Revert "Revert "Revert "Refactoring of extension methods in source packages (#78620)" (#78850)""

This reverts commit 27ae586.

Author: tmat

src/Analyzers/CSharp/Analyzers/RemoveUnnecessaryNullableDirective/CSharpRemoveUnnecessaryNullableDirectiveDiagnosticAnalyzer.cs

@@ -7,7 +7,6 @@
 using System.Diagnostics.CodeAnalysis;
 using System.Threading;
 using Microsoft.CodeAnalysis.CodeStyle;
-using Microsoft.CodeAnalysis.Collections;
 using Microsoft.CodeAnalysis.CSharp;
 using Microsoft.CodeAnalysis.CSharp.Analyzers.RemoveUnnecessaryNullableDirective;
 using Microsoft.CodeAnalysis.CSharp.Syntax;

src/Analyzers/CSharp/Analyzers/UseSimpleUsingStatement/UseSimpleUsingStatementDiagnosticAnalyzer.cs

@@ -4,7 +4,6 @@
 
 using System.Collections.Generic;
 using System.Collections.Immutable;
-using System.Linq;
 using System.Threading;
 using Microsoft.CodeAnalysis.CodeStyle;
 using Microsoft.CodeAnalysis.CSharp.CodeStyle;

src/Analyzers/CSharp/CodeFixes/UseCollectionExpression/CSharpUseCollectionExpressionForFluentCodeFixProvider.cs

@@ -9,7 +9,6 @@
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.CodeAnalysis.CodeFixes;
-using Microsoft.CodeAnalysis.Collections;
 using Microsoft.CodeAnalysis.CSharp.Formatting;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
 using Microsoft.CodeAnalysis.Diagnostics;
@@ -26,8 +25,8 @@
 namespace Microsoft.CodeAnalysis.CSharp.UseCollectionExpression;
 
 using static CSharpCollectionExpressionRewriter;
-using static CSharpSyntaxTokens;
 using static CSharpUseCollectionExpressionForFluentDiagnosticAnalyzer;
+using static CSharpSyntaxTokens;
 using static SyntaxFactory;
 
 [ExportCodeFixProvider(LanguageNames.CSharp, Name = PredefinedCodeFixProviderNames.UseCollectionExpressionForFluent), Shared]

src/Analyzers/CSharp/CodeFixes/UseLocalFunction/CSharpUseLocalFunctionCodeFixProvider.cs

@@ -14,7 +14,6 @@
 using System.Threading.Tasks;
 using Microsoft.CodeAnalysis.CodeFixes;
 using Microsoft.CodeAnalysis.CodeGeneration;
-using Microsoft.CodeAnalysis.Collections;
 using Microsoft.CodeAnalysis.CSharp.CodeGeneration;
 using Microsoft.CodeAnalysis.CSharp.Extensions;
 using Microsoft.CodeAnalysis.CSharp.Syntax;

src/Analyzers/Core/Analyzers/UseCollectionInitializer/AbstractUseCollectionInitializerDiagnosticAnalyzer.cs

@@ -6,7 +6,6 @@
 using System.Linq;
 using System.Threading;
 using Microsoft.CodeAnalysis.CodeStyle;
-using Microsoft.CodeAnalysis.Collections;
 using Microsoft.CodeAnalysis.Diagnostics;
 using Microsoft.CodeAnalysis.LanguageService;
 using Microsoft.CodeAnalysis.Shared.CodeStyle;

src/Analyzers/Core/Analyzers/UseObjectInitializer/AbstractUseObjectInitializerDiagnosticAnalyzer.cs

@@ -5,7 +5,6 @@
 using System.Collections.Immutable;
 using System.Linq;
 using Microsoft.CodeAnalysis.CodeStyle;
-using Microsoft.CodeAnalysis.Collections;
 using Microsoft.CodeAnalysis.Diagnostics;
 using Microsoft.CodeAnalysis.LanguageService;
 using Microsoft.CodeAnalysis.Shared.Collections;

src/Analyzers/Core/CodeFixes/AddExplicitCast/AbstractAddExplicitCastCodeFixProvider.cs

