Merge pull request dotnet#62065 from jasonmalinowski/highlight-requir…

…ed-methods-in-completion

Improve the experience of completion around required members

src/EditorFeatures/CSharpTest/Completion/CompletionProviders/ObjectInitializerCompletionProviderTests.cs

@@ -996,6 +996,28 @@ static void Main(string[] args)
             await VerifyItemIsAbsentAsync(markup, "this");
         }
 
+        [Fact, Trait(Traits.Feature, Traits.Features.Completion)]
+        public async Task RequiredMembersLabeledAndSelected()
+        {
+            var markup = @"
+class C
+{
+    public required int RequiredField;
+    public required int RequiredProperty { get; set; }
+}
+
+class D
+{
+    static void Main(string[] args)
+    {
+        var t = new C() { $$ };
+    }
+}";
+
+            await VerifyItemExistsAsync(markup, "RequiredField", inlineDescription: FeaturesResources.Required, matchPriority: MatchPriority.Preselect);
+            await VerifyItemExistsAsync(markup, "RequiredProperty", inlineDescription: FeaturesResources.Required);
+        }
+
         [WorkItem(15205, "https://github.com/dotnet/roslyn/issues/15205")]
         [Fact, Trait(Traits.Feature, Traits.Features.Completion)]
         public async Task NestedPropertyInitializers1()

src/Features/Core/Portable/Completion/Providers/AbstractObjectInitializerCompletionProvider.cs

@@ -62,17 +62,32 @@ public override async Task ProvideCompletionsAsync(CompletionContext context)
             var alreadyTypedMembers = GetInitializedMembers(semanticModel.SyntaxTree, position, cancellationToken);
             var uninitializedMembers = members.Where(m => !alreadyTypedMembers.Contains(m.Name));
 
-            uninitializedMembers = uninitializedMembers.Where(m => m.IsEditorBrowsable(context.CompletionOptions.HideAdvancedMembers, semanticModel.Compilation));
+            // Sort the members by name so if we preselect one, it'll be stable
+            uninitializedMembers = uninitializedMembers.Where(m => m.IsEditorBrowsable(context.CompletionOptions.HideAdvancedMembers, semanticModel.Compilation))
+                                                       .OrderBy(m => m.Name);
+
+            var firstUnitializedRequiredMember = true;
 
             foreach (var uninitializedMember in uninitializedMembers)
             {
+                var rules = s_rules;
+
+                // We'll hard select the first required member to make it a bit easier to type out an object initializer
+                // with a bunch of members.
+                if (firstUnitializedRequiredMember && uninitializedMember.IsRequired())
+                {
+                    rules = rules.WithSelectionBehavior(CompletionItemSelectionBehavior.HardSelection).WithMatchPriority(MatchPriority.Preselect);
+                    firstUnitializedRequiredMember = false;
+                }
+
                 context.AddItem(SymbolCompletionItem.CreateWithSymbolId(
                     displayText: EscapeIdentifier(uninitializedMember),
                     displayTextSuffix: "",
                     insertionText: null,
                     symbols: ImmutableArray.Create(uninitializedMember),
                     contextPosition: initializerLocation.SourceSpan.Start,
-                    rules: s_rules));
+                    inlineDescription: uninitializedMember.IsRequired() ? FeaturesResources.Required : null,
+                    rules: rules));
             }
         }
 

src/Features/Core/Portable/Completion/Providers/SymbolCompletionItem.cs

@@ -16,7 +16,7 @@
 
 namespace Microsoft.CodeAnalysis.Completion.Providers
 {
-    internal static partial class SymbolCompletionItem
+    internal static class SymbolCompletionItem
     {
         private const string InsertionTextProperty = "InsertionText";
 

src/Features/Core/Portable/FeaturesResources.resx

@@ -3153,4 +3153,8 @@ Zero-width positive lookbehind assertions are typically used at the beginning of
   <data name="Fixing_0" xml:space="preserve">
     <value>Fixing '{0}'</value>
   </data>
+  <data name="Required" xml:space="preserve">
+    <value>required</value>
+    <comment>Used in the object initializer completion.</comment>
+  </data>
 </root>