diff --git a/src/nvim/buffer_updates.c b/src/nvim/buffer_updates.c
index 1e7cc8520f..79483380c9 100644
--- a/src/nvim/buffer_updates.c
+++ b/src/nvim/buffer_updates.c
@@ -282,10 +282,11 @@ void buf_updates_send_changes(buf_T *buf,
   kv_size(buf->update_callbacks) = j;
 }
 
-void buf_updates_send_splice(buf_T *buf,
-                             int start_row, colnr_T start_col, bcount_t start_byte,
-                             int old_row, colnr_T old_col, bcount_t old_byte,
-                             int new_row, colnr_T new_col, bcount_t new_byte)
+void buf_updates_send_splice(
+    buf_T *buf,
+    int start_row, colnr_T start_col, bcount_t start_byte,
+    int old_row, colnr_T old_col, bcount_t old_byte,
+    int new_row, colnr_T new_col, bcount_t new_byte)
 {
   if (!buf_updates_active(buf)) {
     return;
diff --git a/src/nvim/change.c b/src/nvim/change.c
index 6ffc26332a..5e1ec616f6 100644
--- a/src/nvim/change.c
+++ b/src/nvim/change.c
@@ -1611,7 +1611,7 @@ int open_line(
     }
     ml_replace(curwin->w_cursor.lnum, p_extra, true);
     changed_bytes(curwin->w_cursor.lnum, 0);
-    // TODO: extmark_splice_cols here??
+    // TODO(vigoux): extmark_splice_cols here??
     curwin->w_cursor.lnum--;
     did_append = false;
   }
diff --git a/src/nvim/extmark.c b/src/nvim/extmark.c
index bb981cb2f6..3a04908ccb 100644
--- a/src/nvim/extmark.c
+++ b/src/nvim/extmark.c
@@ -540,7 +540,7 @@ void extmark_adjust(buf_T *buf,
   int old_row, new_row;
   if (amount == MAXLNUM) {
     old_row = (int)(line2 - line1+1);
-    // TODO: ej kasta?
+    // TODO(bfredl): ej kasta?
     old_byte = (bcount_t)buf->deleted_bytes2;
 
     new_row = (int)(amount_after + old_row);
@@ -553,7 +553,8 @@ void extmark_adjust(buf_T *buf,
     new_row = (int)amount;
   }
   if (new_row > 0) {
-    new_byte = ml_find_line_or_offset(buf, line1+new_row, NULL, true)-start_byte;
+    new_byte = ml_find_line_or_offset(buf, line1+new_row, NULL, true)
+      - start_byte;
   }
   extmark_splice_impl(buf,
                       (int)line1-1, 0, start_byte,
@@ -562,10 +563,10 @@ void extmark_adjust(buf_T *buf,
 }
 
 void extmark_splice(buf_T *buf,
-                         int start_row, colnr_T start_col,
-                         int old_row, colnr_T old_col, bcount_t old_byte,
-                         int new_row, colnr_T new_col, bcount_t new_byte,
-                         ExtmarkOp undo)
+                    int start_row, colnr_T start_col,
+                    int old_row, colnr_T old_col, bcount_t old_byte,
+                    int new_row, colnr_T new_col, bcount_t new_byte,
+                    ExtmarkOp undo)
 {
   long offset = ml_find_line_or_offset(buf, start_row+1, NULL, true);
   extmark_splice_impl(buf, start_row, start_col, offset+start_col,
@@ -668,11 +669,12 @@ void extmark_splice_cols(buf_T *buf,
                  0, new_col, new_col, undo);
 }
 
-void extmark_move_region(buf_T *buf,
-                         int start_row, colnr_T start_col, bcount_t start_byte,
-                         int extent_row, colnr_T extent_col, bcount_t extent_byte,
-                         int new_row, colnr_T new_col, bcount_t new_byte,
-                         ExtmarkOp undo)
+void extmark_move_region(
+    buf_T *buf,
+    int start_row, colnr_T start_col, bcount_t start_byte,
+    int extent_row, colnr_T extent_col, bcount_t extent_byte,
+    int new_row, colnr_T new_col, bcount_t new_byte,
+    ExtmarkOp undo)
 {
   // TODO(bfredl): this is not synced to the buffer state inside the callback.
   // But unless we make the undo implementation smarter, this is not ensured
diff --git a/src/nvim/indent.c b/src/nvim/indent.c
index 25a9b38b5d..bb0fdfec01 100644
--- a/src/nvim/indent.c
+++ b/src/nvim/indent.c
@@ -298,9 +298,11 @@ int set_indent(int size, int flags)
     ml_replace(curwin->w_cursor.lnum, newline, false);
     if (!(flags & SIN_NOMARK)) {
       extmark_splice_cols(curbuf,
-                     (int)curwin->w_cursor.lnum-1, skipcols,
-                     (int)(p-oldline) - skipcols, (int)(s-newline) - skipcols,
-                     kExtmarkUndo);
+                          (int)curwin->w_cursor.lnum-1,
+                          skipcols,
+                          (int)(p-oldline) - skipcols,
+                          (int)(s-newline) - skipcols,
+                          kExtmarkUndo);
     }
 
