Continued Extract method cleanup (part 2) (#76585)

Author: CyrusNajmabadi

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

@@ -147,7 +147,7 @@ private async Task<ImmutableArray<SyntaxNode>> CreateStatementsOrInitializerToIn
                 statements = postProcessor.MergeDeclarationStatements(statements);
                 statements = AddAssignmentStatementToCallSite(statements, cancellationToken);
                 statements = await AddInvocationAtCallSiteAsync(statements, cancellationToken).ConfigureAwait(false);
-                statements = AddReturnIfUnreachable(statements);
+                statements = AddReturnIfUnreachable(statements, cancellationToken);
 
                 return statements.CastArray<SyntaxNode>();
             }

src/Features/CSharp/Portable/ExtractMethod/CSharpSelectionResult.ExpressionResult.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
+using System.Threading;
 using Microsoft.CodeAnalysis.CSharp.Extensions;
 using Microsoft.CodeAnalysis.CSharp.LanguageService;
 using Microsoft.CodeAnalysis.CSharp.Symbols;
@@ -45,7 +46,7 @@ public override SyntaxNode GetContainingScope()
                 return CSharpSyntaxFacts.Instance.GetRootStandaloneExpression(scope);
             }
 
-            public override (ITypeSymbol? returnType, bool returnsByRef) GetReturnType()
+            public override (ITypeSymbol? returnType, bool returnsByRef) GetReturnTypeInfo(CancellationToken cancellationToken)
             {
                 if (GetContainingScope() is not ExpressionSyntax node)
                 {
@@ -59,7 +60,7 @@ public override (ITypeSymbol? returnType, bool returnsByRef) GetReturnType()
                 {
                     var variableDeclExpression = node.GetAncestorOrThis<VariableDeclarationSyntax>();
                     if (variableDeclExpression != null)
-                        return (model.GetTypeInfo(variableDeclExpression.Type).Type, returnsByRef: false);
+                        return (model.GetTypeInfo(variableDeclExpression.Type, cancellationToken).Type, returnsByRef: false);
                 }
 
                 if (node.IsExpressionInCast())
@@ -74,7 +75,7 @@ public override (ITypeSymbol? returnType, bool returnsByRef) GetReturnType()
                         return (regularType, returnsByRef);
 
                     if (node.Parent is CastExpressionSyntax castExpression)
-                        return (model.GetTypeInfo(castExpression).Type, returnsByRef: false);
+                        return (model.GetTypeInfo(castExpression, cancellationToken).Type, returnsByRef: false);
                 }
 
                 return GetRegularExpressionType(model, node);

src/Features/CSharp/Portable/ExtractMethod/CSharpSelectionResult.StatementResult.cs

@@ -2,9 +2,9 @@
 // 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.Linq;
+using System.Threading;
+using Microsoft.CodeAnalysis.CSharp.Extensions;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
 using Microsoft.CodeAnalysis.ExtractMethod;
 using Microsoft.CodeAnalysis.Shared.Extensions;
@@ -47,20 +47,16 @@ public override SyntaxNode GetContainingScope()
                 Contract.ThrowIfNull(SemanticDocument);
                 Contract.ThrowIfTrue(IsExtractMethodOnExpression);
 
-                // it contains statements
-                var firstToken = GetFirstTokenInSelection();
-                return firstToken.GetAncestors<SyntaxNode>().FirstOrDefault(n =>
-                {
-                    return n is AccessorDeclarationSyntax or
-                           LocalFunctionStatementSyntax or
-                           BaseMethodDeclarationSyntax or
-                           AccessorDeclarationSyntax or
-                           AnonymousFunctionExpressionSyntax or
-                           CompilationUnitSyntax;
-                });
+                return GetFirstTokenInSelection().GetRequiredParent().AncestorsAndSelf().First(n =>
+                    n is AccessorDeclarationSyntax or
+                         LocalFunctionStatementSyntax or
+                         BaseMethodDeclarationSyntax or
+                         AccessorDeclarationSyntax or
+                         AnonymousFunctionExpressionSyntax or
+                         CompilationUnitSyntax);
             }
 
