[CodeIssues] Add OptionalParameterCouldBeSkippedIssue.

ICSharpCode.NRefactory.CSharp/ICSharpCode.NRefactory.CSharp.csproj

@@ -397,6 +397,7 @@
     <Compile Include="Refactoring\CodeIssues\ReferenceToStaticMemberViaDerivedTypeIssue.cs" />
     <Compile Include="Refactoring\CodeIssues\ParameterCanBeDemotedIssue\IsTypeCriterion.cs" />
     <Compile Include="Refactoring\CodeIssues\FormatStringIssue.cs" />
+    <Compile Include="Refactoring\CodeIssues\OptionalParameterCouldBeSkippedIssue.cs" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\ICSharpCode.NRefactory\ICSharpCode.NRefactory.csproj">

ICSharpCode.NRefactory.CSharp/Refactoring/CodeIssues/OptionalParameterCouldBeSkippedIssue.cs

@@ -0,0 +1,105 @@
+//
+// OptionalParameterCouldBeSkippedIssue.cs
+//
+// Author:
+//       Simon Lindgren <simon.n.lindgren@gmail.com>
+//
+// Copyright (c) 2012 Simon Lindgren
+//
+// 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 ICSharpCode.NRefactory.CSharp.Resolver;
+using System.Linq;
+using ICSharpCode.NRefactory.Semantics;
+
+namespace ICSharpCode.NRefactory.CSharp.Refactoring
+{
+	[IssueDescription("Optional argument has default value and can be skipped",
+	                  Description = "Finds calls to functions where optional parameters are used and the passed argument is the same as the default.",
+	                  Category = IssueCategories.Redundancies,
+	                  Severity = Severity.Hint)]
+	public class OptionalParameterCouldBeSkippedIssue : ICodeIssueProvider
+	{
+		public IEnumerable<CodeIssue> GetIssues(BaseRefactoringContext context)
+		{
+			return new GatherVisitor(context).GetIssues();
+		}
+		
+		class GatherVisitor : GatherVisitorBase
+		{
+			readonly BaseRefactoringContext context;
+			
+			public GatherVisitor(BaseRefactoringContext context) : base (context)
+			{
+				this.context = context;
+			}
+
+			public override void VisitInvocationExpression(InvocationExpression invocationExpression)
+			{
+				base.VisitInvocationExpression(invocationExpression);
+				var invocationResolveResult = context.Resolve(invocationExpression) as CSharpInvocationResolveResult;
+				var argumentToParameterMap = invocationResolveResult.GetArgumentToParameterMap();
+				var resolvedParameters = invocationResolveResult.Member.Parameters;
+				var arguments = invocationExpression.Arguments.ToArray();
+
+				for (int i = arguments.Length - 1; i >= 0; i--) {
+					var parameter = resolvedParameters[argumentToParameterMap[i]];
+					if (parameter.IsParams)
+						// before params optional arguments are needed, or some of the
+						// param arguments will be shifted out of the params into the fixed parameters
+						break;
+					if (!parameter.IsOptional)
+						continue;
+					var argument = arguments[i] as PrimitiveExpression;
+					if (argument == null)
+						continue;
+					var argumentResolveResult = context.Resolve(argument) as ConstantResolveResult;
+					if (parameter.ConstantValue != argumentResolveResult.ConstantValue)
+						// Stop here since any arguments before this one has to be there
+						// enable passing this argument
+						break;
+					var message = context.TranslateString("Argument is identical to the default value");
+					AddIssue(argument, message, GetRemoveNodeAction(invocationExpression, argument));
+				}
+			}
+
+			IEnumerable<CodeAction> GetRemoveNodeAction(InvocationExpression invocationExpression, Expression firstArgumentToRemove)
+			{
+				var argumentsToRemove = invocationExpression.Arguments
+					.Where(arg => arg.StartLocation >= firstArgumentToRemove.StartLocation).ToArray();
+
+				string message;
+				if (argumentsToRemove.Length == 1) {
+					message = context.TranslateString("Remove this argument");
+				} else {
+					message = context.TranslateString("Remove this and the following arguments");
+				}
+				yield return new CodeAction(message, script => {
+					var newArgumentList = invocationExpression.Arguments
+						.Where(arg => !argumentsToRemove.Contains(arg))
+							.Select(argument => argument.Clone());
+					var newInvocation = new InvocationExpression(invocationExpression.Target.Clone(), newArgumentList);
+					script.Replace(invocationExpression, newInvocation);
+
+				});
+			}
+		}
+	}
+}
+

ICSharpCode.NRefactory.Tests/CSharp/CodeIssues/OptionalParameterCouldBeSkippedTests.cs

