diff --git a/src/line_modification.cc b/src/line_modification.cc
deleted file mode 100644
index 5da287fc..00000000
--- a/src/line_modification.cc
+++ /dev/null
@@ -1,105 +0,0 @@
-#include "line_modification.hh"
-
-#include "buffer.hh"
-
-namespace Kakoune
-{
-
-namespace
-{
-
-struct LineChange
-{
-    LineChange(const Buffer::Change& change)
-    {
-        ByteCoord begin = change.begin;
-        ByteCoord end = change.end;
-        if (change.type == Buffer::Change::Insert)
-        {
-            if (change.at_end and begin != ByteCoord{0,0})
-            {
-                kak_assert(begin.column == 0);
-                --begin.line;
-            }
-            pos = begin.line;
-            num = end.line - begin.line;
-        }
-        else
-        {
-            if (change.at_end and begin != ByteCoord{0,0})
-            {
-                kak_assert(begin.column == 0);
-                --begin.line;
-            }
-            pos = begin.line;
-            num = begin.line - end.line;
-        }
-    }
-
-    LineCount pos;
-    LineCount num;
-};
-
-}
-
-std::vector<LineModification> compute_line_modifications(const Buffer& buffer, size_t timestamp)
-{
-    std::vector<LineModification> res;
-    for (auto& buf_change : buffer.changes_since(timestamp))
-    {
-        const LineChange change(buf_change);
-
-        auto pos = std::upper_bound(res.begin(), res.end(), change.pos,
-                                    [](const LineCount& l, const LineModification& c)
-                                    { return l < c.new_line; });
-
-        if (pos != res.begin())
-        {
-            auto& prev = *(pos-1);
-            if (change.pos <= prev.new_line + prev.num_added)
-                --pos;
-            else
-                pos = res.insert(pos, {change.pos - prev.diff(), change.pos, 0, 0});
-        }
-        else
-            pos = res.insert(pos, {change.pos, change.pos, 0, 0});
-
-        auto& modif = *pos;
-        auto next = pos + 1;
-        if (change.num > 0)
-        {
-            modif.num_added += change.num;
-            for (auto it = next; it != res.end(); ++it)
-                it->new_line += change.num;
-        }
-        if (change.num < 0)
-        {
-            const LineCount num_removed = -change.num;
-
-            auto delend = std::upper_bound(next, res.end(), change.pos + num_removed,
-                                           [](const LineCount& l, const LineModification& c)
-                                           { return l < c.new_line; });
-
-            for (auto it = next; it != delend; ++it)
-            {
-                LineCount removed_from_it = (change.pos + num_removed - it->new_line);
-                modif.num_removed += it->num_removed - std::min(removed_from_it, it->num_added);
-                modif.num_added += std::max(0_line, it->num_added - removed_from_it);
-            }
-            next = res.erase(next, delend);
-
-            const LineCount num_added_after_pos =
-                modif.new_line + modif.num_added - change.pos;
-            const LineCount num_removed_from_added =
-                std::min(num_removed, num_added_after_pos);
-            modif.num_added -= num_removed_from_added;
-            modif.num_removed += num_removed - num_removed_from_added;
-
-            for (auto it = next; it != res.end(); ++it)
-                it->new_line -= num_removed;
-        }
-    }
-    return res;
-}
-
-}
diff --git a/src/line_modification.hh b/src/line_modification.hh
deleted file mode 100644
index 3cd2d669..00000000
--- a/src/line_modification.hh
+++ /dev/null
@@ -1,26 +0,0 @@
-#ifndef line_change_watcher_hh_INCLUDED
-#define line_change_watcher_hh_INCLUDED
-
-#include "units.hh"
-#include "utils.hh"
-
-namespace Kakoune
-{
-
-class Buffer;
-
-struct LineModification
-{
-    LineCount old_line; // line position in the old buffer
-    LineCount new_line; // new line position
-    LineCount num_removed; // number of lines removed after this one
-    LineCount num_added; // number of lines added after this one
-
-    LineCount diff() const { return new_line - old_line + num_added - num_removed; }
-};
-
-std::vector<LineModification> compute_line_modifications(const Buffer& buffer, size_t timestamp);
-
-}
-
-#endif // line_change_watcher_hh_INCLUDED