diff --git a/src/ExpressionEvaluator/Core/Source/ExpressionCompiler/PDB/MethodDebugInfo.Native.cs b/src/ExpressionEvaluator/Core/Source/ExpressionCompiler/PDB/MethodDebugInfo.Native.cs
index 800c6d401b9da648fd880dd59f28251ca37c2132..be94d1fd731da59310e85dfe0daeabf93fb4336d 100644
--- a/src/ExpressionEvaluator/Core/Source/ExpressionCompiler/PDB/MethodDebugInfo.Native.cs
+++ b/src/ExpressionEvaluator/Core/Source/ExpressionCompiler/PDB/MethodDebugInfo.Native.cs
@@ -6,6 +6,7 @@
 using System.Diagnostics;
 using System.Linq;
 using System.Reflection.Metadata;
+using Microsoft.CodeAnalysis.Collections;
 using Microsoft.DiaSymReader;
 
 namespace Microsoft.CodeAnalysis.ExpressionEvaluator
@@ -264,7 +265,7 @@ private static bool TryCreateImportRecordFromCSharpImportString(EESymbolProvider
                     .SelectAsArray(s => new HoistedLocalScopeRecord(s.StartOffset, s.EndOffset - s.StartOffset + 1));
             }
 
-            CustomDebugInfoReader.GetCSharpDynamicLocalInfo(
+            GetCSharpDynamicLocalInfo(
                 customDebugInfoBytes,
                 methodToken,
                 methodVersion,
@@ -273,6 +274,128 @@ private static bool TryCreateImportRecordFromCSharpImportString(EESymbolProvider
                 out dynamicLocalConstantMap);
         }
 
