From b0b5351e20a48304fe3dd8ea3fa8148567fad7e7 Mon Sep 17 00:00:00 2001
From: Ivan Basov <basov@hotmail.com>
Date: Thu, 3 Jan 2019 18:04:14 -0800
Subject: [PATCH] async completion: fixing 'Nullable object must have a value'
 when deleting the whole word (#32143)

---
 .../AsyncCompletion/ItemManager.cs            |  4 +--
 .../CSharpCompletionCommandHandlerTests.vb    | 34 +++++++++++++++++++
 2 files changed, 36 insertions(+), 2 deletions(-)

diff --git a/src/EditorFeatures/Core/Implementation/IntelliSense/AsyncCompletion/ItemManager.cs b/src/EditorFeatures/Core/Implementation/IntelliSense/AsyncCompletion/ItemManager.cs
index 8c068148af1..5c619924703 100644
--- a/src/EditorFeatures/Core/Implementation/IntelliSense/AsyncCompletion/ItemManager.cs
+++ b/src/EditorFeatures/Core/Implementation/IntelliSense/AsyncCompletion/ItemManager.cs
@@ -329,8 +329,8 @@ private static bool IsAfterDot(ITextSnapshot snapshot, ITrackingSpan applicableT
             return new FilteredCompletionModel(
                 highlightedList, index, filters,
                 hardSelect ? UpdateSelectionHint.Selected : UpdateSelectionHint.SoftSelected,
-                centerSelection: true, 
-                uniqueItem: matchCount == 1 ? bestFilterResult.Value.VSCompletionItem : default);
+                centerSelection: true,
+                uniqueItem: matchCount == 1 ? bestFilterResult.GetValueOrDefault().VSCompletionItem : default);
         }
 
         private FilteredCompletionModel HandleAllItemsFilteredOut(
diff --git a/src/EditorFeatures/Test2/IntelliSense/CSharpCompletionCommandHandlerTests.vb b/src/EditorFeatures/Test2/IntelliSense/CSharpCompletionCommandHandlerTests.vb
index 1bd0bf2b83b..9fd362476c5 100644
--- a/src/EditorFeatures/Test2/IntelliSense/CSharpCompletionCommandHandlerTests.vb
+++ b/src/EditorFeatures/Test2/IntelliSense/CSharpCompletionCommandHandlerTests.vb
@@ -61,6 +61,40 @@ Namespace Microsoft.CodeAnalysis.Editor.UnitTests.IntelliSense
             End Using
         End Function
 
+        <MemberData(NameOf(AllCompletionImplementations))>
+        <WpfTheory, Trait(Traits.Feature, Traits.Features.Completion)>
+        Public Async Function TestDeletingWholeWordResetCompletionToTheDefaultItem(completionImplementation As CompletionImplementation) As Task
+            Using state = TestStateFactory.CreateCSharpTestState(completionImplementation,
+                              <Document>
+                                  using System;
+
+class C
+{
+    void M()
+    {
+        var replyUri = new Uri("");
+        $$
+    }
+}
+
+                              </Document>)
+
+                state.Workspace.Options = state.Workspace.Options.WithChangedOption(
+                    CompletionOptions.TriggerOnDeletion, LanguageNames.CSharp, True)
+
+                state.SendTypeChars("repl")
+                state.SendTab()
+                For i = 1 To 7
+                    state.SendBackspace()
+                    Await state.WaitForAsynchronousOperationsAsync()
+                Next
+                Await state.AssertCompletionSession()
+
+                state.SendBackspace()
+                Await state.AssertSelectedCompletionItem("AccessViolationException")
+            End Using
+        End Function
+
         <MemberData(NameOf(AllCompletionImplementations))>
         <WpfTheory, Trait(Traits.Feature, Traits.Features.Completion)>
         Public Async Function TestNotAtStartOfExistingWord(completionImplementation As CompletionImplementation) As Task
-- 
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