", "testRandom");
+            var descriptorCollectionProvider = CreateActionDesciprtorCollectionProvider(actionDescriptor);
+
+            var services = new ServiceCollection();
+            services.AddRouting();
+            services.AddSingleton(descriptorCollectionProvider);
+
+            var routeOptionsSetup = new MvcCoreRouteOptionsSetup();
+            services.Configure<RouteOptions>(routeOptionsSetup.Configure);
+
+            var serviceProvider = services.BuildServiceProvider();
+
+            var inlineConstraintResolver = serviceProvider.GetRequiredService<IInlineConstraintResolver>();
+            var constraint = inlineConstraintResolver.ResolveConstraint("exists");
+
+            var values = new RouteValueDictionary()
+            {
+                { "area", "testArea" },
+                { "controller", "testController" },
+                { "action", "testAction" },
+                { "randomKey", "testRandom" }
+            };
+
+            // Act
+            var knownRouteValueConstraint = Assert.IsType<KnownRouteValueConstraint>(constraint);
+            var match = knownRouteValueConstraint.Match(httpContext: null, route: null, "area", values, RouteDirection.IncomingRequest);
+
+            // Assert
+            Assert.True(match);
+        }
 
         [Theory]
         [InlineData("area", RouteDirection.IncomingRequest)]
@@ -55,8 +95,8 @@ namespace Microsoft.AspNetCore.Mvc.Routing
         {
             // Arrange
             var actionDescriptor = CreateActionDescriptor("testArea",
-                                                          "testController",
+                "testController",
-                                                          "testAction");
+                "testAction");
             actionDescriptor.RouteValues.Add("randomKey", "testRandom");
             var httpContext = GetHttpContext(actionDescriptor);
             var route = Mock.Of<IRouter>();
@@ -115,8 +155,8 @@ namespace Microsoft.AspNetCore.Mvc.Routing
         public void RouteValue_IsNotAString_MatchFails(RouteDirection direction)
         {
             var actionDescriptor = CreateActionDescriptor("testArea",
-                                                          controller: null,
+                controller: null,
-                                                          action: null);
+                action: null);
             var httpContext = GetHttpContext(actionDescriptor);
             var route = Mock.Of<IRouter>();
             var values = new RouteValueDictionary()
@@ -157,7 +197,57 @@ namespace Microsoft.AspNetCore.Mvc.Routing
                 ex.Message);
         }
 
-        private static HttpContext GetHttpContext(ActionDescriptor actionDescriptor)
+        [Theory]
+        [InlineData("area", RouteDirection.IncomingRequest)]
+        [InlineData("controller", RouteDirection.IncomingRequest)]
+        [InlineData("action", RouteDirection.IncomingRequest)]
+        [InlineData("randomKey", RouteDirection.IncomingRequest)]
+        [InlineData("area", RouteDirection.UrlGeneration)]
+        [InlineData("controller", RouteDirection.UrlGeneration)]
+        [InlineData("action", RouteDirection.UrlGeneration)]
+        [InlineData("randomKey", RouteDirection.UrlGeneration)]
+        public void ServiceInjected_RouteKey_Exists_MatchSucceeds(string keyName, RouteDirection direction)
+        {
+            // Arrange
+            var actionDescriptor = CreateActionDescriptor("testArea",
+                "testController",
+                "testAction");
+            actionDescriptor.RouteValues.Add("randomKey", "testRandom");
+
+            var provider = CreateActionDesciprtorCollectionProvider(actionDescriptor);
+
+            var constraint = new KnownRouteValueConstraint(provider);
+
+            var values = new RouteValueDictionary()
+            {
+                { "area", "testArea" },
+                { "controller", "testController" },
+                { "action", "testAction" },
+                { "randomKey", "testRandom" }
+            };
+
+            // Act
+            var match = constraint.Match(httpContext: null, route: null, keyName, values, direction);
+
+            // Assert
+            Assert.True(match);
+        }
+
+        private static HttpContext GetHttpContext(ActionDescriptor actionDescriptor, bool setupRequestServices = true)
+        {
+            var descriptorCollectionProvider = CreateActionDesciprtorCollectionProvider(actionDescriptor);
+
+            var context = new Mock<HttpContext>();
+            if (setupRequestServices)
+            {
+                context.Setup(o => o.RequestServices
+                    .GetService(typeof(IActionDescriptorCollectionProvider)))
+                    .Returns(descriptorCollectionProvider);
+            }
+            return context.Object;
+        }
+
+        private static IActionDescriptorCollectionProvider CreateActionDesciprtorCollectionProvider(ActionDescriptor actionDescriptor)
         {
             var actionProvider = new Mock<IActionDescriptorProvider>(MockBehavior.Strict);
 
@@ -176,12 +266,7 @@ namespace Microsoft.AspNetCore.Mvc.Routing
             var descriptorCollectionProvider = new DefaultActionDescriptorCollectionProvider(
                 new[] { actionProvider.Object },
                 Enumerable.Empty<IActionDescriptorChangeProvider>());
-
+            return descriptorCollectionProvider;
-            var context = new Mock<HttpContext>();
-            context.Setup(o => o.RequestServices
-                .GetService(typeof(IActionDescriptorCollectionProvider)))
-                .Returns(descriptorCollectionProvider);
-            return context.Object;
         }
 
         private static ActionDescriptor CreateActionDescriptor(string area, string controller, string action)

test/Microsoft.AspNetCore.Mvc.Core.TestCommon/ActivityReplacer.cs

@@ -0,0 +1,25 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Diagnostics;
+
+namespace Microsoft.AspNetCore.Mvc
+{
+    public class ActivityReplacer : IDisposable
+    {
+        private readonly Activity _activity;
+
+        public ActivityReplacer()
+        {
+            _activity = new Activity("Test");
+            _activity.Start();
+        }
+
+        public void Dispose()
+        {
+            Debug.Assert(Activity.Current == _activity);
+            _activity.Stop();
+        }
+    }
+}

test/Microsoft.AspNetCore.Mvc.Formatters.Xml.Test/ProblemDetailsWrapperTest.cs

@@ -0,0 +1,100 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.IO;
+using System.Linq;
+using System.Runtime.Serialization;
+using System.Text;
+using System.Xml;
+using Xunit;
+
+namespace Microsoft.AspNetCore.Mvc.Formatters.Xml
+{
+    public class ProblemDetailsWrapperTest
+    {
+        [Fact]
+        public void ReadXml_ReadsProblemDetailsXml()
+        {
+            // Arrange
+            var xml = "<?xml version=\"1.0\" encoding=\"utf-8\"?>" +
+                "<ProblemDetails>" +
+                "<Title>Some title</Title>" +
+                "<Status>403</Status>" +
+                "<Instance>Some instance</Instance>" +
+                "<key1>Test Value 1</key1>" +
+                "<_x005B_key2_x005D_>Test Value 2</_x005B_key2_x005D_>" +
+                "<MVC-Empty>Test Value 3</MVC-Empty>" +
+                "</ProblemDetails>";
+            var serializer = new DataContractSerializer(typeof(ProblemDetailsWrapper));
+
+            // Act
+            var value = serializer.ReadObject(
+                new MemoryStream(Encoding.UTF8.GetBytes(xml)));
+
+            // Assert
+            var problemDetails = Assert.IsType<ProblemDetailsWrapper>(value).ProblemDetails;
+            Assert.Equal("Some title", problemDetails.Title);
+            Assert.Equal("Some instance", problemDetails.Instance);
+            Assert.Equal(403, problemDetails.Status);
+
+            Assert.Collection(
+                problemDetails.Extensions.OrderBy(kvp => kvp.Key),
+                kvp =>
+                {
+                    Assert.Empty(kvp.Key);
+                    Assert.Equal("Test Value 3", kvp.Value);
+                },
+                kvp =>
+                {
+                    Assert.Equal("[key2]", kvp.Key);
+                    Assert.Equal("Test Value 2", kvp.Value);
+                },
+                kvp =>
+                {
+                    Assert.Equal("key1", kvp.Key);
+                    Assert.Equal("Test Value 1", kvp.Value);
+                });
+        }
+
+
+        [Fact]
+        public void WriteXml_WritesValidXml()
+        {
+            // Arrange
+            var problemDetails = new ProblemDetails
+            {
+                Title = "Some title",
+                Detail = "Some detail",
+                Extensions =
+                {
+                    ["key1"] = "Test Value 1",
+                    ["[Key2]"] = "Test Value 2",
+                    [""] = "Test Value 3",
+                },
+            };
+
+            var wrapper = new ProblemDetailsWrapper(problemDetails);
+            var outputStream = new MemoryStream();
+            var expectedContent = "<?xml version=\"1.0\" encoding=\"utf-8\"?>" +
+                "<ProblemDetails>" +
+                "<Detail>Some detail</Detail>" +
+                "<Title>Some title</Title>" +
+                "<key1>Test Value 1</key1>" +
+                "<_x005B_Key2_x005D_>Test Value 2</_x005B_Key2_x005D_>" +
+                "<MVC-Empty>Test Value 3</MVC-Empty>" +
+                "</ProblemDetails>";
+
+            // Act
+            using (var xmlWriter = XmlWriter.Create(outputStream))
+            {
+                var dataContractSerializer = new DataContractSerializer(wrapper.GetType());
+                dataContractSerializer.WriteObject(xmlWriter, wrapper);
+            }
+            outputStream.Position = 0;
+            var res = new StreamReader(outputStream, Encoding.UTF8).ReadToEnd();
+
+            // Assert
+            Assert.Equal(expectedContent, res);
+        }
+    }
+}

test/Microsoft.AspNetCore.Mvc.Formatters.Xml.Test/ValidationProblemDetailsWrapperTest.cs

