The following example shows that the content of a reference-type immutable property (an array in this case) is mutable: You can override GetHashCode for immutable reference types. The GetHashCode is used for insertion and lookup in Dictionary and HashTable, for example. Equals() may also be able to short circuit, making it much faster -. Maybe hard to do really well, like if the implementation loops through items in member collections, but should be easy to make a "conservative" rule that catches basic cases like the ones. NET, ReSharper 2023. GetHashCode();. Alternatively return a non-zero constant for GetHashCode. 推荐答案. So even if what you're doing looks similar, it's not the same at all. Started with overriding concepts and I override the methods Equals and GetHashCode. public virtual bool Equals (object obj): This method is used to determine whether the specified object is equal to the current object. . GetHashCode to find the hash code, then for all. ; If. Tip: To prevent the user from interacting with. class Foo { private int _a; // CS0414 private int _b; // No compiler warnings, but ReSharper issues its own warning here public Foo(int value) { _a = 1; _b = value; } }Sorted by: 4. comThe Readonly utility type, released with TypeScript 2. The loop is unrolled by hand, consuming 4 characters per loop for the 32-bit. Combines eight values into a hash code. Comment actions Think I figured it out. In the example above, the methods object in the argument to makeObject has a contextual type that includes ThisType<D & M> and therefore the type of this in methods within the methods object is { x: number, y: number } & { moveBy(dx: number, dy: number): void }. It seemed like there's contradicting goals for GetHashCode when applied to mutable objects, those being: If a. the object was being used as a key to a dictionary when it changed) the problem was with either the change or the fact that it's being used for non-reference equality in the first place, not the fact that the value returned by GetHashCode() changed. cs; Others: BitVector. So: I don't think there's a good solution here, except perhaps to use a different property-grid implementation, or to add a dummy writable property - sorry!Remarks. GetHashCode method non-virtually, even if the object's type has. For the best performance, a hash function must generate a random distribution for all input. For information about ref struct and readonly ref struct types, see the ref structure types article. By default it does it based on the reference to the object, but that means that it's the exact same object, so both would return the same hash. GetHashCode is used to file an object in a Dictionary or Hashtable. The method: ; calls the method System. Non-readonly type member referenced in 'GetHashCode()' NonReadonlyMemberInGetHashCode. 至于 age，这是定期变化的东西，所以最好存储一个. GetHashCode should use only readonly fields in order to return a consistent value. The struct remains a struct. You cannot change it once initialized. Non-accessed positional property (private accessibility) NotAccessedPositionalProperty. For example, a button in the View can be bound to a RelayCommand property in the ViewModel, which will be executed when the button is clicked. name. So long as the hash code returned for nulls is consistent for the type, you should be fine. C# 9. No auto. resharper_nullness_annotation_conflict_with_jet_brains_annotations_highlighting. Also, while a const field is a. Like described by Jon Skeet in this SO answer, it is best practice to pick some prime numbers and multiply these with the single hash codes, then sum everything up. If a non-readonly field is changed after the object is. Immutable. In VB. The Equals method is used for any equality tests on the objects. With all that said, if you want to be on the safe side make sure that your override of GetHashCode() returns the same value during the object's lifetime. 1 Answer. The result of this would be: A. In C# collections, GetHashCode does not use the items in it because it matches collection equality, that is, instance equality, not structural equality. Don't let them initialize by themselves. CS0169: Private field is never used. // Sample for the Environment. Non-readonly fields referenced in GetHashCode() in C#; Nesting async/await methods in C#; Finally is not executed when in a Thread running in a Windows Service;As Equals is a virtual method, we can also override this method under our classes. An inherited abstract property with matching type is overridden. Although ReSharper knows about all these warnings and provides design-time notifications for. net string class immutability asked Dec 23, 2013 at. The property system's primary function is to compute the values of properties, and to provide system notification about values that have changed. Tour Start here for a quick overview of the site Help Center Detailed answers to any questions you might have Meta Discuss the workings and policies of this site1. CS0414: Private field is assigned a constant value but never used. GetHashCode is used to file an object in a Dictionary or Hashtable . The DependencyObject class enables Windows Presentation Foundation (WPF) property system services on its many derived classes. Having a read only property to a class object (as opposed to a struct) only prevents modifying the value of the property, in this case the object reference. This works since typescript 