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> I'm genuinely curious if you have any examples? Nullability checks may be bolted on, but once you enable them, they should consistently prevent you from deali

> I'm genuinely curious if you have any examples? Nullability checks may be bolted on, but once you enable them, they should consistently prevent you from dealing with any null values that you haven't explicitly allowed. I’m not the one you asked, but there’s a difference between you no longer having to deal with null checks and your program no longer having to deal with null checks. The CLR will still do the null checks and fail your program fast when needed. Other languages will require you to properly handle them (or at least, make it obvious where you chose to bluntly abort the program when they occur) I also don’t think C# will prevent you from forgetting to do a if null check in cases where you expect values to sometimes be null.

jolux 4y ago
> I also don’t think C# will prevent you from forgetting to do a if null check in cases where you expect values to sometimes be null. It should throw a warning in situations where a non-nullable value is not clearly non-null when it’s dereferenced. So you won’t get a warning in the body of a method declaration with a non-billable parameter, for example, but you will get a warning if you attempt to pass null into it.
int_19h 4y ago
You're describing C# as it was before nullability tracking. For several years now, it does have a mode in which every reference that can be null must be explicitly checked to be non-null first before you can use it, very similar to Kotlin. https://learn.microsoft.com/en-us/dotnet/csharp/nullable-references#null-state-analysis https://learn.microsoft.com/en-us/dotnet/csharp/nullable-ref... So yes, "will require you to properly handle them" is exactly what I meant.
- Someone 4y ago
  FTA, emphasis added: “Nullable reference types refers to a group of features enabled in a nullable aware context that _minimize_ the likelihood that your code causes the runtime to throw System.NullReferenceException.” That approximates it, and likely gives you most of the benefits, but it isn’t the same as strict enforcement of necessary null checks. There will be cases where the programmer can prove a value isn’t null, but the compiler can’t, and thus, the programmer can choose to ignore the warning. That’s similar to how Java tries to prove that a variable is initialized when being read. (https://docs.oracle.com/javase/specs/jls/se9/html/jls-16.html https://docs.oracle.com/javase/specs/jls/se9/html/jls-16.htm...). Java makes the safe choice, though. It refuses to compile such programs, thus guaranteeing that every local variable and blank final field will be initialized before first use.
  - int_19h 4y ago
    That's exactly why I asked for specific examples of when nullable enforcement does not catch a potential null reference at compile time. I can't think of any such case so long as all the code has it enabled (if not, it's like safe Rust calling into unsafe). And if you ignore the warnings, that's a deliberate opt-out; why even bother with nullability checks then?

jolux 4y ago

> I also don’t think C# will prevent you from forgetting to do a if null check in cases where you expect values to sometimes be null. It should throw a warning in situations where a non-nullable value is not clearly non-null when it’s dereferenced. So you won’t get a warning in the body of a method declaration with a non-billable parameter, for example, but you will get a warning if you attempt to pass null into it.

int_19h 4y ago

You're describing C# as it was before nullability tracking. For several years now, it does have a mode in which every reference that can be null must be explicitly checked to be non-null first before you can use it, very similar to Kotlin. https://learn.microsoft.com/en-us/dotnet/csharp/nullable-references#null-state-analysis https://learn.microsoft.com/en-us/dotnet/csharp/nullable-ref... So yes, "will require you to properly handle them" is exactly what I meant.

Someone 4y ago
FTA, emphasis added: “Nullable reference types refers to a group of features enabled in a nullable aware context that _minimize_ the likelihood that your code causes the runtime to throw System.NullReferenceException.” That approximates it, and likely gives you most of the benefits, but it isn’t the same as strict enforcement of necessary null checks. There will be cases where the programmer can prove a value isn’t null, but the compiler can’t, and thus, the programmer can choose to ignore the warning. That’s similar to how Java tries to prove that a variable is initialized when being read. (https://docs.oracle.com/javase/specs/jls/se9/html/jls-16.html https://docs.oracle.com/javase/specs/jls/se9/html/jls-16.htm...). Java makes the safe choice, though. It refuses to compile such programs, thus guaranteeing that every local variable and blank final field will be initialized before first use.
- int_19h 4y ago
  That's exactly why I asked for specific examples of when nullable enforcement does not catch a potential null reference at compile time. I can't think of any such case so long as all the code has it enabled (if not, it's like safe Rust calling into unsafe). And if you ignore the warnings, that's a deliberate opt-out; why even bother with nullability checks then?