Fix issue trying to generate fields/properties from a top level program

src/Analyzers/CSharp/CodeFixes/GenerateVariable/CSharpGenerateVariableCodeFixProvider.cs

@@ -2,8 +2,6 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
-#nullable disable
-
 using System.Collections.Immutable;
 using System.Composition;
 using System.Diagnostics.CodeAnalysis;
@@ -13,7 +11,6 @@
 using Microsoft.CodeAnalysis.CodeActions;
 using Microsoft.CodeAnalysis.CodeFixes;
 using Microsoft.CodeAnalysis.CodeFixes.GenerateMember;
-using Microsoft.CodeAnalysis.CodeGeneration;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
 using Microsoft.CodeAnalysis.GenerateMember.GenerateVariable;
 using Microsoft.CodeAnalysis.Shared.Extensions;
@@ -40,7 +37,7 @@ public override ImmutableArray<string> FixableDiagnosticIds
     protected override bool IsCandidate(SyntaxNode node, SyntaxToken token, Diagnostic diagnostic)
         => node is SimpleNameSyntax or PropertyDeclarationSyntax or MemberBindingExpressionSyntax;
 
-    protected override SyntaxNode GetTargetNode(SyntaxNode node)
+    protected override SyntaxNode? GetTargetNode(SyntaxNode node)
     {
         if (node.IsKind(SyntaxKind.MemberBindingExpression))
         {

src/Analyzers/Core/CodeFixes/GenerateVariable/AbstractGenerateVariableService.State.cs

@@ -170,8 +170,8 @@ private async Task<bool> TryInitializeAsync(
 
         internal bool CanGeneratePropertyOrField()
         {
-            return ContainingType is { IsImplicitClass: false }
-                && ContainingType.GetMembers(WellKnownMemberNames.TopLevelStatementsEntryPointMethodName).IsEmpty;
+            return this.TypeToGenerateIn is { IsImplicitClass: false }
+                && TypeToGenerateIn.GetMembers(WellKnownMemberNames.TopLevelStatementsEntryPointMethodName).IsEmpty;
         }
 
         internal bool CanGenerateLocal()

src/Analyzers/Core/CodeFixes/GenerateVariable/AbstractGenerateVariableService.cs

@@ -2,16 +2,13 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
-#nullable disable
-
 using System.Collections.Immutable;
 using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.CodeAnalysis.AddParameter;
 using Microsoft.CodeAnalysis.CodeActions;
 using Microsoft.CodeAnalysis.CodeGeneration;
-using Microsoft.CodeAnalysis.CodeStyle;
 using Microsoft.CodeAnalysis.Internal.Log;
 using Microsoft.CodeAnalysis.PooledObjects;
 using Microsoft.CodeAnalysis.Shared.Extensions;
@@ -24,10 +21,6 @@ internal abstract partial class AbstractGenerateVariableService<TService, TSimpl
     where TSimpleNameSyntax : TExpressionSyntax
     where TExpressionSyntax : SyntaxNode
 {
-    protected AbstractGenerateVariableService()
-    {
-    }
-
     protected abstract bool IsExplicitInterfaceGeneration(SyntaxNode node);
     protected abstract bool IsIdentifierNameGeneration(SyntaxNode node);
 
@@ -47,9 +40,7 @@ public async Task<ImmutableArray<CodeAction>> GenerateVariableAsync(
 
             var state = await State.GenerateAsync((TService)this, semanticDocument, node, cancellationToken).ConfigureAwait(false);
             if (state == null)
-            {
                 return [];
-            }
 
             using var _ = ArrayBuilder<CodeAction>.GetInstance(out var actions);
 

src/Features/CSharpTest/GenerateVariable/GenerateVariableTests.cs

@@ -21,7 +21,8 @@
 namespace Microsoft.CodeAnalysis.Editor.CSharp.UnitTests.GenerateVariable;
 
 [Trait(Traits.Feature, Traits.Features.CodeActionsGenerateVariable)]
-public class GenerateVariableTests : AbstractCSharpDiagnosticProviderBasedUserDiagnosticTest_NoEditor
+public sealed class GenerateVariableTests(ITestOutputHelper logger)
+    : AbstractCSharpDiagnosticProviderBasedUserDiagnosticTest_NoEditor(logger)
 {
     private const int FieldIndex = 0;
     private const int ReadonlyFieldIndex = 1;
@@ -30,11 +31,6 @@ public class GenerateVariableTests : AbstractCSharpDiagnosticProviderBasedUserDi
     private const int Parameter = 4;
     private const int ParameterAndOverrides = 5;
 
-    public GenerateVariableTests(ITestOutputHelper logger)
-        : base(logger)
-    {
-    }
-
     internal override (DiagnosticAnalyzer?, CodeFixProvider) CreateDiagnosticProviderAndFixer(Workspace workspace)
         => (null, new CSharpGenerateVariableCodeFixProvider());
 
@@ -11135,4 +11131,23 @@ void M()
             }
             """);
     }
+
+    [Fact, WorkItem("https://github.com/dotnet/roslyn/issues/58491")]
+    public async Task TestGeneratePropertiesFromTopLevel()
+    {
+        await TestInRegularAndScriptAsync(
+            """
+            var x = new Test() { [|A|] = 1, B = 1 };
+            class Test
+            {
+            }
+            """,
+            """
+            var x = new Test() { A = 1, B = 1 };
+            class Test
+            {
+                public int A { get; internal set; }
+            }
+            """);
+    }
 }