@@ -0,0 +1,226 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.IO;
+using System.Linq;
+using System.Runtime.Serialization;
+using System.Text;
+using System.Xml;
+using Xunit;
+
+namespace Microsoft.AspNetCore.Mvc.Formatters.Xml
+{
+    public class ValidationProblemDetailsWrapperTest
+    {
+        [Fact]
+        public void ReadXml_ReadsValidationProblemDetailsXml()
+        {
+            // Arrange
+            var xml = "<?xml version=\"1.0\" encoding=\"utf-8\"?>" +
+                "<ValidationProblemDetails>" +
+                "<Title>Some title</Title>" +
+                "<Status>400</Status>" +
+                "<Instance>Some instance</Instance>" +
+                "<key1>Test Value 1</key1>" +
+                "<_x005B_key2_x005D_>Test Value 2</_x005B_key2_x005D_>" +
+                "<MVC-Errors>" +
+                "<error1>Test error 1 Test error 2</error1>" +
+                "<_x005B_error2_x005D_>Test error 3</_x005B_error2_x005D_>" +
+                "<MVC-Empty>Test error 4</MVC-Empty>" +
+                "</MVC-Errors>" +
+                "</ValidationProblemDetails>";
+            var serializer = new DataContractSerializer(typeof(ValidationProblemDetailsWrapper));
+
+            // Act
+            var value = serializer.ReadObject(
+                new MemoryStream(Encoding.UTF8.GetBytes(xml)));
+
+            // Assert
+            var problemDetails = Assert.IsType<ValidationProblemDetailsWrapper>(value).ProblemDetails;
+            Assert.Equal("Some title", problemDetails.Title);
+            Assert.Equal("Some instance", problemDetails.Instance);
+            Assert.Equal(400, problemDetails.Status);
+
+            Assert.Collection(
+                problemDetails.Extensions.OrderBy(kvp => kvp.Key),
+                kvp =>
+                {
+                    Assert.Equal("[key2]", kvp.Key);
+                    Assert.Equal("Test Value 2", kvp.Value);
+                },
+                kvp =>
+                {
+                    Assert.Equal("key1", kvp.Key);
+                    Assert.Equal("Test Value 1", kvp.Value);
+                });
+
+            Assert.Collection(
+                problemDetails.Errors.OrderBy(kvp => kvp.Key),
+                kvp =>
+                {
+                    Assert.Empty(kvp.Key);
+                    Assert.Equal(new[] { "Test error 4" }, kvp.Value);
+                },
+                kvp =>
+                {
+                    Assert.Equal("[error2]", kvp.Key);
+                    Assert.Equal(new[] { "Test error 3" }, kvp.Value);
+                },
+                kvp =>
+                {
+                    Assert.Equal("error1", kvp.Key);
+                    Assert.Equal(new[] { "Test error 1 Test error 2" }, kvp.Value);
+                });
+        }
+
+        [Fact]
+        public void ReadXml_ReadsValidationProblemDetailsXml_WithNoErrors()
+        {
+            // Arrange
+            var xml = "<?xml version=\"1.0\" encoding=\"utf-8\"?>" +
+                "<ValidationProblemDetails>" +
+                "<Title>Some title</Title>" +
+                "<Status>400</Status>" +
+                "<Instance>Some instance</Instance>" +
+                "<key1>Test Value 1</key1>" +
+                "<_x005B_key2_x005D_>Test Value 2</_x005B_key2_x005D_>" +
+                "</ValidationProblemDetails>";
+            var serializer = new DataContractSerializer(typeof(ValidationProblemDetailsWrapper));
+
+            // Act
+            var value = serializer.ReadObject(
+                new MemoryStream(Encoding.UTF8.GetBytes(xml)));
+
+            // Assert
+            var problemDetails = Assert.IsType<ValidationProblemDetailsWrapper>(value).ProblemDetails;
+            Assert.Equal("Some title", problemDetails.Title);
+            Assert.Equal("Some instance", problemDetails.Instance);
+            Assert.Equal(400, problemDetails.Status);
+
+            Assert.Collection(
+                problemDetails.Extensions,
+                kvp =>
+                {
+                    Assert.Equal("key1", kvp.Key);
+                    Assert.Equal("Test Value 1", kvp.Value);
+                },
+                kvp =>
+                {
+                    Assert.Equal("[key2]", kvp.Key);
+                    Assert.Equal("Test Value 2", kvp.Value);
+                });
+
+            Assert.Empty(problemDetails.Errors);
+        }
+
+        [Fact]
+        public void ReadXml_ReadsValidationProblemDetailsXml_WithEmptyErrorsElement()
+        {
+            // Arrange
+            var xml = "<?xml version=\"1.0\" encoding=\"utf-8\"?>" +
+                "<ValidationProblemDetails>" +
+                "<Title>Some title</Title>" +
+                "<Status>400</Status>" +
+                "<MVC-Errors />" +
+                "</ValidationProblemDetails>";
+            var serializer = new DataContractSerializer(typeof(ValidationProblemDetailsWrapper));
+
+            // Act
+            var value = serializer.ReadObject(
+                new MemoryStream(Encoding.UTF8.GetBytes(xml)));
+
+            // Assert
+            var problemDetails = Assert.IsType<ValidationProblemDetailsWrapper>(value).ProblemDetails;
+            Assert.Equal("Some title", problemDetails.Title);
+            Assert.Equal(400, problemDetails.Status);
+            Assert.Empty(problemDetails.Errors);
+        }
+
+        [Fact]
+        public void WriteXml_WritesValidXml()
+        {
+            // Arrange
+            var problemDetails = new ValidationProblemDetails
+            {
+                Title = "Some title",
+                Detail = "Some detail",
+                Extensions =
+                {
+                    ["key1"] = "Test Value 1",
+                    ["[Key2]"] = "Test Value 2"
+                },
+                Errors =
+                {
+                    { "error1", new[] {"Test error 1", "Test error 2" } },
+                    { "[error2]", new[] {"Test error 3" } },
+                    { "", new[] { "Test error 4" } },
+                }
+            };
+
+            var wrapper = new ValidationProblemDetailsWrapper(problemDetails);
+            var outputStream = new MemoryStream();
+            var expectedContent = "<?xml version=\"1.0\" encoding=\"utf-8\"?>" +
+                "<ValidationProblemDetails>" +
+                "<Detail>Some detail</Detail>" +
+                "<Title>Some title</Title>" +
+                "<key1>Test Value 1</key1>" +
+                "<_x005B_Key2_x005D_>Test Value 2</_x005B_Key2_x005D_>" +
+                "<MVC-Errors>" +
+                "<error1>Test error 1 Test error 2</error1>" +
+                "<_x005B_error2_x005D_>Test error 3</_x005B_error2_x005D_>" +
+                "<MVC-Empty>Test error 4</MVC-Empty>" +
+                "</MVC-Errors>" +
+                "</ValidationProblemDetails>";
+
+            // Act
+            using (var xmlWriter = XmlWriter.Create(outputStream))
+            {
+                var dataContractSerializer = new DataContractSerializer(wrapper.GetType());
+                dataContractSerializer.WriteObject(xmlWriter, wrapper);
+            }
+            outputStream.Position = 0;
+            var res = new StreamReader(outputStream, Encoding.UTF8).ReadToEnd();
+
+            // Assert
+            Assert.Equal(expectedContent, res);
+        }
+
+        [Fact]
+        public void WriteXml_WithNoValidationErrors()
+        {
+            // Arrange
+            var problemDetails = new ValidationProblemDetails
+            {
+                Title = "Some title",
+                Detail = "Some detail",
+                Extensions =
+                {
+                    ["key1"] = "Test Value 1",
+                    ["[Key2]"] = "Test Value 2"
+                },
+            };
+
+            var wrapper = new ValidationProblemDetailsWrapper(problemDetails);
+            var outputStream = new MemoryStream();
+            var expectedContent = "<?xml version=\"1.0\" encoding=\"utf-8\"?>" +
+                "<ValidationProblemDetails>" +
+                "<Detail>Some detail</Detail>" +
+                "<Title>Some title</Title>" +
+                "<key1>Test Value 1</key1>" +
+                "<_x005B_Key2_x005D_>Test Value 2</_x005B_Key2_x005D_>" +
+                "</ValidationProblemDetails>";
+
+            // Act
+            using (var xmlWriter = XmlWriter.Create(outputStream))
+            {
+                var dataContractSerializer = new DataContractSerializer(wrapper.GetType());
+                dataContractSerializer.WriteObject(xmlWriter, wrapper);
+            }
+            outputStream.Position = 0;
+            var res = new StreamReader(outputStream, Encoding.UTF8).ReadToEnd();
+
+            // Assert
+            Assert.Equal(expectedContent, res);
+        }
+    }
+}

test/Microsoft.AspNetCore.Mvc.Formatters.Xml.Test/WrapperProviderFactoryExtensionsTest.cs

