* Give message correct path.

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

@@ -267,7 +267,7 @@ namespace Microsoft.AspNetCore.Mvc.Razor
         }
 
         /// <summary>
-        /// Section '{0}' is not defined in path '{1}'.
+        /// The layout page '{0}' cannot find the section '{1}' in the content page '{2}'.
         /// </summary>
         internal static string SectionNotDefined
         {
@@ -275,11 +275,11 @@ namespace Microsoft.AspNetCore.Mvc.Razor
         }
 
         /// <summary>
-        /// Section '{0}' is not defined in path '{1}'.
+        /// The layout page '{0}' cannot find the section '{1}' in the content page '{2}'.
         /// </summary>
-        internal static string FormatSectionNotDefined(object p0, object p1)
+        internal static string FormatSectionNotDefined(object p0, object p1, object p2)
         {
-            return string.Format(CultureInfo.CurrentCulture, GetString("SectionNotDefined"), p0, p1);
+            return string.Format(CultureInfo.CurrentCulture, GetString("SectionNotDefined"), p0, p1, p2);
         }
 
         /// <summary>

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

@@ -443,7 +443,7 @@ namespace Microsoft.AspNetCore.Mvc.Razor
             // null  or false. Consequently defer the prefix generation until we encounter the attribute value.
             if (attributeValuesCount != 1)
             {
-               WritePositionTaggedLiteral(writer, prefix, prefixOffset);
+                WritePositionTaggedLiteral(writer, prefix, prefixOffset);
             }
         }
 
@@ -800,7 +800,11 @@ namespace Microsoft.AspNetCore.Mvc.Razor
             else if (required)
             {
                 // If the section is not found, and it is not optional, throw an error.
-                throw new InvalidOperationException(Resources.FormatSectionNotDefined(sectionName, Path));
+                var message = Resources.FormatSectionNotDefined(
+                    ViewContext.ExecutingFilePath,
+                    sectionName,
+                    ViewContext.View.Path);
+                throw new InvalidOperationException(message);
             }
             else
             {

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

@@ -166,7 +166,7 @@
     <value>{0} invocation in '{1}' is invalid. The section '{2}' has already been rendered.</value>
   </data>
   <data name="SectionNotDefined" xml:space="preserve">
-    <value>Section '{0}' is not defined in path '{1}'.</value>
+    <value>The layout page '{0}' cannot find the section '{1}' in the content page '{2}'.</value>
   </data>
   <data name="SectionsNotRendered" xml:space="preserve">
     <value>The following sections have been defined but have not been rendered by the page at '{0}': '{1}'.</value>

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

@@ -4,6 +4,7 @@
 using System.Net.Http;
 using System.Threading.Tasks;
 using Xunit;
+using System.Net;
 
 namespace Microsoft.AspNetCore.Mvc.FunctionalTests
 {
@@ -93,5 +94,21 @@ Non Shared Partial
             // Assert
             Assert.Equal(expected, body.Trim(), ignoreLineEndingDifferences: true);
         }
+
+        [Fact]
+        public async Task PartialLayout_ThrowsIfRequiredSectionMissing()
+        {
+            // Arrange
+            var path = "http://localhost/PartialViewEngine/ViewPartialMissingSection";
+
+            // Act
+            var content = await (await Client.GetAsync(path)).Content.ReadAsStringAsync();
+
+            // Assert
+            Assert.Contains(
+                "The layout page '/Views/Shared/_PartialLayout.cshtml' cannot find the section " +
+                    "'section' in the content page '/Views/PartialViewEngine/PartialMissingSection.cshtml'.",
+                WebUtility.HtmlDecode(content));
+        }
     }
 }

test/Microsoft.AspNetCore.Mvc.Razor.Test/RazorPageTest.cs

@@ -284,11 +284,12 @@ namespace Microsoft.AspNetCore.Mvc.Razor
         public async Task RenderSection_ThrowsIfRequiredSectionIsNotFound()
         {
             // Arrange
+            var context = CreateViewContext(viewPath: "/Views/TestPath/Test.cshtml");
+            context.ExecutingFilePath = "/Views/Shared/_Layout.cshtml";
             var page = CreatePage(v =>
             {
-                v.Path = "/Views/TestPath/Test.cshtml";
                 v.RenderSection("bar");
-            });
+            }, context: context);
             page.PreviousSectionWriters = new Dictionary<string, RenderAsyncDelegate>
             {
                 { "baz", _nullRenderAsyncDelegate }
@@ -296,7 +297,9 @@ namespace Microsoft.AspNetCore.Mvc.Razor
 
             // Act & Assert
             var ex = await Assert.ThrowsAsync<InvalidOperationException>(() => page.ExecuteAsync());
-            Assert.Equal("Section 'bar' is not defined in path '/Views/TestPath/Test.cshtml'.", ex.Message);
+            var message = $"The layout page '/Views/Shared/_Layout.cshtml' cannot find the section 'bar'" +
+                " in the content page '/Views/TestPath/Test.cshtml'.";
+            Assert.Equal(message, ex.Message);
         }
 
         [Fact]
@@ -1188,7 +1191,7 @@ namespace Microsoft.AspNetCore.Mvc.Razor
             return view.Object;
         }
 
-        private static ViewContext CreateViewContext(TextWriter writer = null)
+        private static ViewContext CreateViewContext(TextWriter writer = null, string viewPath = null)
         {
             writer = writer ?? new StringWriter();
             var httpContext = new DefaultHttpContext();
@@ -1200,9 +1203,14 @@ namespace Microsoft.AspNetCore.Mvc.Razor
                 httpContext,
                 new RouteData(),
                 new ActionDescriptor());
+            var viewMock = new Mock<IView>();
+            if (!string.IsNullOrEmpty(viewPath))
+            {
+                viewMock.Setup(v => v.Path).Returns(viewPath);
+            }
             return new ViewContext(
                 actionContext,
-                Mock.Of<IView>(),
+                viewMock.Object,
                 new ViewDataDictionary(new EmptyModelMetadataProvider()),
                 Mock.Of<ITempDataDictionary>(),
                 writer,

test/WebSites/RazorWebSite/Controllers/PartialViewEngineController.cs

@@ -42,5 +42,10 @@ namespace RazorWebSite.Controllers
             };
             return PartialView(model);
         }
+
+        public IActionResult ViewPartialMissingSection()
+        {
+            return View();
+        }
     }
 }

test/WebSites/RazorWebSite/Views/PartialViewEngine/PartialMissingSection.cshtml

@@ -0,0 +1,3 @@
+@{
+    Layout = "_PartialLayout";
+}

test/WebSites/RazorWebSite/Views/PartialViewEngine/ViewPartialMissingSection.cshtml

@@ -0,0 +1,4 @@
+@{
+    Layout = null;
+}
+<partial>@Html.Partial("PartialMissingSection")</partial>

test/WebSites/RazorWebSite/Views/Shared/_PartialLayout.cshtml

@@ -0,0 +1,21 @@
+<!DOCTYPE html>
+
+<html>
+<head>
+</head>
+<body>
+    <div>
+        @RenderBody()
+    </div>
+    @{
+        try
+        {
+            RenderSection("section");
+        }
+        catch (InvalidOperationException ex)
+        {
+            <p>@ex.Message</p>
+        }
+    }
+</body>
+</html>