@@ -8,7 +8,6 @@
 using System.Threading.Tasks;
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.CodeActions;
-using Microsoft.CodeAnalysis.Collections;
 using Microsoft.CodeAnalysis.Editing;
 using Microsoft.CodeAnalysis.LanguageService;
 using Microsoft.CodeAnalysis.PooledObjects;

src/Analyzers/Core/CodeFixes/AddParameter/AbstractAddParameterCodeFixProvider.cs

@@ -11,7 +11,6 @@
 using Microsoft.CodeAnalysis.CodeActions;
 using Microsoft.CodeAnalysis.CodeFixes;
 using Microsoft.CodeAnalysis.CodeGeneration;
-using Microsoft.CodeAnalysis.Collections;
 using Microsoft.CodeAnalysis.LanguageService;
 using Microsoft.CodeAnalysis.PooledObjects;
 using Microsoft.CodeAnalysis.Shared.Collections;

src/Analyzers/Core/CodeFixes/AliasAmbiguousType/AbstractAliasAmbiguousTypeCodeFixProvider.cs

@@ -10,7 +10,6 @@
 using Microsoft.CodeAnalysis.AddImport;
 using Microsoft.CodeAnalysis.CodeActions;
 using Microsoft.CodeAnalysis.CodeFixes;
-using Microsoft.CodeAnalysis.Collections;
 using Microsoft.CodeAnalysis.Editing;
 using Microsoft.CodeAnalysis.LanguageService;
 using Microsoft.CodeAnalysis.PooledObjects;

src/Analyzers/Core/CodeFixes/ConflictMarkerResolution/AbstractConflictMarkerCodeFixProvider.cs

@@ -5,7 +5,6 @@
 using System;
 using System.Collections.Immutable;
 using System.Diagnostics;
-using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.CodeAnalysis.CodeActions;

src/Analyzers/Core/CodeFixes/ImplementInterface/ImplementInterfaceGenerator_Property.cs

@@ -5,7 +5,6 @@
 using System.Collections.Immutable;
 using System.Linq;
 using Microsoft.CodeAnalysis.CodeGeneration;
-using Microsoft.CodeAnalysis.Collections;
 using Microsoft.CodeAnalysis.Editing;
 using Microsoft.CodeAnalysis.ImplementType;
 using Microsoft.CodeAnalysis.LanguageService;

src/Analyzers/Core/CodeFixes/NamingStyle/NamingStyleCodeFixProvider.cs

@@ -12,7 +12,6 @@
 using System.Threading.Tasks;
 using System.Xml.Linq;
 using Microsoft.CodeAnalysis.CodeActions;
-using Microsoft.CodeAnalysis.Collections;
 using Microsoft.CodeAnalysis.Diagnostics;
 using Microsoft.CodeAnalysis.LanguageService;
 using Microsoft.CodeAnalysis.NamingStyles;

src/Analyzers/VisualBasic/Tests/AddRequiredParentheses/AddRequiredParenthesesTests.vb

@@ -2,6 +2,12 @@
 ' 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.AddRequiredParentheses
+Imports Microsoft.CodeAnalysis.CodeFixes
+Imports Microsoft.CodeAnalysis.Diagnostics
+Imports Microsoft.CodeAnalysis.Editor.VisualBasic.UnitTests.Diagnostics
+Imports Microsoft.CodeAnalysis.VisualBasic.AddRequiredParentheses
+
 Imports VerifyVB = Microsoft.CodeAnalysis.Editor.UnitTests.CodeActions.VisualBasicCodeFixVerifier(Of Microsoft.CodeAnalysis.VisualBasic.AddRequiredParentheses.VisualBasicAddRequiredParenthesesForBinaryLikeExpressionDiagnosticAnalyzer, Microsoft.CodeAnalysis.AddRequiredParentheses.AddRequiredParenthesesCodeFixProvider)
 
 Namespace Microsoft.CodeAnalysis.Editor.VisualBasic.UnitTests.AddRequiredParentheses

src/Analyzers/VisualBasic/Tests/GenerateEnumMember/GenerateEnumMemberTests.vb

@@ -3,8 +3,8 @@
 ' See the LICENSE file in the project root for more information.
 