4. IImmutableStack<T>. When you declare a primary constructor on a record, the compiler. The only requirement to GetHashCode is: If two objects compare as equal, the GetHashCode method for each object must return the same value. GetHashCode() A simplified, non-randomised version of string. Here is what I understood from MSDN: in order to determine the presence of an element, Contains is supposed to call GetHashCode first and Equals then. The expression that is used to initialize a property cannot be null, an anonymous function, or a pointer type. They are defined by using at least one modifier (such as Visibility, Static Keyword, or, as of PHP 8. Is it possible in MVC 3 to set a ReadOnly Attribute to true or false on Model depending of a property in the same class? maybe something like : ReadOnly ( (yyy)?false:true) public double? xxx { get; set; } I need to do it in the model or in the controller. If you want to suppress only a single violation, add preprocessor directives to your source file to disable and then re-enable the rule. Collections. To avoid any problem you should make sure that the static field csvSeparator field is only assigned by the class constructor method of your class. DataSysDescription("DataColumnReadOnlyDescr")>] member. Interesting question. #pragma warning restore IDE0070. 4). Properties can also be marked as readonly for TypeScript. Here at NDepend we enjoy so much immutable types that several rules help enforce this property: Fields should be marked as ReadOnly when. This could be supported today by an analyzer. For example: public partial class myClass { public override bool Equals(object obj) { return. The readonly modifier in C# exists typically to mark a field (not property) as readonly. If the member could be either a class or a struct then assignment to its properties could be unreliable, working sometimes but not others. An override of Object. Aug 26, 2022 at 8:05. #nullable enable public record Product { public readonly string Name; public readonly int CategoryId; public readonly string Phone; public readonly Address Address; public readonly Manager Manager; } Non-nullable property 'Name' is uninitialized. 16. The same applies to methods that have a void return type. Sorted by: 25. Please note that your GetHashCode must go hand in hand with your Equals method. get_Prop set_Prop ToString Equals GetHashCode GetType get_Prop is the function that implements the getter. First, it's a read-only property. This way not only you'll be able to set your field as readonly, but also the rule won't warn anymore. MachineName}" // This example produces the following results: // (Any result that is lengthy, specific to the machine on which this sample was tested, or reveals information that should remain secure, has. Suggestions cannot be applied while the Code Inspection: Nullable attribute usage with declaration having value or void type A hash code is a numeric value that is used to insert and identify an object in a hash-based collection such as the Dictionary<TKey,TValue> Hashtable DictionaryBase GetHashCode method provides this hash code for algorithms that need quick checks of object equality. name. checkboxes ; radio boxes ; file upload. In C#, it is generally not recommended to reference non-readonly fields in the GetHashCode() method of a class. taken from Microsoft)Implementing IEquatable<T> for a Value Type. IndexOf members, the code. If you override the equals method to do a special comparison of two objects and the two objects are considered the same by the method, then the hash code of the two objects must also be the same. Property assignments should not be made for "readonly" fields not constrained to reference types BugFlags enumerations should explicitly initialize all their members Bug"GetHashCode" should not reference mutable fields BugResults of integer division should not be assigned to floating point variables Bug3. name. The value of a. Id is a primitive value, ie. It seems wanting to do something like the latter is fairly common; perhaps the best solution I've seen is to just define a struct outside the method. Marking a parameter as “readonly ref” or “in” does not make the value it refers to immutable. This feature could be confused with immutable types which aim to enforce deep immutability but is much stricter in that every field must also be of an immutable type. GetHashCode() in your GetHashCode<T> method. One way is to just keep accumulating and multiplying by 17 like I've done. The contract requires that GetHashCode() gives the same integer result for any two equal objects. This rule raises an issue when a non-private. Object meaning that every object you create will inherit a default implementation from the base class. Introduction. class Foo { private int _a; // CS0414 private int _b; // No compiler warnings, but ReSharper issues its own warning here public Foo(int value) { _a = 1; _b = value; } }Non-readonly fields referenced in GetHashCode() in C#; ASP. According to the guideline from the question, the hashcode of B would not change. e. Hashing is designed to provide a value that doesn’t change for a given object, no matter what happens to it – hence it’s best to depend only on readonly fields in your GetHashCode method. This would work much better than simply return 1 from GetHashCode. Any legitimate implementation of IEquatable<T>. You can make the strings on Foo readonly and it should be at that point. 