1 files changed, 84 insertions, 0 deletions
diff --git a/main/src/addins/CSharpBinding/MonoDevelop.CSharp.Diagnostics/RemoveUnnecessaryCast/RemoveUnnecessaryCastDiagnosticAnalyzerBase.cs b/main/src/addins/CSharpBinding/MonoDevelop.CSharp.Diagnostics/RemoveUnnecessaryCast/RemoveUnnecessaryCastDiagnosticAnalyzerBase.cs
new file mode 100644
index 0000000000..615293f380
--- /dev/null
+++ b/main/src/addins/CSharpBinding/MonoDevelop.CSharp.Diagnostics/RemoveUnnecessaryCast/RemoveUnnecessaryCastDiagnosticAnalyzerBase.cs
@@ -0,0 +1,84 @@
+// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+using System;
+using System.Collections.Generic;
+using System.Collections.Immutable;
+using System.Linq;
+using System.Threading;
+using Microsoft.CodeAnalysis.Diagnostics;
+using Microsoft.CodeAnalysis.Shared.Extensions;
+using Microsoft.CodeAnalysis.Text;
+using Roslyn.Utilities;
+using MonoDevelop.Core;
+using Microsoft.CodeAnalysis;
+using ICSharpCode.NRefactory6.CSharp;
+
+namespace MonoDevelop.CSharp.Diagnostics.RemoveUnnecessaryCast
+{
+	internal abstract class RemoveUnnecessaryCastDiagnosticAnalyzerBase<TLanguageKindEnum> : DiagnosticAnalyzer where TLanguageKindEnum : struct
+	{
+		private static string s_localizableTitle = GettextCatalog.GetString ("Remove Unnecessary Cast");
+		private static string s_localizableMessage = GettextCatalog.GetString ("Cast is redundant.");
+
+		private static readonly DiagnosticDescriptor s_descriptor = new DiagnosticDescriptor(IDEDiagnosticIds.RemoveUnnecessaryCastDiagnosticId,
+			s_localizableTitle,
+			s_localizableMessage,
+			DiagnosticAnalyzerCategories.RedundanciesInCode,
+			DiagnosticSeverity.Warning,
+			isEnabledByDefault: true,
+			customTags: DiagnosticCustomTags.Unnecessary);
+
+		#region Interface methods
+
+		public override ImmutableArray<DiagnosticDescriptor> SupportedDiagnostics
+		{
+			get
+			{
+				return ImmutableArray.Create(s_descriptor);
+			}
+		}
+
+		public override void Initialize(AnalysisContext context)
+		{
+			context.RegisterSyntaxNodeAction(
+				(nodeContext) =>
+				{
+					Diagnostic diagnostic;
+					if (TryRemoveCastExpression(nodeContext.SemanticModel, nodeContext.Node, out diagnostic, nodeContext.CancellationToken))
+					{
+						nodeContext.ReportDiagnostic(diagnostic);
+					}
+				},
+				this.SyntaxKindsOfInterest.ToArray());
+		}
+
+		public abstract ImmutableArray<TLanguageKindEnum> SyntaxKindsOfInterest { get; }
+
+		#endregion
+
+		protected abstract bool IsUnnecessaryCast(SemanticModel model, SyntaxNode node, CancellationToken cancellationToken);
+		protected abstract TextSpan GetDiagnosticSpan(SyntaxNode node);
+
+		private bool TryRemoveCastExpression(
+			SemanticModel model, SyntaxNode node, out Diagnostic diagnostic, CancellationToken cancellationToken)
+		{
+			diagnostic = default(Diagnostic);
+			if (model.IsFromGeneratedCode (cancellationToken))
+				return false;
+			if (!IsUnnecessaryCast(model, node, cancellationToken))
+			{
+				return false;
+			}
+
+			var tree = model.SyntaxTree;
+			var span = GetDiagnosticSpan(node);
+			if (tree.OverlapsHiddenPosition(span, cancellationToken))
+			{
+				return false;
+			}
+
+			diagnostic = Diagnostic.Create(s_descriptor, tree.GetLocation(span));
+			return true;
+		}
+	}
+}