Merge branch 'master' into yagebu/option-fixes

6 files changed, 1007 insertions, 281 deletions

diff --git a/src/nvim/eval/decode.c b/src/nvim/eval/decode.c
index 9c9c2c2dc8..17799b500c 100644
--- a/src/nvim/eval/decode.c
+++ b/src/nvim/eval/decode.c
@@ -60,8 +60,8 @@ static inline void create_special_dict(typval_T *const rettv,
   dictitem_T *const type_di = tv_dict_item_alloc_len(S_LEN("_TYPE"));
   type_di->di_tv.v_type = VAR_LIST;
   type_di->di_tv.v_lock = VAR_UNLOCKED;
-  type_di->di_tv.vval.v_list = (list_T *) eval_msgpack_type_lists[type];
-  type_di->di_tv.vval.v_list->lv_refcount++;
+  type_di->di_tv.vval.v_list = (list_T *)eval_msgpack_type_lists[type];
+  tv_list_ref(type_di->di_tv.vval.v_list);
   tv_dict_add(dict, type_di);
   dictitem_T *const val_di = tv_dict_item_alloc_len(S_LEN("_VAL"));
   val_di->di_tv = val;
@@ -120,16 +120,14 @@ static inline int json_decoder_pop(ValuesStackItem obj,
     last_container = kv_last(*container_stack);
   }
   if (last_container.container.v_type == VAR_LIST) {
-    if (last_container.container.vval.v_list->lv_len != 0
+    if (tv_list_len(last_container.container.vval.v_list) != 0
         && !obj.didcomma) {
       EMSG2(_("E474: Expected comma before list item: %s"), val_location);
       tv_clear(&obj.val);
       return FAIL;
     }
     assert(last_container.special_val == NULL);
-    listitem_T *obj_li = tv_list_item_alloc();
-    obj_li->li_tv = obj.val;
-    tv_list_append(last_container.container.vval.v_list, obj_li);
+    tv_list_append_owned_tv(last_container.container.vval.v_list, obj.val);
   } else if (last_container.stack_index == kv_size(*stack) - 2) {
     if (!obj.didcolon) {
       EMSG2(_("E474: Expected colon before dictionary value: %s"),
@@ -152,14 +150,10 @@ static inline int json_decoder_pop(ValuesStackItem obj,
       }
       obj_di->di_tv = obj.val;
     } else {
-      list_T *const kv_pair = tv_list_alloc();
+      list_T *const kv_pair = tv_list_alloc(2);
       tv_list_append_list(last_container.special_val, kv_pair);
-      listitem_T *const key_li = tv_list_item_alloc();
-      key_li->li_tv = key.val;
-      tv_list_append(kv_pair, key_li);
-      listitem_T *const val_li = tv_list_item_alloc();
-      val_li->li_tv = obj.val;
-      tv_list_append(kv_pair, val_li);
+      tv_list_append_owned_tv(kv_pair, key.val);
+      tv_list_append_owned_tv(kv_pair, obj.val);
     }
   } else {
     // Object with key only
@@ -227,14 +221,19 @@ static inline int json_decoder_pop(ValuesStackItem obj,
 /// Create a new special dictionary that ought to represent a MAP
 ///
 /// @param[out]  ret_tv  Address where new special dictionary is saved.
+/// @param[in]  len  Expected number of items to be populated before list
+///                  becomes accessible from VimL. It is still valid to
+///                  underpopulate a list, value only controls how many elements
+///                  will be allocated in advance. @see ListLenSpecials.
 ///
 /// @return [allocated] list which should contain key-value pairs. Return value
 ///                     may be safely ignored.
-list_T *decode_create_map_special_dict(typval_T *const ret_tv)
+list_T *decode_create_map_special_dict(typval_T *const ret_tv,
+                                       const ptrdiff_t len)
   FUNC_ATTR_NONNULL_ALL
 {
-  list_T *const list = tv_list_alloc();
-  list->lv_refcount++;
+  list_T *const list = tv_list_alloc(len);
+  tv_list_ref(list);
   create_special_dict(ret_tv, kMPMap, ((typval_T) {
     .v_type = VAR_LIST,
     .v_lock = VAR_UNLOCKED,
@@ -266,11 +265,11 @@ typval_T decode_string(const char *const s, const size_t len,
 {
   assert(s != NULL || len == 0);
   const bool really_hasnul = (hasnul == kNone
-                              ? memchr(s, NUL, len) != NULL
+                              ? ((s != NULL) && (memchr(s, NUL, len) != NULL))
                               : (bool)hasnul);
   if (really_hasnul) {
-    list_T *const list = tv_list_alloc();
-    list->lv_refcount++;
+    list_T *const list = tv_list_alloc(kListLenMayKnow);
+    tv_list_ref(list);
     typval_T tv;
     create_special_dict(&tv, binary ? kMPBinary : kMPString, ((typval_T) {
       .v_type = VAR_LIST,
@@ -291,7 +290,7 @@ typval_T decode_string(const char *const s, const size_t len,
       .v_type = VAR_STRING,
       .v_lock = VAR_UNLOCKED,
       .vval = { .v_string = (char_u *)(
-          s_allocated ? (char *)s : xmemdupz(s, len)) },
+          (s == NULL || s_allocated) ? (char *)s : xmemdupz(s, len)) },
     };
   }
 }
@@ -738,8 +737,9 @@ json_decode_string_cycle_start:
