Share code in extract method (#76673)

Author: CyrusNajmabadi

src/Features/CSharp/Portable/ExtractMethod/CSharpMethodExtractor.CSharpCodeGenerator.cs

@@ -573,14 +573,6 @@ protected override bool LastStatementOrHasReturnStatementInReturnableConstruct()
                 return statements[index + 1].Kind() == SyntaxKind.ReturnStatement;
             }
 
-            protected override SyntaxToken CreateIdentifier(string name)
-                => name.ToIdentifierToken();
-
-            protected override StatementSyntax CreateReturnStatement(string[] identifierNames)
-                => identifierNames.Length == 0 ? ReturnStatement() :
-                   identifierNames.Length == 1 ? ReturnStatement(IdentifierName(identifierNames[0])) :
-                   ReturnStatement(TupleExpression([.. identifierNames.Select(n => Argument(n.ToIdentifierName()))]));
-
             protected override ExpressionSyntax CreateCallSignature()
             {
                 var methodName = CreateMethodNameForInvocation().WithAdditionalAnnotations(Simplifier.Annotation);

src/Features/Core/Portable/ExtractMethod/MethodExtractor.CodeGenerator.cs

@@ -82,7 +82,6 @@ protected CodeGenerator(
             protected abstract IMethodSymbol GenerateMethodDefinition(SyntaxNode insertionPointNode, CancellationToken cancellationToken);
             protected abstract bool ShouldLocalFunctionCaptureParameter(SyntaxNode node);
 
-            protected abstract SyntaxToken CreateIdentifier(string name);
             protected abstract SyntaxToken CreateMethodName();
             protected abstract bool LastStatementOrHasReturnStatementInReturnableConstruct();
 
@@ -93,7 +92,6 @@ protected CodeGenerator(
             protected abstract TExpressionSyntax CreateCallSignature();
             protected abstract TStatementSyntax CreateDeclarationStatement(ImmutableArray<VariableInfo> variables, TExpressionSyntax initialValue, CancellationToken cancellationToken);
             protected abstract TStatementSyntax CreateAssignmentExpressionStatement(ImmutableArray<VariableInfo> variables, TExpressionSyntax rvalue);
-            protected abstract TStatementSyntax CreateReturnStatement(params string[] identifierNames);
 
             protected abstract ImmutableArray<TStatementSyntax> GetInitialStatementsForMethodDefinitions();
 
@@ -223,7 +221,22 @@ protected ImmutableArray<TStatementSyntax> AddReturnIfUnreachable(
                 if (LastStatementOrHasReturnStatementInReturnableConstruct())
                     return statements;
 
-                return statements.Concat(CreateReturnStatement());
+                return statements.Concat(CreateReturnStatement([]));
+            }
+
+            private TExecutableStatementSyntax CreateReturnStatement(ImmutableArray<TExpressionSyntax> expressions)
+            {
+                var generator = this.SemanticDocument.GetRequiredLanguageService<SyntaxGenerator>();
+                return (TExecutableStatementSyntax)generator.ReturnStatement(CreateReturnExpression(expressions));
+            }
+
+            private TExpressionSyntax CreateReturnExpression(ImmutableArray<TExpressionSyntax> expressions)
+            {
+                var generator = this.SemanticDocument.GetRequiredLanguageService<SyntaxGenerator>();
+                return
+                    expressions.Length == 0 ? null :
+                    expressions.Length == 1 ? expressions[0] :
+                    (TExpressionSyntax)generator.TupleExpression(expressions.Select(generator.Argument));
             }
 
             protected async Task<ImmutableArray<TStatementSyntax>> AddInvocationAtCallSiteAsync(
@@ -288,7 +301,11 @@ protected ImmutableArray<TStatementSyntax> AppendReturnStatementIfNeeded(Immutab
                 if (AnalyzerResult.VariablesToUseAsReturnValue.IsEmpty)
                     return statements;
 
-                return statements.Concat(CreateReturnStatement([.. AnalyzerResult.VariablesToUseAsReturnValue.Select(b => b.Name)]));
+                var generator = this.SemanticDocument.GetRequiredLanguageService<SyntaxGenerator>();
+                return statements.Concat(CreateReturnStatement(
+                    AnalyzerResult.VariablesToUseAsReturnValue.SelectAsArray(
+                        static (v, generator) => (TExpressionSyntax)generator.IdentifierName(v.Name),
+                        generator)));
             }
 
             protected static HashSet<SyntaxAnnotation> CreateVariableDeclarationToRemoveMap(

src/Features/Core/Portable/ExtractMethod/SelectionResult.cs

@@ -142,7 +142,7 @@ private bool CheckNodesInSelection(Func<ISyntaxFacts, SyntaxNode, bool> predicat
                 if (syntaxFacts.IsAnonymousOrLocalFunction(current))
                     continue;
 
-                if (current.Span.OverlapsWith(span) && predicate(syntaxFacts, current))
+                if (predicate(syntaxFacts, current))
                     return true;
 
                 // Only dive into child nodes within the span being extracted.

src/Features/VisualBasic/Portable/ExtractMethod/VisualBasicMethodExtractor.VisualBasicCodeGenerator.vb

@@ -309,20 +309,6 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.ExtractMethod
                     Return declStatements.Concat(statements)
                 End Function
 
-                Protected Overrides Function CreateIdentifier(name As String) As SyntaxToken
-                    Return name.ToIdentifierToken()
-                End Function
-
-                Protected Overrides Function CreateReturnStatement(ParamArray identifierNames As String()) As StatementSyntax
-                    Contract.ThrowIfTrue(identifierNames.Length > 1)
-
-                    If identifierNames.Length = 0 Then
-                        Return SyntaxFactory.ReturnStatement()
-                    End If
-
-                    Return SyntaxFactory.ReturnStatement(identifierNames(0).ToIdentifierName())
-                End Function
-
                 Protected Overrides Function LastStatementOrHasReturnStatementInReturnableConstruct() As Boolean
                     Dim lastStatement = GetLastStatementOrInitializerSelectedAtCallSite()
                     Dim container = lastStatement.GetAncestorsOrThis(Of SyntaxNode).Where(Function(n) n.IsReturnableConstruct()).FirstOrDefault()