diff --git a/src/EditorFeatures/CSharpTest/EditAndContinue/ActiveStatementTests.cs b/src/EditorFeatures/CSharpTest/EditAndContinue/ActiveStatementTests.cs
index 62f77c29d5b22e18c41aae3ec6709d03b59987b0..018de093b6b5f9a5123371cebd18410cbe841b80 100644
--- a/src/EditorFeatures/CSharpTest/EditAndContinue/ActiveStatementTests.cs
+++ b/src/EditorFeatures/CSharpTest/EditAndContinue/ActiveStatementTests.cs
@@ -7856,6 +7856,76 @@ static async void F()
             edits.VerifyRudeDiagnostics(active);
         }
 
+        [Fact]
+        public void AsyncMethodEdit_Semantics()
+        {
+            string src1 = @"
+using System;
+using System.Threading.Tasks;
+
+class C
+{
+    static async Task<int> F()
+    {
+        Console.WriteLine(1);
+        return await Task.FromResult(1);
+    }
+}
+";
+            string src2 = @"
+using System;
+using System.Threading.Tasks;
+
+class C
+{
+    static async Task<int> F()
+    {
+        Console.WriteLine(2);
+        return await Task.FromResult(1);
+    }
+}
+";
+            var edits = GetTopEdits(src1, src2);
+            var active = GetActiveStatements(src1, src2);
+
+            edits.VerifySemanticDiagnostics();
+        }
+
+        [Fact]
+        public void IteratorMethodEdit_Semantics()
+        {
+            string src1 = @"
+using System;
+using System.Collections.Generic;
+
+class C
+{
+    static IEnumerable<int> F()
+    {
+        Console.WriteLine(1);
+        yield return 1;
+    }
+}
+";
+            string src2 = @"
+using System;
+using System.Collections.Generic;
+
+class C
+{
+    static IEnumerable<int> F()
+    {
+        Console.WriteLine(2);
+        yield return 2;
+    }
+}
+";
+            var edits = GetTopEdits(src1, src2);
+            var active = GetActiveStatements(src1, src2);
+
+            edits.VerifySemanticDiagnostics();
+        }
+
         #endregion
 
         #region Misplaced AS 
diff --git a/src/EditorFeatures/VisualBasicTest/EditAndContinue/ActiveStatementTests.vb b/src/EditorFeatures/VisualBasicTest/EditAndContinue/ActiveStatementTests.vb
index 14f8c38cf2e6e9af468e21e818fcd5a11e07ec85..030872158bf651c3411abcf9db773044878536fb 100644
--- a/src/EditorFeatures/VisualBasicTest/EditAndContinue/ActiveStatementTests.vb
+++ b/src/EditorFeatures/VisualBasicTest/EditAndContinue/ActiveStatementTests.vb
@@ -5143,6 +5143,60 @@ End Class
 
             edits.VerifyRudeDiagnostics(active)
         End Sub
+
+        <Fact>
+        Public Sub AsyncMethodEdit_Semantics()
+            Dim src1 = "
+Imports System
+Imports System.Threading.Tasks
+Class C
+    Async Function F() As Task(Of Integer)
+        Console.WriteLine(1)
+        Await Task.FromResult(1)
+    End Function
+End Class
+"
+            Dim src2 = "
+Imports System
+Imports System.Threading.Tasks
+Class C
+    Async Function F() As Task(Of Integer)
+        Console.WriteLine(2)
+        Await Task.FromResult(1)
+    End Function
+End Class
+"
+            Dim edits = GetTopEdits(src1, src2)
+
+            edits.VerifySemanticDiagnostics()
+        End Sub
+
+        <Fact>
+        Public Sub IteratorMethodEdit_Semantics()
+            Dim src1 = "
+Imports System
+Imports System.Collections.Generic
+Class C
+    Iterator Function F() As IEnumerable(Of Integer)
+        Console.WriteLine(1)
+        Yield 1
+    End Function
+End Class
+"
+            Dim src2 = "
+Imports System
+Imports System.Collections.Generic
+Class C
+    Iterator Function F() As IEnumerable(Of Integer)
+        Console.WriteLine(2)
+        Yield 1
+    End Function
+End Class
+"
+            Dim edits = GetTopEdits(src1, src2)
+
+            edits.VerifySemanticDiagnostics()
+        End Sub
 #End Region
 
 #Region "On Error"
diff --git a/src/Features/Core/Portable/EditAndContinue/AbstractEditAndContinueAnalyzer.cs b/src/Features/Core/Portable/EditAndContinue/AbstractEditAndContinueAnalyzer.cs
index 9d4657dd8155b257566feaf1b9dae97621b7a97d..245e6d7322627850e10209c388db5a54571275e2 100644
--- a/src/Features/Core/Portable/EditAndContinue/AbstractEditAndContinueAnalyzer.cs
+++ b/src/Features/Core/Portable/EditAndContinue/AbstractEditAndContinueAnalyzer.cs
@@ -2312,7 +2312,7 @@ public ConstructorEdit(INamedTypeSymbol oldType)
                             {
                                 var updatedMember = updatedMembers[updatedMemberIndex];
 
-                                ReportStateMachineRudeEdits(updatedMember, oldSymbol, diagnostics);
+                                ReportStateMachineRudeEdits(oldModel.Compilation, updatedMember, oldSymbol, diagnostics);
 
                                 bool newBodyHasLambdas;
                                 ReportLambdaAndClosureRudeEdits(
@@ -3703,6 +3703,7 @@ private bool AreEquivalentClosureScopes(SyntaxNode oldScopeOpt, SyntaxNode newSc
         #region State Machines
 
         private void ReportStateMachineRudeEdits(
+            Compilation oldCompilation,
             UpdatedMemberInfo updatedInfo, 
             ISymbol oldMember, 
             List<RudeEditDiagnostic> diagnostics)
@@ -3719,7 +3720,7 @@ private bool AreEquivalentClosureScopes(SyntaxNode oldScopeOpt, SyntaxNode newSc
 
             // We assume that the attributes, if exist, are well formed.
             // If not an error will be reported during EnC delta emit.
-            if (oldMember.ContainingAssembly.GetTypeByMetadataName(stateMachineAttributeQualifiedName) == null)
+            if (oldCompilation.GetTypeByMetadataName(stateMachineAttributeQualifiedName) == null)
             {
                 diagnostics.Add(new RudeEditDiagnostic(
                     RudeEditKind.UpdatingStateMachineMethodMissingAttribute,