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Implemented analyzer, code fix, and tests
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Lines changed: 336 additions & 3 deletions

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‎StyleCop.Analyzers/StyleCop.Analyzers.Test/ReadabilityRules/SA1129UnitTests.cs‎

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// Copyright (c) Tunnel Vision Laboratories, LLC. All Rights Reserved.
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// Licensed under the Apache License, Version 2.0. See LICENSE in the project root for license information.
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namespace StyleCop.Analyzers.Test.ReadabilityRules
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{
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using System;
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using System.Collections.Generic;
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using System.Threading;
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using System.Threading.Tasks;
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using Analyzers.ReadabilityRules;
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using Microsoft.CodeAnalysis.CodeFixes;
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using Microsoft.CodeAnalysis.Diagnostics;
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using TestHelper;
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using Xunit;
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/// <summary>
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/// Unit tests for the <see cref="SA1129DoNotUseDefaultValueTypeConstructor"/> class.
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/// </summary>
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public class SA1129UnitTests : CodeFixVerifier
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{
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/// <summary>
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/// Verifies that new expressions for reference types will not generate diagnostics.
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/// </summary>
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/// <returns>A <see cref="Task"/> representing the asynchronous unit test.</returns>
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[Fact]
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public async Task VerifyReferenceTypeCreationAsync()
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{
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var testCode = @"public class TestClass
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{
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public void TestMethod()
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{
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var v1 = new TestClass2();
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var v2 = new TestClass2(1);
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}
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private class TestClass2
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{
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public TestClass2()
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{
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}
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public TestClass2(int x)
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{
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}
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}
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}
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";
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await this.VerifyCSharpDiagnosticAsync(testCode, EmptyDiagnosticResults, CancellationToken.None).ConfigureAwait(false);
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}
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/// <summary>
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/// Verifies that new expressions for value types with parameters will not generate diagnostics.
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/// </summary>
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/// <returns>A <see cref="Task"/> representing the asynchronous unit test.</returns>
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[Fact]
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public async Task VerifyValueTypeWithParametersCreationAsync()
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{
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var testCode = @"public class TestClass
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{
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public void TestMethod()
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{
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var v1 = new TestStruct(1);
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var v2 = new TestStruct(1) { TestProperty = 2 };
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var v3 = new TestStruct() { TestProperty = 2 };
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}
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private struct TestStruct
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{
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public TestStruct(int x)
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{
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TestProperty = x;
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}
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public int TestProperty { get; set; }
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}
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}
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";
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await this.VerifyCSharpDiagnosticAsync(testCode, EmptyDiagnosticResults, CancellationToken.None).ConfigureAwait(false);
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}
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/// <summary>
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/// Verifies that new expressions for value types without parameters will generate diagnostics.
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/// </summary>
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/// <returns>A <see cref="Task"/> representing the asynchronous unit test.</returns>
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[Fact]
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public async Task VerifyInvalidValueTypeCreationAsync()
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{
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var testCode = @"public class TestClass
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{
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public void TestMethod()
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{
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var v1 = new TestStruct();
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}
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private struct TestStruct
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{
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public int TestProperty { get; set; }
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}
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}
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";
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var fixedTestCode = @"public class TestClass
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{
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public void TestMethod()
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{
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var v1 = default(TestStruct);
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}
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private struct TestStruct
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{
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public int TestProperty { get; set; }
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}
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}
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";
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DiagnosticResult[] expected =
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{
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this.CSharpDiagnostic().WithLocation(5, 18)
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};
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await this.VerifyCSharpDiagnosticAsync(testCode, expected, CancellationToken.None).ConfigureAwait(false);
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await this.VerifyCSharpDiagnosticAsync(fixedTestCode, EmptyDiagnosticResults, CancellationToken.None).ConfigureAwait(false);
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await this.VerifyCSharpFixAsync(testCode, fixedTestCode).ConfigureAwait(false);
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}
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/// <summary>
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/// Verifies that the codefix will preserve surrounding trivia.
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/// </summary>
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/// <returns>A <see cref="Task"/> representing the asynchronous unit test.</returns>
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[Fact]
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public async Task VerifyTriviaPreservationAsync()
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{
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var testCode = @"public class TestClass
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{
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public void TestMethod()
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{
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var v1 = /* c1 */ new TestStruct(); // c2
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var v2 =
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#if true
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new TestStruct();
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#else
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new TestStruct() { TestProperty = 3 };
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#endif
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}
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private struct TestStruct
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{
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public int TestProperty { get; set; }
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}
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}
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";
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var fixedTestCode = @"public class TestClass
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{
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public void TestMethod()
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{
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var v1 = /* c1 */ default(TestStruct); // c2
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var v2 =
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#if true
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default(TestStruct);
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#else
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new TestStruct() { TestProperty = 3 };
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#endif
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}
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private struct TestStruct
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{
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public int TestProperty { get; set; }
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}
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}
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";
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DiagnosticResult[] expected =
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{
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this.CSharpDiagnostic().WithLocation(5, 27),
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this.CSharpDiagnostic().WithLocation(9, 13)
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};
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await this.VerifyCSharpDiagnosticAsync(testCode, expected, CancellationToken.None).ConfigureAwait(false);
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await this.VerifyCSharpDiagnosticAsync(fixedTestCode, EmptyDiagnosticResults, CancellationToken.None).ConfigureAwait(false);
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await this.VerifyCSharpFixAsync(testCode, fixedTestCode).ConfigureAwait(false);
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}
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/// <inheritdoc/>
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protected override IEnumerable<DiagnosticAnalyzer> GetCSharpDiagnosticAnalyzers()
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{
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yield return new SA1129DoNotUseDefaultValueTypeConstructor();
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}
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/// <inheritdoc/>
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protected override CodeFixProvider GetCSharpCodeFixProvider()
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{
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return new SA1129CodeFixProvider();
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}
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}
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}