@@ -0,0 +1,34 @@
+// 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 Xunit;
+
+namespace Microsoft.AspNetCore.Mvc.Formatters.Xml
+{
+    public class WrapperProviderFactoryExtensionsTest
+    {
+        [Fact]
+        public void GetDefaultProviderFactories_GetsFactoriesUsedByInputAndOutputFormatters()
+        {
+            // Act
+            var factoryProviders = WrapperProviderFactoriesExtensions.GetDefaultProviderFactories();
+
+            // Assert
+            Assert.Collection(
+                factoryProviders,
+                factory => Assert.IsType<SerializableErrorWrapperProviderFactory>(factory),
+                factory =>
+                {
+                    var wrapperProviderFactory = Assert.IsType<WrapperProviderFactory>(factory);
+                    Assert.Equal(typeof(ProblemDetails), wrapperProviderFactory.DeclaredType);
+                    Assert.Equal(typeof(ProblemDetailsWrapper), wrapperProviderFactory.WrappingType);
+                },
+                factory =>
+                {
+                    var wrapperProviderFactory = Assert.IsType<WrapperProviderFactory>(factory);
+                    Assert.Equal(typeof(ValidationProblemDetails), wrapperProviderFactory.DeclaredType);
+                    Assert.Equal(typeof(ValidationProblemDetailsWrapper), wrapperProviderFactory.WrappingType);
+                });
+        }
+    }
+}

test/Microsoft.AspNetCore.Mvc.Formatters.Xml.Test/WrapperProviderFactoryTest.cs

@@ -0,0 +1,63 @@
+// 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 Xunit;
+
+namespace Microsoft.AspNetCore.Mvc.Formatters.Xml
+{
+    public class WrapperProviderFactoryTest
+    {
+        [Fact]
+        public void GetProvider_ReturnsNull_IfTypeDoesNotMatch()
+        {
+            // Arrange
+            var provider = new WrapperProviderFactory(
+                typeof(ProblemDetails),
+                typeof(ProblemDetailsWrapper),
+                _ => null);
+            var context = new WrapperProviderContext(typeof(SerializableError), isSerialization: true);
+
+            // Act
+            var result = provider.GetProvider(context);
+
+            // Assert
+            Assert.Null(result);
+        }
+
+        [Fact]
+        public void GetProvider_ReturnsNull_IfTypeIsSubtype()
+        {
+            // Arrange
+            var provider = new WrapperProviderFactory(
+                typeof(ProblemDetails),
+                typeof(ProblemDetailsWrapper),
+                _ => null);
+            var context = new WrapperProviderContext(typeof(ValidationProblemDetails), isSerialization: true);
+
+            // Act
+            var result = provider.GetProvider(context);
+
+            // Assert
+            Assert.Null(result);
+        }
+
+        [Fact]
+        public void GetProvider_ReturnsValue_IfTypeMatches()
+        {
+            // Arrange
+            var expected = new object();
+            var providerFactory = new WrapperProviderFactory(
+                typeof(ProblemDetails),
+                typeof(ProblemDetailsWrapper),
+                _ => expected);
+            var context = new WrapperProviderContext(typeof(ProblemDetails), isSerialization: true);
+
+            // Act
+            var provider = providerFactory.GetProvider(context);
+            var result = provider.Wrap(new ProblemDetails());
+
+            // Assert
+            Assert.Same(expected, result);
+        }
+    }
+}

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

@@ -2,6 +2,7 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System.Collections.Generic;
+using System.Diagnostics;
 using System.Linq;
 using System.Net;
 using System.Net.Http;
@@ -10,6 +11,7 @@ using System.Threading.Tasks;
 using BasicWebSite.Models;
 using Microsoft.AspNetCore.Hosting;
 using Newtonsoft.Json;
+using Newtonsoft.Json.Linq;
 using Xunit;
 
 namespace Microsoft.AspNetCore.Mvc.FunctionalTests
@@ -34,37 +36,48 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
         public async Task ActionsReturnBadRequest_WhenModelStateIsInvalid()
         {
             // Arrange
-            var contactModel = new Contact
+            using (new ActivityReplacer())
             {
-                Name = "Abc",
+                var contactModel = new Contact
-                City = "Redmond",
-                State = "WA",
-                Zip = "Invalid",
-            };
-            var contactString = JsonConvert.SerializeObject(contactModel);
-
-            // Act
-            var response = await Client.PostAsJsonAsync("/contact", contactModel);
-
-            // Assert
-            await response.AssertStatusCodeAsync(HttpStatusCode.BadRequest);
-            Assert.Equal("application/problem+json", response.Content.Headers.ContentType.MediaType);
-            var problemDetails = JsonConvert.DeserializeObject<ValidationProblemDetails>(await response.Content.ReadAsStringAsync());
-            Assert.Collection(
-                problemDetails.Errors.OrderBy(kvp => kvp.Key),
-                kvp =>
                 {
-                    Assert.Equal("Name", kvp.Key);
+                    Name = "Abc",
-                    var error = Assert.Single(kvp.Value);
+                    City = "Redmond",
-                    Assert.Equal("The field Name must be a string with a minimum length of 5 and a maximum length of 30.", error);
+                    State = "WA",
-                },
+                    Zip = "Invalid",
-                kvp =>
+                };
-                {
+                var contactString = JsonConvert.SerializeObject(contactModel);
-                    Assert.Equal("Zip", kvp.Key);
+
-                    var error = Assert.Single(kvp.Value);
+                // Act
-                    Assert.Equal("The field Zip must match the regular expression '\\d{5}'.", error);
+                var response = await Client.PostAsJsonAsync("/contact", contactModel);
-                }
+
-            );
+                // Assert
+                await response.AssertStatusCodeAsync(HttpStatusCode.BadRequest);
+                Assert.Equal("application/problem+json", response.Content.Headers.ContentType.MediaType);
+                var problemDetails = JsonConvert.DeserializeObject<ValidationProblemDetails>(await response.Content.ReadAsStringAsync());
+                Assert.Collection(
+                    problemDetails.Errors.OrderBy(kvp => kvp.Key),
+                    kvp =>
+                    {
+                        Assert.Equal("Name", kvp.Key);
+                        var error = Assert.Single(kvp.Value);
+                        Assert.Equal("The field Name must be a string with a minimum length of 5 and a maximum length of 30.", error);
+                    },
+                    kvp =>
+                    {
+                        Assert.Equal("Zip", kvp.Key);
+                        var error = Assert.Single(kvp.Value);
+                        Assert.Equal("The field Zip must match the regular expression '\\d{5}'.", error);
+                    }
+                );
+
+                Assert.Collection(
+                    problemDetails.Extensions,
+                    kvp =>
+                    {
+                        Assert.Equal("traceId", kvp.Key);
+                        Assert.Equal(Activity.Current.Id, kvp.Value);
+                    });
+            }
         }
 
         [Fact]
@@ -97,6 +110,10 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
 
             // Assert
             await response.AssertStatusCodeAsync(HttpStatusCode.UnsupportedMediaType);
+            var content = await response.Content.ReadAsStringAsync();
+            var problemDetails = JsonConvert.DeserializeObject<ProblemDetails>(content);
+            Assert.Equal((int)HttpStatusCode.UnsupportedMediaType, problemDetails.Status);
+            Assert.Equal("Unsupported Media Type", problemDetails.Title);
         }
 