2 introduces the third way of passing arguments: using in -modifier. Likewise, a readonly struct can be placed in a non-readonly field. It also states in section 4. The with keyword clones the original property and changes the required properties before the initalization is complete. Contribute to icsharpcode/RefactoringEssentials development by creating an account on GitHub. . C. Warning. However, after you changed your MyProperty; GetHashCode() does not return the same value therefore it can not be look. Sort a List<T> by object property in C#; Parse command line arguments in C#; Get the URL of the current page in C#; . GetHashCode () is used to differentiate between instances quickly, and Equals () is used to verify equality (whatever that means to you). Reply. This can lead to unexpected behavior when using GetHashCode, as it will return different values for two objects that are logically equivalent but have different. It seems to me that all most answers here were sidetracked into talking about immutability or hashcode guarantees, instead of answering the original question. GetHashCode(), which must in turn have semantics compatible with the class's override of Equals(Object). _Foo. You need to override the two methods for any number of reasons. 同事轉來ReSharper的警告：Non-readonly fields referenced in GetHashCode()，GetHashCode的計算來源必須保證不會變動，而使用readonly欄位是最直接有效的做法。而我這才注意，MSDNTwoDPoint範例，其中的x, y就是readonly，代表它們只能在建構時指定，事後不得變更。而我原本的寫法. The important point to note here is when a first item is added to Dictionary GetHasCode is called and the Hash code ineterger is saved against the object. NET Framework 64-bit version of string. The Problem: Now here's the problem: Property '_uri' has no initializer and is not definitely assigned in the constructor. e. The compiler creates a defensive copy of a readonly variable that contains a struct (that could be an in parameter, but also a readonly field) when you call a method on that struct. and 2. Warning Add this suggestion to a batch that can be applied as a single commit. If a struct is passed into a Dictionary object to be used as a key, for example, a copy is made, and any internals which are used to compute the hash code will be effectively. This is because the GetHashCode() method is used. Load 7. It doesn't matter what value you put after it or if you put any value after it, it will still see it as readonly. I think it's better explain on example why you should override GetHashCode when you override equality members, and also why you should not use mutable. age. "a" and "b" would have a different hash, but "a" and "a" would return the same hash. The inability to have readonly properties was proposed as a potential reason to use fields instead of properties. Warning. The only thing I didn't like about this is the Default property violates the purity assumption of a property getter. ToLowerInvariant() in C#; SmtpClient with Gmail in C#; Previous;Drawbacks. You use the record modifier to define a reference type that provides built-in functionality for encapsulating data. That way Dictionary and HashSet still works, but it will be the worst time complexity for key lookup, since all instances will "collide". We have some very large solutions (many dozens of projects, pushing triple digits in one of them), and there will be a need to update a reference to a ce. ) For example, if your object has an int. Any subsequent test to see if the object is in the <code>Hashtable</code> will return a false negative. Anonymous types contain one or more public read-only properties. Press Control+R, C or choose Code | Reformat and Cleanup… from the main menu . Members of this base class are protected and are intended to be used through a derived class only. This suggestion is invalid because no changes were made to the code. EditorFor (o=>o. 4 the following: Through const declarations it is possible to declare constants of the simple types (§10. A third option is to throw a NotSupportedException. However, the data that a reference-type property refers to can be changed. private readonly int. Most important quote: It is not a good idea to override operator == in mutable types. Add this suggestion to a batch that can be applied as a single commit. Learn more about TeamsSuppress a warning. In this scenario, you would like to clone the original instance and change the property which differs. Non-readonly struct is passed as in-parameter. If a struct is passed into a Dictionary object. This means the properties of the constructed type cannot be reassigned. No, the stack trace of an exception in C# can never be null. NET Core with React template returns index. GetEditor(editorBaseType) End Function ' Specifies the. My idea is to block the instruction Html. Problem: Int32 is too small for even a simple object such as this. If a common use-case is comparing objects according to one of their properties, you could add an additional constructor and implement and call it like this: public GenericEqualityComparer (Func<T, object> projection) { compareFunction = (t1, t2) => projection (t1). Sometimes I need value objects without fields (message headers, schemas, etc. Reversed. – Tim Schmelter. Properties. 