Implemented implicit types for new expressions

With C# 9.0, the `new` keyword only needs a type declaration if the type is otherwise unknown (e.g., `var`) or ambiguous (e.g., with an interface, or overloaded method). Otherwise, it can just use `new()`. This is especially useful for property initializers, which can be incredibly repetitive.

Note: This apparently cannot be done for generics (e.g., `new T()` cannot become `new()`). I'll need to look into that, but for now it's useful to know that it doesn't work.

Author: JeremyCaney

OnTopic.AspNetCore.Mvc.Tests/OnTopic.AspNetCore.Mvc.Tests.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <TargetFramework>netcoreapp3.0</TargetFramework>
     <IsPackable>false</IsPackable>
+    <LangVersion>9.0</LangVersion>
   </PropertyGroup>
 
   <ItemGroup>

OnTopic.AspNetCore.Mvc.Tests/TopicControllerTest.cs

@@ -73,7 +73,7 @@ public TopicControllerTest() {
         RouteData               = routes,
         ActionDescriptor        = new ControllerActionDescriptor()
       };
-      _context                  = new ControllerContext(actionContext);
+      _context                  = new(actionContext);
 
     }
 
@@ -131,11 +131,11 @@ public void SitemapController_Index_ReturnsSitemapXml() {
 
       var actionContext         = new ActionContext {
         HttpContext             = new DefaultHttpContext(),
-        RouteData               = new RouteData(),
+        RouteData               = new(),
         ActionDescriptor        = new ControllerActionDescriptor()
       };
       var controller            = new SitemapController(_topicRepository) {
-        ControllerContext       = new ControllerContext(actionContext)
+        ControllerContext       = new(actionContext)
       };
       var result                = controller.Index() as ContentResult;
       var model                 = result.Content as string;

OnTopic.AspNetCore.Mvc.Tests/ValidateTopicAttributeTest.cs

@@ -40,7 +40,7 @@ public static ActionExecutingContext GetActionExecutingContext(Controller contro
 
       var actionContext = new ActionContext(
         new DefaultHttpContext(),
-        new RouteData(),
+        new(),
         new ControllerActionDescriptor(),
         modelState
       );
@@ -63,10 +63,10 @@ public static ActionExecutingContext GetActionExecutingContext(Controller contro
     ///   Generates a barebones <see cref="ControllerContext"/> for testing a controller.
     /// </summary>
     public static ControllerContext GetControllerContext() =>
-      new ControllerContext(
-        new ActionContext() {
+      new(
+        new() {
           HttpContext               = new DefaultHttpContext(),
-          RouteData                 = new RouteData(),
+          RouteData                 = new(),
           ActionDescriptor          = new ControllerActionDescriptor()
         }
       );
@@ -78,7 +78,7 @@ public static ControllerContext GetControllerContext() =>
     ///   Generates a barebones <see cref="ControllerContext"/> for testing a controller.
     /// </summary>
     public static TopicController GetTopicController(Topic topic) =>
-      new TopicController(
+      new(
           new DummyTopicRepository(),
           new DummyTopicMappingService()
       ) {

OnTopic.AspNetCore.Mvc/Controllers/SitemapController.cs

@@ -146,7 +146,7 @@ public virtual ActionResult Index(bool indent = false, bool includeMetadata = fa
     /// <returns>A Sitemap.org sitemap.</returns>
     [Obsolete("The GenerateSitemap() method should not be public. It will be marked private in OnTopic Library 5.0.")]
     public virtual XDocument GenerateSitemap(Topic rootTopic, bool includeMetadata = false) =>
-      new XDocument(
+      new(
         new XElement(_sitemapNamespace + "urlset",
           from topic in rootTopic?.Children
           select AddTopic(topic, includeMetadata)