 Imports Microsoft.CodeAnalysis.CodeFixes
-Imports Microsoft.CodeAnalysis.Diagnostics
 Imports Microsoft.CodeAnalysis.VisualBasic.CodeFixes.GenerateEnumMember
+Imports Microsoft.CodeAnalysis.Diagnostics
 
 Namespace Microsoft.CodeAnalysis.Editor.VisualBasic.UnitTests.Diagnostics.GenerateEnumMember
     <Trait(Traits.Feature, Traits.Features.CodeActionsGenerateEnumMember)>

src/Analyzers/VisualBasic/Tests/GenerateMethod/GenerateConversionTests.vb

@@ -3,8 +3,8 @@
 ' See the LICENSE file in the project root for more information.
 
 Imports Microsoft.CodeAnalysis.CodeFixes
-Imports Microsoft.CodeAnalysis.Diagnostics
 Imports Microsoft.CodeAnalysis.VisualBasic.CodeFixes.GenerateMethod
+Imports Microsoft.CodeAnalysis.Diagnostics
 
 Namespace Microsoft.CodeAnalysis.Editor.VisualBasic.UnitTests.Diagnostics.GenerateMethod
     Partial Public NotInheritable Class GenerateMethodTests

src/Analyzers/VisualBasic/Tests/ImplementAbstractClass/ImplementAbstractClassTests.vb

@@ -2,10 +2,12 @@
 ' 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.CodeActions
 Imports Microsoft.CodeAnalysis.CodeFixes
 Imports Microsoft.CodeAnalysis.Diagnostics
 Imports Microsoft.CodeAnalysis.Editor.VisualBasic.UnitTests.Diagnostics
 Imports Microsoft.CodeAnalysis.ImplementType
+Imports Microsoft.CodeAnalysis.SymbolSearch
 Imports Microsoft.CodeAnalysis.VisualBasic.ImplementAbstractClass
 
 Namespace Microsoft.CodeAnalysis.Editor.VisualBasic.UnitTests.ImplementAbstractClass

src/Analyzers/VisualBasic/Tests/ImplementAbstractClass/ImplementAbstractClassTests_FixAllTests.vb

@@ -2,6 +2,8 @@
 ' 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.VisualBasic.ImplementAbstractClass
+
 Namespace Microsoft.CodeAnalysis.Editor.VisualBasic.UnitTests.ImplementAbstractClass
     Partial Public Class ImplementAbstractClassTests
 

src/Analyzers/VisualBasic/Tests/ImplementInterface/ImplementInterfaceTests.vb

@@ -2,10 +2,12 @@
 ' 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.CodeActions
 Imports Microsoft.CodeAnalysis.CodeFixes
 Imports Microsoft.CodeAnalysis.Diagnostics
 Imports Microsoft.CodeAnalysis.Editor.VisualBasic.UnitTests.Diagnostics
 Imports Microsoft.CodeAnalysis.ImplementType
+Imports Microsoft.CodeAnalysis.SymbolSearch
 Imports Microsoft.CodeAnalysis.VisualBasic.ImplementInterface
 
 Namespace Microsoft.CodeAnalysis.Editor.VisualBasic.UnitTests.ImplementInterface

src/Analyzers/VisualBasic/Tests/Iterator/IteratorTests.vb

@@ -2,7 +2,12 @@
 ' 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.CodeFixes
+Imports Microsoft.CodeAnalysis.Diagnostics
+Imports Microsoft.CodeAnalysis.Editor.VisualBasic.UnitTests.Diagnostics
 Imports Microsoft.CodeAnalysis.Testing
+Imports Microsoft.CodeAnalysis.VisualBasic.CodeFixes.Iterator
+
 Imports VerifyConvertToIterator = Microsoft.CodeAnalysis.Editor.UnitTests.CodeActions.VisualBasicCodeFixVerifier(Of Microsoft.CodeAnalysis.Testing.EmptyDiagnosticAnalyzer, Microsoft.CodeAnalysis.VisualBasic.CodeFixes.Iterator.VisualBasicConvertToIteratorCodeFixProvider)
 Imports VerifyConvertToYield = Microsoft.CodeAnalysis.Editor.UnitTests.CodeActions.VisualBasicCodeFixVerifier(Of Microsoft.CodeAnalysis.Testing.EmptyDiagnosticAnalyzer, Microsoft.CodeAnalysis.VisualBasic.CodeFixes.Iterator.VisualBasicChangeToYieldCodeFixProvider)
 

src/Analyzers/VisualBasic/Tests/NewLines/ConsecutiveStatementPlacement/ConsecutiveStatementPlacementTests.vb

@@ -3,6 +3,7 @@
 ' See the LICENSE file in the project root for more information.
 
