If you’re arriving at this a little late, like me, it turns out the .NET team addressed it through a bunch of parameter attributes like MaybeNullWhen(returnValue: true) in the System.Diagnostics.CodeAnalysis space which you can use for the try pattern. Returning a swift-style nullable reference type works well, but the try pattern lets you return things … Read more
thing isn’t null. Since structs can’t be null, so Nullable<int> can’t be null. The thing is… it is just compiler magic. You think it is null. In fact, the HasValue is just set to false. If you call GetValueOrDefault it checks if HasValue is true or false: public T GetValueOrDefault(T defaultValue) { return HasValue ? … Read more
The point here is that int? i = null; does not create a variable i which is null, but (by performing an implicit cast) a Nullable<int> instance which does not have a value. This means the object/instance is not null (and as Nullable<T> is a struct/value type it actually can’t be null) and therefore has … Read more
Well firstly, Nullable<T> is a struct, so there isn’t an object as such. You can’t call GetType(), as that will box the value (at which point you either get null and thus an exception, or a boxed non-nullable value and therefore not the type you want). (Boxing is what’s messing up your assertion here – … Read more
In my case, I ran into this problem with Visual Studio 2022 when I changed the target framework from .NET Standard 2.1 to .NET Standard 2.0. I solved my problem by removing <Nullable>enable</Nullable> in the .csproj file and restarting Visual Studio. Original .csproj file: <PropertyGroup> <TargetFramework>netstandard2.1</TargetFramework> <Nullable>enable</Nullable> </PropertyGroup> New .csproj file: <PropertyGroup> <TargetFramework>netstandard2.0</TargetFramework> </PropertyGroup>
I agree with Stuart Marks that list == null ? Stream.empty() : list.stream() is the right way to do this (see his answer), or at least the right way to do this pre-Java 9 (see edit below), but I’ll leave this answer up to demonstrate usage of the Optional API. <T> Stream<T> getStream(List<T> list) { … Read more
Embeddable components (or composite elements, whatever you want to call them) usually contain more than one property and thus are mapped to more than one column. The entire component being null can therefore be treated in different ways; J2EE spec does not dictate one way or another. Hibernate considers component to be NULL if all … Read more
It is possible to use PropTypes.oneOf([null]).isRequired. It should allow null, and nothing else. You can combine that with any other type: PropTypes.oneOfType([ PropTypes.string.isRequired, PropTypes.oneOf([null]).isRequired, ]).isRequired Edit: I just had this prop type fail for me when given a null prop using prop-types 15.7.2, so I’m not sure this works anymore (if it ever did?). I … Read more
There are two things going on: 1) The compiler treats “null” not as a null reference but as a null value… the null value for whatever type it needs to convert to. In the case of a Nullable<T> it’s just the value which has False for the HasValue field/property. So if you have a variable … Read more
Re: your latest update: This is a bug in the nullable arithmetic optimizer. The nullable optimizer will remove the unnecessary conversion to int? when you do something like: short? s = null; int? x = s + 1; The unoptimized codegen does the equivalent of: short? s = null; int? x; int? temp = s.HasValue … Read more