     if (flags & SIN_CHANGED) {
diff --git a/src/nvim/memline.c b/src/nvim/memline.c
index 9dde4a401b..ebd86a3f7d 100644
--- a/src/nvim/memline.c
+++ b/src/nvim/memline.c
@@ -257,11 +257,11 @@ int ml_open(buf_T *buf)
   /*
    * init fields in memline struct
    */
-  buf->b_ml.ml_stack_size = 0;   /* no stack yet */
-  buf->b_ml.ml_stack = NULL;    /* no stack yet */
-  buf->b_ml.ml_stack_top = 0;   /* nothing in the stack */
-  buf->b_ml.ml_locked = NULL;   /* no cached block */
-  buf->b_ml.ml_line_lnum = 0;   /* no cached line */
+  buf->b_ml.ml_stack_size = 0;   // no stack yet
+  buf->b_ml.ml_stack = NULL;    // no stack yet
+  buf->b_ml.ml_stack_top = 0;   // nothing in the stack
+  buf->b_ml.ml_locked = NULL;   // no cached block
+  buf->b_ml.ml_line_lnum = 0;   // no cached line
   buf->b_ml.ml_line_offset = 0;
   buf->b_ml.ml_chunksize = NULL;
 
@@ -832,12 +832,12 @@ void ml_recover(bool checkext)
   /*
    * init fields in memline struct
    */
-  buf->b_ml.ml_stack_size = 0;          /* no stack yet */
-  buf->b_ml.ml_stack = NULL;            /* no stack yet */
-  buf->b_ml.ml_stack_top = 0;           /* nothing in the stack */
-  buf->b_ml.ml_line_lnum = 0;           /* no cached line */
+  buf->b_ml.ml_stack_size = 0;          // no stack yet
+  buf->b_ml.ml_stack = NULL;            // no stack yet
+  buf->b_ml.ml_stack_top = 0;           // nothing in the stack
+  buf->b_ml.ml_line_lnum = 0;           // no cached line
   buf->b_ml.ml_line_offset = 0;
-  buf->b_ml.ml_locked = NULL;           /* no locked block */
+  buf->b_ml.ml_locked = NULL;           // no locked block
   buf->b_ml.ml_flags = 0;
 
   /*
diff --git a/test/functional/lua/buffer_updates_spec.lua b/test/functional/lua/buffer_updates_spec.lua
index a798d4fcbb..3da230fb7e 100644
--- a/test/functional/lua/buffer_updates_spec.lua
+++ b/test/functional/lua/buffer_updates_spec.lua
@@ -255,15 +255,14 @@ describe('lua buffer event callbacks: on_bytes', function()
   -- nvim_buf_get_offset forces a flush of the memline). To be safe run the
   -- test both ways.
   local function check(verify)
-    local lastsize
     meths.buf_set_lines(0, 0, -1, true, origlines)
     local shadow = deepcopy(origlines)
     local shadowbytes = table.concat(shadow, '\n') .. '\n'
     if verify then
-      lastsize = meths.buf_get_offset(0, meths.buf_line_count(0))
+      meths.buf_get_offset(0, meths.buf_line_count(0))
     end
-    exec_lua("return test_register(...)", 0, "test1",false,utf_sizes)
-    local tick = meths.buf_get_changedtick(0)
+    exec_lua("return test_register(...)", 0, "test1",false, nil)
+    meths.buf_get_changedtick(0)
 
     local verify_name = "test1"
     local function check_events(expected)
@@ -272,7 +271,7 @@ describe('lua buffer event callbacks: on_bytes', function()
       if verify then
         for _, event in ipairs(events) do
           if event[1] == verify_name and event[2] == "bytes" then
-            local _, _, buf, tick, start_row, start_col, start_byte, old_row, old_col, old_byte, new_row, new_col, new_byte = unpack(event)
+            local _, _, _, _, _, _, start_byte, _, _, old_byte, _, _, new_byte = unpack(event)
             local before = string.sub(shadowbytes, 1, start_byte)
             -- no text in the tests will contain 0xff bytes (invalid UTF-8)
             -- so we can use it as marker for unknown bytes