         [Fact]
@@ -112,8 +129,8 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
             };
             var expected = new Dictionary<string, string[]>
             {
-                {"Name", new string[] {"The field Name must be a string with a minimum length of 5 and a maximum length of 30."}},
+                {"Name", new[] {"The field Name must be a string with a minimum length of 5 and a maximum length of 30."}},
-                {"Zip", new string[]{ @"The field Zip must match the regular expression '\d{5}'."}}
+                {"Zip", new[] { @"The field Zip must match the regular expression '\d{5}'."}}
             };
             var contactString = JsonConvert.SerializeObject(contactModel);
 
@@ -248,14 +265,88 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
         [Fact]
         public async Task ClientErrorResultFilterExecutesForStatusCodeResults()
         {
+            using (new ActivityReplacer())
+            {
+                // Act
+                var response = await Client.GetAsync("/contact/ActionReturningStatusCodeResult");
+
+                // Assert
+                await response.AssertStatusCodeAsync(HttpStatusCode.NotFound);
+                var content = await response.Content.ReadAsStringAsync();
+                var problemDetails = JsonConvert.DeserializeObject<ProblemDetails>(content);
+                Assert.Equal(404, problemDetails.Status);
+                Assert.Collection(
+                    problemDetails.Extensions,
+                    kvp =>
+                    {
+                        Assert.Equal("traceId", kvp.Key);
+                        Assert.Equal(Activity.Current.Id, kvp.Value);
+                    });
+            }
+        }
+
+        [Fact]
+        public async Task SerializingProblemDetails_IgnoresNullValuedProperties()
+        {
+            // Arrange
+            var expected = new[] { "status", "title", "traceId", "type" };
+
             // Act
             var response = await Client.GetAsync("/contact/ActionReturningStatusCodeResult");
 
             // Assert
             await response.AssertStatusCodeAsync(HttpStatusCode.NotFound);
             var content = await response.Content.ReadAsStringAsync();
-            var problemDetails = JsonConvert.DeserializeObject<ProblemDetails>(content);
+
-            Assert.Equal(404, problemDetails.Status);
+            // Verify that null-valued properties on ProblemDetails are not serialized.
+            var json = JObject.Parse(content);
+            Assert.Equal(expected, json.Properties().OrderBy(p => p.Name).Select(p => p.Name));
+        }
+
+        [Fact]
+        public async Task SerializingProblemDetails_WithAllValuesSpecified()
+        {
+            // Arrange
+            var expected = new[] { "detail", "instance", "status", "title", "tracking-id", "type" };
+
+            // Act
+            var response = await Client.GetAsync("/contact/ActionReturningProblemDetails");
+
+            // Assert
+            await response.AssertStatusCodeAsync(HttpStatusCode.NotFound);
+            var content = await response.Content.ReadAsStringAsync();
+            var json = JObject.Parse(content);
+            Assert.Equal(expected, json.Properties().OrderBy(p => p.Name).Select(p => p.Name));
+        }
+
+        [Fact]
+        public async Task SerializingValidationProblemDetails_WithExtensionData()
+        {
+            // Act
+            var response = await Client.GetAsync("/contact/ActionReturningValidationProblemDetails");
+
+            // Assert
+            await response.AssertStatusCodeAsync(HttpStatusCode.BadRequest);
+            var content = await response.Content.ReadAsStringAsync();
+            var validationProblemDetails = JsonConvert.DeserializeObject<ValidationProblemDetails>(content);
+
+            Assert.Equal("Error", validationProblemDetails.Title);
+            Assert.Equal(400, validationProblemDetails.Status);
+            Assert.Collection(
+                validationProblemDetails.Extensions,
+                kvp =>
+                {
+                    Assert.Equal("tracking-id", kvp.Key);
+                    Assert.Equal("27", kvp.Value);
+                });
+
+            Assert.Collection(
+                validationProblemDetails.Errors,
+                kvp =>
+                {
+                    Assert.Equal("Error1", kvp.Key);
+                    Assert.Equal(new[] { "Error Message" }, kvp.Value);
+                });
         }
     }
 }

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

@@ -1180,9 +1180,9 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
                 },
                 responseType =>
                 {
-                    Assert.Equal(typeof(void).FullName, responseType.ResponseType);
+                    Assert.Equal(typeof(ProblemDetails).FullName, responseType.ResponseType);
                     Assert.Equal(404, responseType.StatusCode);
-                    Assert.Empty(responseType.ResponseFormats);
+                    Assert.Equal(expectedMediaTypes, GetSortedMediaTypes(responseType));
                 });
         }
 
@@ -1215,7 +1215,7 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
         public async Task ApiConvention_ForMethodWithResponseTypeAttributes()
         {
             // Arrange
-            var expectedMediaTypes = new[] { "application/json", "application/xml", "text/json", "text/xml" };
+            var expectedMediaTypes = new[] { "application/json" };
 
             // Act
             var response = await Client.PostAsync(
@@ -1236,15 +1236,18 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
                 },
                 responseType =>
                 {
-                    Assert.Equal(typeof(void).FullName, responseType.ResponseType);
+                    Assert.Equal(typeof(ProblemDetails).FullName, responseType.ResponseType);
                     Assert.Equal(403, responseType.StatusCode);
-                    Assert.Empty(responseType.ResponseFormats);
+                    Assert.Equal(expectedMediaTypes, GetSortedMediaTypes(responseType));
                 });
         }
 
         [Fact]
         public async Task ApiConvention_ForPostMethodThatMatchesConvention()
         {
+            // Arrange
+            var expectedMediaTypes = new[] { "application/json", "application/xml", "text/json", "text/xml" };
+
             // Act
             var response = await Client.PostAsync(
                 $"ApiExplorerResponseTypeWithApiConventionController/PostTaskOfProduct",
@@ -1268,15 +1271,18 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
                 },
                 responseType =>
                 {
-                    Assert.Equal(typeof(void).FullName, responseType.ResponseType);
+                    Assert.Equal(typeof(ProblemDetails).FullName, responseType.ResponseType);
                     Assert.Equal(400, responseType.StatusCode);
-                    Assert.Empty(responseType.ResponseFormats);
+                    Assert.Equal(expectedMediaTypes, GetSortedMediaTypes(responseType));
                 });
         }
 
         [Fact]
         public async Task ApiConvention_ForPutActionThatMatchesConvention()
         {
+            // Arrange
+            var expectedMediaTypes = new[] { "application/json", "application/xml", "text/json", "text/xml" };
+
             // Act
             var response = await Client.PutAsync(
                 $"ApiExplorerResponseTypeWithApiConventionController/Put",
@@ -1300,21 +1306,24 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
                 },
                 responseType =>
                 {
-                    Assert.Equal(typeof(void).FullName, responseType.ResponseType);
+                    Assert.Equal(typeof(ProblemDetails).FullName, responseType.ResponseType);
                     Assert.Equal(400, responseType.StatusCode);
-                    Assert.Empty(responseType.ResponseFormats);
+                    Assert.Equal(expectedMediaTypes, GetSortedMediaTypes(responseType));
                 },
                 responseType =>
                 {
-                    Assert.Equal(typeof(void).FullName, responseType.ResponseType);
+                    Assert.Equal(typeof(ProblemDetails).FullName, responseType.ResponseType);
                     Assert.Equal(404, responseType.StatusCode);
-                    Assert.Empty(responseType.ResponseFormats);
+                    Assert.Equal(expectedMediaTypes, GetSortedMediaTypes(responseType));
                 });
         }
 
         [Fact]
         public async Task ApiConvention_ForDeleteActionThatMatchesConvention()
         {
+            // Arrange
+            var expectedMediaTypes = new[] { "application/json", "application/xml", "text/json", "text/xml" };
+
             // Act
             var response = await Client.DeleteAsync(
                 $"ApiExplorerResponseTypeWithApiConventionController/DeleteProductAsync");
@@ -1337,21 +1346,24 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
                 },
                 responseType =>
                 {
-                    Assert.Equal(typeof(void).FullName, responseType.ResponseType);
+                    Assert.Equal(typeof(ProblemDetails).FullName, responseType.ResponseType);
                     Assert.Equal(400, responseType.StatusCode);
-                    Assert.Empty(responseType.ResponseFormats);
+                    Assert.Equal(expectedMediaTypes, GetSortedMediaTypes(responseType));
                 },
                 responseType =>
                 {
-                    Assert.Equal(typeof(void).FullName, responseType.ResponseType);
+                    Assert.Equal(typeof(ProblemDetails).FullName, responseType.ResponseType);
                     Assert.Equal(404, responseType.StatusCode);
-                    Assert.Empty(responseType.ResponseFormats);
+                    Assert.Equal(expectedMediaTypes, GetSortedMediaTypes(responseType));
                 });
         }
 