7. Non-accessed positional property (private accessibility) NotAccessedPositionalProperty. I would expect True. Non-readonly type member referenced in 'GetHashCode()' NonReadonlyMemberInGetHashCode. @DeniseSkidmore If you try to call GetHashCode on null you'll get a null reference exception. When you pass [a readonly struct] into an in parameter, the compiler sees that it's readonly and won't create the defensive copy. Non-readonly type member referenced in 'GetHashCode()' NonReadonlyMemberInGetHashCode. GetHashCode () Return hash End Function. Contains (relation2) The output is: False. readonly will never cover all use cases solely because of the fact that it does not handle runtime immutability. Examples. Having a read only property to a class object (as opposed to a struct) only prevents modifying the value of the property, in this case the object reference. Although Powershell doesn’t have real readonly class properties, we can mimic them in two elegant ways: Class methods as getter and setter functions. NET Framework 4 documentation Guidelines for Implementing Equals and the Equality Operator (==) omits that statement, although one post in. The RuntimeHelpers. net-4. GetHashCode () * 17 + this. . All you have done is create a second Tuple and assigned tplTemp to it's value. ) this [key] = settings [key] //. cs; SyntaxTriviaList. NET Core with React template returns index. The factory can then check the collection of previously created objects. Just to make it clear: There is one important thing about Dictionary<TKey, TValue> and GetHashCode (): Dictionary uses GetHashCode to determine if two keys are equal i. You should rather implement GetHashCode() like in this question : SO - What is the best algorithm for. You can use components and containers in a variety of scenarios, both visual and non. resharper_not_accessed_positional_property_local_highlighting. Supported Code Analyzers"," 120 code analyzers for C#"," "," Suggests using the class declaring a static function when calling it. GetHashCode() A simplified, non-randomised version of string. This is know as the "once" feature in Eiffel. AllowedItem'. And if you can just use reference equality (when you'd never have two different instances of your class that can be equal) then you can safely use Equals and GetHashCode that are inherited from Object. I always made a wrong assumption between the concept of GetHashCode and a "MD5 hash" of a downloaded file. internal class Person {. I figured out 1. Combines four values into a hash code. Tour Start here for a quick overview of the site Help Center Detailed answers to any questions you might have Meta Discuss the workings and policies of this siteNon-read only alternative to anonymous types in C#; Non-readonly fields referenced in GetHashCode() in C#; NonSerialized on property in C#; Non-static method requires a target C#; Non-static method requires a target in C#; Non-unique enum values in C#; Non-virtual interface design pattern in C#/C++; Not able to reference Image source with. GetHashCode (). It provides a detailed trace of the sequence of method calls that led to the exception being thrown, along with the file name and line number where each method call occurred. In general, for mutable reference types, you should override GetHashCode only if:. SomeProperty = newValue; If it only needs to be able to do the second, the field could be readonly but you still have the problem of people fetching the property being able to mutate the object. 0c++. We then add the offset of the value we want to read to. GetHashCode() non. For best results, the hash code must be based on the value of an instance field or property instead of a static field or property. Non-readonly fields referenced in GetHashCode() in C#; ASP. The most common scenario is to initialize an anonymous type with properties from another type. Every type that is used as the key in a dictionary must implement Equals and GetHashCode. The DeclaringType property retrieves a reference to the Type object for the type that declares this member. NET Framework 4. In this scenario, you would like to clone the original instance and change the property which differs. @bitbonk Usually, both GetHashCode() and Equals() need to look at all fields of both objects (Equals has to do this if it the hashcodes are equal or not-checked). GetHashCode should use only readonly fields in order to return a consistent value. resharper_non_readonly_member_in_get_hash_code_highlighting. internal class Person { public string name; public int age; public string lname; public Person (string name, int age, string lname) { this. The guidelines are here on MSDN. I think you misunderstood. Primarily I came up with this "very simple code": internal class Person { public string name; public int age; public string lname; public Person (string name, int age, string lname) {. . These two methods are. – Eldritch Conundrum. So the user may declare an init-only property in place of a synthesized mutable one. It simply returns true if the values are equal. A class that overrides only one of Equals(object) and GetHashCode() is likely to violate the contract of the GetHashCode() method. io, to see the code generated by the compiler in each case. When you override GetHashCode () you also need to override Equals (), operator== and operator!