diff --git a/ostd/algorithm.hh b/ostd/algorithm.hh
index 704a50b..080a56b 100644
--- a/ostd/algorithm.hh
+++ b/ostd/algorithm.hh
@@ -556,20 +556,6 @@ inline auto equal(R &&range) {
     };
 }
 
-template<typename R>
-R slice_until(R range1, R range2) {
-    return range1.slice(0, range1.distance_front(range2));
-}
-
-template<typename R>
-inline auto slice_until(R &&range) {
-    return [range = std::forward<R>(range)](auto &&obj) mutable {
-        return slice_until(
-            std::forward<decltype(obj)>(obj), std::forward<R>(range)
-        );
-    };
-}
-
 /* algos that modify ranges or work with output ranges */
 
 template<typename R1, typename R2>
@@ -769,13 +755,6 @@ public:
         return p_range.equals_front(r.p_range);
     }
 
-    range_difference_t<T> distance_front(map_range const &r) const {
-        return p_range.distance_front(r.p_range);
-    }
-    range_difference_t<T> distance_back(map_range const &r) const {
-        return p_range.distance_back(r.p_range);
-    }
-
     void pop_front() { p_range.pop_front(); }
     void pop_back() { p_range.pop_back(); }
 
diff --git a/ostd/range.hh b/ostd/range.hh
index e928a14..1906214 100644
--- a/ostd/range.hh
+++ b/ostd/range.hh
@@ -627,13 +627,6 @@ public:
         return p_range.equals_front(r.p_range);
     }
 
-    difference_type distance_front(reverse_range const &r) const {
-        return -p_range.distance_back(r.p_range);
-    }
-    difference_type distance_back(reverse_range const &r) const {
-        return -p_range.distance_front(r.p_range);
-    }
-
     void pop_front() { p_range.pop_back(); }
     void pop_back() { p_range.pop_front(); }
 
@@ -697,13 +690,6 @@ public:
         return p_range.equals_back(r.p_range);
     }
 
-    difference_type distance_front(move_range const &r) const {
-        return p_range.distance_front(r.p_range);
-    }
-    difference_type distance_back(move_range const &r) const {
-        return p_range.distance_back(r.p_range);
-    }
-
     void pop_front() { p_range.pop_front(); }
     void pop_back() { p_range.pop_back(); }
 
@@ -1261,10 +1247,6 @@ struct iterator_range: input_range<iterator_range<T>> {
         return p_beg == range.p_beg;
     }
 
-    difference_type distance_front(iterator_range const &range) const {
-        return range.p_beg - p_beg;
-    }
-
     /* satisfy bidirectional_range */
     void pop_back() {
         /* rely on iterators to do their own checks */
@@ -1297,10 +1279,6 @@ struct iterator_range: input_range<iterator_range<T>> {
         return p_end == range.p_end;
     }
 
-    ptrdiff_t distance_back(iterator_range const &range) const {
-        return range.p_end - p_end;
-    }
-
     /* satisfy finite_random_access_range */
     size_type size() const { return size_type(p_end - p_beg); }
 
diff --git a/ostd/string.hh b/ostd/string.hh
index 0a777f0..a1c2d65 100644
--- a/ostd/string.hh
+++ b/ostd/string.hh
@@ -97,10 +97,6 @@ public:
         return p_beg == range.p_beg;
     }
 
-    ptrdiff_t distance_front(basic_char_range const &range) const {
-        return range.p_beg - p_beg;
-    }
-
     void pop_back() {
         if (p_end == p_beg) {
             return;
@@ -121,10 +117,6 @@ public:
         return p_end == range.p_end;
     }
 
-    ptrdiff_t distance_back(basic_char_range const &range) const {
-        return range.p_end - p_end;
-    }
-
     size_t size() const { return p_end - p_beg; }
 
     basic_char_range slice(size_t start, size_t end) const {