[release/7.0-rc1] Fix nullable annotations on generic math interfaces #74116
Conversation
![github-actions[bot]](https://avatars.githubusercontent.com/in/15368?s=60&v=4){kind=small}
- All `where TSelf : ...` constraints become `where TSelf : ...?`. Without this, trying to define a type like `Matrix<T> where T : INumber<T>?` in order to support nullable T types warns because `INumber<T>` constrains its `T` (`TSelf`) to be non-nullable. - All `where TOther : ...` constraints are changed to be oblivious. They can't be correctly annotated as there's no way to express the nullability relationship with the nullability of TSelf. - Use `[MaybeNullWhen(false)] out T` instead of `[NotNullWhen(true)] out T?`, as we do with other generics, since if the instantiation of `T` is nullable, we can't guarantee `NotNullWhen(true)`. - Make `IEqualityOperators` `==` and `!=` accept `TSelf?`. This keeps it consistent with `IEquatable<T>.Equals(T?)`, `IEqualityComparer<in T>.Equals(T?, T?)`, `IEqualityComparer.Equals(object?, object?)`, `IStructuralEquatable.Equals(object?, IEqualityComparer)`, and `object.Equals(object?)` which all allow null even if generic and the generic is non-null. It in turn enables checks like `T.Zero == default` without nullability warnings.
|
Note regarding the This serves as a reminder for when your PR is modifying a ref *.cs file and adding/modifying public APIs, to please make sure the API implementation in the src *.cs file is documented with triple slash comments, so the PR reviewers can sign off that change. |
|
Tagging subscribers to this area: @dotnet/area-system-numerics Issue DetailsBackport of #74025 to release/7.0-rc1 /cc @stephentoub Customer ImpactTestingRiskIMPORTANT: Is this backport for a servicing release? If so and this change touches code that ships in a NuGet package, please make certain that you have added any necessary package authoring and gotten it explicitly reviewed.
|
|
Approved for RC1 as "1. Broken or significantly incomplete 7.0 scenario". This is new API and needs to be correctly annotated. |
ghost
locked as resolved and limited conversation to collaborators
Backport of #74025 to release/7.0-rc1
/cc @stephentoub
Customer Impact
Testing
Risk
IMPORTANT: Is this backport for a servicing release? If so and this change touches code that ships in a NuGet package, please make certain that you have added any necessary package authoring and gotten it explicitly reviewed.