ExtractMethodCodeRefactoringProvider does not work with top-level statements #44260
Description
Add the following top level statement:
System.Console.WriteLine("string");
Select the string literal using mouse, observe ExtractMethodCodeRefactoringProvider to crash:
System.NullReferenceException : Object reference not set to an instance of an object.
Microsoft.CodeAnalysis.CSharp.Workspaces.dll!Microsoft.CodeAnalysis.CSharp.CodeGeneration.CSharpCodeGenerationService.AddStatementsWorker<Microsoft.CodeAnalysis.SyntaxNode>(Microsoft.CodeAnalysis.SyntaxNode destinationMember, System.Collections.Generic.IEnumerable<Microsoft.CodeAnalysis.SyntaxNode> statements, Microsoft.CodeAnalysis.CodeGeneration.CodeGenerationOptions options, System.Threading.CancellationToken cancellationToken) Line 498 C#
Microsoft.CodeAnalysis.CSharp.Workspaces.dll!Microsoft.CodeAnalysis.CSharp.CodeGeneration.CSharpCodeGenerationService.AddStatements<Microsoft.CodeAnalysis.SyntaxNode>(Microsoft.CodeAnalysis.SyntaxNode destinationMember, System.Collections.Generic.IEnumerable<Microsoft.CodeAnalysis.SyntaxNode> statements, Microsoft.CodeAnalysis.CodeGeneration.CodeGenerationOptions options, System.Threading.CancellationToken cancellationToken) Line 488 C#
> Microsoft.CodeAnalysis.Features.dll!Microsoft.CodeAnalysis.ExtractMethod.MethodExtractor.CodeGenerator<Microsoft.CodeAnalysis.CSharp.Syntax.StatementSyntax, Microsoft.CodeAnalysis.CSharp.Syntax.ExpressionSyntax, Microsoft.CodeAnalysis.SyntaxNode>.GenerateAsync(System.Threading.CancellationToken cancellationToken) Line 100 C#
Microsoft.CodeAnalysis.CSharp.Features.dll!Microsoft.CodeAnalysis.CSharp.ExtractMethod.CSharpMethodExtractor.CSharpCodeGenerator.GenerateAsync(Microsoft.CodeAnalysis.ExtractMethod.InsertionPoint insertionPoint, Microsoft.CodeAnalysis.ExtractMethod.SelectionResult selectionResult, Microsoft.CodeAnalysis.ExtractMethod.MethodExtractor.AnalyzerResult analyzerResult, Microsoft.CodeAnalysis.Options.OptionSet options, bool localFunction, System.Threading.CancellationToken cancellationToken) Line 48 C#
Microsoft.CodeAnalysis.CSharp.Features.dll!Microsoft.CodeAnalysis.CSharp.ExtractMethod.CSharpMethodExtractor.GenerateCodeAsync(Microsoft.CodeAnalysis.ExtractMethod.InsertionPoint insertionPoint, Microsoft.CodeAnalysis.ExtractMethod.SelectionResult selectionResult, Microsoft.CodeAnalysis.ExtractMethod.MethodExtractor.AnalyzerResult analyzeResult, Microsoft.CodeAnalysis.Options.OptionSet options, System.Threading.CancellationToken cancellationToken) Line 94 C#
Microsoft.CodeAnalysis.Features.dll!Microsoft.CodeAnalysis.ExtractMethod.MethodExtractor.ExtractMethodAsync(System.Threading.CancellationToken cancellationToken) Line 65 C#
Microsoft.CodeAnalysis.Features.dll!Microsoft.CodeAnalysis.ExtractMethod.AbstractExtractMethodService<Microsoft.CodeAnalysis.CSharp.ExtractMethod.CSharpSelectionValidator, Microsoft.CodeAnalysis.CSharp.ExtractMethod.CSharpMethodExtractor, Microsoft.CodeAnalysis.CSharp.ExtractMethod.CSharpSelectionResult>.ExtractMethodAsync(Microsoft.CodeAnalysis.Document document, Microsoft.CodeAnalysis.Text.TextSpan textSpan, bool localFunction, Microsoft.CodeAnalysis.Options.OptionSet options, System.Threading.CancellationToken cancellationToken) Line 44 C#
Microsoft.CodeAnalysis.Features.dll!Microsoft.CodeAnalysis.ExtractMethod.ExtractMethodService.ExtractMethodAsync(Microsoft.CodeAnalysis.Document document, Microsoft.CodeAnalysis.Text.TextSpan textSpan, bool localFunction, Microsoft.CodeAnalysis.Options.OptionSet options, System.Threading.CancellationToken cancellationToken) Line 16 C#
Microsoft.CodeAnalysis.Features.dll!Microsoft.CodeAnalysis.CodeRefactorings.ExtractMethod.ExtractMethodCodeRefactoringProvider.ExtractLocalFunctionAsync(Microsoft.CodeAnalysis.Document document, Microsoft.CodeAnalysis.Text.TextSpan textSpan, System.Threading.CancellationToken cancellationToken) Line 102 C#
Microsoft.CodeAnalysis.Features.dll!Microsoft.CodeAnalysis.CodeRefactorings.ExtractMethod.ExtractMethodCodeRefactoringProvider.GetCodeActionsAsync(Microsoft.CodeAnalysis.Document document, Microsoft.CodeAnalysis.Text.TextSpan textSpan, System.Threading.CancellationToken cancellationToken) Line 70 C#
The following line throws because options is null;
private TDeclarationNode AddStatementsWorker<TDeclarationNode>(
TDeclarationNode destinationMember,
IEnumerable<SyntaxNode> statements,
CodeGenerationOptions options,
CancellationToken cancellationToken) where TDeclarationNode : SyntaxNode
{
var location = options.BestLocation;
However the method is indirectly called by Microsoft.CodeAnalysis.Features.dll!Microsoft.CodeAnalysis.ExtractMethod.MethodExtractor.CodeGenerator<Microsoft.CodeAnalysis.CSharp.Syntax.StatementSyntax, Microsoft.CodeAnalysis.CSharp.Syntax.ExpressionSyntax, Microsoft.CodeAnalysis.SyntaxNode>.GenerateAsync through an interface where options is an optional parameter with default value null and the argument is not provided explicitly.
Relates to #43563 (test plan for "top-level statements")