Do not offer to convert object initializers to a compound assignment.

src/EditorFeatures/CSharpTest/UseCompoundAssignment/UseCompoundAssignmentTests.cs

@@ -7,6 +7,7 @@
 using Microsoft.CodeAnalysis.Diagnostics;
 using Microsoft.CodeAnalysis.Editor.CSharp.UnitTests.Diagnostics;
 using Microsoft.CodeAnalysis.Test.Utilities;
+using Roslyn.Test.Utilities;
 using Xunit;
 
 namespace Microsoft.CodeAnalysis.Editor.CSharp.UnitTests.UseCompoundAssignment
@@ -739,6 +740,26 @@ void M(int a, int b)
     {
         b = (a += 10);
     }
+}");
+        }
+
+        [WorkItem(33382, "https://github.com/dotnet/roslyn/issues/33382")]
+        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsUseCompoundAssignment)]
+        public async Task TestNotOnObjectInitializer()
+        {
+            await TestMissingAsync(
+@"
+struct InsertionPoint
+{
+	int level;
+
+	InsertionPoint Up()
+	{
+		return new InsertionPoint
+        {
+			level [||]= level - 1,
+		};
+	}
 }");
         }
     }

src/Features/Core/Portable/UseCompoundAssignment/AbstractUseCompoundAssignmentDiagnosticAnalyzer.cs

@@ -1,8 +1,6 @@
 // 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.Immutable;
-using System.Diagnostics;
-using System.Linq;
 using System.Threading;
 using Microsoft.CodeAnalysis.CodeStyle;
 using Microsoft.CodeAnalysis.Diagnostics;
@@ -107,6 +105,13 @@ private void AnalyzeAssignment(SyntaxNodeAnalysisContext context)
                 return;
             }
 
+            // Don't offer if this is `x = x + 1` inside an obj initializer like:
+            // `new Point { x = x + 1 }`
+            if (_syntaxFacts.IsObjectInitializerNamedAssignmentIdentifier(assignmentLeft))
+            {
+                return;
+            }
+
             // Syntactically looks promising.  But we can only safely do this if 'expr'
             // is side-effect-free since we will be changing the number of times it is
             // executed from twice to once.