Enumerable.Min<TSource>() and Enumerable.Max<TSource>() wording regarding null for reference types is misleading

[binki]

In regards to null, the documentation states this:

If TSource is a reference type and the source sequence is empty or contains only values that are null, this method returns null.

However, I found the following behavior:

Console.WriteLine($"new[]{{ new int?(), }}.Min() == new int?(): {new[] { new int?(), }.Min() == new int?()}");
Console.WriteLine($"new int?[]{{ }}.Min() == new int?(): {new[] { new int?(), }.Min() == new int?()}");

has output:

new[]{ new int?(), }.Min() == new int?(): True
new int?[]{ }.Min() == new int?(): True

int? (Nullable<int>) is a value type, not a reference type. It is true that (object)new int?() == null is true, so it triggers the behavior of .Min() which returns default(TSource) and the same behavior in .Max()` instead of throwing. However, from reading the documentation, I would expect the throw-on-empty behavior.

Please clarify the documentation (which seems to also omit any mention of the throw-on-empty behavior for non-reference types).

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Issue Details

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In regards to null, the documentation states this:

If TSource is a reference type and the source sequence is empty or contains only values that are null, this method returns null.

However, I found the following behavior:

Console.WriteLine($"new[]{{ new int?(), }}.Min() == new int?(): {new[] { new int?(), }.Min() == new int?()}");
Console.WriteLine($"new int?[]{{ }}.Min() == new int?(): {new[] { new int?(), }.Min() == new int?()}");

has output:

new[]{ new int?(), }.Min() == new int?(): True
new int?[]{ }.Min() == new int?(): True

int? (Nullable<int>) is a value type, not a reference type. It is true that (object)new int?() == null is true, so it triggers the behavior of .Min() which returns default(TSource) and the same behavior in .Max()` instead of throwing. However, from reading the documentation, I would expect the throw-on-empty behavior.

Please clarify the documentation (which seems to also omit any mention of the throw-on-empty behavior for non-reference types).

Author:	binki
Assignees:	-
Labels:	untriaged, Pri3, area-System.Linq
Milestone:	-

[eiriktsarpalis]

Hi @binki, indeed, the documentation should say "If TSource is a nullable type". Would you be interested in contributing a PR that corrects this?