 Imports Microsoft.CodeAnalysis.CodeStyle
+
 Imports VerifyVB = Microsoft.CodeAnalysis.Editor.UnitTests.CodeActions.VisualBasicCodeFixVerifier(Of
     Microsoft.CodeAnalysis.VisualBasic.NewLines.ConsecutiveStatementPlacement.VisualBasicConsecutiveStatementPlacementDiagnosticAnalyzer,
     Microsoft.CodeAnalysis.NewLines.ConsecutiveStatementPlacement.ConsecutiveStatementPlacementCodeFixProvider)

src/Analyzers/VisualBasic/Tests/QualifyMemberAccess/QualifyMemberAccessTests.vb

@@ -5,8 +5,8 @@
 Imports Microsoft.CodeAnalysis.CodeFixes
 Imports Microsoft.CodeAnalysis.CodeStyle
 Imports Microsoft.CodeAnalysis.Diagnostics
-Imports Microsoft.CodeAnalysis.Editor.VisualBasic.UnitTests.Diagnostics
 Imports Microsoft.CodeAnalysis.Options
+Imports Microsoft.CodeAnalysis.Editor.VisualBasic.UnitTests.Diagnostics
 Imports Microsoft.CodeAnalysis.VisualBasic.QualifyMemberAccess
 
 Namespace Microsoft.CodeAnalysis.Editor.VisualBasic.UnitTests.QualifyMemberAccess

src/Analyzers/VisualBasic/Tests/RemoveUnnecessaryParentheses/RemoveUnnecessaryParenthesesTests.vb

@@ -4,6 +4,7 @@
 
 Imports Microsoft.CodeAnalysis.CodeFixes
 Imports Microsoft.CodeAnalysis.Diagnostics
+Imports Microsoft.CodeAnalysis.Editor.UnitTests.Workspaces
 Imports Microsoft.CodeAnalysis.Editor.VisualBasic.UnitTests.Diagnostics
 Imports Microsoft.CodeAnalysis.Text
 Imports Microsoft.CodeAnalysis.VisualBasic.RemoveUnnecessaryParentheses

src/Analyzers/VisualBasic/Tests/SimplifyLinqExpression/VisualBasicSimplifyLinqExpressionTests.vb

@@ -2,6 +2,9 @@
 ' 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.Editor.UnitTests.CodeActions
+Imports Microsoft.CodeAnalysis.SimplifyLinqExpression
+
 Imports VerifyVB = Microsoft.CodeAnalysis.Editor.UnitTests.CodeActions.VisualBasicCodeFixVerifier(Of
     Microsoft.CodeAnalysis.VisualBasic.SimplifyLinqExpression.VisualBasicSimplifyLinqExpressionDiagnosticAnalyzer,
     Microsoft.CodeAnalysis.SimplifyLinqExpression.SimplifyLinqExpressionCodeFixProvider)

src/Analyzers/VisualBasic/Tests/UseCoalesceExpression/UseCoalesceExpressionForIfNullStatementCheckTests.vb

@@ -2,6 +2,12 @@
 ' 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.CodeFixes
+Imports Microsoft.CodeAnalysis.Diagnostics
+Imports Microsoft.CodeAnalysis.Editor.VisualBasic.UnitTests.Diagnostics
+Imports Microsoft.CodeAnalysis.UseCoalesceExpression
+Imports Microsoft.CodeAnalysis.VisualBasic.UseCoalesceExpression
+
 Imports VerifyVB = Microsoft.CodeAnalysis.Editor.UnitTests.CodeActions.VisualBasicCodeFixVerifier(Of
     Microsoft.CodeAnalysis.VisualBasic.UseCoalesceExpression.VisualBasicUseCoalesceExpressionForIfNullStatementCheckDiagnosticAnalyzer,
     Microsoft.CodeAnalysis.VisualBasic.UseCoalesceExpression.VisualBasicUseCoalesceExpressionForIfNullStatementCheckCodeFixProvider)

src/Analyzers/VisualBasic/Tests/UseIsNullCheck/UseIsNullCheckForReferenceEqualsTests.vb

@@ -3,9 +3,9 @@
 ' See the LICENSE file in the project root for more information.
 
