diff --git a/ICSharpCode.NRefactory.CSharp/ICSharpCode.NRefactory.CSharp.csproj b/ICSharpCode.NRefactory.CSharp/ICSharpCode.NRefactory.CSharp.csproj
index 9d7d64485a..c38f7f7cf1 100644
--- a/ICSharpCode.NRefactory.CSharp/ICSharpCode.NRefactory.CSharp.csproj
+++ b/ICSharpCode.NRefactory.CSharp/ICSharpCode.NRefactory.CSharp.csproj
@@ -266,6 +266,7 @@
+
diff --git a/ICSharpCode.NRefactory.CSharp/Refactoring/CodeIssues/CompareBooleanWithTrueOrFalseIssue.cs b/ICSharpCode.NRefactory.CSharp/Refactoring/CodeIssues/CompareBooleanWithTrueOrFalseIssue.cs
new file mode 100644
index 0000000000..31db4ea97f
--- /dev/null
+++ b/ICSharpCode.NRefactory.CSharp/Refactoring/CodeIssues/CompareBooleanWithTrueOrFalseIssue.cs
@@ -0,0 +1,84 @@
+//
+// CompareBooleanWithTrueOrFalseIssue.cs
+//
+// Author:
+// Mansheng Yang
+//
+// Copyright (c) 2012 Mansheng Yang
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+using System.Collections.Generic;
+using System.Linq;
+using ICSharpCode.NRefactory.PatternMatching;
+
+namespace ICSharpCode.NRefactory.CSharp.Refactoring
+{
+ [IssueDescription ("Comparison of boolean with 'true' or 'false'",
+ Description = "Comparison of a boolean value with 'true' or 'false' constant.",
+ Category = IssueCategories.Redundancies,
+ Severity = Severity.Warning,
+ IssueMarker = IssueMarker.Underline)]
+ public class CompareBooleanWithTrueOrFalseIssue : ICodeIssueProvider
+ {
+ public IEnumerable GetIssues (BaseRefactoringContext context)
+ {
+ return new GatherVisitor (context).GetIssues ();
+ }
+
+ class GatherVisitor : GatherVisitorBase
+ {
+ static readonly Pattern pattern = new Choice {
+ PatternHelper.CommutativeOperator(
+ new NamedNode ("const", new Choice { new PrimitiveExpression(true), new PrimitiveExpression(false) }),
+ BinaryOperatorType.Equality, new AnyNode("expr")),
+ PatternHelper.CommutativeOperator(
+ new NamedNode ("const", new Choice { new PrimitiveExpression(true), new PrimitiveExpression(false) }),
+ BinaryOperatorType.InEquality, new AnyNode("expr")),
+ };
+
+ static InsertParenthesesVisitor insertParenthesesVisitor = new InsertParenthesesVisitor ();
+
+ public GatherVisitor (BaseRefactoringContext ctx)
+ : base (ctx)
+ {
+ }
+
+ public override void VisitBinaryOperatorExpression (BinaryOperatorExpression binaryOperatorExpression)
+ {
+ base.VisitBinaryOperatorExpression (binaryOperatorExpression);
+
+ var match = pattern.Match (binaryOperatorExpression);
+ if (!match.Success)
+ return;
+
+ AddIssue (binaryOperatorExpression, ctx.TranslateString ("Simplify boolean comparison"), scrpit => {
+ var expr = match.Get ("expr").First ().Clone ();
+ var boolConstant = (bool)match.Get ("const").First ().Value;
+ if ((binaryOperatorExpression.Operator == BinaryOperatorType.InEquality && boolConstant) ||
+ (binaryOperatorExpression.Operator == BinaryOperatorType.Equality && !boolConstant)) {
+ expr = new UnaryOperatorExpression (UnaryOperatorType.Not, expr);
+ expr.AcceptVisitor (insertParenthesesVisitor);
+ }
+ scrpit.Replace (binaryOperatorExpression, expr);
+ });
+ }
+ }
+ }
+}
diff --git a/ICSharpCode.NRefactory.Tests/CSharp/CodeIssues/CompareBooleanWithTrueOrFalseIssueTests.cs b/ICSharpCode.NRefactory.Tests/CSharp/CodeIssues/CompareBooleanWithTrueOrFalseIssueTests.cs
new file mode 100644
index 0000000000..b258a45aec
--- /dev/null
+++ b/ICSharpCode.NRefactory.Tests/CSharp/CodeIssues/CompareBooleanWithTrueOrFalseIssueTests.cs
@@ -0,0 +1,87 @@
+//
+// CompareBooleanWithTrueOrFalseIssueTests.cs
+//
+// Author:
+// Mansheng Yang
+//
+// Copyright (c) 2012 Mansheng Yang
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+using ICSharpCode.NRefactory.CSharp.Refactoring;
+using NUnit.Framework;
+
+namespace ICSharpCode.NRefactory.CSharp.CodeIssues
+{
+ [TestFixture]
+ public class CompareBooleanWithTrueOrFalseIssueTests : InspectionActionTestBase
+ {
+ [Test]
+ public void Test ()
+ {
+ var input = @"
+class TestClass
+{
+ void TestMethod (bool x)
+ {
+ bool y;
+ y = x == true;
+ y = x != false;
+ y = x != true;
+ y = x == false;
+ }
+}";
+ var output = @"
+class TestClass
+{
+ void TestMethod (bool x)
+ {
+ bool y;
+ y = x;
+ y = x;
+ y = !x;
+ y = !x;
+ }
+}";
+ Test (input, 4, output);
+ }
+
+ [Test]
+ public void TestInsertParenthese ()
+ {
+ var input = @"
+class TestClass
+{
+ void TestMethod ()
+ {
+ bool y = 2 > 1 == false;
+ }
+}";
+ var output = @"
+class TestClass
+{
+ void TestMethod ()
+ {
+ bool y = !(2 > 1);
+ }
+}";
+ Test (input, 1, output);
+ }
+ }
+}
diff --git a/ICSharpCode.NRefactory.Tests/ICSharpCode.NRefactory.Tests.csproj b/ICSharpCode.NRefactory.Tests/ICSharpCode.NRefactory.Tests.csproj
index 29f9a9035d..833d0c0a6c 100644
--- a/ICSharpCode.NRefactory.Tests/ICSharpCode.NRefactory.Tests.csproj
+++ b/ICSharpCode.NRefactory.Tests/ICSharpCode.NRefactory.Tests.csproj
@@ -119,6 +119,7 @@
+