diff --git a/src/Compilers/CSharp/Test/Emit/Emit/EditAndContinue/EditAndContinueClosureTests.cs b/src/Compilers/CSharp/Test/Emit/Emit/EditAndContinue/EditAndContinueClosureTests.cs
index 003401a3770ab..16def4e4ea2af 100644
--- a/src/Compilers/CSharp/Test/Emit/Emit/EditAndContinue/EditAndContinueClosureTests.cs
+++ b/src/Compilers/CSharp/Test/Emit/Emit/EditAndContinue/EditAndContinueClosureTests.cs
@@ -309,7 +309,7 @@ void F()
             CheckEncLogDefinitions(reader1,
                 Row(1, TableIndex.MethodDef, EditAndContinueOperation.Default),
                 Row(3, TableIndex.MethodDef, EditAndContinueOperation.Default),
-                Row(5, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
+                Row(4, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
         }
 
         [Fact]
@@ -362,7 +362,7 @@ void F()
             CheckEncLogDefinitions(reader1,
                 Row(1, TableIndex.MethodDef, EditAndContinueOperation.Default),
                 Row(3, TableIndex.MethodDef, EditAndContinueOperation.Default),
-                Row(5, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
+                Row(4, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
 
             var testData0 = new CompilationTestData();
             var bytes0 = compilation0.EmitToArray(testData: testData0);
@@ -477,7 +477,7 @@ void F<T>()
                 Row(2, TableIndex.StandAloneSig, EditAndContinueOperation.Default),
                 Row(1, TableIndex.MethodDef, EditAndContinueOperation.Default),
                 Row(3, TableIndex.MethodDef, EditAndContinueOperation.Default),
-                Row(5, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
+                Row(4, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
         }
 
         [Fact]
@@ -532,7 +532,7 @@ int F(int a)
                 Row(2, TableIndex.StandAloneSig, EditAndContinueOperation.Default),
                 Row(1, TableIndex.MethodDef, EditAndContinueOperation.Default),
                 Row(3, TableIndex.MethodDef, EditAndContinueOperation.Default),
-                Row(5, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
+                Row(4, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
         }
 
         [Fact]
@@ -586,7 +586,7 @@ int F(int a)
                 Row(2, TableIndex.StandAloneSig, EditAndContinueOperation.Default),
                 Row(1, TableIndex.MethodDef, EditAndContinueOperation.Default),
                 Row(3, TableIndex.MethodDef, EditAndContinueOperation.Default),
-                Row(5, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
+                Row(4, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
         }
 
         [Fact]
@@ -786,7 +786,7 @@ int F(int a)
                 Row(2, TableIndex.StandAloneSig, EditAndContinueOperation.Default),
                 Row(1, TableIndex.MethodDef, EditAndContinueOperation.Default),
                 Row(3, TableIndex.MethodDef, EditAndContinueOperation.Default),
-                Row(6, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
+                Row(4, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
         }
 
         [Fact]
@@ -1076,8 +1076,8 @@ void F()
                 Row(18, TableIndex.MethodDef, EditAndContinueOperation.Default),
                 Row(19, TableIndex.MethodDef, EditAndContinueOperation.Default),
                 Row(20, TableIndex.MethodDef, EditAndContinueOperation.Default),
-                Row(17, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                Row(18, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
+                Row(15, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                Row(16, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
         }
 
         [Fact]
@@ -1153,7 +1153,7 @@ void F()
                 Row(10, TableIndex.MethodDef, EditAndContinueOperation.Default),
                 Row(12, TableIndex.MethodDef, EditAndContinueOperation.Default),
                 Row(15, TableIndex.MethodDef, EditAndContinueOperation.Default),
-                Row(15, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
+                Row(14, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
         }
 
         [Fact]
@@ -1240,9 +1240,9 @@ public void F()
                 Row(8, TableIndex.MethodDef, EditAndContinueOperation.Default),
                 Row(10, TableIndex.MethodDef, EditAndContinueOperation.Default),
                 Row(12, TableIndex.MethodDef, EditAndContinueOperation.Default),
-                Row(10, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                Row(11, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                Row(12, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
+                Row(5, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                Row(7, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                Row(9, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
         }
 
         [Fact]
@@ -1322,7 +1322,7 @@ public void F()
                 Row(6, TableIndex.MethodDef, EditAndContinueOperation.Default),
                 Row(9, TableIndex.MethodDef, EditAndContinueOperation.Default),
                 Row(10, TableIndex.MethodDef, EditAndContinueOperation.Default),
-                Row(7, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
+                Row(5, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
         }
 
         [Fact]
@@ -1399,7 +1399,7 @@ public void F()
                 Row(4, TableIndex.MethodDef, EditAndContinueOperation.Default),
                 Row(6, TableIndex.MethodDef, EditAndContinueOperation.Default),
                 Row(9, TableIndex.MethodDef, EditAndContinueOperation.Default),
-                Row(7, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
+                Row(5, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
         }
 
         [Fact]
@@ -4002,7 +4002,7 @@ .maxstack  2
                 Row(2, TableIndex.StandAloneSig, EditAndContinueOperation.Default),
                 Row(1, TableIndex.MethodDef, EditAndContinueOperation.Default),
                 Row(3, TableIndex.MethodDef, EditAndContinueOperation.Default),
-                Row(7, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
+                Row(4, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
         }
 
         [Fact]
@@ -4087,7 +4087,7 @@ .maxstack  2
                 Row(2, TableIndex.StandAloneSig, EditAndContinueOperation.Default),
                 Row(1, TableIndex.MethodDef, EditAndContinueOperation.Default),
                 Row(3, TableIndex.MethodDef, EditAndContinueOperation.Default),
-                Row(6, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
+                Row(4, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
         }
 
         [Fact]
@@ -4160,7 +4160,7 @@ .maxstack  2
             CheckEncLogDefinitions(reader1,
                 Row(1, TableIndex.MethodDef, EditAndContinueOperation.Default),
                 Row(3, TableIndex.MethodDef, EditAndContinueOperation.Default),
-                Row(5, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
+                Row(4, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
         }
 
         [Fact]
diff --git a/src/Compilers/CSharp/Test/Emit/Emit/EditAndContinue/EditAndContinueStateMachineTests.cs b/src/Compilers/CSharp/Test/Emit/Emit/EditAndContinue/EditAndContinueStateMachineTests.cs
index 7dae6013bdcab..77d26eb3af244 100644
--- a/src/Compilers/CSharp/Test/Emit/Emit/EditAndContinue/EditAndContinueStateMachineTests.cs
+++ b/src/Compilers/CSharp/Test/Emit/Emit/EditAndContinue/EditAndContinueStateMachineTests.cs
@@ -536,9 +536,13 @@ static IEnumerable<int> F()
 
                 using (var md1 = diff1.GetMetadata())
                 {
+                    CheckAttributes(md1.Reader,
+                        new CustomAttributeRow(Handle(0, TableIndex.MethodDef), Handle(0, TableIndex.MemberRef)));  // row id 0 == delete
+
                     CheckEncLogDefinitions(md1.Reader,
                         Row(3, TableIndex.StandAloneSig, EditAndContinueOperation.Default),
-                        Row(1, TableIndex.MethodDef, EditAndContinueOperation.Default));
+                        Row(1, TableIndex.MethodDef, EditAndContinueOperation.Default),
+                        Row(1, TableIndex.CustomAttribute, EditAndContinueOperation.Default)); // Delete IteratorStateMachineAttribute
                 }
             }
         }
@@ -583,9 +587,15 @@ static Task<int> F()
 
                 using (var md1 = diff1.GetMetadata())
                 {
+                    CheckAttributes(md1.Reader,
+                        new CustomAttributeRow(Handle(0, TableIndex.MethodDef), Handle(0, TableIndex.MemberRef)),  // row id 0 == delete
+                        new CustomAttributeRow(Handle(0, TableIndex.MethodDef), Handle(0, TableIndex.MemberRef))); // row id 0 == delete
+
                     CheckEncLogDefinitions(md1.Reader,
                         Row(3, TableIndex.StandAloneSig, EditAndContinueOperation.Default),
-                        Row(1, TableIndex.MethodDef, EditAndContinueOperation.Default));
+                        Row(1, TableIndex.MethodDef, EditAndContinueOperation.Default),
+                        Row(1, TableIndex.CustomAttribute, EditAndContinueOperation.Default),  // Delete AsyncStateMachineAttribute
+                        Row(2, TableIndex.CustomAttribute, EditAndContinueOperation.Default));  // Delete DebuggerStepThroughAttribute
                 }
             }
         }
@@ -674,12 +684,12 @@ static async Task<int> F(int a)
                         Row(6, TableIndex.MethodDef, EditAndContinueOperation.Default),
                         Row(9, TableIndex.MethodDef, EditAndContinueOperation.Default),
                         Row(12, TableIndex.MethodDef, EditAndContinueOperation.Default),
-                        Row(16, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                        Row(17, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                        Row(18, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                        Row(19, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                        Row(20, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                        Row(21, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
+                        Row(1, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                        Row(2, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                        Row(6, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                        Row(7, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                        Row(8, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                        Row(9, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
                 }
             }
         }
@@ -738,8 +748,8 @@ static IEnumerable<int> F()
                         Row(1, TableIndex.MethodDef, EditAndContinueOperation.Default),
                         Row(4, TableIndex.MethodDef, EditAndContinueOperation.Default),
                         Row(5, TableIndex.MethodDef, EditAndContinueOperation.Default),
-                        Row(13, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                        Row(14, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
+                        Row(1, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                        Row(7, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
 
                     diff1.VerifyIL("C.<F>d__0.System.Collections.IEnumerator.MoveNext", @"
 {
@@ -875,8 +885,8 @@ static async Task<int> F()
                         Row(4, TableIndex.StandAloneSig, EditAndContinueOperation.Default),
                         Row(1, TableIndex.MethodDef, EditAndContinueOperation.Default),
                         Row(4, TableIndex.MethodDef, EditAndContinueOperation.Default),
-                        Row(8, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                        Row(9, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
+                        Row(1, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                        Row(2, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
 
                     diff1.VerifyIL("C.<F>d__0.System.Runtime.CompilerServices.IAsyncStateMachine.MoveNext", @"
 {
@@ -1146,8 +1156,8 @@ static IEnumerable<int> F(int p)
                         Row(1, TableIndex.MethodDef, EditAndContinueOperation.Default),
                         Row(4, TableIndex.MethodDef, EditAndContinueOperation.Default),
                         Row(5, TableIndex.MethodDef, EditAndContinueOperation.Default),
-                        Row(13, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                        Row(14, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
+                        Row(1, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                        Row(7, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
 
                     diff1.VerifyIL("C.<F>d__0.System.Collections.IEnumerator.MoveNext", @"
 {
@@ -1250,8 +1260,8 @@ static IEnumerable<int> F(int p)
                         Row(1, TableIndex.MethodDef, EditAndContinueOperation.Default),
                         Row(4, TableIndex.MethodDef, EditAndContinueOperation.Default),
                         Row(5, TableIndex.MethodDef, EditAndContinueOperation.Default),
-                        Row(13, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                        Row(14, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
+                        Row(1, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                        Row(7, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
 
                     diff1.VerifyIL("C.<F>d__0.System.Collections.IEnumerator.MoveNext", @"
 {
@@ -1361,8 +1371,8 @@ static IEnumerable<int> F(int p)
                         Row(1, TableIndex.MethodDef, EditAndContinueOperation.Default),
                         Row(4, TableIndex.MethodDef, EditAndContinueOperation.Default),
                         Row(5, TableIndex.MethodDef, EditAndContinueOperation.Default),
-                        Row(13, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                        Row(14, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
+                        Row(1, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                        Row(7, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
 
