Simplify code.

src/Compilers/CSharp/Portable/Emitter/EditAndContinue/CSharpDefinitionMap.cs

@@ -5,12 +5,10 @@
 using System.Collections.Immutable;
 using System.Diagnostics;
 using System.Reflection.Metadata;
-using Microsoft.Cci;
 using Microsoft.CodeAnalysis.CodeGen;
 using Microsoft.CodeAnalysis.CSharp.Symbols;
 using Microsoft.CodeAnalysis.CSharp.Symbols.Metadata.PE;
 using Microsoft.CodeAnalysis.Emit;
-using Microsoft.CodeAnalysis.Symbols;
 
 namespace Microsoft.CodeAnalysis.CSharp.Emit
 {

src/Compilers/Core/Portable/Emit/EditAndContinue/DefinitionMap.cs

@@ -8,7 +8,6 @@
 using System.Linq;
 using System.Reflection.Metadata;
 using System.Reflection.Metadata.Ecma335;
-using Microsoft.Cci;
 using Microsoft.CodeAnalysis.CodeGen;
 using Microsoft.CodeAnalysis.Symbols;
 using Roslyn.Utilities;

src/Compilers/Core/Portable/Emit/EditAndContinue/EncVariableSlotAllocator.cs

@@ -11,7 +11,7 @@
 
 namespace Microsoft.CodeAnalysis.Emit
 {
-    internal class EncVariableSlotAllocator : VariableSlotAllocator
+    internal sealed class EncVariableSlotAllocator : VariableSlotAllocator
     {
         // symbols:
         private readonly SymbolMatcher _symbolMap;

src/Compilers/VisualBasic/Portable/Emit/EditAndContinue/VisualBasicDefinitionMap.vb

@@ -3,10 +3,8 @@
 Imports System.Collections.Immutable
 Imports System.Reflection.Metadata
 Imports System.Runtime.InteropServices
-Imports Microsoft.Cci
 Imports Microsoft.CodeAnalysis.CodeGen
 Imports Microsoft.CodeAnalysis.Emit
-Imports Microsoft.CodeAnalysis.Symbols
 Imports Microsoft.CodeAnalysis.VisualBasic.Symbols
 Imports Microsoft.CodeAnalysis.VisualBasic.Symbols.Metadata.PE
 

src/Compilers/VisualBasic/Portable/Emit/EditAndContinue/VisualBasicEncVariableSlotAllocator.vb

 ' Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
-Imports System.Collections.Immutable
-Imports Microsoft.Cci
-Imports Microsoft.CodeAnalysis.CodeGen
 Imports Microsoft.CodeAnalysis.Emit
-Imports Microsoft.CodeAnalysis.Symbols
 
 Namespace Microsoft.CodeAnalysis.VisualBasic.Emit
     Friend Class VisualBasicLambdaSyntaxHelper