Lean 4 fork for HoTT-compatible kernel extensions (Path types, transport, HITs). Maintained against upstream leanprover/lean4.
@kha the following idiom is not safe
```
while (is_pi(t)) {
t = whnf(binding_body(t));
}
```
`whnf(e)` assumes that `e` does not have dangling deBruijn variables.
We should use (the more expensive):
```
while (is_pi(t)) {
t = whnf(instantiate(binding_body(t), locals.push_local_from_binding(t)));
}
```
BTW, this problem is not related to the assertion violation at #1930
I just stumbled on it when fixing the violation.
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