                     diff1.VerifyIL("C.<F>d__0.System.Collections.IEnumerator.MoveNext", @"
 {
@@ -1469,8 +1479,8 @@ static IEnumerable<int> F()
                         Row(1, TableIndex.MethodDef, EditAndContinueOperation.Default),
                         Row(4, TableIndex.MethodDef, EditAndContinueOperation.Default),
                         Row(5, TableIndex.MethodDef, EditAndContinueOperation.Default),
-                        Row(13, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                        Row(14, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
+                        Row(1, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                        Row(7, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
 
                     diff1.VerifyIL("C.<F>d__0.System.Collections.IEnumerator.MoveNext", @"
 {
@@ -1586,8 +1596,8 @@ static IEnumerable<int> F()
                         Row(1, TableIndex.MethodDef, EditAndContinueOperation.Default),
                         Row(4, TableIndex.MethodDef, EditAndContinueOperation.Default),
                         Row(5, TableIndex.MethodDef, EditAndContinueOperation.Default),
-                        Row(13, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                        Row(14, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
+                        Row(1, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                        Row(7, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
 
                     diff1.VerifyIL("C.<F>d__0.System.Collections.IEnumerator.MoveNext", @"
 {
@@ -1879,10 +1889,10 @@ static async Task<int> H() // updated
                 Row(2, TableIndex.MethodDef, EditAndContinueOperation.Default),
                 Row(6, TableIndex.MethodDef, EditAndContinueOperation.Default),
                 Row(9, TableIndex.MethodDef, EditAndContinueOperation.Default),
-                Row(16, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                Row(17, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                Row(18, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                Row(19, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
+                Row(1, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                Row(2, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                Row(6, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                Row(7, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
 
             diff1.VerifyIL("C.<F>d__0.System.Runtime.CompilerServices.IAsyncStateMachine.MoveNext", @"
 {
@@ -1990,8 +2000,8 @@ .locals init (int V_0,
                 Row(18, TableIndex.Field, EditAndContinueOperation.Default),
                 Row(1, TableIndex.MethodDef, EditAndContinueOperation.Default),
                 Row(6, TableIndex.MethodDef, EditAndContinueOperation.Default),
-                Row(20, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                Row(21, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
+                Row(1, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                Row(2, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
 
             diff2.VerifyIL("C.<F>d__0.System.Runtime.CompilerServices.IAsyncStateMachine.MoveNext", @"
 {
@@ -2103,10 +2113,10 @@ .locals init (int V_0,
                 Row(3, TableIndex.MethodDef, EditAndContinueOperation.Default),
                 Row(9, TableIndex.MethodDef, EditAndContinueOperation.Default),
                 Row(12, TableIndex.MethodDef, EditAndContinueOperation.Default),
-                Row(22, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                Row(23, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                Row(24, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                Row(25, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
+                Row(6, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                Row(7, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                Row(8, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                Row(9, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
         }
 
         [Fact]
@@ -2626,10 +2636,10 @@ static async Task<int> H() // updated
                 Row(5, TableIndex.MethodDef, EditAndContinueOperation.Default),
                 Row(9, TableIndex.MethodDef, EditAndContinueOperation.Default),
                 Row(12, TableIndex.MethodDef, EditAndContinueOperation.Default),
-                Row(16, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                Row(17, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                Row(18, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                Row(19, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
+                Row(5, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                Row(6, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                Row(8, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                Row(9, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
 
             // Note that the new awaiter is allocated slot <>u__3 since <>u__1 and <>u__2 are taken.
             diff1.VerifyIL("C.<F>d__3.System.Runtime.CompilerServices.IAsyncStateMachine.MoveNext", @"
@@ -2766,8 +2776,8 @@ .locals init (int V_0,
                 Row(12, TableIndex.Field, EditAndContinueOperation.Default),
                 Row(4, TableIndex.MethodDef, EditAndContinueOperation.Default),
                 Row(9, TableIndex.MethodDef, EditAndContinueOperation.Default),
-                Row(20, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                Row(21, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
+                Row(5, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                Row(6, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
 
             // Note that the new awaiters are allocated slots <>u__4, <>u__5.
             diff2.VerifyIL("C.<F>d__3.System.Runtime.CompilerServices.IAsyncStateMachine.MoveNext", @"
@@ -2910,10 +2920,10 @@ .locals init (int V_0,
                 Row(6, TableIndex.MethodDef, EditAndContinueOperation.Default),
                 Row(12, TableIndex.MethodDef, EditAndContinueOperation.Default),
                 Row(15, TableIndex.MethodDef, EditAndContinueOperation.Default),
-                Row(22, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                Row(23, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                Row(24, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                Row(25, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
+                Row(8, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                Row(9, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                Row(11, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                Row(12, TableIndex.CustomAttribute, EditAndContinueOperation.Default));
         }
 
         [Fact]
diff --git a/src/Compilers/CSharp/Test/Emit/Emit/EditAndContinue/EditAndContinueTests.cs b/src/Compilers/CSharp/Test/Emit/Emit/EditAndContinue/EditAndContinueTests.cs
index 0652a0d96bc13..3a6e5142eb10f 100644
--- a/src/Compilers/CSharp/Test/Emit/Emit/EditAndContinue/EditAndContinueTests.cs
+++ b/src/Compilers/CSharp/Test/Emit/Emit/EditAndContinue/EditAndContinueTests.cs
@@ -359,6 +359,692 @@ static void Main() { }
                 Handle(2, TableIndex.AssemblyRef));
         }
 