         [Fact]
         public async Task ApiConvention_ForActionWtihApiConventionMethod()
         {
+            // Arrange
+            var expectedMediaTypes = new[] { "application/json", "application/xml", "text/json", "text/xml" };
+
             // Act
             var response = await Client.PostAsync(
                 "ApiExplorerResponseTypeWithApiConventionController/PostItem",
@@ -1371,9 +1383,9 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
                 },
                 responseType =>
                 {
-                    Assert.Equal(typeof(void).FullName, responseType.ResponseType);
+                    Assert.Equal(typeof(ProblemDetails).FullName, responseType.ResponseType);
                     Assert.Equal(409, responseType.StatusCode);
-                    Assert.Empty(responseType.ResponseFormats);
+                    Assert.Equal(expectedMediaTypes, GetSortedMediaTypes(responseType));
                 });
         }
 

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

@@ -128,7 +128,7 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
             Assert.Equal("From Header - HelloWorld", body);
         }
 
-        [Fact(Skip = "https://github.com/aspnet/Routing/issues/721")]
+        [Fact]
         public async Task ActionModelSuppressedForPathMatching_CannotBeRouted()
         {
             // Arrange & Act

test/Microsoft.AspNetCore.Mvc.FunctionalTests/Infrastructure/HttpClientExtensions.cs

@@ -53,7 +53,7 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
 
             throw new StatusCodeMismatchException
             {
-                ExpectedStatusCode = HttpStatusCode.OK,
+                ExpectedStatusCode = expectedStatusCode,
                 ActualStatusCode = response.StatusCode,
                 ResponseContent = responseContent,
             };
@@ -71,7 +71,7 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
             {
                 get
                 {
-                    return $"Excepted status code 200. Actual {ActualStatusCode}. Response Content:" + Environment.NewLine + ResponseContent;
+                    return $"Excepted status code {ExpectedStatusCode}. Actual {ActualStatusCode}. Response Content:" + Environment.NewLine + ResponseContent;
                 }
             }
         }

test/Microsoft.AspNetCore.Mvc.FunctionalTests/Microsoft.AspNetCore.Mvc.FunctionalTests.csproj

@@ -10,6 +10,7 @@
 
   <ItemGroup>
     <Compile Include="..\Microsoft.AspNetCore.Mvc.Formatters.Xml.Test\XmlAssert.cs" />
+    <Compile Include="..\Microsoft.AspNetCore.Mvc.Core.TestCommon\ActivityReplacer.cs" />
     <EmbeddedResource Include="compiler\resources\**\*" />
     <None Include="xunit.runner.json" CopyToOutputDirectory="PreserveNewest" />
   </ItemGroup>

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

@@ -72,6 +72,30 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
             public string[] Routers { get; set; }
         }
 
+        [Fact]
+        public async Task DataTokens_ReturnsDataTokensForRoute()
+        {
+            // Arrange & Act
+            var response = await Client.GetAsync("http://localhost/DataTokensRoute/DataTokens/Index");
+
+            // Assert
+            var body = await response.Content.ReadAsStringAsync();
+            var result = JsonConvert.DeserializeObject<Dictionary<string, object>>(body);
+            Assert.Single(result, kvp => kvp.Key == "hasDataTokens" && ((bool)kvp.Value) == true);
+        }
+
+        [Fact]
+        public async Task DataTokens_ReturnsNoDataTokensForRoute()
+        {
+            // Arrange & Act
+            var response = await Client.GetAsync("http://localhost/DataTokens/Index");
+
+            // Assert
+            var body = await response.Content.ReadAsStringAsync();
+            var result = JsonConvert.DeserializeObject<Dictionary<string, object>>(body);
+            Assert.Empty(result);
+        }
+
         [Fact]
         public virtual async Task ConventionalRoutedController_ActionIsReachable()
         {
@@ -1259,6 +1283,19 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
             Assert.Equal("/Home/Contact", contactLink.GetAttribute("href"));
         }
 
+        [Fact]
+        public async Task CanRunMiddlewareAfterRouting()
+        {
+            // Act
+            var response = await Client.GetAsync("/afterrouting");
+
+            // Assert
+            await response.AssertStatusCodeAsync(HttpStatusCode.OK);
+            var content = await response.Content.ReadAsStringAsync();
+            Assert.Equal("Hello from middleware after routing", content);
+        }
+
+
         protected static LinkBuilder LinkFrom(string url)
         {
             return new LinkBuilder(url);

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

@@ -1,6 +1,7 @@
 // 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.Diagnostics;
 using System.Net;
 using System.Net.Http;
 using System.Net.Http.Headers;
@@ -208,5 +209,85 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
                 "</ArrayOfSerializableErrorWrapper>",
                 result);
         }
+
+        [Fact]
+        public async Task ProblemDetails_IsSerialized()
+        {
+            // Arrange
+            using (new ActivityReplacer())
+            {
+                var expected = "<ProblemDetails>" +
+                    "<Status>404</Status>" +
+                    "<Title>Not Found</Title>" +
+                    "<Type>https://tools.ietf.org/html/rfc7231#section-6.5.4</Type>" +
+                    $"<traceId>{Activity.Current.Id}</traceId>" +
+                    "</ProblemDetails>";
+
+                // Act
+                var response = await Client.GetAsync("/api/XmlDataContractApi/ActionReturningClientErrorStatusCodeResult");
+
+                // Assert
+                await response.AssertStatusCodeAsync(HttpStatusCode.NotFound);
+                var content = await response.Content.ReadAsStringAsync();
+                XmlAssert.Equal(expected, content);
+            }
+        }
+
+        [Fact]
+        public async Task ProblemDetails_WithExtensionMembers_IsSerialized()
+        {
+            // Arrange
+            var expected = @"<ProblemDetails><Instance>instance</Instance><Status>404</Status><Title>title</Title>
+<Correlation>correlation</Correlation><Accounts>Account1 Account2</Accounts></ProblemDetails>";
+
+            // Act
+            var response = await Client.GetAsync("/api/XmlDataContractApi/ActionReturningProblemDetails");
+
+            // Assert
+            await response.AssertStatusCodeAsync(HttpStatusCode.NotFound);
+            var content = await response.Content.ReadAsStringAsync();
+            XmlAssert.Equal(expected, content);
+        }
+
+        [Fact]
+        public async Task ValidationProblemDetails_IsSerialized()
+        {
+            // Arrange
+            using (new ActivityReplacer())
+            {
+                var expected = "<ValidationProblemDetails>" +
+                "<Status>400</Status>" +
+                "<Title>One or more validation errors occurred.</Title>" +
+                $"<traceId>{Activity.Current.Id}</traceId>" +
+                "<MVC-Errors>" +
+                "<State>The State field is required.</State>" +
+                "</MVC-Errors>" +
+                "</ValidationProblemDetails>";
+
+                // Act
+                var response = await Client.GetAsync("/api/XmlDataContractApi/ActionReturningValidationProblem");
+
+                // Assert
+                await response.AssertStatusCodeAsync(HttpStatusCode.BadRequest);
+                var content = await response.Content.ReadAsStringAsync();
+                XmlAssert.Equal(expected, content);
+            }
+        }
+
+        [Fact]
+        public async Task ValidationProblemDetails_WithExtensionMembers_IsSerialized()
+        {
+            // Arrange
+            var expected = @"<ValidationProblemDetails><Detail>some detail</Detail><Status>400</Status><Title>One or more validation errors occurred.</Title>
+<Type>some type</Type><CorrelationId>correlation</CorrelationId><MVC-Errors><Error1>ErrorValue</Error1></MVC-Errors></ValidationProblemDetails>";
+
+            // Act
+            var response = await Client.GetAsync("/api/XmlDataContractApi/ActionReturningValidationDetailsWithMetadata");
+
+            // Assert
+            await response.AssertStatusCodeAsync(HttpStatusCode.BadRequest);
+            var content = await response.Content.ReadAsStringAsync();
+            XmlAssert.Equal(expected, content);
+        }
     }
-}
+}