+        /// <exception cref="InvalidOperationException">Bad data.</exception>
+        private static void GetCSharpDynamicLocalInfo(
+            byte[] customDebugInfo,
+            int methodToken,
+            int methodVersion,
+            IEnumerable<ISymUnmanagedScope> scopes,
+            out ImmutableDictionary<int, ImmutableArray<bool>> dynamicLocalMap,
+            out ImmutableDictionary<string, ImmutableArray<bool>> dynamicLocalConstantMap)
+        {
+            dynamicLocalMap = ImmutableDictionary<int, ImmutableArray<bool>>.Empty;
+            dynamicLocalConstantMap = ImmutableDictionary<string, ImmutableArray<bool>>.Empty;
+
+            var record = CustomDebugInfoReader.TryGetCustomDebugInfoRecord(customDebugInfo, CustomDebugInfoKind.DynamicLocals);
+            if (record.IsDefault)
+            {
+                return;
+            }
+
+            ImmutableDictionary<int, ImmutableArray<bool>>.Builder localBuilder = null;
+            ImmutableDictionary<string, ImmutableArray<bool>>.Builder constantBuilder = null;
+
+            var dynamicLocals = RemoveAmbiguousLocals(CustomDebugInfoReader.DecodeDynamicLocalsRecord(record), scopes);
+            foreach (var dynamicLocal in dynamicLocals)
+            {
+                int slot = dynamicLocal.SlotId;
+                var flags = GetFlags(dynamicLocal);
+                if (slot < 0)
+                {
+                    constantBuilder = constantBuilder ?? ImmutableDictionary.CreateBuilder<string, ImmutableArray<bool>>();
+                    constantBuilder[dynamicLocal.Name] = flags;
+                }
+                else
+                {
+                    localBuilder = localBuilder ?? ImmutableDictionary.CreateBuilder<int, ImmutableArray<bool>>();
+                    localBuilder[slot] = flags;
+                }
+            }
+
+            if (localBuilder != null)
+            {
+                dynamicLocalMap = localBuilder.ToImmutable();
+            }
+
+            if (constantBuilder != null)
+            {
+                dynamicLocalConstantMap = constantBuilder.ToImmutable();
+            }
+        }
+
+        private static ImmutableArray<bool> GetFlags(DynamicLocalInfo bucket)
+        {
+            int flagCount = bucket.FlagCount;
+            ulong flags = bucket.Flags;
+            var builder = ArrayBuilder<bool>.GetInstance(flagCount);
+            for (int i = 0; i < flagCount; i++)
+            {
+                builder.Add((flags & (1u << i)) != 0);
+            }
+            return builder.ToImmutableAndFree();
+        }
+
+        /// <summary>
+        /// Dynamic CDI encodes slot id and name for each dynamic local variable, but only name for a constant. 
+        /// Constants have slot id set to 0. As a result there is a potential for ambiguity. If a variable in a slot 0
+        /// and a constant defined anywhere in the method body have the same name we can't say which one 
+        /// the dynamic flags belong to (if there is a dynamic record for at least one of them).
+        /// 
+        /// This method removes ambiguous dynamic records.
+        /// </summary>
+        private static ImmutableArray<DynamicLocalInfo> RemoveAmbiguousLocals(
+            ImmutableArray<DynamicLocalInfo> dynamicLocals,
+            IEnumerable<ISymUnmanagedScope> scopes)
+        {
+            const byte DuplicateName = 0;
+            const byte VariableName = 1;
+            const byte ConstantName = 2;
+
+            var localNames = PooledDictionary<string, byte>.GetInstance();
+
+            var firstLocal = scopes.SelectMany(scope => scope.GetLocals()).FirstOrDefault(variable => variable.GetSlot() == 0);
+            if (firstLocal != null)
+            {
+                localNames.Add(firstLocal.GetName(), VariableName);
+            }
+
+            foreach (var scope in scopes)
+            {
+                foreach (var constant in scope.GetConstants())
+                {
+                    string name = constant.GetName();
+                    localNames[name] = localNames.ContainsKey(name) ? DuplicateName : ConstantName;
+                }
+            }
+
+            var builder = ArrayBuilder<DynamicLocalInfo>.GetInstance();
+            foreach (var dynamicLocal in dynamicLocals)
+            {
+                int slot = dynamicLocal.SlotId;
+                var name = dynamicLocal.Name;
+                if (slot == 0)
+                {
+                    byte localOrConstant;
+                    localNames.TryGetValue(name, out localOrConstant);
+                    if (localOrConstant == DuplicateName)
+                    {
+                        continue;
+                    }
+
+                    if (localOrConstant == ConstantName)
+                    {
+                        slot = -1;
+                    }
+                }
+
+                builder.Add(new DynamicLocalInfo(dynamicLocal.FlagCount, dynamicLocal.Flags, slot, name));
+            }
+
+            var result = builder.ToImmutableAndFree();
+            localNames.Free();
+            return result;
+        }
+
         private static void ReadVisualBasicImportsDebugInfo(
             ISymUnmanagedReader reader,
             int methodToken,
diff --git a/src/Test/PdbUtilities/Pdb/PdbToXml.cs b/src/Test/PdbUtilities/Pdb/PdbToXml.cs
index 43c63d760436a97f90d1edc24fc44bc4174325ef..f4c6692e4a254e39178a21d9d8c5bdef5c400bbc 100644
--- a/src/Test/PdbUtilities/Pdb/PdbToXml.cs
+++ b/src/Test/PdbUtilities/Pdb/PdbToXml.cs
@@ -453,12 +453,12 @@ private void WriteDynamicLocalsCustomDebugInfo(CustomDebugInfoRecord record)
 
             _writer.WriteStartElement("dynamicLocals");
 
-            var buckets = CDI.DecodeDynamicLocalsRecord(record.Data);
+            var dynamicLocals = CDI.DecodeDynamicLocalsRecord(record.Data);
 
-            foreach (DynamicLocalBucket bucket in buckets)
+            foreach (DynamicLocalInfo dynamicLocal in dynamicLocals)
             {
-                ulong flags = bucket.Flags;
-                int flagCount = bucket.FlagCount;
+                ulong flags = dynamicLocal.Flags;
+                int flagCount = dynamicLocal.FlagCount;
 