+        [Fact]
+        public void ModifyMethod_WithAttributes1()
+        {
+            var source0 =
+@"class C
+{
+    static void Main() { }
+    [System.ComponentModel.Description(""The F method"")]
+    static string F() { return null; }
+}";
+            var source1 =
+@"class C
+{
+    static void Main() { }
+    [System.ComponentModel.Description(""The F method"")]
+    static string F() { return string.Empty; }
+}";
+            var source2 =
+@"[System.ComponentModel.Browsable(false)]
+class C
+{
+    static void Main() { }
+    [System.ComponentModel.Description(""The F method""), System.ComponentModel.Category(""Methods"")]
+    static string F() { return string.Empty; }
+}";
+            var source3 =
+@"[System.ComponentModel.Browsable(false)]
+class C
+{
+    static void Main() { }
+    [System.ComponentModel.Browsable(false), System.ComponentModel.Description(""The F method""), System.ComponentModel.Category(""Methods"")]
+    static string F() { return string.Empty; }
+}";
+
+            var compilation0 = CreateCompilation(source0, options: TestOptions.DebugExe, targetFramework: TargetFramework.NetStandard20);
+            var compilation1 = compilation0.WithSource(source1);
+            var compilation2 = compilation1.WithSource(source2);
+            var compilation3 = compilation2.WithSource(source3);
+
+            var method0 = compilation0.GetMember<MethodSymbol>("C.F");
+
+            // Verify full metadata contains expected rows.
+            var bytes0 = compilation0.EmitToArray();
+            using var md0 = ModuleMetadata.CreateFromImage(bytes0);
+            var reader0 = md0.MetadataReader;
+
+            CheckNames(reader0, reader0.GetTypeDefNames(), "<Module>", "C");
+            CheckNames(reader0, reader0.GetMethodDefNames(), "Main", "F", ".ctor");
+            CheckNames(reader0, reader0.GetMemberRefNames(), /*CompilationRelaxationsAttribute.*/".ctor", /*RuntimeCompatibilityAttribute.*/".ctor", /*Object.*/".ctor", /*DebuggableAttribute*/".ctor", /*DescriptionAttribute*/".ctor");
+
+            Assert.Equal(4, reader0.CustomAttributes.Count);
+
+            var generation0 = EmitBaseline.CreateInitialBaseline(
+                md0,
+                EmptyLocalsProvider);
+            var method1 = compilation1.GetMember<MethodSymbol>("C.F");
+
+            var diff1 = compilation1.EmitDifference(
+                generation0,
+                ImmutableArray.Create(SemanticEdit.Create(SemanticEditKind.Update, method0, method1)));
+
+            // Verify delta metadata contains expected rows.
+            using var md1 = diff1.GetMetadata();
+            var reader1 = md1.Reader;
+            var readers = new[] { reader0, reader1 };
+
+            EncValidation.VerifyModuleMvid(1, reader0, reader1);
+
+            CheckNames(readers, reader1.GetTypeDefNames());
+            CheckNames(readers, reader1.GetMethodDefNames(), "F");
+            CheckNames(readers, reader1.GetMemberRefNames(), /*DescriptionAttribute*/".ctor", /*String.*/"Empty");
+
+            Assert.Equal(1, reader1.CustomAttributes.Count);
+
+            CheckEncLog(reader1,
+                Row(2, TableIndex.AssemblyRef, EditAndContinueOperation.Default),
+                Row(6, TableIndex.MemberRef, EditAndContinueOperation.Default),
+                Row(7, TableIndex.MemberRef, EditAndContinueOperation.Default),
+                Row(7, TableIndex.TypeRef, EditAndContinueOperation.Default),
+                Row(8, TableIndex.TypeRef, EditAndContinueOperation.Default),
+                Row(9, TableIndex.TypeRef, EditAndContinueOperation.Default),
+                Row(2, TableIndex.StandAloneSig, EditAndContinueOperation.Default),
+                Row(2, TableIndex.MethodDef, EditAndContinueOperation.Default),
+                Row(4, TableIndex.CustomAttribute, EditAndContinueOperation.Default)); // Row 4, so updating existing CustomAttribute
+
+            CheckEncMap(reader1,
+                Handle(7, TableIndex.TypeRef),
+                Handle(8, TableIndex.TypeRef),
+                Handle(9, TableIndex.TypeRef),
+                Handle(2, TableIndex.MethodDef),
+                Handle(6, TableIndex.MemberRef),
+                Handle(7, TableIndex.MemberRef),
+                Handle(4, TableIndex.CustomAttribute),
+                Handle(2, TableIndex.StandAloneSig),
+                Handle(2, TableIndex.AssemblyRef));
+
+            var method2 = compilation2.GetMember<MethodSymbol>("C.F");
+            var diff2 = compilation2.EmitDifference(
+                diff1.NextGeneration,
+                ImmutableArray.Create(
+                    SemanticEdit.Create(SemanticEditKind.Update, compilation1.GetMember("C"), compilation2.GetMember("C")),
+                    SemanticEdit.Create(SemanticEditKind.Update, method1, method2)));
+
+            // Verify delta metadata contains expected rows.
+            using var md2 = diff2.GetMetadata();
+            var reader2 = md2.Reader;
+            readers = new[] { reader0, reader1, reader2 };
+
+            CheckNames(readers, reader2.GetTypeDefNames(), "C");
+            CheckNames(readers, reader2.GetMethodDefNames(), "F");
+            CheckNames(readers, reader2.GetMemberRefNames(), /*DescriptionAttribute*/".ctor", /*BrowsableAttribute*/".ctor", /*CategoryAttribute*/".ctor", /*String.*/"Empty");
+
+            Assert.Equal(3, reader2.CustomAttributes.Count);
+
+            CheckEncLog(reader2,
+                Row(3, TableIndex.AssemblyRef, EditAndContinueOperation.Default),
+                Row(8, TableIndex.MemberRef, EditAndContinueOperation.Default),
+                Row(9, TableIndex.MemberRef, EditAndContinueOperation.Default),
+                Row(10, TableIndex.MemberRef, EditAndContinueOperation.Default),
+                Row(11, TableIndex.MemberRef, EditAndContinueOperation.Default),
+                Row(10, TableIndex.TypeRef, EditAndContinueOperation.Default),
+                Row(11, TableIndex.TypeRef, EditAndContinueOperation.Default),
+                Row(12, TableIndex.TypeRef, EditAndContinueOperation.Default),
+                Row(13, TableIndex.TypeRef, EditAndContinueOperation.Default),
+                Row(14, TableIndex.TypeRef, EditAndContinueOperation.Default),
+                Row(3, TableIndex.StandAloneSig, EditAndContinueOperation.Default),
+                Row(2, TableIndex.TypeDef, EditAndContinueOperation.Default),
+                Row(2, TableIndex.MethodDef, EditAndContinueOperation.Default),
+                Row(4, TableIndex.CustomAttribute, EditAndContinueOperation.Default),  // Row 4, updating the existing custom attribute
+                Row(5, TableIndex.CustomAttribute, EditAndContinueOperation.Default),  // Row 5, adding a new CustomAttribute
+                Row(6, TableIndex.CustomAttribute, EditAndContinueOperation.Default)); // Row 6 adding a new CustomAttribute
+
+            CheckEncMap(reader2,
+                Handle(10, TableIndex.TypeRef),
+                Handle(11, TableIndex.TypeRef),
+                Handle(12, TableIndex.TypeRef),
+                Handle(13, TableIndex.TypeRef),
+                Handle(14, TableIndex.TypeRef),
+                Handle(2, TableIndex.TypeDef),
+                Handle(2, TableIndex.MethodDef),
+                Handle(8, TableIndex.MemberRef),
+                Handle(9, TableIndex.MemberRef),
+                Handle(10, TableIndex.MemberRef),
+                Handle(11, TableIndex.MemberRef),
+                Handle(4, TableIndex.CustomAttribute),
+                Handle(5, TableIndex.CustomAttribute),
+                Handle(6, TableIndex.CustomAttribute),
+                Handle(3, TableIndex.StandAloneSig),
+                Handle(3, TableIndex.AssemblyRef));
+
+            var method3 = compilation3.GetMember<MethodSymbol>("C.F");
+            var diff3 = compilation3.EmitDifference(
+                diff2.NextGeneration,
+                ImmutableArray.Create(SemanticEdit.Create(SemanticEditKind.Update, method2, method3)));
+
+            // Verify delta metadata contains expected rows.
+            using var md3 = diff3.GetMetadata();
+            var reader3 = md3.Reader;
+            readers = new[] { reader0, reader1, reader2, reader3 };
+
+            CheckNames(readers, reader3.GetTypeDefNames());
+            CheckNames(readers, reader3.GetMethodDefNames(), "F");
+            CheckNames(readers, reader3.GetMemberRefNames(), /*BrowsableAttribute*/".ctor", /*DescriptionAttribute*/".ctor", /*CategoryAttribute*/".ctor", /*String.*/"Empty");
+
+            CheckEncLog(reader3,
+                Row(4, TableIndex.AssemblyRef, EditAndContinueOperation.Default),
+                Row(12, TableIndex.MemberRef, EditAndContinueOperation.Default),
+                Row(13, TableIndex.MemberRef, EditAndContinueOperation.Default),
+                Row(14, TableIndex.MemberRef, EditAndContinueOperation.Default),
+                Row(15, TableIndex.MemberRef, EditAndContinueOperation.Default),
+                Row(15, TableIndex.TypeRef, EditAndContinueOperation.Default),
+                Row(16, TableIndex.TypeRef, EditAndContinueOperation.Default),
+                Row(17, TableIndex.TypeRef, EditAndContinueOperation.Default),
+                Row(18, TableIndex.TypeRef, EditAndContinueOperation.Default),
+                Row(19, TableIndex.TypeRef, EditAndContinueOperation.Default),
+                Row(4, TableIndex.StandAloneSig, EditAndContinueOperation.Default),
+                Row(2, TableIndex.MethodDef, EditAndContinueOperation.Default),
+                Row(4, TableIndex.CustomAttribute, EditAndContinueOperation.Default), // Row 4, updating the existing custom attribute
+                Row(5, TableIndex.CustomAttribute, EditAndContinueOperation.Default), // Row 5, updating a row that was new in Generation 2
+                Row(7, TableIndex.CustomAttribute, EditAndContinueOperation.Default)); // Row 7, adding a new CustomAttribute, and skipping row 6 which is not for the method being emitted
+
+            CheckEncMap(reader3,
+                Handle(15, TableIndex.TypeRef),
+                Handle(16, TableIndex.TypeRef),
+                Handle(17, TableIndex.TypeRef),
+                Handle(18, TableIndex.TypeRef),
+                Handle(19, TableIndex.TypeRef),
+                Handle(2, TableIndex.MethodDef),
+                Handle(12, TableIndex.MemberRef),
+                Handle(13, TableIndex.MemberRef),
+                Handle(14, TableIndex.MemberRef),
+                Handle(15, TableIndex.MemberRef),
+                Handle(4, TableIndex.CustomAttribute),
+                Handle(5, TableIndex.CustomAttribute),
+                Handle(7, TableIndex.CustomAttribute),
+                Handle(4, TableIndex.StandAloneSig),
+                Handle(4, TableIndex.AssemblyRef));
+        }
+
+        [Fact]
+        public void ModifyMethod_WithAttributes2()
+        {
+            var source0 =
+@"[System.ComponentModel.Browsable(false)]
+class C
+{
+    static void Main() { }
+    [System.ComponentModel.Description(""The F method"")]
+    static string F() { return null; }
+}
+[System.ComponentModel.Browsable(false)]
+class D
+{
+    [System.ComponentModel.Description(""A"")]
+    static string A() { return null; }
+}
+";
+            var source1 =
+@"
+[System.ComponentModel.Browsable(false)]
+class C
+{
+    static void Main() { }
+    [System.ComponentModel.Description(""The F method""), System.ComponentModel.Browsable(false), System.ComponentModel.Category(""Methods"")]
+    static string F() { return null; }
+}
+[System.ComponentModel.Browsable(false)]
+class D
+{
+    [System.ComponentModel.Description(""A""), System.ComponentModel.Category(""Methods"")]
+    static string A() { return null; }
+}
+";
+
+            var compilation0 = CreateCompilation(source0, options: TestOptions.DebugExe, targetFramework: TargetFramework.NetStandard20);
+            var compilation1 = compilation0.WithSource(source1);
+
+            var method0_1 = compilation0.GetMember<MethodSymbol>("C.F");
+            var method0_2 = compilation0.GetMember<MethodSymbol>("D.A");
+
+            // Verify full metadata contains expected rows.
+            var bytes0 = compilation0.EmitToArray();
+            using var md0 = ModuleMetadata.CreateFromImage(bytes0);
+            var reader0 = md0.MetadataReader;
+
+            CheckNames(reader0, reader0.GetTypeDefNames(), "<Module>", "C", "D");
+            CheckNames(reader0, reader0.GetMethodDefNames(), "Main", "F", ".ctor", "A", ".ctor");
+            CheckNames(reader0, reader0.GetMemberRefNames(), /*CompilationRelaxationsAttribute.*/".ctor", /*RuntimeCompatibilityAttribute.*/".ctor", /*Object.*/".ctor", /*DebuggableAttribute*/".ctor", /*DescriptionAttribute*/".ctor", /*BrowsableAttribute*/".ctor");
+
+            CheckAttributes(reader0,
+                new CustomAttributeRow(Handle(1, TableIndex.Assembly), Handle(1, TableIndex.MemberRef)),
+                new CustomAttributeRow(Handle(1, TableIndex.Assembly), Handle(2, TableIndex.MemberRef)),
+                new CustomAttributeRow(Handle(1, TableIndex.Assembly), Handle(3, TableIndex.MemberRef)),
+                new CustomAttributeRow(Handle(2, TableIndex.MethodDef), Handle(5, TableIndex.MemberRef)),
+                new CustomAttributeRow(Handle(2, TableIndex.TypeDef), Handle(4, TableIndex.MemberRef)),
+                new CustomAttributeRow(Handle(3, TableIndex.TypeDef), Handle(4, TableIndex.MemberRef)),
+                new CustomAttributeRow(Handle(4, TableIndex.MethodDef), Handle(5, TableIndex.MemberRef)));
+
+            var generation0 = EmitBaseline.CreateInitialBaseline(
+                md0,
+                EmptyLocalsProvider);
+            var method1_1 = compilation1.GetMember<MethodSymbol>("C.F");
+            var method1_2 = compilation1.GetMember<MethodSymbol>("D.A");
+
+            var diff1 = compilation1.EmitDifference(
+                generation0,
+                ImmutableArray.Create(
+                    SemanticEdit.Create(SemanticEditKind.Update, method0_1, method1_1),
+                    SemanticEdit.Create(SemanticEditKind.Update, method0_2, method1_2)));
+
+            // Verify delta metadata contains expected rows.
+            using var md1 = diff1.GetMetadata();
+            var reader1 = md1.Reader;
+            var readers = new[] { reader0, reader1 };
+
+            EncValidation.VerifyModuleMvid(1, reader0, reader1);
+
+            CheckNames(readers, reader1.GetTypeDefNames());
+            CheckNames(readers, reader1.GetMethodDefNames(), "F", "A");
+            CheckNames(readers, reader1.GetMemberRefNames(), /*BrowsableAttribute*/".ctor", /*CategoryAttribute*/".ctor", /*DescriptionAttribute*/".ctor");
+
+            CheckAttributes(reader1,
+                new CustomAttributeRow(Handle(2, TableIndex.MethodDef), Handle(8, TableIndex.MemberRef)),
+                new CustomAttributeRow(Handle(2, TableIndex.MethodDef), Handle(7, TableIndex.MemberRef)),
+                new CustomAttributeRow(Handle(2, TableIndex.MethodDef), Handle(9, TableIndex.MemberRef)),
+                new CustomAttributeRow(Handle(4, TableIndex.MethodDef), Handle(8, TableIndex.MemberRef)),
+                new CustomAttributeRow(Handle(4, TableIndex.MethodDef), Handle(9, TableIndex.MemberRef)));
+
+            CheckEncLog(reader1,
+                Row(2, TableIndex.AssemblyRef, EditAndContinueOperation.Default),
+                Row(7, TableIndex.MemberRef, EditAndContinueOperation.Default),
+                Row(8, TableIndex.MemberRef, EditAndContinueOperation.Default),
+                Row(9, TableIndex.MemberRef, EditAndContinueOperation.Default),
+                Row(8, TableIndex.TypeRef, EditAndContinueOperation.Default),
+                Row(9, TableIndex.TypeRef, EditAndContinueOperation.Default),
+                Row(10, TableIndex.TypeRef, EditAndContinueOperation.Default),
+                Row(11, TableIndex.TypeRef, EditAndContinueOperation.Default),
+                Row(2, TableIndex.StandAloneSig, EditAndContinueOperation.Default),
+                Row(2, TableIndex.MethodDef, EditAndContinueOperation.Default),
+                Row(4, TableIndex.MethodDef, EditAndContinueOperation.Default),
+                Row(4, TableIndex.CustomAttribute, EditAndContinueOperation.Default),    // update existing row
+                Row(8, TableIndex.CustomAttribute, EditAndContinueOperation.Default),    // add new row
+                Row(9, TableIndex.CustomAttribute, EditAndContinueOperation.Default),    // add new row
+                Row(7, TableIndex.CustomAttribute, EditAndContinueOperation.Default),    // update existing row
+                Row(10, TableIndex.CustomAttribute, EditAndContinueOperation.Default));  // add new row
+
+            CheckEncMap(reader1,
+                Handle(8, TableIndex.TypeRef),
+                Handle(9, TableIndex.TypeRef),
+                Handle(10, TableIndex.TypeRef),
+                Handle(11, TableIndex.TypeRef),
+                Handle(2, TableIndex.MethodDef),
+                Handle(4, TableIndex.MethodDef),
+                Handle(7, TableIndex.MemberRef),
+                Handle(8, TableIndex.MemberRef),
+                Handle(9, TableIndex.MemberRef),
+                Handle(4, TableIndex.CustomAttribute),
+                Handle(7, TableIndex.CustomAttribute),
+                Handle(8, TableIndex.CustomAttribute),
+                Handle(9, TableIndex.CustomAttribute),
+                Handle(10, TableIndex.CustomAttribute),
+                Handle(2, TableIndex.StandAloneSig),
+                Handle(2, TableIndex.AssemblyRef));
+        }
+
+        [Fact]
+        public void ModifyMethod_DeleteAttributes1()
+        {
+            var source0 =
+@"class C
+{
+    static void Main() { }
+    [System.ComponentModel.Description(""The F method"")]
+    static string F() { return null; }
+}";
+            var source1 =
+@"class C
+{
+    static void Main() { }
+    static string F() { return string.Empty; }
+}";
+            var source2 =
+@"class C
+{
+    static void Main() { }
+    [System.ComponentModel.Description(""The F method"")]
+    static string F() { return string.Empty; }
+}";
+
+            var compilation0 = CreateCompilation(source0, options: TestOptions.DebugExe, targetFramework: TargetFramework.NetStandard20);
+            var compilation1 = compilation0.WithSource(source1);
+            var compilation2 = compilation1.WithSource(source2);
+
+            var method0 = compilation0.GetMember<MethodSymbol>("C.F");
+
+            // Verify full metadata contains expected rows.
+            var bytes0 = compilation0.EmitToArray();
+            using var md0 = ModuleMetadata.CreateFromImage(bytes0);
+            var reader0 = md0.MetadataReader;
+
+            CheckNames(reader0, reader0.GetTypeDefNames(), "<Module>", "C");
+            CheckNames(reader0, reader0.GetMethodDefNames(), "Main", "F", ".ctor");
+            CheckNames(reader0, reader0.GetMemberRefNames(), /*CompilationRelaxationsAttribute.*/".ctor", /*RuntimeCompatibilityAttribute.*/".ctor", /*Object.*/".ctor", /*DebuggableAttribute*/".ctor", /*DescriptionAttribute*/".ctor");
+
+            CheckAttributes(reader0,
+                new CustomAttributeRow(Handle(1, TableIndex.Assembly), Handle(1, TableIndex.MemberRef)),
+                new CustomAttributeRow(Handle(1, TableIndex.Assembly), Handle(2, TableIndex.MemberRef)),
+                new CustomAttributeRow(Handle(1, TableIndex.Assembly), Handle(3, TableIndex.MemberRef)),
+                new CustomAttributeRow(Handle(2, TableIndex.MethodDef), Handle(4, TableIndex.MemberRef)));
+
+            var generation0 = EmitBaseline.CreateInitialBaseline(
+                md0,
+                EmptyLocalsProvider);
+            var method1 = compilation1.GetMember<MethodSymbol>("C.F");
+
+            var diff1 = compilation1.EmitDifference(
+                generation0,
+                ImmutableArray.Create(SemanticEdit.Create(SemanticEditKind.Update, method0, method1)));
+
+            // Verify delta metadata contains expected rows.
+            using var md1 = diff1.GetMetadata();
+            var reader1 = md1.Reader;
+            var readers = new[] { reader0, reader1 };
+
+            EncValidation.VerifyModuleMvid(1, reader0, reader1);
+
+            CheckNames(readers, reader1.GetTypeDefNames());
+            CheckNames(readers, reader1.GetMethodDefNames(), "F");
+            CheckNames(readers, reader1.GetMemberRefNames(), /*String.*/"Empty");
+
+            CheckAttributes(reader1,
+                new CustomAttributeRow(Handle(0, TableIndex.MethodDef), Handle(0, TableIndex.MemberRef)));  // Parent row id is 0, signifying a delete
+
+            CheckEncLog(reader1,
+                Row(2, TableIndex.AssemblyRef, EditAndContinueOperation.Default),
+                Row(6, TableIndex.MemberRef, EditAndContinueOperation.Default),
+                Row(7, TableIndex.TypeRef, EditAndContinueOperation.Default),
+                Row(8, TableIndex.TypeRef, EditAndContinueOperation.Default),
+                Row(2, TableIndex.StandAloneSig, EditAndContinueOperation.Default),
+                Row(2, TableIndex.MethodDef, EditAndContinueOperation.Default),
+                Row(4, TableIndex.CustomAttribute, EditAndContinueOperation.Default)); // Row 4, so updating existing CustomAttribute
+
+            CheckEncMap(reader1,
+                Handle(7, TableIndex.TypeRef),
+                Handle(8, TableIndex.TypeRef),
+                Handle(2, TableIndex.MethodDef),
+                Handle(6, TableIndex.MemberRef),
+                Handle(4, TableIndex.CustomAttribute),
+                Handle(2, TableIndex.StandAloneSig),
+                Handle(2, TableIndex.AssemblyRef));
+
+            var method2 = compilation2.GetMember<MethodSymbol>("C.F");
+            var diff2 = compilation2.EmitDifference(
+                diff1.NextGeneration,
+                ImmutableArray.Create(SemanticEdit.Create(SemanticEditKind.Update, method1, method2)));
+
+            // Verify delta metadata contains expected rows.
+            using var md2 = diff2.GetMetadata();
+            var reader2 = md2.Reader;
+            readers = new[] { reader0, reader1, reader2 };
+
+            EncValidation.VerifyModuleMvid(2, reader1, reader2);
+
+            CheckNames(readers, reader2.GetTypeDefNames());
+            CheckNames(readers, reader2.GetMethodDefNames(), "F");
+            CheckNames(readers, reader2.GetMemberRefNames(), /*DescriptionAttribute*/".ctor", /*String.*/"Empty");
+
+            CheckAttributes(reader2,
+                new CustomAttributeRow(Handle(2, TableIndex.MethodDef), Handle(7, TableIndex.MemberRef)));
+
+            CheckEncLog(reader2,
+                Row(3, TableIndex.AssemblyRef, EditAndContinueOperation.Default),
+                Row(7, TableIndex.MemberRef, EditAndContinueOperation.Default),
+                Row(8, TableIndex.MemberRef, EditAndContinueOperation.Default),
+                Row(9, TableIndex.TypeRef, EditAndContinueOperation.Default),
+                Row(10, TableIndex.TypeRef, EditAndContinueOperation.Default),
+                Row(11, TableIndex.TypeRef, EditAndContinueOperation.Default),
+                Row(3, TableIndex.StandAloneSig, EditAndContinueOperation.Default),
+                Row(2, TableIndex.MethodDef, EditAndContinueOperation.Default),
+                Row(4, TableIndex.CustomAttribute, EditAndContinueOperation.Default)); // Row 4, updating the original row back to a real one
+
+            CheckEncMap(reader2,
+                Handle(9, TableIndex.TypeRef),
+                Handle(10, TableIndex.TypeRef),
+                Handle(11, TableIndex.TypeRef),
+                Handle(2, TableIndex.MethodDef),
+                Handle(7, TableIndex.MemberRef),
+                Handle(8, TableIndex.MemberRef),
+                Handle(4, TableIndex.CustomAttribute),
+                Handle(3, TableIndex.StandAloneSig),
+                Handle(3, TableIndex.AssemblyRef));
+        }
+
+        [Fact]
+        public void ModifyMethod_DeleteAttributes2()
+        {
+            var source0 =
+@"class C
+{
+    static void Main() { }
+    static string F() { return null; }
+}";
+            var source1 =
+@"class C
+{
+    static void Main() { }
+    [System.ComponentModel.Description(""The F method"")]
+    static string F() { return string.Empty; }
+}";
+            var source2 = source0; // Remove the attribute we just added
+            var source3 = source1; // Add the attribute back again
+
+            var compilation0 = CreateCompilation(source0, options: TestOptions.DebugExe, targetFramework: TargetFramework.NetStandard20);
+            var compilation1 = compilation0.WithSource(source1);
+            var compilation2 = compilation1.WithSource(source2);
+            var compilation3 = compilation1.WithSource(source3);
+
+            var method0 = compilation0.GetMember<MethodSymbol>("C.F");
+
+            // Verify full metadata contains expected rows.
+            var bytes0 = compilation0.EmitToArray();
+            using var md0 = ModuleMetadata.CreateFromImage(bytes0);
+            var reader0 = md0.MetadataReader;
+
+            CheckNames(reader0, reader0.GetTypeDefNames(), "<Module>", "C");
+            CheckNames(reader0, reader0.GetMethodDefNames(), "Main", "F", ".ctor");
+            CheckNames(reader0, reader0.GetMemberRefNames(), /*CompilationRelaxationsAttribute.*/".ctor", /*RuntimeCompatibilityAttribute.*/".ctor", /*Object.*/".ctor", /*DebuggableAttribute*/".ctor");
+
+            CheckAttributes(reader0,
+                new CustomAttributeRow(Handle(1, TableIndex.Assembly), Handle(1, TableIndex.MemberRef)),
+                new CustomAttributeRow(Handle(1, TableIndex.Assembly), Handle(2, TableIndex.MemberRef)),
+                new CustomAttributeRow(Handle(1, TableIndex.Assembly), Handle(3, TableIndex.MemberRef)));
+
+            var generation0 = EmitBaseline.CreateInitialBaseline(
+                md0,
+                EmptyLocalsProvider);
+            var method1 = compilation1.GetMember<MethodSymbol>("C.F");
+
+            var diff1 = compilation1.EmitDifference(
+                generation0,
+                ImmutableArray.Create(SemanticEdit.Create(SemanticEditKind.Update, method0, method1)));
+
+            // Verify delta metadata contains expected rows.
+            using var md1 = diff1.GetMetadata();
+            var reader1 = md1.Reader;
+            var readers = new[] { reader0, reader1 };
+
+            EncValidation.VerifyModuleMvid(1, reader0, reader1);
+
+            CheckNames(readers, reader1.GetTypeDefNames());
+            CheckNames(readers, reader1.GetMethodDefNames(), "F");
+            CheckNames(readers, reader1.GetMemberRefNames(), /*DescriptionAttribute*/".ctor", /*String.*/"Empty");
+
+            CheckAttributes(reader1,
+                new CustomAttributeRow(Handle(2, TableIndex.MethodDef), Handle(5, TableIndex.MemberRef)));
+
+            CheckEncLog(reader1,
+                Row(2, TableIndex.AssemblyRef, EditAndContinueOperation.Default),
+                Row(5, TableIndex.MemberRef, EditAndContinueOperation.Default),
+                Row(6, TableIndex.MemberRef, EditAndContinueOperation.Default),
+                Row(6, TableIndex.TypeRef, EditAndContinueOperation.Default),
+                Row(7, TableIndex.TypeRef, EditAndContinueOperation.Default),
+                Row(8, TableIndex.TypeRef, EditAndContinueOperation.Default),
+                Row(2, TableIndex.StandAloneSig, EditAndContinueOperation.Default),
+                Row(2, TableIndex.MethodDef, EditAndContinueOperation.Default),
+                Row(4, TableIndex.CustomAttribute, EditAndContinueOperation.Default)); // Row 4, so adding a new CustomAttribute
+
+            CheckEncMap(reader1,
+                Handle(6, TableIndex.TypeRef),
+                Handle(7, TableIndex.TypeRef),
+                Handle(8, TableIndex.TypeRef),
+                Handle(2, TableIndex.MethodDef),
+                Handle(5, TableIndex.MemberRef),
+                Handle(6, TableIndex.MemberRef),
+                Handle(4, TableIndex.CustomAttribute),
+                Handle(2, TableIndex.StandAloneSig),
+                Handle(2, TableIndex.AssemblyRef));
+
+            var method2 = compilation2.GetMember<MethodSymbol>("C.F");
+            var diff2 = compilation2.EmitDifference(
+                diff1.NextGeneration,
+                ImmutableArray.Create(
+                    SemanticEdit.Create(SemanticEditKind.Update, method1, method2)));
+
+            // Verify delta metadata contains expected rows.
+            using var md2 = diff2.GetMetadata();
+            var reader2 = md2.Reader;
+            readers = new[] { reader0, reader1, reader2 };
+
+            CheckNames(readers, reader2.GetTypeDefNames());
+            CheckNames(readers, reader2.GetMethodDefNames(), "F");
+            CheckNames(readers, reader2.GetMemberRefNames());
+
+            CheckAttributes(reader2,
+                new CustomAttributeRow(Handle(0, TableIndex.MethodDef), Handle(0, TableIndex.MemberRef)));  // 0, delete
+
+            CheckEncLog(reader2,
+                Row(3, TableIndex.AssemblyRef, EditAndContinueOperation.Default),
+                Row(9, TableIndex.TypeRef, EditAndContinueOperation.Default),
+                Row(3, TableIndex.StandAloneSig, EditAndContinueOperation.Default),
+                Row(2, TableIndex.MethodDef, EditAndContinueOperation.Default),
+                Row(4, TableIndex.CustomAttribute, EditAndContinueOperation.Default)); // Row 4, so updating existing CustomAttribute
+
+            CheckEncMap(reader2,
+                Handle(9, TableIndex.TypeRef),
+                Handle(2, TableIndex.MethodDef),
+                Handle(4, TableIndex.CustomAttribute),
+                Handle(3, TableIndex.StandAloneSig),
+                Handle(3, TableIndex.AssemblyRef));
+
+            var method3 = compilation3.GetMember<MethodSymbol>("C.F");
+            var diff3 = compilation3.EmitDifference(
+                diff2.NextGeneration,
+                ImmutableArray.Create(
+                    SemanticEdit.Create(SemanticEditKind.Update, method2, method3)));
+
+            // Verify delta metadata contains expected rows.
+            using var md3 = diff3.GetMetadata();
+            var reader3 = md3.Reader;
+            readers = new[] { reader0, reader1, reader2, reader3 };
+
+            CheckNames(readers, reader3.GetTypeDefNames());
+            CheckNames(readers, reader3.GetMethodDefNames(), "F");
+            CheckNames(readers, reader3.GetMemberRefNames(), /*DescriptionAttribute*/".ctor", /*String.*/"Empty");
+
+            CheckAttributes(reader3,
+                new CustomAttributeRow(Handle(2, TableIndex.MethodDef), Handle(7, TableIndex.MemberRef)));
+
+            CheckEncLog(reader3,
+                Row(4, TableIndex.AssemblyRef, EditAndContinueOperation.Default),
+                Row(7, TableIndex.MemberRef, EditAndContinueOperation.Default),
+                Row(8, TableIndex.MemberRef, EditAndContinueOperation.Default),
+                Row(10, TableIndex.TypeRef, EditAndContinueOperation.Default),
+                Row(11, TableIndex.TypeRef, EditAndContinueOperation.Default),
+                Row(12, TableIndex.TypeRef, EditAndContinueOperation.Default),
+                Row(4, TableIndex.StandAloneSig, EditAndContinueOperation.Default),
+                Row(2, TableIndex.MethodDef, EditAndContinueOperation.Default),
+                Row(4, TableIndex.CustomAttribute, EditAndContinueOperation.Default)); // Row 4, update the previously deleted row
+
+            CheckEncMap(reader3,
+                Handle(10, TableIndex.TypeRef),
+                Handle(11, TableIndex.TypeRef),
+                Handle(12, TableIndex.TypeRef),
+                Handle(2, TableIndex.MethodDef),
+                Handle(7, TableIndex.MemberRef),
+                Handle(8, TableIndex.MemberRef),
+                Handle(4, TableIndex.CustomAttribute),
+                Handle(4, TableIndex.StandAloneSig),
+                Handle(4, TableIndex.AssemblyRef));
+        }
+
+        [Fact]
+        public void AddMethod_WithAttributes()
+        {
+            var source0 =
+@"class C
+{
+    static void Main() { }
+}";
+            var source1 =
+@"class C
+{
+    static void Main() { }
+    [System.ComponentModel.Description(""The F method"")]
+    static string F() { return string.Empty; }
+}";
+            var compilation0 = CreateCompilation(source0, options: TestOptions.DebugExe, targetFramework: TargetFramework.NetStandard20);
+            var compilation1 = compilation0.WithSource(source1);
+
+            // Verify full metadata contains expected rows.
+            var bytes0 = compilation0.EmitToArray();
+            using var md0 = ModuleMetadata.CreateFromImage(bytes0);
+            var reader0 = md0.MetadataReader;
+
+            CheckNames(reader0, reader0.GetTypeDefNames(), "<Module>", "C");
+            CheckNames(reader0, reader0.GetMethodDefNames(), "Main", ".ctor");
+            CheckNames(reader0, reader0.GetMemberRefNames(), /*CompilationRelaxationsAttribute.*/".ctor", /*RuntimeCompatibilityAttribute.*/".ctor", /*Object.*/".ctor", /*DebuggableAttribute*/".ctor");
+
+            Assert.Equal(3, reader0.CustomAttributes.Count);
+
+            var generation0 = EmitBaseline.CreateInitialBaseline(
+                md0,
+                EmptyLocalsProvider);
+            var method1 = compilation1.GetMember<MethodSymbol>("C.F");
+
+            var diff1 = compilation1.EmitDifference(
+                generation0,
+                ImmutableArray.Create(SemanticEdit.Create(SemanticEditKind.Insert, null, method1)));
+
+            // Verify delta metadata contains expected rows.
+            using var md1 = diff1.GetMetadata();
+            var reader1 = md1.Reader;
+            var readers = new[] { reader0, reader1 };
+
+            EncValidation.VerifyModuleMvid(1, reader0, reader1);
+
+            CheckNames(readers, reader1.GetTypeDefNames());
+            CheckNames(readers, reader1.GetMethodDefNames(), "F");
+            CheckNames(readers, reader1.GetMemberRefNames(), /*DescriptionAttribute*/".ctor", /*String.*/"Empty");
+
+            Assert.Equal(1, reader1.CustomAttributes.Count);
+
+            CheckEncLog(reader1,
+                Row(2, TableIndex.AssemblyRef, EditAndContinueOperation.Default),
+                Row(5, TableIndex.MemberRef, EditAndContinueOperation.Default),
+                Row(6, TableIndex.MemberRef, EditAndContinueOperation.Default),
+                Row(6, TableIndex.TypeRef, EditAndContinueOperation.Default),
+                Row(7, TableIndex.TypeRef, EditAndContinueOperation.Default),
+                Row(8, TableIndex.TypeRef, EditAndContinueOperation.Default),
+                Row(1, TableIndex.StandAloneSig, EditAndContinueOperation.Default),
+                Row(2, TableIndex.TypeDef, EditAndContinueOperation.AddMethod),
+                Row(3, TableIndex.MethodDef, EditAndContinueOperation.Default),
+                Row(4, TableIndex.CustomAttribute, EditAndContinueOperation.Default)); // Row 4, a new attribute
+
+            CheckEncMap(reader1,
+                Handle(6, TableIndex.TypeRef),
+                Handle(7, TableIndex.TypeRef),
+                Handle(8, TableIndex.TypeRef),
+                Handle(3, TableIndex.MethodDef),
+                Handle(5, TableIndex.MemberRef),
+                Handle(6, TableIndex.MemberRef),
+                Handle(4, TableIndex.CustomAttribute),
+                Handle(1, TableIndex.StandAloneSig),
+                Handle(2, TableIndex.AssemblyRef));
+        }
+
         [WorkItem(962219, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/962219")]
         [Fact]
         public void PartialMethod()
@@ -2266,6 +2952,7 @@ [B] static void M2<[A]T>() { }
                 Row(8, TableIndex.Param, EditAndContinueOperation.Default),
                 Row(15, TableIndex.MethodDef, EditAndContinueOperation.AddParameter),
                 Row(9, TableIndex.Param, EditAndContinueOperation.Default),
+                Row(7, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
                 Row(13, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
                 Row(14, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
                 Row(15, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
@@ -2274,7 +2961,6 @@ [B] static void M2<[A]T>() { }
                 Row(18, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
                 Row(19, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
                 Row(20, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                Row(21, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
                 Row(4, TableIndex.MethodSemantics, EditAndContinueOperation.Default),
                 Row(5, TableIndex.MethodSemantics, EditAndContinueOperation.Default),
                 Row(6, TableIndex.MethodSemantics, EditAndContinueOperation.Default),
@@ -2300,6 +2986,7 @@ [B] static void M2<[A]T>() { }
                 Handle(13, TableIndex.MemberRef),
                 Handle(14, TableIndex.MemberRef),
                 Handle(15, TableIndex.MemberRef),
+                Handle(7, TableIndex.CustomAttribute),
                 Handle(13, TableIndex.CustomAttribute),
                 Handle(14, TableIndex.CustomAttribute),
                 Handle(15, TableIndex.CustomAttribute),
@@ -2308,7 +2995,6 @@ [B] static void M2<[A]T>() { }
                 Handle(18, TableIndex.CustomAttribute),
                 Handle(19, TableIndex.CustomAttribute),
                 Handle(20, TableIndex.CustomAttribute),
-                Handle(21, TableIndex.CustomAttribute),
                 Handle(3, TableIndex.StandAloneSig),
                 Handle(4, TableIndex.StandAloneSig),
                 Handle(2, TableIndex.Event),
diff --git a/src/Compilers/Core/Portable/Emit/EditAndContinue/DeltaMetadataWriter.cs b/src/Compilers/Core/Portable/Emit/EditAndContinue/DeltaMetadataWriter.cs
index 353c61b7f2e88..46b3955fa274d 100644
--- a/src/Compilers/Core/Portable/Emit/EditAndContinue/DeltaMetadataWriter.cs
+++ b/src/Compilers/Core/Portable/Emit/EditAndContinue/DeltaMetadataWriter.cs
@@ -38,6 +38,18 @@ internal sealed class DeltaMetadataWriter : MetadataWriter
         private readonly EventOrPropertyMapIndex _propertyMap;
         private readonly MethodImplIndex _methodImpls;
 