= . I used GetHashCode to verify if an object changed since the last time it. hash == y. However, a user can tab to it, highlight it, and copy the text from it. The GetHashCode function takes this operation away from the class and allows some external entity to decide if two hash codes are equal. More specifically, we couldn’t use the object initializer to set readonly properties. The method is private if the record type is sealed. Local. The in -modifier is a way to pass the argument via readonly reference. This differs from a constant declared with the const modifier, which must have its value set at compile time. ] if you want to see them and DO NOT have a valid object to examine, you will need to go look at the docs for that object. You can suppress this inspection to ignore specific issues, change its severity level to make the issues less or more noticeable, or disable it altogether. For fields that hold a mutable reference type, the read-only modifier prevents the field value from being overwritten but does not protect the mutable type from modification. (co-author and co-editor). In these scenarios the notion of in-process reference is irrelevant. When you declare a primary constructor on a record, the compiler generates public. Let me explain how this function is created: If you override the Equals function of a class, R# suggests you to create equality members. e. In C# this would no compile, because you can't use ref with a variable that is readonly. What does RuntimeHelpers. The implementation of equality methods (that is Equals() and GetHashCode()) as well as equality operators (that is == and !=) in the Object class guarantees reference equality. In C#, it is generally not recommended to reference non-readonly fields in the GetHashCode() method of a class. that the method does not mutate the state of the instance). . Within each of the access groups, order by static, then non-static: (SA1204) static; non-static; Within each of the static/non-static groups of fields, order by readonly, then non-readonly : (SA1214 and SA1215) readonly; non-readonly; An unrolled list is 130 lines long, so I won't unroll it here. The <code>readonly</code> keyword enforces that another instance can’t be assigned to the field, but it cannot keep the contents from being updated. Notes to Implementers. GetHashCode method always calls the Object. We then join the validation errors into a single. Non-readonly fields referenced in GetHashCode() in C#; How to train multiple models in a single script in TensorFlow when there are GPUs present? Flatten list of lists in python; How does asyncio actually work? Dropping infinite values from dataframes in pandas? Sort dataframe by string length in python; Where is the history file for ipythonJava 8 introduced a new feature into HashMap whereby when a significant number of keys fall into the hash bucket and the key type implements Comparable<T> (broadly equivalent to . Q&A for database professionals who wish to improve their database skills and learn from others in the communityThe configuration options are readonly, hence the setter is private: it should only be used once to initialize the value. It’s official: C# 9. Class member variables are called properties. The following code example demonstrates several members of the ReadOnlyCollection<T> class. In this MWE you can see that it is possible to define getter for a private readonly property. And according to this : Why is ValueType. GetHashCode used in CoreFX. position); } public readonly struct Location2 { // The order matters! // The default GetHashCode version will get a hashcode of the first field public int Position. GetHashCode () ==> false. Hash codes are created from state (values inside) of the structure / object. GetHashCode() taken from open source projects. DateTime (2011,06,04) should equal DateTime (2011,06,04). string, int, long, Guid etc. Only implement IEquatable<T> for structs or sealed classes. Non-readonly fields referenced in GetHashCode() in C#; C# SQLite-net define multi column unique;. Non-readonly field referenced in GetHashcode. Combines seven values into a hash code. Equals (b) is true, a. [sigh. g. An inherited abstract property with matching type is. Collections; using. e. ReadOnly : bool with get, set [<System. TheseSince GetHashCode should return the same hash code for instances that are equal, and should be immutable after construction, any general-purpose Tuple implementation that overrides Equals and GetHashCode will necessarily have readonly properties for the wrapped items. Combines seven values into a hash code. By voting up you can indicate which examples are most useful and appropriate. Select one or more items in the Solution Explorer to make fields readonly in the files under these nodes and their child items. Aug 29, 2013 at 9:10. Or, it could be as complicated as you need it to be. But, remember - records are immutable. that the method does not mutate the state of the instance). GetHashCode(), use. To a certain extent, they are. Equals(Object). The GetHashCode method can be overridden by a derived type. Returning different values for different objects is a matter of performance: GetHashCode always. Creates a frozen copy of the Freezable, using base (non-animated) property values. This attribute allows a field value to be set in the constructor of the same class. The GetHashCode method returns a hash code value for a specific key value. Combines five values into a hash code. That way Dictionary and HashSet still works, but it will be the worst time complexity for key lookup, since all instances will "collide". " and the one for ValueType says "If you call the derived type's GetHashCode method, the return value is not likely to be suitable for use as a key in a hash table. Equals in C#; How to get date from day of year in C#; When to use IList and when to use List in C#; Run Command Prompt Commands in C#; How to compare time part of datetime in C#; Non-readonly fields referenced in GetHashCode() in C#This needs more upvote. Name = name; } public String Name { get; private set; } } But that wouldn't allow him to do p. DataSysDescription("DataColumnReadOnlyDescr")] public bool ReadOnly { get; set; } member this. It's fast, it's simple, it's correct, and it usually gives a good distribution. C# compiler can issue a number of warnings regarding unused fields: CS0649: Field is never assigned to, and will always have its default value. 