Use standard pattern

src/Analyzers/CSharp/CodeFixes/UseImplicitObjectCreation/CSharpUseImplicitObjectCreationCodeFixProvider.cs

@@ -15,6 +15,7 @@
 using Microsoft.CodeAnalysis.CSharp.Syntax;
 using Microsoft.CodeAnalysis.Diagnostics;
 using Microsoft.CodeAnalysis.Editing;
+using Microsoft.CodeAnalysis.Host.Mef;
 using Microsoft.CodeAnalysis.Shared.Extensions;
 using Roslyn.Utilities;
 
@@ -24,7 +25,7 @@ namespace Microsoft.CodeAnalysis.CSharp.UseImplicitObjectCreation
     internal class CSharpUseImplicitObjectCreationCodeFixProvider : SyntaxEditorBasedCodeFixProvider
     {
         [ImportingConstructor]
-        [SuppressMessage("RoslynDiagnosticsReliability", "RS0033:Importing constructor should be [Obsolete]", Justification = "Used in test code: https://github.com/dotnet/roslyn/issues/42814")]
+        [Obsolete(MefConstruction.ImportingConstructorMessage, error: true)]
         public CSharpUseImplicitObjectCreationCodeFixProvider()
         {
         }

src/Analyzers/CSharp/Tests/UseImplicitObjectCreation/CSharpUseImplicitObjectCreationTests.cs

@@ -512,6 +512,28 @@ class C
                 FixedCode = @"
 using System.Collections.Generic;
 class C
+{
+    System.Collections.Generic.List<int> list = new();
+}",
+                LanguageVersion = CodeAnalysis.CSharp.LanguageVersion.CSharp9,
+            }.RunAsync();
+        }
+
+        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsUseImplicitObjectCreation)]
+        public async Task TestAlias()
+        {
+            await new VerifyCS.Test
+            {
+                TestCode = @"
+using System.Collections.Generic;
+using X = System.Collections.Generic.List<int>;
+class C
+{
+    System.Collections.Generic.List<int> list = new [|X|]();
+}",
+                FixedCode = @"
+using System.Collections.Generic;
+class C
 {
     System.Collections.Generic.List<int> list = new();
 }",