Add DecompilerSettings.OptionalArguments

ICSharpCode.Decompiler/CSharp/CallBuilder.cs

@@ -125,12 +125,12 @@ namespace ICSharpCode.Decompiler.CSharp
 			// We only allow removing optional arguments in the following cases:
 			// - call arguments are not in expanded form
 			// - there are no named arguments
-			// This value has the following following values:
+			// This value has the following values:
 			// -2 - there are no optional arguments
 			// -1 - optional arguments are forbidden
 			// >= 0 - the index of the first argument that can be removed, because it is optional
 			// and is the default value of the parameter. 
-			int firstOptionalArgumentIndex = -2;
+			int firstOptionalArgumentIndex = expressionBuilder.settings.OptionalArguments ? -2 : -1;
 			for (int i = firstParamIndex; i < callArguments.Count; i++) {
 				IParameter parameter;
 				if (argumentToParameterMap != null) {

ICSharpCode.Decompiler/DecompilerSettings.cs

@@ -63,7 +63,7 @@ namespace ICSharpCode.Decompiler
 			if (languageVersion < CSharp.LanguageVersion.CSharp4) {
 				dynamic = false;
 				namedArguments = false;
-				// * optional arguments (not supported yet)
+				optionalArguments = false;
 			}
 			if (languageVersion < CSharp.LanguageVersion.CSharp5) {
 				asyncAwait = false;
@@ -688,6 +688,21 @@ namespace ICSharpCode.Decompiler
 			}
 		}
 
+		bool optionalArguments = true;
+
+		/// <summary>
+		/// Gets/Sets whether optional arguments should be removed, if possible.
+		/// </summary>
+		public bool OptionalArguments {
+			get { return optionalArguments; }
+			set {
+				if (optionalArguments != value) {
+					optionalArguments = value;
+					OnPropertyChanged();
+				}
+			}
+		}
+
 		#region Options to aid VB decompilation
 		bool assumeArrayLengthFitsIntoInt32 = true;