C#•3mo ago

Have nullable types been changed?

C#
var client = clients.Find(c => c?.id == id);
if (client is null)
    return Button.None;

return client.inputQueue.Dequeue();

C#
var client = clients.Find(c => c?.id == id);
if (client is null)
    return Button.None;

return client.inputQueue.Dequeue();

C#
var client = clients.Find(c => c?.id == id);
if (client is null)
    return Button.None;

return client.inputQueue.Dequeue();

C#
var client = clients.Find(c => c?.id == id);
if (client is null)
    return Button.None;

return client.inputQueue.Dequeue();

this code should work since the null check should make client non nullable after but it doesn't. Client is still a nullable type after the check.

reflectronic•10/10/25, 1:07 PM

nothing has changed here, this never worked

reflectronic•10/10/25, 1:08 PM

the compiler does not know that the code you wrote in the query is related to the return value

Angius•10/10/25, 3:21 PM

var client = clients.Find(c => c?.id == id);
if (client is not SkibidiClient cl)
    return Button.None;

return cl.inputQueue.Dequeue();

var client = clients.Find(c => c?.id == id);
if (client is not SkibidiClient cl)
    return Button.None;

return cl.inputQueue.Dequeue();

this works

markiel•10/10/25, 4:53 PM

I have never used .Find().Find().
Is this .netframework?

Mmarkiel I have never used `.Find()`. Is this .netframework?

Angius•10/10/25, 5:20 PM

https://learn.microsoft.com/en-us/dotnet/api/system.collections.generic.list-1.find?view=net-9.0

Angius•10/10/25, 5:20 PM

markiel•10/10/25, 5:24 PM

oh, well, it seems like a redundant to .First().First()

Rreflectronic the compiler does not know that the code you wrote in the query is related to th...

VaskoOP•10/10/25, 6:38 PM

The compiler does static flow analysis to determine type nullability, the if check should result in the compiler knowing that in subsequent code, client is not null

reflectronic•10/10/25, 6:38 PM

oh, that

reflectronic•10/10/25, 6:38 PM

no, it does not change the type of the variable

Rreflectronic no, it does not change the type of the variable

VaskoOP•10/10/25, 6:39 PM

What does that mean?

VaskoOP•10/10/25, 6:39 PM

VaskoOP•10/10/25, 6:40 PM

I am pretty sure this used to work

reflectronic•10/10/25, 6:40 PM

i am not sure what you mean

reflectronic•10/10/25, 6:40 PM

there is no warning in the code you sent

Angius•10/10/25, 6:43 PM

C# is statically-typed, so variables cannot just change the type

Angius•10/10/25, 6:43 PM

Foo? f = MaybeFoo();
if (f is null) return;
DoStuff(f); // f is still a `Foo?`

Foo? f = MaybeFoo();
if (f is null) return;
DoStuff(f); // f is still a `Foo?`

reflectronic•10/10/25, 6:43 PM

the clientclient variable is a Button?Button? because you declared it with varvar

Angius•10/10/25, 6:44 PM

The compiler/analyzer/whatever knows that ff is now not null, but the type remains unchanged

reflectronic•10/10/25, 6:44 PM

the null state of the variable is different from the type of the variable. it could be a nullable variable, but in a certain section of the code, protected by a null check, it is known to be non-null

Have nullable types been changed?

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