+        // For the EncLog table we need to know which things we're emitting custom attributes for so we can
+        // correctly map the attributes to row numbers of existing attributes for that target
+        private readonly Dictionary<EntityHandle, int> _customAttributeParentCounts;
+
+        // For the EncMap table we need to keep a list of exactly which rows in the CustomAttributes table are updated
+        // since we spread these out amongst existing rows, it's not just a contiguous set
+        private readonly List<int> _customAttributeEncMapRows;
+
+        // Keep track of which CustomAttributes rows are added in this and previous deltas, over what is in the
+        // original metadata
+        private readonly Dictionary<EntityHandle, ImmutableArray<int>> _customAttributesAdded;
+
         private readonly HeapOrReferenceIndex<AssemblyIdentity> _assemblyRefIndex;
         private readonly HeapOrReferenceIndex<string> _moduleRefIndex;
         private readonly InstanceAndStructuralReferenceIndex<ITypeMemberReference> _memberRefIndex;
@@ -90,6 +102,10 @@ public DeltaMetadataWriter(
             _propertyMap = new EventOrPropertyMapIndex(this.TryGetExistingPropertyMapIndex, sizes[(int)TableIndex.PropertyMap]);
             _methodImpls = new MethodImplIndex(this, sizes[(int)TableIndex.MethodImpl]);
 