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

@@ -1,6 +1,7 @@
 // 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.Diagnostics;
 using System.Net;
 using System.Net.Http;
 using System.Net.Http.Headers;
@@ -183,5 +184,85 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
                 "<key4>key2-error</key4></SerializableErrorWrapper></ArrayOfSerializableErrorWrapper>",
                 result);
         }
+
+        [Fact]
+        public async Task ProblemDetails_IsSerialized()
+        {
+            // Arrange
+            using (new ActivityReplacer())
+            {
+                var expected = "<ProblemDetails>" +
+                    "<Status>404</Status>" +
+                    "<Title>Not Found</Title>" +
+                    "<Type>https://tools.ietf.org/html/rfc7231#section-6.5.4</Type>" +
+                    $"<traceId>{Activity.Current.Id}</traceId>" +
+                    "</ProblemDetails>";
+
+                // Act
+                var response = await Client.GetAsync("/api/XmlSerializerApi/ActionReturningClientErrorStatusCodeResult");
+
+                // Assert
+                await response.AssertStatusCodeAsync(HttpStatusCode.NotFound);
+                var content = await response.Content.ReadAsStringAsync();
+                XmlAssert.Equal(expected, content);
+            }
+        }
+
+        [Fact]
+        public async Task ProblemDetails_WithExtensionMembers_IsSerialized()
+        {
+            // Arrange
+            var expected = @"<ProblemDetails><Instance>instance</Instance><Status>404</Status><Title>title</Title>
+<Correlation>correlation</Correlation><Accounts>Account1 Account2</Accounts></ProblemDetails>";
+
+            // Act
+            var response = await Client.GetAsync("/api/XmlSerializerApi/ActionReturningProblemDetails");
+
+            // Assert
+            await response.AssertStatusCodeAsync(HttpStatusCode.NotFound);
+            var content = await response.Content.ReadAsStringAsync();
+            XmlAssert.Equal(expected, content);
+        }
+
+        [Fact]
+        public async Task ValidationProblemDetails_IsSerialized()
+        {
+            // Arrange
+            using (new ActivityReplacer())
+            {
+                var expected = "<ValidationProblemDetails>" +
+               "<Status>400</Status>" +
+               "<Title>One or more validation errors occurred.</Title>" +
+               $"<traceId>{Activity.Current.Id}</traceId>" +
+               "<MVC-Errors>" +
+               "<State>The State field is required.</State>" +
+               "</MVC-Errors>" +
+               "</ValidationProblemDetails>";
+
+                // Act
+                var response = await Client.GetAsync("/api/XmlSerializerApi/ActionReturningValidationProblem");
+
+                // Assert
+                await response.AssertStatusCodeAsync(HttpStatusCode.BadRequest);
+                var content = await response.Content.ReadAsStringAsync();
+                XmlAssert.Equal(expected, content);
+            }
+        }
+
+        [Fact]
+        public async Task ValidationProblemDetails_WithExtensionMembers_IsSerialized()
+        {
+            // Arrange
+            var expected = @"<ValidationProblemDetails><Detail>some detail</Detail><Status>400</Status><Title>One or more validation errors occurred.</Title>
+<Type>some type</Type><CorrelationId>correlation</CorrelationId><MVC-Errors><Error1>ErrorValue</Error1></MVC-Errors></ValidationProblemDetails>";
+
+            // Act
+            var response = await Client.GetAsync("/api/XmlSerializerApi/ActionReturningValidationDetailsWithMetadata");
+
+            // Assert
+            await response.AssertStatusCodeAsync(HttpStatusCode.BadRequest);
+            var content = await response.Content.ReadAsStringAsync();
+            XmlAssert.Equal(expected, content);
+        }
     }
 }

test/Microsoft.AspNetCore.Mvc.FunctionalTests/xunit.runner.json

@@ -1,3 +1,4 @@
 {
-  "shadowCopy": false
+  "shadowCopy": false,
+  "longRunningTestSeconds": 60
 }

test/Microsoft.AspNetCore.Mvc.Test/IntegrationTest/CompatibilitySwitchIntegrationTest.cs

@@ -43,7 +43,7 @@ namespace Microsoft.AspNetCore.Mvc.IntegrationTest
             Assert.False(mvcOptions.EnableEndpointRouting);
             Assert.Null(mvcOptions.MaxValidationDepth);
             Assert.True(apiBehaviorOptions.SuppressUseValidationProblemDetailsForInvalidModelStateResponses);
-            Assert.True(apiBehaviorOptions.SuppressUseClientErrorFactory);
+            Assert.True(apiBehaviorOptions.SuppressMapClientErrors);
         }
 
         [Fact]
@@ -72,7 +72,7 @@ namespace Microsoft.AspNetCore.Mvc.IntegrationTest
             Assert.False(mvcOptions.EnableEndpointRouting);
             Assert.Null(mvcOptions.MaxValidationDepth);
             Assert.True(apiBehaviorOptions.SuppressUseValidationProblemDetailsForInvalidModelStateResponses);
-            Assert.True(apiBehaviorOptions.SuppressUseClientErrorFactory);
+            Assert.True(apiBehaviorOptions.SuppressMapClientErrors);
         }
 
         [Fact]
@@ -101,7 +101,7 @@ namespace Microsoft.AspNetCore.Mvc.IntegrationTest
             Assert.True(mvcOptions.EnableEndpointRouting);
             Assert.Equal(32, mvcOptions.MaxValidationDepth);
             Assert.False(apiBehaviorOptions.SuppressUseValidationProblemDetailsForInvalidModelStateResponses);
-            Assert.False(apiBehaviorOptions.SuppressUseClientErrorFactory);
+            Assert.False(apiBehaviorOptions.SuppressMapClientErrors);
         }
 
         [Fact]
@@ -130,7 +130,7 @@ namespace Microsoft.AspNetCore.Mvc.IntegrationTest
             Assert.True(mvcOptions.EnableEndpointRouting);
             Assert.Equal(32, mvcOptions.MaxValidationDepth);
             Assert.False(apiBehaviorOptions.SuppressUseValidationProblemDetailsForInvalidModelStateResponses);
-            Assert.False(apiBehaviorOptions.SuppressUseClientErrorFactory);
+            Assert.False(apiBehaviorOptions.SuppressMapClientErrors);
         }
 
         // This just does the minimum needed to be able to resolve these options.

test/Microsoft.AspNetCore.Mvc.ViewFeatures.Test/Internal/PagedCharBufferTest.cs

@@ -469,14 +469,14 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures.Internal
 
             // Assert - 1
             Assert.Equal(0, buffer.Length);
-            Assert.Equal(1, buffer.Pages.Count);
+            Assert.Single(buffer.Pages);
 
             // Act - 2
             buffer.Append("efgh");
 
             // Assert - 2
             Assert.Equal(4, buffer.Length);
-            Assert.Equal(1, buffer.Pages.Count);
+            Assert.Single(buffer.Pages);
             Assert.Equal(new[] { 'e', 'f', 'g', 'h' }, buffer.Pages[0].Take(buffer.Length));
         }
     }

test/Microsoft.AspNetCore.Mvc.ViewFeatures.Test/RemoteAttributeTest.cs

@@ -1045,7 +1045,7 @@ namespace Microsoft.AspNetCore.Mvc
             serviceCollection.AddRouting();
 
             serviceCollection.AddSingleton<IInlineConstraintResolver>(
-                provider => new DefaultInlineConstraintResolver(provider.GetRequiredService<IOptions<RouteOptions>>()));
+                provider => new DefaultInlineConstraintResolver(provider.GetRequiredService<IOptions<RouteOptions>>(), provider));
 
             if (localizerFactory != null)
             {

test/Mvc.Api.Analyzers.Test/AddResponseTypeAttributeCodeFixProviderIntegrationTest.cs

@@ -33,6 +33,18 @@ namespace Microsoft.AspNetCore.Mvc.Api.Analyzers
         [Fact]
         public Task CodeFixAddsFullyQualifiedProducesResponseType() => RunTest();
 
+        [Fact]
+        public Task CodeFixAddsNumericLiteralForNonExistingStatusCodeConstants() => RunTest();
+
+        [Fact]
+        public Task CodeFixAddsStatusCodesFromMethodParameters() => RunTest();
+
+        [Fact]
+        public Task CodeFixAddsStatusCodesFromConstructorParameters() => RunTest();
+
+        [Fact]
+        public Task CodeFixAddsStatusCodesFromObjectInitializer() => RunTest();
+
         private async Task RunTest([CallerMemberName] string testMethod = "")
         {
             // Arrange

test/Mvc.Api.Analyzers.Test/TestFiles/AddResponseTypeAttributeCodeFixProviderIntegrationTest/CodeFixAddsNumericLiteralForNonExistingStatusCodeConstants.Input.cs

@@ -0,0 +1,17 @@
+namespace Microsoft.AspNetCore.Mvc.Api.Analyzers._INPUT_
+{
+    [ApiController]
+    [Route("[controller]/[action]")]
+    public class CodeFixAddsNumericLiteralForNonExistingStatusCodeConstantsController : ControllerBase
+    {
+        public IActionResult GetItem(int id)
+        {
+            if (id == 0)
+            {
+                return StatusCode(345);
+            }
+
+            return Ok(new object());
+        }
+    }
+}

test/Mvc.Api.Analyzers.Test/TestFiles/AddResponseTypeAttributeCodeFixProviderIntegrationTest/CodeFixAddsNumericLiteralForNonExistingStatusCodeConstants.Output.cs