@@ -0,0 +1,162 @@
+//
+// OptionalParameterCouldBeSkippedTests.cs
+//
+// Author:
+//       Simon Lindgren <simon.n.lindgren@gmail.com>
+//
+// Copyright (c) 2012 Simon Lindgren
+//
+// 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;
+using NUnit.Framework;
+using ICSharpCode.NRefactory.CSharp.CodeActions;
+using ICSharpCode.NRefactory.CSharp.Refactoring;
+
+namespace ICSharpCode.NRefactory.CSharp.CodeIssues
+{
+	[TestFixture]
+	public class OptionalParameterCouldBeSkippedTests : InspectionActionTestBase
+	{
+		[Test]
+		public void SimpleCase()
+		{
+			var input = @"
+class TestClass
+{
+	void Foo(string a1 = ""a1"")
+	{
+	}
+
+	void Bar()
+	{
+		Foo (""a1"");
+	}
+}";
+			TestRefactoringContext context;
+			var issues = GetIssues(new OptionalParameterCouldBeSkippedIssue(), input, out context);
+			Assert.AreEqual(1, issues.Count);
+			var issue = issues [0];
+			Assert.AreEqual(1, issue.Actions.Count);
+				
+			CheckFix(context, issues [0], @"
+class TestClass
+{
+	void Foo(string a1 = ""a1"")
+	{
+	}
+
+	void Bar()
+	{
+		Foo ();
+	}
+}");
+		}
+
+		[Test]
+		public void IgnoresAllParametersPreceedingANeededOne()
+		{
+			var input = @"
+class TestClass
+{
+	void Foo(string a1 = ""a1"", string a2 = ""a2"", string a3 = ""a3"")
+	{
+	}
+
+	void Bar()
+	{
+		Foo (""a1"", ""Another string"", ""a3"");
+	}
+}";
+			TestRefactoringContext context;
+			var issues = GetIssues(new OptionalParameterCouldBeSkippedIssue(), input, out context);
+			Assert.AreEqual(1, issues.Count);
+			var issue = issues [0];
+			Assert.AreEqual(1, issue.Actions.Count);
+			
+			CheckFix(context, issues [0], @"
+class TestClass
+{
+	void Foo(string a1 = ""a1"", string a2 = ""a2"", string a3 = ""a3"")
+	{
+	}
+
+	void Bar()
+	{
+		Foo (""a1"", ""Another string"");
+	}
+}");
+		}
+		
+		[Test]
+		public void ChecksParametersIfParamsAreUnused()
+		{
+			var input = @"
+class TestClass
+{
+	void Foo(string a1 = ""a1"", string a2 = ""a2"", string a3 = ""a3"", params string[] extraStrings)
+	{
+	}
+
+	void Bar()
+	{
+		Foo (""a1"", ""a2"", ""a3"");
+	}
+}";
+			TestRefactoringContext context;
+			var issues = GetIssues(new OptionalParameterCouldBeSkippedIssue(), input, out context);
+			Assert.AreEqual(3, issues.Count);
+			var issue = issues [0];
+			Assert.AreEqual(1, issue.Actions.Count);
+			
+			CheckFix(context, issues [2], @"
+class TestClass
+{
+	void Foo(string a1 = ""a1"", string a2 = ""a2"", string a3 = ""a3"", params string[] extraStrings)
+	{
+	}
+
+	void Bar()
+	{
+		Foo ();
+	}
+}");
+		}
+
+		[Test]
+		public void IgnoresIfParamsAreUsed()
+		{
+			var input = @"
+class TestClass
+{
+	void Foo(string a1 = ""a1"", string a2 = ""a2"", string a3 = ""a3"", params string[] extraStrings)
+	{
+	}
+
+	void Bar()
+	{
+		Foo (""a1"", ""a2"", ""a3"", ""extraString"");
+	}
+}";
+			TestRefactoringContext context;
+			var issues = GetIssues(new OptionalParameterCouldBeSkippedIssue(), input, out context);
+			Assert.AreEqual(0, issues.Count);
+		}
+	}
+}
+

ICSharpCode.NRefactory.Tests/ICSharpCode.NRefactory.Tests.csproj

@@ -292,6 +292,7 @@
     <Compile Include="CSharp\CodeIssues\ParameterCanBeDemotedIssue\IsTypeCriterionTests.cs" />
     <Compile Include="Utils\CompositeFormatStringParser\CompositeFormatStringParserTests.cs" />
     <Compile Include="CSharp\CodeIssues\FormatStringTests.cs" />
+    <Compile Include="CSharp\CodeIssues\OptionalParameterCouldBeSkippedTests.cs" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\..\Mono.Cecil\Mono.Cecil.csproj">