Merge pull request #40681 from allisonchou/ExtractMethodUsingBug

Fix for extract method crashes when extracting an invalid using statement

src/EditorFeatures/CSharpTest/CodeActions/ExtractMethod/ExtractLocalFunctionTests.cs

@@ -4250,6 +4250,53 @@ bool NewMethod()
             await TestInRegularAndScriptAsync(input, expected, CodeActionIndex, options: Option(CSharpCodeStyleOptions.PreferStaticLocalFunction, CodeStyleOptions.FalseWithSilentEnforcement));
         }
 
+        [WorkItem(40654, "https://github.com/dotnet/roslyn/issues/40654")]
+        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsExtractLocalFunction)]
+        public async Task TestOnInvalidUsingStatement_MultipleStatements()
+        {
+            var input = @"
+class C
+{
+    void M()
+    {
+        [|var v = 0;
+        using System;|]
+    }
+}";
+            var expected = @"
+class C
+{
+    void M()
+    {
+        {|Rename:NewMethod|}();
+
+        static void NewMethod()
+        {
+            var v = 0;
+            using System;
+        }
+    }
+}";
+            await TestInRegularAndScriptAsync(input, expected, CodeActionIndex);
+        }
+
+        [WorkItem(40654, "https://github.com/dotnet/roslyn/issues/40654")]
+        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsExtractLocalFunction)]
+        public async Task TestMissingOnUsingStatement()
+        {
+            await TestMissingInRegularAndScriptAsync(
+@"class C
+{
+    void M()
+    {
+        void L()
+        {
+            [|using System;|]
+        }
+    }
+}");
+        }
+
         [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsExtractLocalFunction)]
         public async Task TestMissingInLocalFunctionDeclaration_ExpressionBody()
         {

src/EditorFeatures/CSharpTest/CodeActions/ExtractMethod/ExtractMethodTests.cs

@@ -3751,7 +3751,7 @@ private static bool NewMethod()
             await TestInRegularAndScriptAsync(input, expected);
         }
 
-        [Fact, WorkItem(40209, "https://github.com/dotnet/roslyn/issues/40209"), Trait(Traits.Feature, Traits.Features.CodeActionsExtractLocalFunction)]
+        [Fact, WorkItem(40209, "https://github.com/dotnet/roslyn/issues/40209"), Trait(Traits.Feature, Traits.Features.CodeActionsExtractMethod)]
         public async Task TestNaming_CamelCase_VerifyLocalFunctionSettingsDontApply()
         {
             var input = @"
@@ -3798,7 +3798,7 @@ private static bool NewMethod()
             await TestInRegularAndScriptAsync(input, expected);
         }
 
-        [Fact, WorkItem(40209, "https://github.com/dotnet/roslyn/issues/40209"), Trait(Traits.Feature, Traits.Features.CodeActionsExtractLocalFunction)]
+        [Fact, WorkItem(40209, "https://github.com/dotnet/roslyn/issues/40209"), Trait(Traits.Feature, Traits.Features.CodeActionsExtractMethod)]
         public async Task TestNaming_CamelCase_VerifyLocalFunctionSettingsDontApply_GetName()
         {
             var input = @"
@@ -3842,5 +3842,49 @@ private static int GetA()
 
             await TestInRegularAndScriptAsync(input, expected);
         }
+
+        [WorkItem(40654, "https://github.com/dotnet/roslyn/issues/40654")]
+        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsExtractMethod)]
+        public async Task TestOnInvalidUsingStatement_MultipleStatements()
+        {
+            var input = @"
+class C
+{
+    void M()
+    {
+        [|var v = 0;
+        using System;|]
+    }
+}";
+            var expected = @"
+class C
+{
+    void M()
+    {
+        {|Rename:NewMethod|}();
+    }
+
+    private static void NewMethod()
+    {
+        var v = 0;
+        using System;
+    }
+}";
+            await TestInRegularAndScriptAsync(input, expected);
+        }
+
+        [WorkItem(40654, "https://github.com/dotnet/roslyn/issues/40654")]
+        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsExtractMethod)]
+        public async Task TestMissingOnInvalidUsingStatement()
+        {
+            await TestMissingInRegularAndScriptAsync(
+@"class C
+{
+    void M()
+    {
+        [|using System;|]
+    }
+}");
+        }
     }
 }

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

@@ -337,7 +337,7 @@ private OperationStatus CheckActiveStatements(IEnumerable<StatementSyntax> state
 
                 foreach (var statement in statements)
                 {
-                    if (!(statement is LocalDeclarationStatementSyntax declarationStatement))
+                    if (!(statement is LocalDeclarationStatementSyntax declarationStatement) || declarationStatement.Declaration.Variables.FullSpan.IsEmpty)
                     {
                         // if given statement is not decl statement.
                         yield return statement;

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

@@ -486,6 +486,12 @@ private IList<VariableInfo> GetMethodParameters(ICollection<VariableInfo> variab
                         continue;
                     }
 
+                    // If the variable doesn't have a name, it is invalid.
+                    if (symbol.Name.IsEmpty())
+                    {
+                        continue;
+                    }
+
                     if (!TryGetVariableStyle(
                             bestEffort, symbolMap, symbol, model, type,
                             captured, dataFlowIn, dataFlowOut, alwaysAssigned, variableDeclared,