GenerateProperty: do not propose to generate a setter if the field is readonly.

ICSharpCode.NRefactory.CSharp/Refactoring/CodeActions/GeneratePropertyAction.cs

@@ -1,4 +1,4 @@
-// 
+// 
 // GenerateProperty.cs
 //  
 // Author:
@@ -51,7 +51,7 @@ namespace ICSharpCode.NRefactory.CSharp.Refactoring
 				}
 			}
 			var field = initializer.Parent as FieldDeclaration;
-			if (field == null) {
+			if (field == null || field.HasModifier(Modifiers.Readonly) || field.HasModifier(Modifiers.Const)) {
 				yield break;
 			}
 			var resolveResult = context.Resolve(initializer) as MemberResolveResult;

ICSharpCode.NRefactory.Tests/CSharp/CodeActions/ContextActionTestBase.cs

@@ -84,7 +84,11 @@ namespace ICSharpCode.NRefactory.CSharp.CodeActions
 		
 		protected static void TestWrongContext<T> (string input) where T : ICodeActionProvider, new ()
 		{
-			ICodeActionProvider action = new T ();
+			TestWrongContext (new T(), input);
+		}
+		
+		protected static void TestWrongContext (ICodeActionProvider action, string input)
+		{
 			var context = TestRefactoringContext.Create (input);
 			bool isValid = action.GetActions (context).Any ();
 			if (!isValid)

ICSharpCode.NRefactory.Tests/CSharp/CodeActions/GeneratePropertyTests.cs

@@ -1,4 +1,4 @@
-// 
+// 
 // GeneratePropertyTests.cs
 //  
 // Author:
@@ -107,5 +107,31 @@ class TestClass
 	int myField, myOtherField;
 }");
 		}
+		
+		[Test]
+		public void CannotGeneratePropertyForReadOnlyField()
+		{
+			TestWrongContext (
+				new GeneratePropertyAction (),
+				"using System;" + Environment.NewLine +
+					"class TestClass" + Environment.NewLine +
+					"{" + Environment.NewLine +
+					"	readonly int $myField;" + Environment.NewLine +
+					"}"
+			);
+		}
+		
+		[Test]
+		public void CannotGeneratePropertyForConst()
+		{
+			TestWrongContext (
+				new GeneratePropertyAction (),
+				"using System;" + Environment.NewLine +
+					"class TestClass" + Environment.NewLine +
+					"{" + Environment.NewLine +
+					"	const int $myField = 0;" + Environment.NewLine +
+					"}"
+			);
+		}
 	}
 }