                 PooledStringBuilder pooled = PooledStringBuilder.GetInstance();
                 StringBuilder flagsBuilder = pooled.Builder;
@@ -470,8 +470,8 @@ private void WriteDynamicLocalsCustomDebugInfo(CustomDebugInfoRecord record)
                 _writer.WriteStartElement("bucket");
                 _writer.WriteAttributeString("flagCount", CultureInvariantToString(flagCount));
                 _writer.WriteAttributeString("flags", pooled.ToStringAndFree());
-                _writer.WriteAttributeString("slotId", CultureInvariantToString(bucket.SlotId));
-                _writer.WriteAttributeString("localName", bucket.Name);
+                _writer.WriteAttributeString("slotId", CultureInvariantToString(dynamicLocal.SlotId));
+                _writer.WriteAttributeString("localName", dynamicLocal.Name);
                 _writer.WriteEndElement(); //bucket
             }
 
diff --git a/src/Test/PdbUtilities/Shared/CustomDebugInfoReader.cs b/src/Test/PdbUtilities/Shared/CustomDebugInfoReader.cs
index 69bbaf9a3e3e8dadf8dc76844c54eae95eacea7d..bcc402d147304e3eb9f89d9fb1ff5ee824a7f451 100644
--- a/src/Test/PdbUtilities/Shared/CustomDebugInfoReader.cs
+++ b/src/Test/PdbUtilities/Shared/CustomDebugInfoReader.cs
@@ -226,12 +226,12 @@ public static string DecodeForwardIteratorRecord(ImmutableArray<byte> bytes)
         /// Exposed for <see cref="T:Roslyn.Test.PdbUtilities.PdbToXmlConverter"/>.
         /// </remarks>
         /// <exception cref="InvalidOperationException">Bad data.</exception>
-        public static ImmutableArray<DynamicLocalBucket> DecodeDynamicLocalsRecord(ImmutableArray<byte> bytes)
+        public static ImmutableArray<DynamicLocalInfo> DecodeDynamicLocalsRecord(ImmutableArray<byte> bytes)
         {
             int offset = 0;
             int bucketCount = ReadInt32(bytes, ref offset);
 
-            var builder = ArrayBuilder<DynamicLocalBucket>.GetInstance(bucketCount);
+            var builder = ArrayBuilder<DynamicLocalInfo>.GetInstance(bucketCount);
             for (int i = 0; i < bucketCount; i++)
             {
                 const int FlagBytesCount = 64;
@@ -269,8 +269,7 @@ public static ImmutableArray<DynamicLocalBucket> DecodeDynamicLocalsRecord(Immut
 
                 var name = pooled.ToStringAndFree();
 
-                var bucket = new DynamicLocalBucket(flagCount, flags, slotId, name);
-                builder.Add(bucket);
+                builder.Add(new DynamicLocalInfo(flagCount, flags, slotId, name));
             }
 
             return builder.ToImmutableAndFree();
@@ -475,140 +474,6 @@ public static ImmutableArray<string> GetVisualBasicImportStrings(this ISymUnmana
             return importStrings;
         }
 