OnTopic.AspNetCore.Mvc/Controllers/TopicController.cs

@@ -122,7 +122,7 @@ public async virtual Task<IActionResult> IndexAsync(string path) {
     /// <returns>The created <see cref="TopicViewResult"/> object for the response.</returns>
     [NonAction]
     public virtual TopicViewResult TopicView(object model, string? viewName = null) =>
-      new TopicViewResult(ViewData, TempData, model, CurrentTopic?.ContentType, viewName);
+      new(ViewData, TempData, model, CurrentTopic?.ContentType, viewName);
 
   } //Class
 } //Namespace

OnTopic.Data.Sql/SqlTopicRepository.cs

@@ -269,7 +269,7 @@ public override int Save([NotNull]Topic topic, bool isRecursive = false, bool is
       | Attempt to resolve outstanding relationships
       \-----------------------------------------------------------------------------------------------------------------------*/
       foreach (var unresolvedTopic in unresolvedTopics) {
-        Save(unresolvedTopic, false, isDraft, connection, new List<Topic>(), version);
+        Save(unresolvedTopic, false, isDraft, connection, new(), version);
       }
 
       /*------------------------------------------------------------------------------------------------------------------------

OnTopic.Tests/AttributeValueCollectionTest.cs

@@ -453,7 +453,7 @@ public void Add_ValidAttributeValue_IsReturned() {
       var topic = TopicFactory.Create("Test", "Container");
 
       topic.Attributes.Remove("Key");
-      topic.Attributes.Add(new AttributeValue("Key", "NewKey", false));
+      topic.Attributes.Add(new("Key", "NewKey", false));
 
       Assert.AreEqual<string>("NewKey", topic.Key);
 
@@ -473,7 +473,7 @@ public void Add_ValidAttributeValue_IsReturned() {
     public void Add_InvalidAttributeValue_ThrowsException() {
       var topic = TopicFactory.Create("Test", "Container");
       topic.Attributes.Remove("Key");
-      topic.Attributes.Add(new AttributeValue("Key", "# ?"));
+      topic.Attributes.Add(new("Key", "# ?"));
     }
 
     /*==========================================================================================================================

OnTopic.Tests/BindingModels/ContentTypeDescriptorTopicBindingModel.cs

@@ -21,9 +21,9 @@ public class ContentTypeDescriptorTopicBindingModel : BasicTopicBindingModel {
 
     public ContentTypeDescriptorTopicBindingModel(string? key = null) : base(key, "ContentTypeDescriptor") { }
 
-    public List<RelatedTopicBindingModel> ContentTypes { get; } = new List<RelatedTopicBindingModel>();
+    public List<RelatedTopicBindingModel> ContentTypes { get; } = new();
 
-    public List<AttributeDescriptorTopicBindingModel> Attributes { get; } = new List<AttributeDescriptorTopicBindingModel>();
+    public List<AttributeDescriptorTopicBindingModel> Attributes { get; } = new();
 
   } //Class
 } //Namespace

OnTopic.Tests/BindingModels/InvalidChildrenTopicBindingModel.cs

@@ -22,7 +22,7 @@ public class InvalidChildrenTopicBindingModel : BasicTopicBindingModel {
 
     public InvalidChildrenTopicBindingModel(string? key = null) : base(key, "Page") { }
 
-    public List<BasicTopicBindingModel> Children { get; } = new List<BasicTopicBindingModel>();
+    public List<BasicTopicBindingModel> Children { get; } = new();
 
   } //Class
 } //Namespace

OnTopic.Tests/BindingModels/InvalidReferenceNameTopicBindingModel.cs

@@ -22,7 +22,7 @@ public class InvalidReferenceNameTopicBindingModel : BasicTopicBindingModel {
 
     public InvalidReferenceNameTopicBindingModel(string? key = null) : base(key, "Page") { }
 
-    public RelatedTopicBindingModel TopicReference { get; } = new RelatedTopicBindingModel();
+    public RelatedTopicBindingModel TopicReference { get; } = new();
 
   } //Class
 } //Namespace