@@ -0,0 +1,22 @@
+using Microsoft.AspNetCore.Http;
+
+namespace Microsoft.AspNetCore.Mvc.Api.Analyzers._OUTPUT_
+{
+    [ApiController]
+    [Route("[controller]/[action]")]
+    public class CodeFixAddsNumericLiteralForNonExistingStatusCodeConstantsController : ControllerBase
+    {
+        [ProducesResponseType(StatusCodes.Status200OK)]
+        [ProducesResponseType(345)]
+        [ProducesDefaultResponseType]
+        public IActionResult GetItem(int id)
+        {
+            if (id == 0)
+            {
+                return StatusCode(345);
+            }
+
+            return Ok(new object());
+        }
+    }
+}

test/Mvc.Api.Analyzers.Test/TestFiles/AddResponseTypeAttributeCodeFixProviderIntegrationTest/CodeFixAddsStatusCodesFromConstructorParameters.Input.cs

@@ -0,0 +1,38 @@
+using Microsoft.AspNetCore.Http;
+
+namespace Microsoft.AspNetCore.Mvc.Api.Analyzers._INPUT_
+{
+    [ApiController]
+    [Route("[controller]/[action]")]
+    public class CodeFixAddsStatusCodesFromConstructorParametersController : ControllerBase
+    {
+        private const int FieldStatusCode = 201;
+
+        public IActionResult GetItem(int id)
+        {
+            if (id == 0)
+            {
+                return new StatusCodeResult(422);
+            }
+
+            if (id == 1)
+            {
+                return new StatusCodeResult(StatusCodes.Status202Accepted);
+            }
+
+            if (id == 2)
+            {
+                const int localStatusCode = 204;
+
+                return new StatusCodeResult(localStatusCode);
+            }
+
+            if (id == 3)
+            {
+                return new StatusCodeResult(FieldStatusCode);
+            }
+
+            return Ok(new object());
+        }
+    }
+}

test/Mvc.Api.Analyzers.Test/TestFiles/AddResponseTypeAttributeCodeFixProviderIntegrationTest/CodeFixAddsStatusCodesFromConstructorParameters.Output.cs

@@ -0,0 +1,44 @@
+using Microsoft.AspNetCore.Http;
+
+namespace Microsoft.AspNetCore.Mvc.Api.Analyzers._OUTPUT_
+{
+    [ApiController]
+    [Route("[controller]/[action]")]
+    public class CodeFixAddsStatusCodesFromConstructorParametersController : ControllerBase
+    {
+        private const int FieldStatusCode = 201;
+
+        [ProducesResponseType(StatusCodes.Status200OK)]
+        [ProducesResponseType(StatusCodes.Status201Created)]
+        [ProducesResponseType(StatusCodes.Status202Accepted)]
+        [ProducesResponseType(StatusCodes.Status204NoContent)]
+        [ProducesResponseType(StatusCodes.Status422UnprocessableEntity)]
+        [ProducesDefaultResponseType]
+        public IActionResult GetItem(int id)
+        {
+            if (id == 0)
+            {
+                return new StatusCodeResult(422);
+            }
+
+            if (id == 1)
+            {
+                return new StatusCodeResult(StatusCodes.Status202Accepted);
+            }
+
+            if (id == 2)
+            {
+                const int localStatusCode = 204;
+
+                return new StatusCodeResult(localStatusCode);
+            }
+
+            if (id == 3)
+            {
+                return new StatusCodeResult(FieldStatusCode);
+            }
+
+            return Ok(new object());
+        }
+    }
+}

test/Mvc.Api.Analyzers.Test/TestFiles/AddResponseTypeAttributeCodeFixProviderIntegrationTest/CodeFixAddsStatusCodesFromMethodParameters.Input.cs

@@ -0,0 +1,38 @@
+using Microsoft.AspNetCore.Http;
+
+namespace Microsoft.AspNetCore.Mvc.Api.Analyzers._INPUT_
+{
+    [ApiController]
+    [Route("[controller]/[action]")]
+    public class CodeFixAddsStatusCodesFromMethodParametersController : ControllerBase
+    {
+        private const int FieldStatusCode = 201;
+
+        public IActionResult GetItem(int id)
+        {
+            if (id == 0)
+            {
+                return StatusCode(422);
+            }
+
+            if (id == 1)
+            {
+                return StatusCode(StatusCodes.Status202Accepted);
+            }
+
+            if (id == 2)
+            {
+                const int localStatusCode = 204;
+
+                return StatusCode(localStatusCode);
+            }
+
+            if (id == 3)
+            {
+                return StatusCode(FieldStatusCode);
+            }
+
+            return Ok(new object());
+        }
+    }
+}

test/Mvc.Api.Analyzers.Test/TestFiles/AddResponseTypeAttributeCodeFixProviderIntegrationTest/CodeFixAddsStatusCodesFromMethodParameters.Output.cs

@@ -0,0 +1,44 @@
+using Microsoft.AspNetCore.Http;
+
+namespace Microsoft.AspNetCore.Mvc.Api.Analyzers._OUTPUT_
+{
+    [ApiController]
+    [Route("[controller]/[action]")]
+    public class CodeFixAddsStatusCodesFromMethodParametersController : ControllerBase
+    {
+        private const int FieldStatusCode = 201;
+
+        [ProducesResponseType(StatusCodes.Status200OK)]
+        [ProducesResponseType(StatusCodes.Status201Created)]
+        [ProducesResponseType(StatusCodes.Status202Accepted)]
+        [ProducesResponseType(StatusCodes.Status204NoContent)]
+        [ProducesResponseType(StatusCodes.Status422UnprocessableEntity)]
+        [ProducesDefaultResponseType]
+        public IActionResult GetItem(int id)
+        {
+            if (id == 0)
+            {
+                return StatusCode(422);
+            }
+
+            if (id == 1)
+            {
+                return StatusCode(StatusCodes.Status202Accepted);
+            }
+
+            if (id == 2)
+            {
+                const int localStatusCode = 204;
+
+                return StatusCode(localStatusCode);
+            }
+
+            if (id == 3)
+            {
+                return StatusCode(FieldStatusCode);
+            }
+
+            return Ok(new object());
+        }
+    }
+}

test/Mvc.Api.Analyzers.Test/TestFiles/AddResponseTypeAttributeCodeFixProviderIntegrationTest/CodeFixAddsStatusCodesFromObjectInitializer.Input.cs

@@ -0,0 +1,51 @@
+using Microsoft.AspNetCore.Http;
+
+namespace Microsoft.AspNetCore.Mvc.Api.Analyzers._INPUT_
+{
+    [ApiController]
+    [Route("[controller]/[action]")]
+    public class CodeFixAddsStatusCodesFromObjectInitializerController : ControllerBase
+    {
+        private const int FieldStatusCode = 201;
+
+        public IActionResult GetItem(int id)
+        {
+            if (id == 0)
+            {
+                return new ObjectResult(new object())
+                {
+                    StatusCode = 422
+                };
+            }
+
+            if (id == 1)
+            {
+                return new ObjectResult(new object())
+                {
+                    StatusCode = StatusCodes.Status202Accepted
+                };
+            }
+
+            if (id == 2)
+            {
+                const int localStatusCode = 204;
+
+                return new ObjectResult(new object())
+                {
+                    StatusCode = localStatusCode
+                };
+            }
+
+            if (id == 3)
+            {
+                return new ObjectResult(new object())
+                {
+                    ContentTypes = { "application/json" },
+                    StatusCode = FieldStatusCode
+                };
+            }
+
+            return Ok(new object());
+        }
+    }
+}

test/Mvc.Api.Analyzers.Test/TestFiles/AddResponseTypeAttributeCodeFixProviderIntegrationTest/CodeFixAddsStatusCodesFromObjectInitializer.Output.cs

