In .NET 7, we will stabilize the API surface area and implementations for Generic Math features.

Prerequisites

• Ensure the C++/CLI compatibility issue with static abstracts in interfaces has been addressed
  • Partner with the WPF team to ensure that fix has been integrated and validated
• Confirm Native AOT scenarios work with static abstract interface members on primitive types
• Confirm Mono AOT scenarios work with static abstract interface members on primitive types

Work Items

• [Mono] implement static virtual methods in interfaces support #49904 Ensure mono is compatible with static abstracts in interfaces
  • Generic math does not work in WASM AOT #60447
  • [iOS][tvOS] Generic math IntPtr SByte and Int16 test failures #61920
  • [mono] Default Interface Implementation of Static Virtual Methods #67540
• Crossgen2 support for static virtual method resolution #54063
• Implement new generic math operator interfaces in System.Numeric types #58162
• Add reciprocal and SinCos methods to IFloatingPoint #58607
• Use generic math in System.Numerics.Vectors test utils #60365
• [API Proposal]: Generic math Assign operators #60536
• Cannot understand the API design of Generic Math INumber.Create[XXXX] methods #62296
• Add default method support to virtual statics #64717

Language Features

• [Proposal]: Checked Operators csharplang#4665
• [Proposal]: Relaxing shift operator requirements csharplang#4666
• [Proposal]: Unsigned right shift operator csharplang#4682
• [Open issue]: static abstract interfaces and static classes csharplang#5783
• Default Interface Methods support
  • Runtime (@davidwrighton)
    • Mainline scenarios
    • Allowing overrides within the interfaces (not required for Preview 4)
  • Compiler (@AlekseyTs)
• nint vs IntPtr differences (@tannergooding)
• self constraint (this language feature is not approved at this time)

Acceptance Criteria

• Present the feature set at the MVP summit to solicit feedback (@MadsTorgersen)
• Consider moving the advanced interfaces into a namespace other than System
• Consider making interface implementations implicit
• Reference APIs are integrated into System.Runtime without the need for the System.Runtime.Experimental package installation
• The [RequiresPreviewFeatures] attribute is removed from all Generic Math APIs
• Propose and implement a Roslyn Analyzer for spotting IntPtr vs. nint behavioral differences to highlight the altered behavior
• Partner with ecosystem package authors to garner feedback on the APIs
• Validate usability in F#
• Author a blog post / demo

Community Validation

The following community members and products will be contacted for validation of compatibility with this feature set. We will aim for validation from them before Preview 4 ships.

• ILSpy
• dotPeek
• source.dot.net
• Unity
• Profilers