+            _customAttributeParentCounts = new Dictionary<EntityHandle, int>();
+            _customAttributeEncMapRows = new List<int>();
+            _customAttributesAdded = new Dictionary<EntityHandle, ImmutableArray<int>>();
+
             _assemblyRefIndex = new HeapOrReferenceIndex<AssemblyIdentity>(this, lastRowId: sizes[(int)TableIndex.AssemblyRef]);
             _moduleRefIndex = new HeapOrReferenceIndex<string>(this, lastRowId: sizes[(int)TableIndex.ModuleRef]);
             _memberRefIndex = new InstanceAndStructuralReferenceIndex<ITypeMemberReference>(this, new MemberRefComparer(this), lastRowId: sizes[(int)TableIndex.MemberRef]);
@@ -171,6 +187,7 @@ internal EmitBaseline GetDelta(EmitBaseline baseline, Compilation compilation, G
                 eventMapAdded: AddRange(_previousGeneration.EventMapAdded, _eventMap.GetAdded()),
                 propertyMapAdded: AddRange(_previousGeneration.PropertyMapAdded, _propertyMap.GetAdded()),
                 methodImplsAdded: AddRange(_previousGeneration.MethodImplsAdded, _methodImpls.GetAdded()),
+                customAttributesAdded: AddRange(_previousGeneration.CustomAttributesAdded, _customAttributesAdded, replace: true),
                 tableEntriesAdded: ImmutableArray.Create(tableSizes),
                 // Blob stream is concatenated aligned.
                 blobStreamLengthAdded: metadataSizes.GetAlignedHeapSize(HeapIndex.Blob) + _previousGeneration.BlobStreamLengthAdded,
@@ -692,6 +709,17 @@ private EncLocalInfo CreateEncLocalInfo(ILocalDefinition localDef, byte[] signat
             return new EncLocalInfo(localDef.SlotInfo, translatedType, localDef.Constraints, signature);
         }
 