‎StyleCop.Analyzers/StyleCop.Analyzers.Test/StyleCop.Analyzers.Test.csproj‎

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@@ -303,6 +303,7 @@
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<Compile Include="ReadabilityRules\SA1126UnitTests.cs" />
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<Compile Include="ReadabilityRules\SA1127UnitTests.cs" />
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<Compile Include="ReadabilityRules\SA1128UnitTests.cs" />
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<Compile Include="ReadabilityRules\SA1129UnitTests.cs" />
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<Compile Include="ReadabilityRules\SA1130UnitTests.cs" />
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<Compile Include="ReadabilityRules\SA1132UnitTests.cs" />
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<Compile Include="Settings\SettingsFileCodeFixProviderUnitTests.cs" />

‎StyleCop.Analyzers/StyleCop.Analyzers/ReadabilityRules/ReadabilityResources.Designer.cs‎

Lines changed: 10 additions & 1 deletion
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‎StyleCop.Analyzers/StyleCop.Analyzers/ReadabilityRules/ReadabilityResources.resx‎

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<data name="SA1128Title" xml:space="preserve">
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<value>Put constructor initializers on their own line</value>
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</data>
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<data name="SA1129CodeFix" xml:space="preserve">
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<value>Replace with default(T)</value>
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</data>
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<data name="SA1129Description" xml:space="preserve">
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<value>When creating a new instance of a value type T, the syntax 'default(T)' is functionally equivalent to the syntax 'new T()'. To avoid confusion regarding the behavior of the resulting instance, the first form is preferred.</value>
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</data>
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<data name="SA1129MessageFormat" xml:space="preserve">
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<value />
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<value>Do not use default value type constructor</value>
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</data>
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<data name="SA1129Title" xml:space="preserve">
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<value>Do not use default value type constructor</value>

‎StyleCop.Analyzers/StyleCop.Analyzers/ReadabilityRules/SA1129CodeFixProvider.cs‎

