Fix implementation of ReplaceBackingFieldUsage and ReplaceEventFieldAnnotation (see #540)

ICSharpCode.Decompiler/CSharp/Transforms/PatternStatementTransform.cs

@@ -78,16 +78,6 @@ namespace ICSharpCode.Decompiler.CSharp.Transforms
 			result = TransformFor(expressionStatement);
 			if (result != null)
 				return result;
-			if (context.Settings.AutomaticProperties) {
-				result = ReplaceBackingFieldUsage(expressionStatement);
-				if (result != null)
-					return result;
-			}
-			if (context.Settings.AutomaticEvents) {
-				result = ReplaceEventFieldAnnotation(expressionStatement);
-				if (result != null)
-					return result;
-			}
 			return base.VisitExpressionStatement(expressionStatement);
 		}
 
@@ -524,10 +514,27 @@ namespace ICSharpCode.Decompiler.CSharp.Transforms
 					section.Remove();
 			}
 		}
+		#endregion
 
-		ExpressionStatement ReplaceBackingFieldUsage(ExpressionStatement expressionStatement)
+		public override AstNode VisitIdentifier(Identifier identifier)
+		{
+			if (context.Settings.AutomaticProperties) {
+				var newIdentifier = ReplaceBackingFieldUsage(identifier);
+				if (newIdentifier != null) {
+					identifier.ReplaceWith(newIdentifier);
+					return newIdentifier;
+				}
+			}
+			if (context.Settings.AutomaticEvents) {
+				var newIdentifier = ReplaceEventFieldAnnotation(identifier);
+				if (newIdentifier != null)
+					return newIdentifier;
+			}
+			return base.VisitIdentifier(identifier);
+		}
+
+		Identifier ReplaceBackingFieldUsage(Identifier identifier)
 		{
-			foreach (var identifier in expressionStatement.Descendants.OfType<Identifier>()) {
 			if (identifier.Name.StartsWith("<") && identifier.Name.EndsWith(">k__BackingField")) {
 				var parent = identifier.Parent;
 				var mrr = parent.Annotation<MemberResolveResult>();
@@ -536,32 +543,30 @@ namespace ICSharpCode.Decompiler.CSharp.Transforms
 					var propertyName = identifier.Name.Substring(1, identifier.Name.Length - 1 - ">k__BackingField".Length);
 					var property = field.DeclaringTypeDefinition.GetProperties(p => p.Name == propertyName, GetMemberOptions.IgnoreInheritedMembers).FirstOrDefault();
 					if (property != null) {
-							identifier.ReplaceWith(Identifier.Create(propertyName));
 						parent.RemoveAnnotations<MemberResolveResult>();
 						parent.AddAnnotation(new MemberResolveResult(mrr.TargetResult, property));
-						}
+						return Identifier.Create(propertyName);
 					}
 				}
 			}
 			return null;
 		}
 
-		ExpressionStatement ReplaceEventFieldAnnotation(ExpressionStatement expressionStatement)
+		Identifier ReplaceEventFieldAnnotation(Identifier identifier)
 		{
-			foreach (var identifier in expressionStatement.Descendants.OfType<Identifier>()) {
 			var parent = identifier.Parent;
 			var mrr = parent.Annotation<MemberResolveResult>();
 			var field = mrr?.Member as IField;
-				if (field == null) continue;
+			if (field == null)
+				return null;
 			var @event = field.DeclaringType.GetEvents(ev => ev.Name == field.Name, GetMemberOptions.IgnoreInheritedMembers).SingleOrDefault();
 			if (@event != null) {
 				parent.RemoveAnnotations<MemberResolveResult>();
 				parent.AddAnnotation(new MemberResolveResult(mrr.TargetResult, @event));
-				}
+				return identifier;
 			}
 			return null;
 		}
-		#endregion
 
 		#region Automatic Events
 		static readonly Accessor automaticEventPatternV2 = new Accessor {