@@ -0,0 +1,57 @@
+using Microsoft.AspNetCore.Http;
+
+namespace Microsoft.AspNetCore.Mvc.Api.Analyzers._OUTPUT_
+{
+    [ApiController]
+    [Route("[controller]/[action]")]
+    public class CodeFixAddsStatusCodesFromObjectInitializerController : ControllerBase
+    {
+        private const int FieldStatusCode = 201;
+
+        [ProducesResponseType(StatusCodes.Status200OK)]
+        [ProducesResponseType(StatusCodes.Status201Created)]
+        [ProducesResponseType(StatusCodes.Status202Accepted)]
+        [ProducesResponseType(StatusCodes.Status204NoContent)]
+        [ProducesResponseType(StatusCodes.Status422UnprocessableEntity)]
+        [ProducesDefaultResponseType]
+        public IActionResult GetItem(int id)
+        {
+            if (id == 0)
+            {
+                return new ObjectResult(new object())
+                {
+                    StatusCode = 422
+                };
+            }
+
+            if (id == 1)
+            {
+                return new ObjectResult(new object())
+                {
+                    StatusCode = StatusCodes.Status202Accepted
+                };
+            }
+
+            if (id == 2)
+            {
+                const int localStatusCode = 204;
+
+                return new ObjectResult(new object())
+                {
+                    StatusCode = localStatusCode
+                };
+            }
+
+            if (id == 3)
+            {
+                return new ObjectResult(new object())
+                {
+                    ContentTypes = { "application/json" },
+                    StatusCode = FieldStatusCode
+                };
+            }
+
+            return Ok(new object());
+        }
+    }
+}

test/WebSites/BasicWebSite/Controllers/ContactApiController.cs

@@ -91,6 +91,41 @@ namespace BasicWebSite
             return NotFound();
         }
 
+        [HttpGet("[action]")]
+        public ActionResult<int> ActionReturningProblemDetails()
+        {
+            return NotFound(new ProblemDetails
+            {
+                Title = "Not Found",
+                Type = "Type",
+                Detail = "Detail",
+                Status = 404,
+                Instance = "Instance",
+                Extensions =
+                {
+                    ["tracking-id"] = 27,
+                },
+            });
+        }
+
+        [HttpGet("[action]")]
+        public ActionResult<int> ActionReturningValidationProblemDetails()
+        {
+            return BadRequest(new ValidationProblemDetails
+            {
+                Title = "Error",
+                Status = 400,
+                Extensions =
+                {
+                    ["tracking-id"] = "27",
+                },
+                Errors =
+                {
+                    { "Error1", new[] { "Error Message" } },
+                },
+            });
+        }
+
         private class TestModelBinder : IModelBinder
         {
             public Task BindModelAsync(ModelBindingContext bindingContext)

test/WebSites/RoutingWebSite/Controllers/DataTokensController.cs

@@ -0,0 +1,15 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using Microsoft.AspNetCore.Mvc;
+
+namespace RoutingWebSite
+{
+    public class DataTokensController : Controller
+    {
+        public object Index()
+        {
+            return RouteData.DataTokens;
+        }
+    }
+}

test/WebSites/RoutingWebSite/Startup.cs

@@ -2,6 +2,7 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.AspNetCore.Mvc.Infrastructure;
 using Microsoft.Extensions.DependencyInjection;
@@ -24,12 +25,19 @@ namespace RoutingWebSite
         {
             app.UseMvc(routes =>
             {
+                routes.MapRoute(
+                    "DataTokensRoute",
+                    "DataTokensRoute/{controller}/{action}",
+                    defaults: null,
+                    constraints: new { controller = "DataTokens" },
+                    dataTokens: new { hasDataTokens = true });
+
                 routes.MapAreaRoute(
-                   "flightRoute",
+                    "flightRoute",
-                   "adminRoute",
+                    "adminRoute",
-                   "{area:exists}/{controller}/{action}",
+                    "{area:exists}/{controller}/{action}",
-                   new { controller = "Home", action = "Index" },
+                    defaults: new { controller = "Home", action = "Index" },
-                   new { area = "Travel" });
+                    constraints: new { area = "Travel" });
 
                 routes.MapRoute(
                     "ActionAsMethod",
@@ -40,6 +48,11 @@ namespace RoutingWebSite
                     "RouteWithOptionalSegment",
                     "{controller}/{action}/{path?}");
             });
+
+            app.Map("/afterrouting", b => b.Run(c =>
+            {
+                return c.Response.WriteAsync("Hello from middleware after routing");
+            }));
         }
     }
 }

test/WebSites/RoutingWebSite/StartupWith21Compat.cs

@@ -2,6 +2,7 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.AspNetCore.Mvc.Infrastructure;
 using Microsoft.Extensions.DependencyInjection;
@@ -24,12 +25,19 @@ namespace RoutingWebSite
         {
             app.UseMvc(routes =>
             {
+                routes.MapRoute(
+                    "DataTokensRoute",
+                    "DataTokensRoute/{controller}/{action}",
+                    defaults: null,
+                    constraints: new { controller = "DataTokens" },
+                    dataTokens: new { hasDataTokens = true });
+
                 routes.MapAreaRoute(
-                   "flightRoute",
+                    "flightRoute",
-                   "adminRoute",
+                    "adminRoute",
-                   "{area:exists}/{controller}/{action}",
+                    "{area:exists}/{controller}/{action}",
-                   new { controller = "Home", action = "Index" },
+                    defaults: new { controller = "Home", action = "Index" },
-                   new { area = "Travel" });
+                    constraints: new { area = "Travel" });
 
                 routes.MapRoute(
                     "ActionAsMethod",
@@ -40,6 +48,11 @@ namespace RoutingWebSite
                     "RouteWithOptionalSegment",
                     "{controller}/{action}/{path?}");
             });
+
+            app.Map("/afterrouting", b => b.Run(c =>
+            {
+                return c.Response.WriteAsync("Hello from middleware after routing");
+            }));
         }
     }
 }

test/WebSites/XmlFormattersWebSite/Controllers/XmlApiControllerBase.cs

@@ -0,0 +1,55 @@
+// 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.Mvc;
+using XmlFormattersWebSite.Models;
+
+namespace XmlFormattersWebSite
+{
+    [ApiController]
+    [Route("api/[controller]/[action]")]
+    public abstract class XmlApiControllerBase : ControllerBase
+    {
+        [HttpGet]
+        public ActionResult<Person> ActionReturningClientErrorStatusCodeResult()
+            => NotFound();
+
+        [HttpGet]
+        public ActionResult<Person> ActionReturningProblemDetails()
+        {
+            return NotFound(new ProblemDetails
+            {
+                Instance = "instance",
+                Title = "title",
+                Extensions =
+                {
+                    ["Correlation"] = "correlation",
+                    ["Accounts"] = new[] { "Account1", "Account2" },
+                },
+            });
+        }
+
+        [HttpGet]
+        public ActionResult<Person> ActionReturningValidationProblem([FromQuery] Address address)
+            => throw new NotImplementedException();
+
+        [HttpGet]
+        public ActionResult<Person> ActionReturningValidationDetailsWithMetadata()
+        {
+            return new BadRequestObjectResult(new ValidationProblemDetails
+            {
+                Detail = "some detail",
+                Type = "some type",
+                Extensions =
+                {
+                    ["CorrelationId"] = "correlation",
+                },
+                Errors =
+                {
+                    ["Error1"] = new[] { "ErrorValue"},
+                },
+            });
+        }
+    }
+}

test/WebSites/XmlFormattersWebSite/Controllers/XmlDataContractApiController.cs

@@ -0,0 +1,29 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.Mvc.Filters;
+using Microsoft.AspNetCore.Mvc.Formatters;
+
+namespace XmlFormattersWebSite
+{
+    [SetupOutputFormatters]
+    public class XmlDataContractApiController : XmlApiControllerBase
+    {
+        private class SetupOutputFormattersAttribute : ResultFilterAttribute
+        {
+            public override void OnResultExecuting(ResultExecutingContext context)
+            {
+                if (!(context.Result is ObjectResult objectResult))
+                {
+                    return;
+                }
+
+                // Both kinds of Xml serializers are configured for this application and use custom content-types to do formatter
+                // selection. The globally configured formatters rely on custom content-type to perform conneg which does not play
+                // well the ProblemDetails returning filters that defaults to using application/xml. We'll explicitly select the formatter for this controller.
+                objectResult.Formatters.Add(new XmlDataContractSerializerOutputFormatter());
+            }
+        }
+    }
+}

test/WebSites/XmlFormattersWebSite/Controllers/XmlSerializedApiController.cs

@@ -0,0 +1,29 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.Mvc.Filters;
+using Microsoft.AspNetCore.Mvc.Formatters;
+
+namespace XmlFormattersWebSite
+{
+    [SetupOutputFormatters]
+    public class XmlSerializerApiController : XmlApiControllerBase
+    {
+        private class SetupOutputFormattersAttribute : ResultFilterAttribute
+        {
+            public override void OnResultExecuting(ResultExecutingContext context)
+            {
+                if (!(context.Result is ObjectResult objectResult))
+                {
+                    return;
+                }
+
+                // Both kinds of Xml serializers are configured for this application and use custom content-types to do formatter
+                // selection. The globally configured formatters rely on custom content-type to perform conneg which does not play
+                // well the ProblemDetails returning filters that defaults to using application/xml. We'll explicitly select the formatter for this controller.
+                objectResult.Formatters.Add(new XmlSerializerOutputFormatter());
+            }
+        }
+    }
+}