Lean 4 fork for HoTT-compatible kernel extensions (Path types, transport, HITs). Maintained against upstream leanprover/lean4.
977ae92e43
This PR removes a rather ugly hack in the module system, exposing the bodies of theorems whose type mention `WellFounded`. The original motivation was that reducing well-founded definitions (e.g. in `by rfl`) requires reducing proofs, so they need to be available. But reducing proofs is generally fraught with peril, and we have been nudging our users away from using it for a while, e.g. in #5182. Since the module system is opt-in and users will gradually migrate to it, it may be reasonable to expect them to avoid reducing well-founded recursion in the process This way we don't need hacks like this (which, without evidence, I believe would be incomplete anyways) and we get the nice guarantee that within the module system, theorems bodies are always private. |
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