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Dana JansensandRichard Smith
4a0c1ddd8e
Allow partially identifying a named constraint inside its definition, and allow the query self in an impl lookup with a non-identified facet type to be used to provide witnesses from that facet type. This allows impl lookup on `Self` to find `require` decls that have been written earlier in the named constraint, so that the named constraint to be used to provide witnesses from inside its definition. But disallow an incomplete named constraint from being part of an identified facet type, to prevent forming facet values that store a witness set that can be invalidated as the named constraint adds interfaces to its identified facet type. This was discussed in open discussion [on 2026-03-12](https://docs.google.com/document/d/1mjllGO3ZCL4qGt9uJHUtcxKoHAGEY7Y999ie4EtBWB8/edit?tab=t.0#heading=h.1dvbbrp5a6t3). --------- Co-authored-by: Richard Smith <richard@metafoo.co.uk>
Generics
This directory contains the collection of documents describing the generics feature of Carbon:
- Overview - A high-level description of the generics design, with pointers to other design documents that dive deeper into individual topics
- Goals - The motivation and principles guiding the design direction
- Terminology - A glossary establishing common terminology for describing the design
- Detailed design - In-depth description
- Appendix: Coherence - Describes the rationale for Carbon's choice to have coherent generics, and the alternatives.
- Appendix: Rewrite constraints - Describes the detailed rules governing rewrite constraints, and why resolving them terminates.
- Appendix: Witness tables - Describes an implementation strategy for checked generics, and Carbon's rationale for only using it for dynamic dispatch.