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// Copyright (c) Tunnel Vision Laboratories, LLC. All Rights Reserved.
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// Licensed under the Apache License, Version 2.0. See LICENSE in the project root for license information.
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namespace StyleCop.Analyzers.ReadabilityRules
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{
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using System.Collections.Immutable;
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using System.Composition;
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using System.Linq;
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using System.Threading;
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using System.Threading.Tasks;
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using Helpers;
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using Microsoft.CodeAnalysis;
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using Microsoft.CodeAnalysis.CodeActions;
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using Microsoft.CodeAnalysis.CodeFixes;
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using Microsoft.CodeAnalysis.CSharp;
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using Microsoft.CodeAnalysis.CSharp.Syntax;
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/// <summary>
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/// Implements a code fix for <see cref="SA1129DoNotUseDefaultValueTypeConstructor"/>.
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/// </summary>
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[ExportCodeFixProvider(LanguageNames.CSharp, Name = nameof(SA1129CodeFixProvider))]
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[Shared]
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internal class SA1129CodeFixProvider : CodeFixProvider
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{
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public override ImmutableArray<string> FixableDiagnosticIds { get; } =
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ImmutableArray.Create(SA1129DoNotUseDefaultValueTypeConstructor.DiagnosticId);
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/// <inheritdoc/>
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public override FixAllProvider GetFixAllProvider()
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{
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return FixAll.Instance;
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}
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public override Task RegisterCodeFixesAsync(CodeFixContext context)
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{
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foreach (var diagnostic in context.Diagnostics.Where(d => this.FixableDiagnosticIds.Contains(d.Id)))
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{
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context.RegisterCodeFix(
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CodeAction.Create(
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ReadabilityResources.SA1129CodeFix,
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cancellationToken => GetTransformedDocumentAsync(context.Document, diagnostic, cancellationToken),
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equivalenceKey: nameof(SA1129CodeFixProvider)),
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diagnostic);
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}
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return SpecializedTasks.CompletedTask;
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}
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private static async Task<Document> GetTransformedDocumentAsync(Document document, Diagnostic diagnostic, CancellationToken cancellationToken)
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{
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var syntaxRoot = await document.GetSyntaxRootAsync(cancellationToken).ConfigureAwait(false);
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var newExpression = syntaxRoot.FindNode(diagnostic.Location.SourceSpan);
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var newSyntaxRoot = syntaxRoot.ReplaceNode(newExpression, GetReplacementNode(newExpression));
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return document.WithSyntaxRoot(newSyntaxRoot);
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}
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private static SyntaxNode GetReplacementNode(SyntaxNode node)
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{
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var newExpression = (ObjectCreationExpressionSyntax)node;
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return SyntaxFactory.DefaultExpression(newExpression.Type)
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.WithLeadingTrivia(newExpression.GetLeadingTrivia())
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.WithTrailingTrivia(newExpression.GetTrailingTrivia());
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}
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private class FixAll : DocumentBasedFixAllProvider
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{
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public static FixAllProvider Instance { get; } =
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new FixAll();
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protected override string CodeActionTitle { get; } =
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ReadabilityResources.SA1129CodeFix;
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protected override async Task<SyntaxNode> FixAllInDocumentAsync(FixAllContext fixAllContext, Document document)
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{
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var diagnostics = await fixAllContext.GetDocumentDiagnosticsAsync(document).ConfigureAwait(false);
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if (diagnostics.IsEmpty)
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{
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return null;
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}
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var syntaxRoot = await document.GetSyntaxRootAsync(fixAllContext.CancellationToken).ConfigureAwait(false);
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var nodes = diagnostics.Select(diagnostic => syntaxRoot.FindNode(diagnostic.Location.SourceSpan));
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return syntaxRoot.ReplaceNodes(nodes, (originalNode, rewrittenNode) => GetReplacementNode(rewrittenNode));
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}
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}
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}
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}

‎StyleCop.Analyzers/StyleCop.Analyzers/ReadabilityRules/SA1129DoNotUseDefaultValueTypeConstructor.cs‎

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@@ -5,6 +5,8 @@ namespace StyleCop.Analyzers.ReadabilityRules
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{
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using System.Collections.Immutable;
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using Microsoft.CodeAnalysis;
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using Microsoft.CodeAnalysis.CSharp;
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using Microsoft.CodeAnalysis.CSharp.Syntax;
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using Microsoft.CodeAnalysis.Diagnostics;
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/// <summary>
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/// <inheritdoc/>
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public override void Initialize(AnalysisContext context)
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{
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// TODO: Implement analysis
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context.RegisterCompilationStartAction(HandleCompilationStart);
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}
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private static void HandleCompilationStart(CompilationStartAnalysisContext context)
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{
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context.RegisterSyntaxNodeActionHonorExclusions(HandleNewExpression, SyntaxKind.ObjectCreationExpression);
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}
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private static void HandleNewExpression(SyntaxNodeAnalysisContext context)
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{
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ObjectCreationExpressionSyntax newExpression = (ObjectCreationExpressionSyntax)context.Node;
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var typeToCreate = context.SemanticModel.GetTypeInfo(newExpression, context.CancellationToken);
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if (typeToCreate.Type.IsReferenceType)
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{
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return;
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}
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if (newExpression.ArgumentList.Arguments.Count > 0)
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{
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return;
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}
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if (newExpression.Initializer != null)
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{
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return;
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}
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context.ReportDiagnostic(Diagnostic.Create(Descriptor, newExpression.GetLocation()));
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}
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}
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}

‎StyleCop.Analyzers/StyleCop.Analyzers/StyleCop.Analyzers.csproj‎

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<Compile Include="ReadabilityRules\SA1127GenericTypeConstraintsMustBeOnOwnLine.cs" />
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<Compile Include="ReadabilityRules\SA1128CodeFixProvider.cs" />
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<Compile Include="ReadabilityRules\SA1128ConstructorInitializerMustBeOnOwnLine.cs" />
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<Compile Include="ReadabilityRules\SA1129CodeFixProvider.cs" />
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<Compile Include="ReadabilityRules\SA1129DoNotUseDefaultValueTypeConstructor.cs" />
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<Compile Include="ReadabilityRules\SA1130UseLambdaSyntax.cs" />
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<Compile Include="ReadabilityRules\SA1131UseReadableConditions.cs" />

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