SemIR::FacetValue lowers to context.GetTypeAsValue(), which produces a
constant of LLVM type %type (context.GetTypeType()). However,
SemIR::FacetType previously fell back to an anonymous empty struct {},
causing an argument type mismatch assertion failure when passing a
FacetValue to a function expecting a FacetType parameter.
Identified by @danakj in #7731
Assisted-by: Antigravity with Gemini
David Blaikie
3339dd85de