diff --git a/src/Microsoft.AspNetCore.Mvc.Core/Formatters/TextOutputFormatter.cs b/src/Microsoft.AspNetCore.Mvc.Core/Formatters/TextOutputFormatter.cs
index 8f7f3df05c..26e07e59b3 100644
--- a/src/Microsoft.AspNetCore.Mvc.Core/Formatters/TextOutputFormatter.cs
+++ b/src/Microsoft.AspNetCore.Mvc.Core/Formatters/TextOutputFormatter.cs
@@ -185,7 +185,7 @@ namespace Microsoft.AspNetCore.Mvc.Formatters
                 for (var i = 0; i < acceptValues.Count; i++)
                 {
                     var charset = acceptValues[i].Value;
-                    if (!string.IsNullOrEmpty(charset))
+                    if (!StringSegment.IsNullOrEmpty(charset))
                     {
                         for (var j = 0; j < SupportedEncodings.Count; j++)
                         {
diff --git a/test/Microsoft.AspNetCore.Mvc.Formatters.Json.Test/JsonOutputFormatterTests.cs b/test/Microsoft.AspNetCore.Mvc.Formatters.Json.Test/JsonOutputFormatterTests.cs
index f79b865dba..15e735a328 100644
--- a/test/Microsoft.AspNetCore.Mvc.Formatters.Json.Test/JsonOutputFormatterTests.cs
+++ b/test/Microsoft.AspNetCore.Mvc.Formatters.Json.Test/JsonOutputFormatterTests.cs
@@ -477,7 +477,7 @@ namespace Microsoft.AspNetCore.Mvc.Formatters
             var headers = new HeaderDictionary();
             request.Setup(r => r.ContentType).Returns(contentType.ToString());
             request.SetupGet(r => r.Headers).Returns(headers);
-            headers[HeaderNames.AcceptCharset] = contentType.Charset;
+            headers[HeaderNames.AcceptCharset] = contentType.Charset.ToString();
             var response = new Mock<HttpResponse>();
             response.SetupGet(f => f.Body).Returns(responseStream ?? new MemoryStream());
             var httpContext = new Mock<HttpContext>();
diff --git a/test/Microsoft.AspNetCore.Mvc.Formatters.Xml.Test/XmlDataContractSerializerOutputFormatterTest.cs b/test/Microsoft.AspNetCore.Mvc.Formatters.Xml.Test/XmlDataContractSerializerOutputFormatterTest.cs
index acabb49213..e5b06fdfed 100644
--- a/test/Microsoft.AspNetCore.Mvc.Formatters.Xml.Test/XmlDataContractSerializerOutputFormatterTest.cs
+++ b/test/Microsoft.AspNetCore.Mvc.Formatters.Xml.Test/XmlDataContractSerializerOutputFormatterTest.cs
@@ -645,7 +645,7 @@ namespace Microsoft.AspNetCore.Mvc.Formatters.Xml
             var request = new Mock<HttpRequest>();
 
             var headers = new HeaderDictionary();
-            headers["Accept-Charset"] = MediaTypeHeaderValue.Parse(contentType).Charset;
+            headers["Accept-Charset"] = MediaTypeHeaderValue.Parse(contentType).Charset.ToString();
             request.Setup(r => r.ContentType).Returns(contentType);
             request.SetupGet(r => r.Headers).Returns(headers);
 
diff --git a/test/Microsoft.AspNetCore.Mvc.Formatters.Xml.Test/XmlSerializerOutputFormatterTest.cs b/test/Microsoft.AspNetCore.Mvc.Formatters.Xml.Test/XmlSerializerOutputFormatterTest.cs
index 6a36e90284..13c3ee6220 100644
--- a/test/Microsoft.AspNetCore.Mvc.Formatters.Xml.Test/XmlSerializerOutputFormatterTest.cs
+++ b/test/Microsoft.AspNetCore.Mvc.Formatters.Xml.Test/XmlSerializerOutputFormatterTest.cs
@@ -406,7 +406,7 @@ namespace Microsoft.AspNetCore.Mvc.Formatters.Xml
             var request = new Mock<HttpRequest>();
 
