mirror of
https://github.com/carbon-language/carbon-lang.git
synced 2026-10-05 18:31:08 +01:00
Dana Jansens
32aa7cb1fa
Identifying a facet type takes both a self and facet type as a pair, and then encode the self into the IdentifiedFacetType. This makes a constraint that requires some _other_ type implements an interface visible in the IdentifiedFacetType. And it will help to enable facet types with `where T impls Z` for `T` that is not `.Self` in the future. IdentifiedFacetTypes are now stored in a CanonicalValueStore instead of a RelationalValueStore as they key is the combination of self and (declared) facet type together now. When the self-type is a facet value (has type FacetType) this is most straightforward. But when it's a type we need to construct a FacetValue to construct a specific for a require decl, to replace the generic binding of the symbolic `Self`, which has type FacetType. To do so, we make a FacetValue with an empty FacetType (equivalent to TypeType). This prevents any looking for witnesses through the FacetType, which matches what you can get from a type directly, requiring witnesses to come from finding an `impl` decl. Add additional InstNamer logic for such empty facet types so they print as `<typename>.type.facet` if possible instead of as just `facet_value`.