Fix generate type with file-scoped namespaces

src/EditorFeatures/CSharpTest/Diagnostics/GenerateType/GenerateTypeTests_Dialog.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.Threading.Tasks;
 using Microsoft.CodeAnalysis.GenerateType;
@@ -78,6 +76,74 @@ class Goo
 isNewFile: false);
         }
 
+        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsGenerateType)]
+        public async Task GenerateTypeInsideFileScopedNamespace1()
+        {
+            await TestWithMockedGenerateTypeDialog(
+initial: @"
+namespace A;
+
+class Program
+{
+    void Main()
+    {
+        [|A.Goo$$|] f;
+    }
+}
+",
+languageName: LanguageNames.CSharp,
+typeName: "Goo",
+expected: @"
+namespace A;
+
+class Program
+{
+    void Main()
+    {
+        A.Goo f;
+    }
+}
+
+class Goo
+{
+}",
+isNewFile: false);
+        }
+
+        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsGenerateType)]
+        public async Task GenerateTypeInsideFileScopedNamespace2()
+        {
+            await TestWithMockedGenerateTypeDialog(
+initial: @"
+namespace A;
+
+class Program
+{
+    void Main()
+    {
+        [|Goo$$|] f;
+    }
+}
+",
+languageName: LanguageNames.CSharp,
+typeName: "Goo",
+expected: @"
+namespace A;
+
+class Program
+{
+    void Main()
+    {
+        Goo f;
+    }
+}
+
+class Goo
+{
+}",
+isNewFile: false);
+        }
+
         [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsGenerateType)]
         public async Task GenerateTypeInsideQualifiedNamespace()
         {

src/Features/CSharp/Portable/CodeRefactorings/SyncNamespace/CSharpChangeNamespaceService.cs

@@ -358,7 +358,11 @@ private static CompilationUnitSyntax MoveMembersFromGlobalToNamespace(Compilatio
 
                 var node = compilationUnit.FindNode(span, getInnermostNodeForTie: true);
 
-                var namespaceDecl = node.AncestorsAndSelf().OfType<BaseNamespaceDeclarationSyntax>().SingleOrDefault();
+                var namespaceDecls = node.AncestorsAndSelf().OfType<BaseNamespaceDeclarationSyntax>().ToImmutableArray();
+                if (namespaceDecls.Length != 1)
+                    return null;
+
+                var namespaceDecl = namespaceDecls[0];
                 if (namespaceDecl == null)
                     return null;
 

src/Features/CSharp/Portable/GenerateType/CSharpGenerateTypeService.cs

@@ -574,12 +574,8 @@ protected override bool IsConversionImplicit(Compilation compilation, ITypeSymbo
                 if (enclosingNamespace != null)
                 {
                     var enclosingNamespaceSymbol = semanticModel.GetSymbolInfo(enclosingNamespace.Name, cancellationToken);
-                    if (enclosingNamespaceSymbol.Symbol != null)
-                    {
-                        return ((INamespaceSymbol)enclosingNamespaceSymbol.Symbol,
-                                namedTypeSymbol,
-                                enclosingNamespace.CloseBraceToken.GetLocation());
-                    }
+                    if (enclosingNamespaceSymbol.Symbol is INamespaceSymbol namespaceSymbol)
+                        return (namespaceSymbol, namedTypeSymbol, enclosingNamespace.GetLastToken().GetLocation());
                 }
             }
 
@@ -593,11 +589,11 @@ protected override bool IsConversionImplicit(Compilation compilation, ITypeSymbo
             return (globalNamespace, rootNamespaceOrType, afterThisLocation);
         }
 
-        private NamespaceDeclarationSyntax FindNamespaceInMemberDeclarations(SyntaxList<MemberDeclarationSyntax> members, int indexDone, List<string> containers)
+        private BaseNamespaceDeclarationSyntax FindNamespaceInMemberDeclarations(SyntaxList<MemberDeclarationSyntax> members, int indexDone, List<string> containers)
         {
             foreach (var member in members)
             {
-                if (member is NamespaceDeclarationSyntax namespaceDeclaration)
+                if (member is BaseNamespaceDeclarationSyntax namespaceDeclaration)
                 {
                     var found = FindNamespaceInNamespace(namespaceDeclaration, indexDone, containers);
                     if (found != null)
@@ -608,7 +604,7 @@ private NamespaceDeclarationSyntax FindNamespaceInMemberDeclarations(SyntaxList<
             return null;
         }
 
-        private NamespaceDeclarationSyntax FindNamespaceInNamespace(NamespaceDeclarationSyntax namespaceDecl, int indexDone, List<string> containers)
+        private BaseNamespaceDeclarationSyntax FindNamespaceInNamespace(BaseNamespaceDeclarationSyntax namespaceDecl, int indexDone, List<string> containers)
         {
             if (namespaceDecl.Name is AliasQualifiedNameSyntax)
                 return null;

src/Features/Core/Portable/GenerateType/AbstractGenerateTypeService.Editor.cs

@@ -435,8 +435,7 @@ private async Task<IEnumerable<CodeActionOperation>> GetGenerateIntoExistingDocu
                     enclosingNamespaceGeneratedTypeToAddAndLocation.Item1,
                     enclosingNamespaceGeneratedTypeToAddAndLocation.Item2,
                     new CodeGenerationOptions(afterThisLocation: enclosingNamespaceGeneratedTypeToAddAndLocation.Item3),
-                    _cancellationToken)
-                    .ConfigureAwait(false);
+                    _cancellationToken).ConfigureAwait(false);
                 var newRoot = await codeGenResult.GetSyntaxRootAsync(_cancellationToken).ConfigureAwait(false);
                 var updatedSolution = solution.WithDocumentSyntaxRoot(generateTypeOptionsResult.ExistingDocument.Id, newRoot, PreservationMode.PreserveIdentity);