+        protected override int AddCustomAttributesToTable(EntityHandle parentHandle, IEnumerable<ICustomAttribute> attributes)
+        {
+            // The base class will write out the actual metadata for us
+            var numAttributesEmitted = base.AddCustomAttributesToTable(parentHandle, attributes);
+
+            // We need to keep track of all of the things attributes could be associated with in this delta, in order to populate the EncLog and Map tables
+            _customAttributeParentCounts.Add(parentHandle, numAttributesEmitted);
+
+            return numAttributesEmitted;
+        }
+
         protected override void PopulateEncLogTableRows(ImmutableArray<int> rowCounts)
         {
             // The EncLog table is a log of all the operations needed
@@ -720,7 +748,7 @@ protected override void PopulateEncLogTableRows(ImmutableArray<int> rowCounts)
             PopulateEncLogTableParameters();
 
             PopulateEncLogTableRows(TableIndex.Constant, previousSizes, deltaSizes);
-            PopulateEncLogTableRows(TableIndex.CustomAttribute, previousSizes, deltaSizes);
+            PopulateEncLogTableCustomAttributes();
             PopulateEncLogTableRows(TableIndex.DeclSecurity, previousSizes, deltaSizes);
             PopulateEncLogTableRows(TableIndex.ClassLayout, previousSizes, deltaSizes);
             PopulateEncLogTableRows(TableIndex.FieldLayout, previousSizes, deltaSizes);
@@ -802,6 +830,118 @@ private void PopulateEncLogTableParameters()
             }
         }
 
+        /// <summary>
+        /// CustomAttributes point to their target via the Parent column so we cannot simply output new rows
+        /// in the delta or we would end up with duplicates, but we also don't want to do complex logic to determine
+        /// which attributes have changes, so we just emit them all.
+        /// This means our logic for emitting CustomAttributes is to update any existing rows, either from the original
+        /// compilation or subsequent deltas, and only add more if we need to. The EncLog table is the thing that tells
+        /// the runtime which row a CustomAttributes row is (ie, new or existing)
+        /// </summary>
+        private void PopulateEncLogTableCustomAttributes()
+        {
+            // List of attributes that need to be emitted to delete a previously emitted attribute
+            var deletedAttributeRows = new List<(int parentRowId, HandleKind kind)>();
+            var customAttributesAdded = new Dictionary<EntityHandle, ArrayBuilder<int>>();
+
+            // The data in _previousGeneration.CustomAttributesAdded is not nicely sorted, or even necessarily contiguous
+            // so we need to map each target onto the rows its attributes occupy so we know which rows to update
+            var lastRowId = _previousGeneration.OriginalMetadata.MetadataReader.GetTableRowCount(TableIndex.CustomAttribute);
+            if (_previousGeneration.CustomAttributesAdded.Count > 0)
+            {
+                lastRowId = _previousGeneration.CustomAttributesAdded.SelectMany(s => s.Value).Max();
+            }
+
+            // Iterate through the parents we emitted custom attributes for, in parent order
+            foreach (var (parent, count) in _customAttributeParentCounts.OrderBy(kvp => CodedIndex.HasCustomAttribute(kvp.Key)))
+            {
+                int index = 0;
+
+                // First we try to update any existing attributes.
+                // GetCustomAttributes does a binary search, so is fast. We presume that the number of rows in the original metadata
+                // greatly outnumbers the amount of parents emitted in this delta so even with repeated searches this is still
+                // quicker than iterating the entire original table, even once.
+                var existingCustomAttributes = _previousGeneration.OriginalMetadata.MetadataReader.GetCustomAttributes(parent);
+                foreach (var attributeHandle in existingCustomAttributes)
+                {
+                    int rowId = MetadataTokens.GetRowNumber(attributeHandle);
+                    AddLogEntryOrDelete(rowId, parent, add: index < count);
+                    index++;
+                }
+
+                // If we emitted any attributes for this parent in previous deltas then we either need to update
+                // them next, or delete them if necessary
+                if (_previousGeneration.CustomAttributesAdded.TryGetValue(parent, out var rowIds))
+                {
+                    foreach (var rowId in rowIds)
+                    {
+                        TrackCustomAttributeAdded(rowId, parent);
+                        AddLogEntryOrDelete(rowId, parent, add: index < count);
+                        index++;
+                    }
+                }
+
+                // Finally if there are still attributes for this parent left, they are additions new to this delta
+                for (int i = index; i < count; i++)
+                {
+                    lastRowId++;
+                    TrackCustomAttributeAdded(lastRowId, parent);
+                    AddEncLogEntry(lastRowId);
+                }
+            }
+
+            // Save the attributes we've emitted, and the ones from previous deltas, for use in the next generation
+            foreach (var (parent, rowIds) in customAttributesAdded)
+            {
+                _customAttributesAdded.Add(parent, rowIds.ToImmutableAndFree());
+            }
+
+            // Add attributes and log entries for everything we've deleted
+            foreach (var row in deletedAttributeRows)
+            {
+                // now emit a "delete" row with a parent that is for the 0 row of the same table as the existing one
+                if (!MetadataTokens.TryGetTableIndex(row.kind, out var tableIndex))
+                {
+                    throw new InvalidOperationException("Trying to delete a custom attribute for a parent kind that doesn't have a matching table index.");
+                }
+                metadata.AddCustomAttribute(MetadataTokens.Handle(tableIndex, 0), MetadataTokens.EntityHandle(TableIndex.MemberRef, 0), value: default);
+
+                AddEncLogEntry(row.parentRowId);
+            }
+
+            void AddEncLogEntry(int rowId)
+            {
+                _customAttributeEncMapRows.Add(rowId);
+                metadata.AddEncLogEntry(
+                    entity: MetadataTokens.CustomAttributeHandle(rowId),
+                    code: EditAndContinueOperation.Default);
+            }
+
+            void AddLogEntryOrDelete(int rowId, EntityHandle parent, bool add)
+            {
+                if (add)
+                {
+                    // Update this row
+                    AddEncLogEntry(rowId);
+                }
+                else
+                {
+                    // Delete this row
+                    deletedAttributeRows.Add((rowId, parent.Kind));
+                }
+            }
+
+            void TrackCustomAttributeAdded(int nextRowId, EntityHandle parent)
+            {
+                if (!customAttributesAdded.TryGetValue(parent, out var existing))
+                {
+                    existing = ArrayBuilder<int>.GetInstance();
+                    customAttributesAdded.Add(parent, existing);
+                }
+                existing.Add(nextRowId);
+            }
+        }
+
         private void PopulateEncLogTableRows<T>(DefinitionIndex<T> index, TableIndex tableIndex)
             where T : class, IDefinition
         {
@@ -854,7 +994,7 @@ protected override void PopulateEncMapTableRows(ImmutableArray<int> rowCounts)
 
             AddReferencedTokens(tokens, TableIndex.Param, previousSizes, deltaSizes);
             AddReferencedTokens(tokens, TableIndex.Constant, previousSizes, deltaSizes);
-            AddReferencedTokens(tokens, TableIndex.CustomAttribute, previousSizes, deltaSizes);
+            AddRowNumberTokens(tokens, _customAttributeEncMapRows, TableIndex.CustomAttribute);
             AddReferencedTokens(tokens, TableIndex.DeclSecurity, previousSizes, deltaSizes);
             AddReferencedTokens(tokens, TableIndex.ClassLayout, previousSizes, deltaSizes);
             AddReferencedTokens(tokens, TableIndex.FieldLayout, previousSizes, deltaSizes);
@@ -981,6 +1121,14 @@ private static void AddDefinitionTokens<T>(ArrayBuilder<EntityHandle> tokens, De
             }
         }
 
+        private static void AddRowNumberTokens(ArrayBuilder<EntityHandle> tokens, IEnumerable<int> rowNumbers, TableIndex tableIndex)
+        {
+            foreach (var row in rowNumbers)
+            {
+                tokens.Add(MetadataTokens.Handle(tableIndex, row));
+            }
+        }
+
         protected override void PopulateEventMapTableRows()
         {
             foreach (var typeId in _eventMap.GetRows())
diff --git a/src/Compilers/Core/Portable/Emit/EditAndContinue/EmitBaseline.cs b/src/Compilers/Core/Portable/Emit/EditAndContinue/EmitBaseline.cs
index b5e2eec851b7e..b16628e10f05b 100644
--- a/src/Compilers/Core/Portable/Emit/EditAndContinue/EmitBaseline.cs
+++ b/src/Compilers/Core/Portable/Emit/EditAndContinue/EmitBaseline.cs
@@ -212,6 +212,7 @@ public static EmitBaseline CreateInitialBaseline(
                 eventMapAdded: new Dictionary<int, int>(),
                 propertyMapAdded: new Dictionary<int, int>(),
                 methodImplsAdded: new Dictionary<MethodImplKey, int>(),
+                customAttributesAdded: new Dictionary<EntityHandle, ImmutableArray<int>>(),
                 tableEntriesAdded: s_emptyTableSizes,
                 blobStreamLengthAdded: 0,
                 stringStreamLengthAdded: 0,
@@ -262,6 +263,7 @@ public static EmitBaseline CreateInitialBaseline(
         internal readonly IReadOnlyDictionary<int, int> EventMapAdded;
         internal readonly IReadOnlyDictionary<int, int> PropertyMapAdded;
         internal readonly IReadOnlyDictionary<MethodImplKey, int> MethodImplsAdded;
+        internal readonly IReadOnlyDictionary<EntityHandle, ImmutableArray<int>> CustomAttributesAdded;
 
         internal readonly ImmutableArray<int> TableEntriesAdded;
 