-            public override (ITypeSymbol returnType, bool returnsByRef) GetReturnType()
+            public override (ITypeSymbol? returnType, bool returnsByRef) GetReturnTypeInfo(CancellationToken cancellationToken)
             {
                 Contract.ThrowIfTrue(IsExtractMethodOnExpression);
 
@@ -70,27 +66,22 @@ public override (ITypeSymbol returnType, bool returnsByRef) GetReturnType()
                 switch (node)
                 {
                     case AccessorDeclarationSyntax access:
-                        // property or event case
-                        if (access.Parent == null || access.Parent.Parent == null)
-                            return default;
-
-                        return semanticModel.GetDeclaredSymbol(access.Parent.Parent) switch
+                        return semanticModel.GetDeclaredSymbol(access.GetRequiredParent().GetRequiredParent(), cancellationToken) switch
                         {
                             IPropertySymbol propertySymbol => (propertySymbol.Type, propertySymbol.ReturnsByRef),
                             IEventSymbol eventSymbol => (eventSymbol.Type, false),
-                            _ => default,
+                            _ => throw ExceptionUtilities.UnexpectedValue(node),
                         };
 
                     case MethodDeclarationSyntax methodDeclaration:
                         {
-                            return semanticModel.GetDeclaredSymbol(methodDeclaration) is not IMethodSymbol method
-                                ? default
-                                : (method.ReturnType, method.ReturnsByRef);
+                            var method = semanticModel.GetRequiredDeclaredSymbol(methodDeclaration, cancellationToken);
+                            return (method.ReturnType, method.ReturnsByRef);
                         }
 
                     case AnonymousFunctionExpressionSyntax function:
                         {
-                            return semanticModel.GetSymbolInfo(function).Symbol is not IMethodSymbol method
+                            return semanticModel.GetSymbolInfo(function, cancellationToken).Symbol is not IMethodSymbol method
                                 ? default
                                 : (method.ReturnType, method.ReturnsByRef);
                         }

src/Features/CSharp/Portable/ExtractMethod/CSharpSelectionResult.cs

@@ -32,7 +32,7 @@ internal abstract partial class CSharpSelectionResult(
     {
         public static async Task<CSharpSelectionResult> CreateAsync(
             SemanticDocument document,
-            SelectionInfo selectionInfo,
+            FinalSelectionInfo selectionInfo,
             bool selectionChanged,
             CancellationToken cancellationToken)
         {
@@ -210,37 +210,23 @@ public override ImmutableArray<StatementSyntax> GetOuterReturnStatements(SyntaxN
         }
 
         public override bool IsFinalSpanSemanticallyValidSpan(
-            TextSpan textSpan, ImmutableArray<StatementSyntax> returnStatements, CancellationToken cancellationToken)
+            ImmutableArray<StatementSyntax> returnStatements, CancellationToken cancellationToken)
         {
             // return statement shouldn't contain any return value
             if (returnStatements.Cast<ReturnStatementSyntax>().Any(r => r.Expression != null))
-            {
                 return false;
-            }
 
-            var lastToken = this.SemanticDocument.Root.FindToken(textSpan.End);
-            if (lastToken.Kind() == SyntaxKind.None)
-            {
-                return false;
-            }
-
-            var container = lastToken.GetAncestors<SyntaxNode>().FirstOrDefault(n => n.IsReturnableConstruct());
+            var container = returnStatements.First().AncestorsAndSelf().FirstOrDefault(n => n.IsReturnableConstruct());
             if (container == null)
-            {
                 return false;
-            }
 
             var body = container.GetBlockBody();
             if (body == null)
-            {
                 return false;
-            }
 
             // make sure that next token of the last token in the selection is the close braces of containing block
-            if (body.CloseBraceToken != lastToken.GetNextToken(includeZeroWidth: true))
-            {
+            if (body.CloseBraceToken != GetLastTokenInSelection().GetNextToken(includeZeroWidth: true))
                 return false;
-            }
 
             // alright, for these constructs, it must be okay to be extracted
             switch (container.Kind())
@@ -253,9 +239,7 @@ public override bool IsFinalSpanSemanticallyValidSpan(
 
             // now, only method is okay to be extracted out
             if (body.Parent is not MethodDeclarationSyntax method)
-            {
                 return false;
-            }
 
             // make sure this method doesn't have return type.
             return method.ReturnType is PredefinedTypeSyntax p &&