Stable type identifiers: a missing piece for crABI and export

ParaDevOne:

• #3435 (export) deals with how to export symbol information dynamically. It requires stable identifiers, but also does not define them.
• The proposal presented in this document will provide the missing piece, which is an unambiguous, deterministic identifier for all types.

I think you misunderstood #3435, what is needs are identifiers based on the "identity" of a type such that if the type changes in some non-ABI compatible way then the identifier will change as well. Your proposal explicitly does not do this.