## Issue #6446 - `approx_adv` broken and unused in `Lazy_exact_nt`
**Issue:** https://github.com/CGAL/cgal/issues/6446
**Problem:** `Lazy_exact_nt<ET>::approx_adv()` (lines 546-547 of
`Number_types/include/CGAL/Lazy_exact_nt.h`) accessed `this->ptr()`
which is a private member of the `Lazy` base class, causing a compile
error under any instantiation. The function is not documented, has no
tests, and has zero callers across the entire codebase.
**Fix:** Removed the `approx_adv()` method entirely. Users who need an
`Interval_nt_advanced` (`Interval_nt<false>`) from a `Lazy_exact_nt` can
use the existing public `approx()` method inherited from the `Lazy` base
class.
**Files changed:**
- `Number_types/include/CGAL/Lazy_exact_nt.h` (-3 lines)
Sebastien Loriot
568fc63ee6