 Imports Microsoft.CodeAnalysis.CodeFixes
+Imports Microsoft.CodeAnalysis.VisualBasic.UseIsNullCheck
 Imports Microsoft.CodeAnalysis.Diagnostics
 Imports Microsoft.CodeAnalysis.Editor.VisualBasic.UnitTests.Diagnostics
-Imports Microsoft.CodeAnalysis.VisualBasic.UseIsNullCheck
 
 Namespace Microsoft.CodeAnalysis.Editor.VisualBasic.UnitTests.UseIsNullCheck
     <Trait(Traits.Feature, Traits.Features.CodeActionsUseIsNullCheck)>

src/Compilers/CSharp/Portable/Binder/Binder.ValueChecks.cs

@@ -7,7 +7,6 @@
 using System.Collections.Immutable;
 using System.Diagnostics;
 using System.Diagnostics.CodeAnalysis;
-using System.Linq;
 using Microsoft.CodeAnalysis.CSharp.CodeGen;
 using Microsoft.CodeAnalysis.CSharp.Symbols;
 using Microsoft.CodeAnalysis.PooledObjects;

src/Compilers/CSharp/Portable/Binder/Binder_Constraints.cs

@@ -5,7 +5,6 @@
 using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Diagnostics;
-using System.Linq;
 using Microsoft.CodeAnalysis.CSharp.Symbols;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
 using Microsoft.CodeAnalysis.PooledObjects;

src/Compilers/CSharp/Portable/Binder/Binder_Patterns.cs

@@ -6,7 +6,6 @@
 using System.Collections.Immutable;
 using System.Diagnostics;
 using System.Diagnostics.CodeAnalysis;
-using System.Linq;
 using Microsoft.CodeAnalysis.CSharp.Symbols;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
 using Microsoft.CodeAnalysis.PooledObjects;

src/Compilers/CSharp/Portable/Binder/DecisionDagBuilder.cs

@@ -9,10 +9,10 @@
 using System.Diagnostics.CodeAnalysis;
 using System.Linq;
 using System.Text;
-using Microsoft.CodeAnalysis.Collections;
 using Microsoft.CodeAnalysis.CSharp.Symbols;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
 using Microsoft.CodeAnalysis.PooledObjects;
+using Microsoft.CodeAnalysis.Shared.Collections;
 using Roslyn.Utilities;
 
 namespace Microsoft.CodeAnalysis.CSharp

src/Compilers/CSharp/Portable/Binder/DecisionDagBuilder_ListPatterns.cs

@@ -3,7 +3,6 @@
 // See the LICENSE file in the project root for more information.
 
 using System.Diagnostics;
-using System.Linq;
 using Microsoft.CodeAnalysis.CSharp.Symbols;
 using Microsoft.CodeAnalysis.PooledObjects;
 

src/Compilers/CSharp/Portable/Binder/InMethodBinder.cs

@@ -8,7 +8,6 @@
 using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Diagnostics;
-using System.Linq;
 using Microsoft.CodeAnalysis.CSharp.Symbols;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
 using Roslyn.Utilities;

src/Compilers/CSharp/Portable/Binder/Semantics/Conversions/ConversionsBase.cs

@@ -7,11 +7,11 @@
 using System.Collections.Immutable;
 using System.Diagnostics;
 using System.Diagnostics.CodeAnalysis;
-using System.Linq;
 using System.Threading;
 using Microsoft.CodeAnalysis.CSharp.Symbols;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
 using Microsoft.CodeAnalysis.PooledObjects;
+using Roslyn.Utilities;
 
 namespace Microsoft.CodeAnalysis.CSharp
 {

src/Compilers/CSharp/Portable/Binder/Semantics/Operators/BinaryOperatorOverloadResolution.cs

