Clean up member inserting completion providers (i.e. overrides and partial completion)

src/EditorFeatures/Core/Implementation/IntelliSense/Completion/CompletionProviders/AbstractMemberInsertingCompletionProvider.cs

@@ -2,10 +2,8 @@
 
 using System.Linq;
 using System.Threading;
-using System.Threading.Tasks;
 using Microsoft.CodeAnalysis.CodeGeneration;
 using Microsoft.CodeAnalysis.Completion;
-using Microsoft.CodeAnalysis.Completion.Providers;
 using Microsoft.CodeAnalysis.Editing;
 using Microsoft.CodeAnalysis.Editor.Host;
 using Microsoft.CodeAnalysis.Editor.Shared.Extensions;
@@ -19,7 +17,7 @@
 
 namespace Microsoft.CodeAnalysis.Editor.Implementation.IntelliSense.Completion
 {
-    internal abstract class AbstractMemberInsertingCompletionProvider : AbstractCompletionProvider, ICustomCommitCompletionProvider
+    internal abstract class AbstractMemberInsertingCompletionProvider : CompletionListProvider, ICustomCommitCompletionProvider
     {
         private IWaitIndicator _waitIndicator;
         private readonly SyntaxAnnotation _annotation = new SyntaxAnnotation();
@@ -37,11 +35,6 @@ internal abstract class AbstractMemberInsertingCompletionProvider : AbstractComp
             _waitIndicator = waitIndicator;
         }
 
-        protected override Task<bool> IsExclusiveAsync(Document documentOpt, int caretPosition, CompletionTriggerInfo triggerInfo, CancellationToken cancellationToken)
-        {
-            return SpecializedTasks.True;
-        }
-
         public void Commit(CompletionItem completionItem, ITextView textView, ITextBuffer subjectBuffer, ITextSnapshot triggerSnapshot, char? commitChar)
         {
             var currentSnapshot = subjectBuffer.CurrentSnapshot;

src/EditorFeatures/Core/Implementation/IntelliSense/Completion/CompletionProviders/AbstractOverrideCompletionProvider.cs

 // Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
 using System.Collections.Generic;
+using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.CodeAnalysis.CodeGeneration;
 using Microsoft.CodeAnalysis.Completion;
 using Microsoft.CodeAnalysis.Editing;
 using Microsoft.CodeAnalysis.Editor.Host;
-using Microsoft.CodeAnalysis.Editor.Implementation.IntelliSense.Completion.CompletionProviders;
 using Microsoft.CodeAnalysis.Shared.Extensions;
 using Microsoft.CodeAnalysis.Text;
 using Roslyn.Utilities;
@@ -29,10 +29,16 @@ internal abstract partial class AbstractOverrideCompletionProvider : AbstractMem
         public abstract bool TryDetermineModifiers(SyntaxToken startToken, SourceText text, int startLine, out Accessibility seenAccessibility, out DeclarationModifiers modifiers);
         protected abstract TextSpan GetTextChangeSpan(SourceText text, int position);
 
-        protected override Task<IEnumerable<CompletionItem>> GetItemsWorkerAsync(Document document, int position, CompletionTriggerInfo triggerInfo, CancellationToken cancellationToken)
+        public override async Task ProduceCompletionListAsync(CompletionListContext context)
         {
-            var state = new ItemGetter(this, document, position, cancellationToken);
-            return state.GetItemsAsync();
+            var state = new ItemGetter(this, context.Document, context.Position, context.CancellationToken);
+            var items = await state.GetItemsAsync().ConfigureAwait(false);
+
+            if (items?.Any() == true)
+            {
+                context.MakeExclusive(true);
+                context.AddItems(items);
+            }
         }
 
         protected override ISymbol GenerateMember(ISymbol newOverriddenMember, INamedTypeSymbol newContainingType, Document newDocument, MemberInsertionCompletionItem completionItem, CancellationToken cancellationToken)

src/EditorFeatures/Core/Implementation/IntelliSense/Completion/CompletionProviders/AbstractPartialCompletionProvider.cs

@@ -39,18 +39,28 @@ public AbstractPartialCompletionProvider(IWaitIndicator waitIndicator)
         protected abstract Task<TextSpan> GetTextChangeSpanAsync(Document document, int position, CancellationToken cancellationToken);
         protected abstract bool IsPartial(IMethodSymbol m);
 
-        protected override async Task<IEnumerable<CompletionItem>> GetItemsWorkerAsync(Document document, int position, CompletionTriggerInfo triggerInfo, CancellationToken cancellationToken)
+        public override async Task ProduceCompletionListAsync(CompletionListContext context)
         {
+            var document = context.Document;
+            var position = context.Position;
+            var cancellationToken = context.CancellationToken;
+
             var tree = await document.GetSyntaxTreeAsync(cancellationToken).ConfigureAwait(false);
 
             DeclarationModifiers modifiers;
             SyntaxToken token;
             if (!IsPartialCompletionContext(tree, position, cancellationToken, out modifiers, out token))
             {
-                return null;
+                return;
             }
 
-            return await CreatePartialItemsAsync(document, position, modifiers, token, cancellationToken).ConfigureAwait(false);
+            var items = await CreatePartialItemsAsync(document, position, modifiers, token, cancellationToken).ConfigureAwait(false);
+
+            if (items?.Any() == true)
+            {
+                context.MakeExclusive(true);
+                context.AddItems(items);
+            }
         }
 
         protected override ISymbol GenerateMember(ISymbol member, INamedTypeSymbol containingType, Document document, MemberInsertionCompletionItem item, CancellationToken cancellationToken)