[CodeIssues] Don't warn for unused parameters on overrides and interf…

…ace implementations.

ICSharpCode.NRefactory.CSharp/Refactoring/CodeIssues/VariableNotUsedIssues/ParameterNotUsedIssue.cs

@@ -25,6 +25,8 @@
 // THE SOFTWARE.
 
 using ICSharpCode.NRefactory.Semantics;
+using System.Linq;
+using ICSharpCode.NRefactory.TypeSystem;
 
 namespace ICSharpCode.NRefactory.CSharp.Refactoring
 {
@@ -51,6 +53,24 @@ public GatherVisitor (BaseRefactoringContext ctx, SyntaxTree unit)
 				this.unit = unit;
 			}
 
+			public override void VisitMethodDeclaration(MethodDeclaration methodDeclaration)
+			{
+				// Only some methods are candidates for the warning
+
+				if (methodDeclaration.Body.IsNull)
+					return;
+				var methodResolveResult = ctx.Resolve(methodDeclaration) as MemberResolveResult;
+				if (methodResolveResult == null)
+					return;
+				var member = methodResolveResult.Member;
+				if (member.IsOverride)
+					return;
+				if (member.ImplementedInterfaceMembers.Any ())
+					return;
+
+				base.VisitMethodDeclaration(methodDeclaration);
+			}
+
 			public override void VisitParameterDeclaration (ParameterDeclaration parameterDeclaration)
 			{
 				base.VisitParameterDeclaration (parameterDeclaration);

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

@@ -43,6 +43,36 @@ void TestMethod (int i)
 }";
 			Test<ParameterNotUsedIssue> (input, 1);
 		}
+
+		[Test]
+		public void TestInterfaceImplementation ()
+		{
+			var input = @"
+interface ITestClass {
+	void TestMethod (int i);
+}
+class TestClass : ITestClass {
+	public void TestMethod (int i)
+	{
+	}
+}";
+			Test<ParameterNotUsedIssue> (input, 0);
+		}
+
+		[Test]
+		public void TestAbstractMethodImplementation ()
+		{
+			var input = @"
+abstract class TestBase {
+	public abstract void TestMethod (int i);
+}
+class TestClass : TestBase {
+	public override void TestMethod (int i)
+	{
+	}
+}";
+			Test<ParameterNotUsedIssue> (input, 0);
+		}
 
 		[Test]
 		public void TestUsedParameter ()