@@ -317,6 +319,7 @@ private EmitBaseline(
             IReadOnlyDictionary<int, int> eventMapAdded,
             IReadOnlyDictionary<int, int> propertyMapAdded,
             IReadOnlyDictionary<MethodImplKey, int> methodImplsAdded,
+            IReadOnlyDictionary<EntityHandle, ImmutableArray<int>> customAttributesAdded,
             ImmutableArray<int> tableEntriesAdded,
             int blobStreamLengthAdded,
             int stringStreamLengthAdded,
@@ -377,6 +380,7 @@ private EmitBaseline(
             EventMapAdded = eventMapAdded;
             PropertyMapAdded = propertyMapAdded;
             MethodImplsAdded = methodImplsAdded;
+            CustomAttributesAdded = customAttributesAdded;
             TableEntriesAdded = tableEntriesAdded;
             BlobStreamLengthAdded = blobStreamLengthAdded;
             StringStreamLengthAdded = stringStreamLengthAdded;
@@ -407,6 +411,7 @@ internal EmitBaseline With(
             IReadOnlyDictionary<int, int> eventMapAdded,
             IReadOnlyDictionary<int, int> propertyMapAdded,
             IReadOnlyDictionary<MethodImplKey, int> methodImplsAdded,
+            IReadOnlyDictionary<EntityHandle, ImmutableArray<int>> customAttributesAdded,
             ImmutableArray<int> tableEntriesAdded,
             int blobStreamLengthAdded,
             int stringStreamLengthAdded,
@@ -438,6 +443,7 @@ internal EmitBaseline With(
                 eventMapAdded,
                 propertyMapAdded,
                 methodImplsAdded,
+                customAttributesAdded,
                 tableEntriesAdded,
                 blobStreamLengthAdded: blobStreamLengthAdded,
                 stringStreamLengthAdded: stringStreamLengthAdded,
diff --git a/src/Compilers/Core/Portable/Emit/EditAndContinue/SymbolMatcher.cs b/src/Compilers/Core/Portable/Emit/EditAndContinue/SymbolMatcher.cs
index c30390aee8bc9..890c0699ec78d 100644
--- a/src/Compilers/Core/Portable/Emit/EditAndContinue/SymbolMatcher.cs
+++ b/src/Compilers/Core/Portable/Emit/EditAndContinue/SymbolMatcher.cs
@@ -51,6 +51,7 @@ public EmitBaseline MapBaselineToCompilation(
                 eventMapAdded: baseline.EventMapAdded,
                 propertyMapAdded: baseline.PropertyMapAdded,
                 methodImplsAdded: baseline.MethodImplsAdded,
+                customAttributesAdded: baseline.CustomAttributesAdded,
                 tableEntriesAdded: baseline.TableEntriesAdded,
                 blobStreamLengthAdded: baseline.BlobStreamLengthAdded,
                 stringStreamLengthAdded: baseline.StringStreamLengthAdded,
diff --git a/src/Compilers/Core/Portable/PEWriter/MetadataWriter.cs b/src/Compilers/Core/Portable/PEWriter/MetadataWriter.cs
index 96e49d321b22f..24ba7a0146f1b 100644
--- a/src/Compilers/Core/Portable/PEWriter/MetadataWriter.cs
+++ b/src/Compilers/Core/Portable/PEWriter/MetadataWriter.cs
@@ -1158,7 +1158,6 @@ private BlobHandle GetMethodSignatureHandleAndBlob(IMethodReference methodRefere
 
             SerializeReturnValueAndParameters(encoder, methodReference, methodReference.ExtraParameters);
 
-
             signatureBlob = builder.ToImmutableArray();
             result = metadata.GetOrAddBlob(signatureBlob);
             _signatureIndex.Add(methodReference, KeyValuePairUtil.Create(result, signatureBlob));
@@ -2091,10 +2090,7 @@ private TypeReferenceHandle GetDummyAssemblyAttributeParent(bool isSecurity, boo
         private void AddModuleAttributesToTable(CommonPEModuleBuilder module)
         {
             Debug.Assert(this.IsFullMetadata);
-            foreach (ICustomAttribute customAttribute in module.GetSourceModuleAttributes())
-            {
-                AddCustomAttributeToTable(EntityHandle.ModuleDefinition, customAttribute);
-            }
+            AddCustomAttributesToTable(EntityHandle.ModuleDefinition, module.GetSourceModuleAttributes());
         }
 
         private void AddCustomAttributesToTable<T>(IEnumerable<T> parentList, TableIndex tableIndex)
@@ -2104,10 +2100,7 @@ private void AddCustomAttributesToTable<T>(IEnumerable<T> parentList, TableIndex
             foreach (var parent in parentList)
             {
                 var parentHandle = MetadataTokens.Handle(tableIndex, parentRowId++);
-                foreach (ICustomAttribute customAttribute in parent.GetAttributes(Context))
-                {
-                    AddCustomAttributeToTable(parentHandle, customAttribute);
-                }
+                AddCustomAttributesToTable(parentHandle, parent.GetAttributes(Context));
             }
         }
 
@@ -2117,33 +2110,19 @@ private void AddCustomAttributesToTable<T>(IEnumerable<T> parentList, Func<T, En
             foreach (var parent in parentList)
             {
                 EntityHandle parentHandle = getDefinitionHandle(parent);
-                foreach (ICustomAttribute customAttribute in parent.GetAttributes(Context))
-                {
-                    AddCustomAttributeToTable(parentHandle, customAttribute);
-                }
+                AddCustomAttributesToTable(parentHandle, parent.GetAttributes(Context));
             }
         }
 
-        private void AddCustomAttributesToTable(
-            EntityHandle handle,
-            ImmutableArray<ICustomAttribute> attributes)
+        protected virtual int AddCustomAttributesToTable(EntityHandle parentHandle, IEnumerable<ICustomAttribute> attributes)
         {
+            int count = 0;
             foreach (var attr in attributes)
             {
-                AddCustomAttributeToTable(handle, attr);
-            }
-        }
-
-        private void AddCustomAttributesToTable(IEnumerable<TypeReferenceWithAttributes> typeRefsWithAttributes)
-        {
-            foreach (var typeRefWithAttributes in typeRefsWithAttributes)
-            {
-                var ifaceHandle = GetTypeHandle(typeRefWithAttributes.TypeRef);
-                foreach (var customAttribute in typeRefWithAttributes.Attributes)
-                {
-                    AddCustomAttributeToTable(ifaceHandle, customAttribute);
-                }
+                count++;
+                AddCustomAttributeToTable(parentHandle, attr);
             }
+            return count;
         }
 
         private void AddCustomAttributeToTable(EntityHandle parentHandle, ICustomAttribute customAttribute)
@@ -2435,7 +2414,6 @@ private void PopulateFileTableRows()
             }
         }
 
-
         private void PopulateGenericParameters(
             ImmutableArray<IGenericParameter> sortedGenericParameters)
         {
diff --git a/src/Compilers/VisualBasic/Test/Emit/Emit/EditAndContinue/EditAndContinueClosureTests.vb b/src/Compilers/VisualBasic/Test/Emit/Emit/EditAndContinue/EditAndContinueClosureTests.vb
index 1e1e3abbe0b7d..d1a70a3446e3e 100644
--- a/src/Compilers/VisualBasic/Test/Emit/Emit/EditAndContinue/EditAndContinueClosureTests.vb
+++ b/src/Compilers/VisualBasic/Test/Emit/Emit/EditAndContinue/EditAndContinueClosureTests.vb
@@ -222,7 +222,7 @@ End Class
                 Row(4, TableIndex.StandAloneSig, EditAndContinueOperation.Default),
                 Row(2, TableIndex.MethodDef, EditAndContinueOperation.Default),
                 Row(3, TableIndex.MethodDef, EditAndContinueOperation.Default),
-                Row(5, TableIndex.CustomAttribute, EditAndContinueOperation.Default))
+                Row(4, TableIndex.CustomAttribute, EditAndContinueOperation.Default))
         End Sub
 
         <Fact>
@@ -435,9 +435,9 @@ End Module
                 Row(7, TableIndex.StandAloneSig, EditAndContinueOperation.Default),
                 Row(6, TableIndex.MethodDef, EditAndContinueOperation.Default),
                 Row(11, TableIndex.MethodDef, EditAndContinueOperation.Default),
-                Row(18, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                Row(19, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                Row(20, TableIndex.CustomAttribute, EditAndContinueOperation.Default))
+                Row(9, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                Row(10, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                Row(14, TableIndex.CustomAttribute, EditAndContinueOperation.Default))
         End Sub
 
         <WorkItem(1067140, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/1067140")>
diff --git a/src/Compilers/VisualBasic/Test/Emit/Emit/EditAndContinue/EditAndContinueStateMachineTests.vb b/src/Compilers/VisualBasic/Test/Emit/Emit/EditAndContinue/EditAndContinueStateMachineTests.vb
index 49aca9d89d25c..fc4bd161e65f5 100644
--- a/src/Compilers/VisualBasic/Test/Emit/Emit/EditAndContinue/EditAndContinueStateMachineTests.vb
+++ b/src/Compilers/VisualBasic/Test/Emit/Emit/EditAndContinue/EditAndContinueStateMachineTests.vb
@@ -911,7 +911,8 @@ End Class
                 Using md1 = diff1.GetMetadata()
                     CheckEncLogDefinitions(md1.Reader,
                         Row(3, TableIndex.StandAloneSig, EditAndContinueOperation.Default),
-                        Row(2, TableIndex.MethodDef, EditAndContinueOperation.Default))
+                        Row(2, TableIndex.MethodDef, EditAndContinueOperation.Default),
+                        Row(4, TableIndex.CustomAttribute, EditAndContinueOperation.Default))
                 End Using
             End Using
         End Sub
@@ -958,7 +959,9 @@ End Class
                 Using md1 = diff1.GetMetadata()
                     CheckEncLogDefinitions(md1.Reader,
                         Row(3, TableIndex.StandAloneSig, EditAndContinueOperation.Default),
-                        Row(2, TableIndex.MethodDef, EditAndContinueOperation.Default))
+                        Row(2, TableIndex.MethodDef, EditAndContinueOperation.Default),
+                        Row(4, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                        Row(5, TableIndex.CustomAttribute, EditAndContinueOperation.Default))
                 End Using
             End Using
         End Sub
@@ -1038,15 +1041,15 @@ End Class
                         Row(6, TableIndex.MethodDef, EditAndContinueOperation.Default),
                         Row(9, TableIndex.MethodDef, EditAndContinueOperation.Default),
                         Row(12, TableIndex.MethodDef, EditAndContinueOperation.Default),
-                        Row(19, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                        Row(20, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                        Row(21, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                        Row(22, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                        Row(23, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                        Row(24, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                        Row(25, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                        Row(26, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                        Row(27, TableIndex.CustomAttribute, EditAndContinueOperation.Default))
+                        Row(4, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                        Row(5, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                        Row(6, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                        Row(7, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                        Row(9, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                        Row(10, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                        Row(13, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                        Row(15, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                        Row(17, TableIndex.CustomAttribute, EditAndContinueOperation.Default))
                 End Using
             End Using
         End Sub
@@ -1101,9 +1104,9 @@ End Class
                         Row(2, TableIndex.MethodDef, EditAndContinueOperation.Default),
                         Row(4, TableIndex.MethodDef, EditAndContinueOperation.Default),
                         Row(5, TableIndex.MethodDef, EditAndContinueOperation.Default),
-                        Row(13, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                        Row(14, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                        Row(15, TableIndex.CustomAttribute, EditAndContinueOperation.Default))
+                        Row(4, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                        Row(6, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                        Row(7, TableIndex.CustomAttribute, EditAndContinueOperation.Default))
                 End Using
 