             var headers = new HeaderDictionary();
-            headers["Accept-Charset"] = MediaTypeHeaderValue.Parse(contentType).Charset;
+            headers["Accept-Charset"] = MediaTypeHeaderValue.Parse(contentType).Charset.ToString();
             request.Setup(r => r.ContentType).Returns(contentType);
             request.SetupGet(r => r.Headers).Returns(headers);
 
diff --git a/test/Microsoft.AspNetCore.Mvc.FunctionalTests/TempDataInCookiesTest.cs b/test/Microsoft.AspNetCore.Mvc.FunctionalTests/TempDataInCookiesTest.cs
index 241cf022ca..7344842d64 100644
--- a/test/Microsoft.AspNetCore.Mvc.FunctionalTests/TempDataInCookiesTest.cs
+++ b/test/Microsoft.AspNetCore.Mvc.FunctionalTests/TempDataInCookiesTest.cs
@@ -53,9 +53,9 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
                 .Select(setCookieValue => SetCookieHeaderValue.Parse(setCookieValue));
             foreach (var cookieTempDataProviderCookie in cookieTempDataProviderCookies)
             {
-                Assert.NotNull(cookieTempDataProviderCookie.Value);
+                Assert.NotNull(cookieTempDataProviderCookie.Value.Value);
                 Assert.Equal("/", cookieTempDataProviderCookie.Path);
-                Assert.Null(cookieTempDataProviderCookie.Domain);
+                Assert.Null(cookieTempDataProviderCookie.Domain.Value);
                 Assert.False(cookieTempDataProviderCookie.Secure);
             }
 
@@ -73,7 +73,7 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
             Assert.NotNull(setCookieHeaderValue);
             Assert.Equal(string.Empty, setCookieHeaderValue.Value);
             Assert.Equal("/", setCookieHeaderValue.Path);
-            Assert.Null(setCookieHeaderValue.Domain);
+            Assert.Null(setCookieHeaderValue.Domain.Value);
             Assert.NotNull(setCookieHeaderValue.Expires);
             Assert.True(setCookieHeaderValue.Expires < DateTimeOffset.Now); // expired cookie
 
@@ -105,7 +105,7 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
                 .FirstOrDefault(setCookieHeaderValue => setCookieHeaderValue.Name == CookieTempDataProvider.CookieName);
             Assert.NotNull(setCookieHeader);
             Assert.Equal("/", setCookieHeader.Path);
-            Assert.Null(setCookieHeader.Domain);
+            Assert.Null(setCookieHeader.Domain.Value);
             Assert.False(setCookieHeader.Secure);
             Assert.Null(setCookieHeader.Expires);
 
@@ -129,7 +129,7 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
             Assert.NotNull(setCookieHeader);
             Assert.Equal(string.Empty, setCookieHeader.Value);
             Assert.Equal("/", setCookieHeader.Path);
-            Assert.Null(setCookieHeader.Domain);
+            Assert.Null(setCookieHeader.Domain.Value);
             Assert.NotNull(setCookieHeader.Expires);
             Assert.True(setCookieHeader.Expires < DateTimeOffset.Now); // expired cookie
         }
@@ -158,7 +158,7 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
                 .FirstOrDefault(setCookieHeaderValue => setCookieHeaderValue.Name == CookieTempDataProvider.CookieName);
             Assert.NotNull(setCookieHeader);
             Assert.Equal("/", setCookieHeader.Path);
-            Assert.Null(setCookieHeader.Domain);
+            Assert.Null(setCookieHeader.Domain.Value);
             Assert.Equal(secureRequest, setCookieHeader.Secure);
             Assert.Null(setCookieHeader.Expires);
         }