Lean 4 fork for HoTT-compatible kernel extensions (Path types, transport, HITs). Maintained against upstream leanprover/lean4.
93683eb455
This PR enables `backward.whnf.reducibleClassField` for v4.29. The support is particularly important when the user marks a class field as `[reducible]` and the transparency mode is `.reducible`. For example, suppose `e` is `a ≤ b` where `a b : Nat`, and `LE.le` is marked as `[reducible]`. Simply unfolding `LE.le` would give `instLENat.1 a b`, which would be stuck because `instLENat` has transparency `[instance_reducible]`. To avoid this, when we unfold a `[reducible]` class field, we also unfold the associated projection `instLENat.1` using `.instances` reducibility, ultimately returning `Nat.le a b`. --------- Co-authored-by: Paul Reichert <6992158+datokrat@users.noreply.github.com> Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com> Co-authored-by: Kim Morrison <kim@tqft.net> |
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