1 introduced Entity types with constructors with parameters feature. So the user may declare an init-only property in place of a synthesized mutable one. Most important quote: It is not a good idea to override operator == in mutable types. NET interface that allows implementing customized equality comparison for collections. NET Framework 4. Java has equals() and hashCode() so that two equivalent objects have the same hash value. The readonly keyword is used to declare a member variable a constant, but allows the value to be calculated at runtime. When you declare a primary constructor on a record, the compiler generates public. Local. Actual Behavior: List of impacted classes where field can easily be marked as. The most common example would be a caller that wants to use strings as keys but use case-insensitive comparisons. GetHashCode() * this. Guideline: The integer returned by GetHashCode should never change. . This applies both for get -only properties, and properties marked [ReadOnly(true)] . Make your base class constructor to take the collection as an argument: public class BaseClass { protected readonly Collection someObject; public BaseClass (Collection object) { someObject = object } } So now when the derived class constructor is called it should call base class. Declaration. You can't mark a method as a constructor there is just no syntax for that. This simply restates the behaviour of readonly without explaining why it's bad to use readonly. Problem: Int32 is too small for even a simple object such as this. Warning. IEqualityComparer<T> is a generic . You use the record modifier to define a reference type that provides built-in functionality for encapsulating data. You can contain components in a container. non-readonly fields, properties with setters, etc. 2. This is not a way to fill a Tuple with values. lname. keys (settings) as Array<keyof Options>). If it only needs to do the first, and actually. Stack Overflow | The World’s Largest Online Community for DevelopersIf you're on C# 7, you should consider using value tuples as your composite key. This would work much better than simply. A hash code is a numeric value that is used to insert and identify an object in a hash-based collection such as the Dictionary<TKey,TValue> Hashtable DictionaryBase GetHashCode method provides this hash code for algorithms that need quick checks of object equality. To summarise what was discussed in the comments:For fields that hold a mutable reference type, the read-only modifier prevents the field value from being overwritten but does not protect the mutable type from modification. This method is called from a TextInput event handler. That not only misses some scenarios where the field could be converted to readonly even though its mutable (if there are no writes and no invocations), but it is also wrong, as you can see in the example. Weak references allow the GC to collect the objects. A readonly field can be assigned multiple times in the field declaration and in any constructor. The implication appears to be that many people do not understand what. Combines six values into a hash code. For information about the service packs and cumulative update list for BizTalk Server, see KB 2555976: Service pack and cumulative update list for BizTalk Server. EditorFor (o=>o. 1 I get warnings in the automatically generated GetHashCode () function. Make your base class constructor to take the collection as an argument: public class BaseClass { protected readonly Collection someObject; public BaseClass (Collection object) { someObject = object } } So now when the derived class constructor is called it should call base class. resharper_not_accessed_positional_property_local_highlighting. public struct ObjectHandle : IEquatable<ObjectHandle> { public object Object; public bool Equals (ObjectHandle. For example, the implementation of the GetHashCode method provided by the String class returns identical hash codes for identical string values. Field: readonly T myField; Property: T myProp { get; } Since it would be very not feasible to detect if a class is immutable, we should probably eliminate that entirely aside from string perhaps. And identifiers fit well with the value-based equality described above. To disable the rule for a file, folder, or project, set its. The default instance of the EqualityComparer<T> class for type T. Rules 1 & 3 are contradictory to me. 25. I want to use these equality rules: If the TypeName property is different, should anyway be considered non-equal. However, when I try to determine if the hashSet contains relation2 I get an unexpected result. Warning in a struct: "Non-readonly field referenced in GetHashcode".