@@ -8,9 +8,9 @@
 using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Diagnostics;
-using Microsoft.CodeAnalysis.Collections;
 using Microsoft.CodeAnalysis.CSharp.Symbols;
 using Microsoft.CodeAnalysis.PooledObjects;
+using Microsoft.CodeAnalysis.Shared.Collections;
 using Roslyn.Utilities;
 
 namespace Microsoft.CodeAnalysis.CSharp

src/Compilers/CSharp/Portable/Binder/Semantics/OverloadResolution/OverloadResolution.cs

@@ -10,9 +10,9 @@
 using System.Diagnostics;
 using System.Linq;
 using Microsoft.Cci;
-using Microsoft.CodeAnalysis.Collections;
 using Microsoft.CodeAnalysis.CSharp.Symbols;
 using Microsoft.CodeAnalysis.PooledObjects;
+using Microsoft.CodeAnalysis.Shared.Collections;
 using Microsoft.CodeAnalysis.Symbols;
 using Roslyn.Utilities;
 

src/Compilers/CSharp/Portable/Binder/SwitchExpressionBinder.cs

@@ -5,10 +5,10 @@
 using System.Collections.Immutable;
 using System.Diagnostics;
 using System.Diagnostics.CodeAnalysis;
-using Microsoft.CodeAnalysis.Collections;
 using Microsoft.CodeAnalysis.CSharp.Symbols;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
 using Microsoft.CodeAnalysis.PooledObjects;
+using Microsoft.CodeAnalysis.Shared.Collections;
 using Roslyn.Utilities;
 
 namespace Microsoft.CodeAnalysis.CSharp

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

@@ -9,9 +9,9 @@
 using System.Collections.Immutable;
 using System.Diagnostics;
 using System.Linq;
-using Microsoft.CodeAnalysis.Collections;
 using Microsoft.CodeAnalysis.CSharp.Symbols;
 using Microsoft.CodeAnalysis.PooledObjects;
+using Microsoft.CodeAnalysis.Shared.Collections;
 using Roslyn.Utilities;
 
 namespace Microsoft.CodeAnalysis.CSharp

src/Compilers/CSharp/Portable/Compilation/CSharpDeterministicKeyBuilder.cs

@@ -3,7 +3,8 @@
 // See the LICENSE file in the project root for more information.
 
 using System;
-using System.Linq;
+using System.Collections.Generic;
+using System.Text;
 using Roslyn.Utilities;
 
 namespace Microsoft.CodeAnalysis.CSharp

src/Compilers/CSharp/Portable/Compilation/CSharpSemanticModel.cs

@@ -10,7 +10,6 @@
 using System.Diagnostics;
 using System.Linq;
 using System.Threading;
-using Microsoft.CodeAnalysis.Collections;
 using Microsoft.CodeAnalysis.CSharp.Symbols;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
 using Microsoft.CodeAnalysis.PooledObjects;

src/Compilers/CSharp/Portable/Compilation/MemberSemanticModel.cs

@@ -11,7 +11,6 @@
 using System.Diagnostics.CodeAnalysis;
 using System.Linq;
 using System.Threading;
-using Microsoft.CodeAnalysis.Collections;
 using Microsoft.CodeAnalysis.CSharp.Symbols;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
 using Microsoft.CodeAnalysis.Operations;

src/Compilers/CSharp/Portable/Compilation/SymbolInfoFactory.cs

@@ -8,7 +8,6 @@
 using System.Collections.Immutable;
 using System.Diagnostics;
 using System.Linq;
-using Microsoft.CodeAnalysis.Collections;
 using Microsoft.CodeAnalysis.CSharp.Symbols;
 using Microsoft.CodeAnalysis.PooledObjects;
 using Roslyn.Utilities;

src/Compilers/CSharp/Portable/Declarations/MergedTypeDeclaration.cs

@@ -8,7 +8,6 @@
 using System.Collections.Immutable;
 using System.Diagnostics;
 using System.Threading;
-using Microsoft.CodeAnalysis.Collections;
 using Microsoft.CodeAnalysis.CSharp.Symbols;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
 using Microsoft.CodeAnalysis.PooledObjects;