                 diff1.VerifyIL("C.VB$StateMachine_1_F.MoveNext()", "
@@ -1250,9 +1253,9 @@ End Class
                         Row(4, TableIndex.StandAloneSig, EditAndContinueOperation.Default),
                         Row(2, TableIndex.MethodDef, EditAndContinueOperation.Default),
                         Row(4, TableIndex.MethodDef, EditAndContinueOperation.Default),
-                        Row(9, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                        Row(10, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                        Row(11, TableIndex.CustomAttribute, EditAndContinueOperation.Default))
+                        Row(4, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                        Row(5, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                        Row(7, TableIndex.CustomAttribute, EditAndContinueOperation.Default))
                 End Using
 
                 diff1.VerifyIL("C.VB$StateMachine_1_F.MoveNext()", "
@@ -1500,9 +1503,9 @@ End Class
                         Row(2, TableIndex.MethodDef, EditAndContinueOperation.Default),
                         Row(4, TableIndex.MethodDef, EditAndContinueOperation.Default),
                         Row(5, TableIndex.MethodDef, EditAndContinueOperation.Default),
-                        Row(13, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                        Row(14, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                        Row(15, TableIndex.CustomAttribute, EditAndContinueOperation.Default))
+                        Row(4, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                        Row(6, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                        Row(7, TableIndex.CustomAttribute, EditAndContinueOperation.Default))
                 End Using
 
                 diff1.VerifyIL("C.VB$StateMachine_1_F.MoveNext()", "
@@ -1614,9 +1617,9 @@ End Class
                         Row(2, TableIndex.MethodDef, EditAndContinueOperation.Default),
                         Row(4, TableIndex.MethodDef, EditAndContinueOperation.Default),
                         Row(5, TableIndex.MethodDef, EditAndContinueOperation.Default),
-                        Row(13, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                        Row(14, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                        Row(15, TableIndex.CustomAttribute, EditAndContinueOperation.Default))
+                        Row(4, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                        Row(6, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                        Row(7, TableIndex.CustomAttribute, EditAndContinueOperation.Default))
                 End Using
 
                 diff1.VerifyIL("C.VB$StateMachine_1_F.MoveNext()", "
@@ -1731,9 +1734,9 @@ End Class
                         Row(2, TableIndex.MethodDef, EditAndContinueOperation.Default),
                         Row(4, TableIndex.MethodDef, EditAndContinueOperation.Default),
                         Row(5, TableIndex.MethodDef, EditAndContinueOperation.Default),
-                        Row(13, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                        Row(14, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                        Row(15, TableIndex.CustomAttribute, EditAndContinueOperation.Default))
+                        Row(4, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                        Row(6, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                        Row(7, TableIndex.CustomAttribute, EditAndContinueOperation.Default))
                 End Using
 
                 diff1.VerifyIL("C.VB$StateMachine_1_F.MoveNext()", "
@@ -1844,9 +1847,9 @@ End Class
                         Row(2, TableIndex.MethodDef, EditAndContinueOperation.Default),
                         Row(4, TableIndex.MethodDef, EditAndContinueOperation.Default),
                         Row(5, TableIndex.MethodDef, EditAndContinueOperation.Default),
-                        Row(13, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                        Row(14, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                        Row(15, TableIndex.CustomAttribute, EditAndContinueOperation.Default))
+                        Row(4, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                        Row(6, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                        Row(7, TableIndex.CustomAttribute, EditAndContinueOperation.Default))
                 End Using
 
                 diff1.VerifyIL("C.VB$StateMachine_1_F.MoveNext()", "
@@ -1987,9 +1990,9 @@ End Class
                         Row(2, TableIndex.MethodDef, EditAndContinueOperation.Default),
                         Row(4, TableIndex.MethodDef, EditAndContinueOperation.Default),
                         Row(5, TableIndex.MethodDef, EditAndContinueOperation.Default),
-                        Row(13, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                        Row(14, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                        Row(15, TableIndex.CustomAttribute, EditAndContinueOperation.Default))
+                        Row(4, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                        Row(6, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                        Row(7, TableIndex.CustomAttribute, EditAndContinueOperation.Default))
                 End Using
 
                 diff1.VerifyIL("C.VB$StateMachine_1_F.MoveNext()", "
@@ -2134,9 +2137,9 @@ End Class
                         Row(4, TableIndex.StandAloneSig, EditAndContinueOperation.Default),
                         Row(2, TableIndex.MethodDef, EditAndContinueOperation.Default),
                         Row(4, TableIndex.MethodDef, EditAndContinueOperation.Default),
-                        Row(9, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                        Row(10, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                        Row(11, TableIndex.CustomAttribute, EditAndContinueOperation.Default))
+                        Row(4, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                        Row(5, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                        Row(7, TableIndex.CustomAttribute, EditAndContinueOperation.Default))
                 End Using
 
                 diff1.VerifyIL("C.VB$StateMachine_1_F.MoveNext()", "
@@ -2296,9 +2299,9 @@ End Class
                         Row(7, TableIndex.Field, EditAndContinueOperation.Default),
                         Row(2, TableIndex.MethodDef, EditAndContinueOperation.Default),
                         Row(4, TableIndex.MethodDef, EditAndContinueOperation.Default),
-                        Row(9, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                        Row(10, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                        Row(11, TableIndex.CustomAttribute, EditAndContinueOperation.Default))
+                        Row(4, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                        Row(5, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                        Row(7, TableIndex.CustomAttribute, EditAndContinueOperation.Default))
                 End Using
 
                 diff1.VerifyIL("C.VB$StateMachine_1_F.MoveNext()", "
@@ -2461,9 +2464,9 @@ End Class
                         Row(7, TableIndex.Field, EditAndContinueOperation.Default),
                         Row(2, TableIndex.MethodDef, EditAndContinueOperation.Default),
                         Row(4, TableIndex.MethodDef, EditAndContinueOperation.Default),
-                        Row(9, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                        Row(10, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                        Row(11, TableIndex.CustomAttribute, EditAndContinueOperation.Default))
+                        Row(4, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                        Row(5, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                        Row(7, TableIndex.CustomAttribute, EditAndContinueOperation.Default))
                 End Using
 
                 diff1.VerifyIL("C.VB$StateMachine_1_F.MoveNext()", "
@@ -2622,9 +2625,9 @@ End Class
                         Row(6, TableIndex.Field, EditAndContinueOperation.Default),
                         Row(2, TableIndex.MethodDef, EditAndContinueOperation.Default),
                         Row(4, TableIndex.MethodDef, EditAndContinueOperation.Default),
-                        Row(9, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                        Row(10, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                        Row(11, TableIndex.CustomAttribute, EditAndContinueOperation.Default))
+                        Row(4, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                        Row(5, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                        Row(7, TableIndex.CustomAttribute, EditAndContinueOperation.Default))
                 End Using
 
                 diff1.VerifyIL("C.VB$StateMachine_1_F.MoveNext()", "
@@ -2930,12 +2933,12 @@ End Class
                     Row(3, TableIndex.MethodDef, EditAndContinueOperation.Default),
                     Row(6, TableIndex.MethodDef, EditAndContinueOperation.Default),
                     Row(9, TableIndex.MethodDef, EditAndContinueOperation.Default),
-                    Row(19, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                    Row(20, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                    Row(21, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                    Row(22, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                    Row(23, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                    Row(24, TableIndex.CustomAttribute, EditAndContinueOperation.Default))
+                    Row(4, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                    Row(5, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                    Row(6, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                    Row(7, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                    Row(13, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                    Row(15, TableIndex.CustomAttribute, EditAndContinueOperation.Default))
 
             diff1.VerifyIL("C.VB$StateMachine_1_F.MoveNext()", "
 {
@@ -3048,9 +3051,9 @@ End Class
                     Row(21, TableIndex.Field, EditAndContinueOperation.Default),
                     Row(2, TableIndex.MethodDef, EditAndContinueOperation.Default),
                     Row(6, TableIndex.MethodDef, EditAndContinueOperation.Default),
-                    Row(25, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                    Row(26, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                    Row(27, TableIndex.CustomAttribute, EditAndContinueOperation.Default))
+                    Row(4, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                    Row(5, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                    Row(13, TableIndex.CustomAttribute, EditAndContinueOperation.Default))
 
             diff2.VerifyIL("C.VB$StateMachine_1_F.MoveNext()", "
 {
@@ -3167,12 +3170,12 @@ End Class
                     Row(4, TableIndex.MethodDef, EditAndContinueOperation.Default),
                     Row(9, TableIndex.MethodDef, EditAndContinueOperation.Default),
                     Row(12, TableIndex.MethodDef, EditAndContinueOperation.Default),
-                    Row(28, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                    Row(29, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                    Row(30, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                    Row(31, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                    Row(32, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                    Row(33, TableIndex.CustomAttribute, EditAndContinueOperation.Default))
+                    Row(6, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                    Row(7, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                    Row(9, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                    Row(10, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                    Row(15, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                    Row(17, TableIndex.CustomAttribute, EditAndContinueOperation.Default))
 
         End Sub
 
@@ -3444,12 +3447,12 @@ End Class
                     Row(6, TableIndex.MethodDef, EditAndContinueOperation.Default),
                     Row(9, TableIndex.MethodDef, EditAndContinueOperation.Default),
                     Row(12, TableIndex.MethodDef, EditAndContinueOperation.Default),
-                    Row(19, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                    Row(20, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                    Row(21, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                    Row(22, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                    Row(23, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                    Row(24, TableIndex.CustomAttribute, EditAndContinueOperation.Default))
+                    Row(6, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                    Row(7, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                    Row(9, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                    Row(10, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                    Row(13, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                    Row(15, TableIndex.CustomAttribute, EditAndContinueOperation.Default))
 
             diff1.VerifyIL("C.VB$StateMachine_4_F.MoveNext()", "
 {
@@ -3603,9 +3606,9 @@ End Class
                     Row(15, TableIndex.Field, EditAndContinueOperation.Default),
                     Row(5, TableIndex.MethodDef, EditAndContinueOperation.Default),
                     Row(9, TableIndex.MethodDef, EditAndContinueOperation.Default),
-                    Row(25, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                    Row(26, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                    Row(27, TableIndex.CustomAttribute, EditAndContinueOperation.Default))
+                    Row(6, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                    Row(7, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                    Row(13, TableIndex.CustomAttribute, EditAndContinueOperation.Default))
 
             diff2.VerifyIL("C.VB$StateMachine_4_F.MoveNext()", "
 {
@@ -3765,12 +3768,12 @@ End Class
                     Row(7, TableIndex.MethodDef, EditAndContinueOperation.Default),
                     Row(12, TableIndex.MethodDef, EditAndContinueOperation.Default),
                     Row(15, TableIndex.MethodDef, EditAndContinueOperation.Default),
-                    Row(28, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                    Row(29, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                    Row(30, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                    Row(31, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                    Row(32, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
-                    Row(33, TableIndex.CustomAttribute, EditAndContinueOperation.Default))
+                    Row(9, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                    Row(10, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                    Row(11, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                    Row(12, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                    Row(15, TableIndex.CustomAttribute, EditAndContinueOperation.Default),
+                    Row(17, TableIndex.CustomAttribute, EditAndContinueOperation.Default))
         End Sub
 
         <Fact>