Add proposal for 'key' modifier #3127
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Implements structural equality.
| protected bool KeyEquals(A a) | ||
| => P1 == a.P1; | ||
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| public static bool operator==(A left, A right) => left.Equals(right); |
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This doesn't check for null?
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Good point! Yeah, it seems good to make this null-aware.
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| Three synthesized members will be added to the type, `T`: |
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This is well more than 3 synthesized members.
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heh, just made up a number before writing this list and forgot to go back
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| Three synthesized members will be added to the type, `T`: | ||
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| 1. override of `object.Equals(object)`. It is an error if a base class has sealed this member. |
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Also consider commenting on what happens if the class has written out implementations of any of these members.
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Then B.Equals could be: public bool Equals(B other) => other.GetType() == typeof(B) && KeyEquals(b);
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No. It can be implemented that way, but it's not required to be implemented that way. The point is to allow the impl (including user overrides) to make the call on what determines equality. |
No. Having it be a virtual method means that you can extend a class (implementation inheritance) without changing its equality contract. |
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Can |
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Why closed? |
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We ended up implementing records without the notion and at the moment I don't think it's worth the additional complexity. |
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I think it would still be useful for records in case you wanted to compare only by certain properties and not all. |
Implements structural equality.