-        /// <exception cref="InvalidOperationException">Bad data.</exception>
-        public static void GetCSharpDynamicLocalInfo(
-            byte[] customDebugInfo,
-            int methodToken,
-            int methodVersion,
-            IEnumerable<ISymUnmanagedScope> scopes,
-            out ImmutableDictionary<int, ImmutableArray<bool>> dynamicLocalMap,
-            out ImmutableDictionary<string, ImmutableArray<bool>> dynamicLocalConstantMap)
-        {
-            dynamicLocalMap = ImmutableDictionary<int, ImmutableArray<bool>>.Empty;
-            dynamicLocalConstantMap = ImmutableDictionary<string, ImmutableArray<bool>>.Empty;
-
-            var record = TryGetCustomDebugInfoRecord(customDebugInfo, CustomDebugInfoKind.DynamicLocals);
-            if (record.IsDefault)
-            {
-                return;
-            }
-
-            ImmutableDictionary<int, ImmutableArray<bool>>.Builder localBuilder = null;
-            ImmutableDictionary<string, ImmutableArray<bool>>.Builder constantBuilder = null;
-
-            var buckets = RemoveAmbiguousLocals(DecodeDynamicLocalsRecord(record), scopes);
-            foreach (var bucket in buckets)
-            {
-                var slot = bucket.SlotId;
-                var flags = GetFlags(bucket);
-                if (slot < 0)
-                {
-                    constantBuilder = constantBuilder ?? ImmutableDictionary.CreateBuilder<string, ImmutableArray<bool>>();
-                    constantBuilder[bucket.Name] = flags;
-                }
-                else
-                {
-                    localBuilder = localBuilder ?? ImmutableDictionary.CreateBuilder<int, ImmutableArray<bool>>();
-                    localBuilder[slot] = flags;
-                }
-            }
-
-            if (localBuilder != null)
-            {
-                dynamicLocalMap = localBuilder.ToImmutable();
-            }
-
-            if (constantBuilder != null)
-            {
-                dynamicLocalConstantMap = constantBuilder.ToImmutable();
-            }
-        }
-
-        /// <summary>
-        /// If there are dynamic locals or constants associated with SlotId == 0, check all locals and
-        /// constants with SlotId == 0 for duplicate names and discard duplicates since we
-        /// cannot determine which local or constant the dynamic info is associated with.
-        /// </summary>
-        private static ImmutableArray<DynamicLocalBucket> RemoveAmbiguousLocals(
-            ImmutableArray<DynamicLocalBucket> locals,
-            IEnumerable<ISymUnmanagedScope> scopes)
-        {
-            const byte DuplicateName = 0;
-            const byte VariableName = 1;
-            const byte ConstantName = 2;
-
-            var localNames = PooledDictionary<string, byte>.GetInstance();
-            var firstLocal = GetFirstLocal(scopes);
-            if (firstLocal != null)
-            {
-                localNames.Add(firstLocal.GetName(), VariableName);
-            }
-
-            foreach (var scope in scopes)
-            {
-                foreach (var constant in scope.GetConstants())
-                {
-                    var name = constant.GetName();
-                    localNames[name] = localNames.ContainsKey(name) ? DuplicateName : ConstantName;
-                }
-            }
-
-            var builder = ArrayBuilder<DynamicLocalBucket>.GetInstance();
-            foreach (var local in locals)
-            {
-                int slot = local.SlotId;
-                var name = local.Name;
-                if (slot == 0)
-                {
-                    byte localOrConstant;
-                    localNames.TryGetValue(name, out localOrConstant);
-                    if (localOrConstant == DuplicateName)
-                    {
-                        continue;
-                    }
-
-                    if (localOrConstant == ConstantName)
-                    {
-                        slot = -1;
-                    }
-                }
-
-                builder.Add(new DynamicLocalBucket(local.FlagCount, local.Flags, slot, name));
-            }
-
-            var result = builder.ToImmutableAndFree();
-            localNames.Free();
-            return result;
-        }
-
-        private static ISymUnmanagedVariable GetFirstLocal(IEnumerable<ISymUnmanagedScope> scopes)
-        {
-            foreach (var scope in scopes)
-            {
-                foreach (var local in scope.GetLocals())
-                {
-                    if (local.GetSlot() == 0)
-                    {
-                        return local;
-                    }
-                }
-            }
-
-            return null;
-        }
-
-        private static ImmutableArray<bool> GetFlags(DynamicLocalBucket bucket)
-        {
-            int flagCount = bucket.FlagCount;
-            ulong flags = bucket.Flags;
-            var builder = ArrayBuilder<bool>.GetInstance(flagCount);
-            for (int i = 0; i < flagCount; i++)
-            {
-                builder.Add((flags & (1u << i)) != 0);
-            }
-            return builder.ToImmutableAndFree();
-        }
-
         private static void CheckVersion(byte globalVersion, int methodToken)
         {
             if (globalVersion != CDI.CdiVersion)
@@ -1032,14 +897,14 @@ public StateMachineHoistedLocalScope(int startoffset, int endOffset)
         }
     }
 
-    internal struct DynamicLocalBucket
+    internal struct DynamicLocalInfo
     {
         public readonly int FlagCount;
         public readonly ulong Flags;
         public readonly int SlotId;
         public readonly string Name;
 
-        public DynamicLocalBucket(int flagCount, ulong flags, int slotId, string name)
+        public DynamicLocalInfo(int flagCount, ulong flags, int slotId, string name)
         {
             this.FlagCount = flagCount;
             this.Flags = flags;