Do not use a constructed method symbol in a BoundMethodDefIndex

src/Compilers/CSharp/Portable/BoundTree/BoundMethodDefIndex.cs

@@ -0,0 +1,16 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.Diagnostics;
+
+namespace Microsoft.CodeAnalysis.CSharp
+{
+    internal partial class BoundMethodDefIndex
+    {
+        private partial void Validate()
+        {
+            Debug.Assert(Method.IsDefinition);
+        }
+    }
+}

src/Compilers/CSharp/Portable/BoundTree/BoundNodes.xml

@@ -739,7 +739,7 @@
 
   <!-- Represents the raw metadata RowId value for a method definition.
        Used by dynamic instrumentation to index into tables or arrays of per-method information. -->
-  <Node Name="BoundMethodDefIndex" Base="BoundExpression">
+  <Node Name="BoundMethodDefIndex" Base="BoundExpression" HasValidate="true">
     <!-- Non-null type is required for this node kind -->
     <Field Name="Type" Type="TypeSymbol" Override="true" Null="disallow"/>
     <Field Name="Method" Type="MethodSymbol"/>

src/Compilers/CSharp/Portable/Lowering/BoundTreeToDifferentEnclosingContextRewriter.cs

@@ -188,6 +188,13 @@ public override BoundNode VisitAwaitableValuePlaceholder(BoundAwaitableValuePlac
                     ;
         }
 
+        public override BoundNode? VisitMethodDefIndex(BoundMethodDefIndex node)
+        {
+            // Cannot replace a MethodDefIndex's Method/Type with a substituted symbol.
+            Debug.Assert(node.Type.Equals(VisitType(node.Type), TypeCompareKind.ConsiderEverything));
+            return node;
+        }
+
         [return: NotNullIfNotNull(nameof(method))]
         public override MethodSymbol? VisitMethodSymbol(MethodSymbol? method)
         {

src/Compilers/CSharp/Test/Emit/Emit/DynamicAnalysis/DynamicAnalysisResourceTests.cs

@@ -20,7 +20,7 @@ namespace Microsoft.CodeAnalysis.CSharp.DynamicAnalysis.UnitTests
 {
     public class DynamicAnalysisResourceTests : CSharpTestBase
     {
-        const string InstrumentationHelperSource = @"
+        public const string InstrumentationHelperSource = @"
 namespace Microsoft.CodeAnalysis.Runtime
 {
     public static class Instrumentation

src/Compilers/VisualBasic/Portable/BoundTree/BoundMethodDefIndex.vb

@@ -0,0 +1,17 @@
+' Licensed to the .NET Foundation under one or more agreements.
+' The .NET Foundation licenses this file to you under the MIT license.
+' See the LICENSE file in the project root for more information.
+
+Imports Microsoft.CodeAnalysis.Text
+Imports Microsoft.CodeAnalysis.VisualBasic.Symbols
+Imports Microsoft.CodeAnalysis.VisualBasic.Syntax
+
+Namespace Microsoft.CodeAnalysis.VisualBasic
+    Partial Friend Class BoundMethodDefIndex
+#If DEBUG Then
+        Private Sub Validate()
+            Debug.Assert(Method.IsDefinition)
+        End Sub
+#End If
+    End Class
+End Namespace

src/Compilers/VisualBasic/Portable/BoundTree/BoundNodes.xml

@@ -256,7 +256,7 @@
 
     <!-- Represents the raw metadata token index value for a method definition.
          Used by dynamic instrumentation to index into tables or arrays of per-method information. -->
-    <Node Name="BoundMethodDefIndex" Base="BoundExpression">
+    <Node Name="BoundMethodDefIndex" Base="BoundExpression" HasValidate="true">
         <!-- Non-null type is required for this node kind -->
         <Field Name="Type" Type="TypeSymbol" Override="true" Null="disallow"/>
         <Field Name="Method" Type="MethodSymbol"/>