         } else if (last_container.special_val == NULL
                    ? (last_container.container.v_type == VAR_DICT
                       ? (DICT_LEN(last_container.container.vval.v_dict) == 0)
-                      : (last_container.container.vval.v_list->lv_len == 0))
-                   : (last_container.special_val->lv_len == 0)) {
+                      : (tv_list_len(last_container.container.vval.v_list)
+                         == 0))
+                   : (tv_list_len(last_container.special_val) == 0)) {
           emsgf(_("E474: Leading comma: %.*s"), LENP(p, e));
           goto json_decode_string_fail;
         }
@@ -848,8 +848,8 @@ json_decode_string_cycle_start:
         break;
       }
       case '[': {
-        list_T *list = tv_list_alloc();
-        list->lv_refcount++;
+        list_T *list = tv_list_alloc(kListLenMayKnow);
+        tv_list_ref(list);
         typval_T tv = {
           .v_type = VAR_LIST,
           .v_lock = VAR_UNLOCKED,
@@ -869,7 +869,7 @@ json_decode_string_cycle_start:
         list_T *val_list = NULL;
         if (next_map_special) {
           next_map_special = false;
-          val_list = decode_create_map_special_dict(&tv);
+          val_list = decode_create_map_special_dict(&tv, kListLenMayKnow);
         } else {
           dict_T *dict = tv_dict_alloc();
           dict->dv_refcount++;
@@ -969,8 +969,8 @@ int msgpack_to_vim(const msgpack_object mobj, typval_T *const rettv)
           .vval = { .v_number = (varnumber_T) mobj.via.u64 },
         };
       } else {
-        list_T *const list = tv_list_alloc();
-        list->lv_refcount++;
+        list_T *const list = tv_list_alloc(4);
+        tv_list_ref(list);
         create_special_dict(rettv, kMPInteger, ((typval_T) {
           .v_type = VAR_LIST,
           .v_lock = VAR_UNLOCKED,
@@ -992,8 +992,8 @@ int msgpack_to_vim(const msgpack_object mobj, typval_T *const rettv)
           .vval = { .v_number = (varnumber_T) mobj.via.i64 },
         };
       } else {
-        list_T *const list = tv_list_alloc();
-        list->lv_refcount++;
+        list_T *const list = tv_list_alloc(4);
+        tv_list_ref(list);
         create_special_dict(rettv, kMPInteger, ((typval_T) {
           .v_type = VAR_LIST,
           .v_lock = VAR_UNLOCKED,
@@ -1038,18 +1038,19 @@ int msgpack_to_vim(const msgpack_object mobj, typval_T *const rettv)
       break;
     }
     case MSGPACK_OBJECT_ARRAY: {
-      list_T *const list = tv_list_alloc();
-      list->lv_refcount++;
+      list_T *const list = tv_list_alloc((ptrdiff_t)mobj.via.array.size);
+      tv_list_ref(list);
       *rettv = (typval_T) {
         .v_type = VAR_LIST,
         .v_lock = VAR_UNLOCKED,
         .vval = { .v_list = list },
       };
       for (size_t i = 0; i < mobj.via.array.size; i++) {
-        listitem_T *const li = tv_list_item_alloc();
-        li->li_tv.v_type = VAR_UNKNOWN;
-        tv_list_append(list, li);
-        if (msgpack_to_vim(mobj.via.array.ptr[i], &li->li_tv) == FAIL) {
+        // Not populated yet, need to create list item to push.
+        tv_list_append_owned_tv(list, (typval_T) { .v_type = VAR_UNKNOWN });
+        if (msgpack_to_vim(mobj.via.array.ptr[i],
+                           TV_LIST_ITEM_TV(tv_list_last(list)))
+            == FAIL) {
           return FAIL;
         }
       }
@@ -1089,30 +1090,33 @@ int msgpack_to_vim(const msgpack_object mobj, typval_T *const rettv)
       }
       break;
 msgpack_to_vim_generic_map: {}
-      list_T *const list = decode_create_map_special_dict(rettv);
+      list_T *const list = decode_create_map_special_dict(
+          rettv, (ptrdiff_t)mobj.via.map.size);
       for (size_t i = 0; i < mobj.via.map.size; i++) {
-        list_T *const kv_pair = tv_list_alloc();
+        list_T *const kv_pair = tv_list_alloc(2);
         tv_list_append_list(list, kv_pair);
-        listitem_T *const key_li = tv_list_item_alloc();
-        key_li->li_tv.v_type = VAR_UNKNOWN;
-        tv_list_append(kv_pair, key_li);
-        listitem_T *const val_li = tv_list_item_alloc();
-        val_li->li_tv.v_type = VAR_UNKNOWN;
-        tv_list_append(kv_pair, val_li);
-        if (msgpack_to_vim(mobj.via.map.ptr[i].key, &key_li->li_tv) == FAIL) {
+
+        typval_T key_tv = { .v_type = VAR_UNKNOWN };
+        if (msgpack_to_vim(mobj.via.map.ptr[i].key, &key_tv) == FAIL) {
+          tv_clear(&key_tv);
           return FAIL;
         }
-        if (msgpack_to_vim(mobj.via.map.ptr[i].val, &val_li->li_tv) == FAIL) {
+        tv_list_append_owned_tv(kv_pair, key_tv);
+
+        typval_T val_tv = { .v_type = VAR_UNKNOWN };
+        if (msgpack_to_vim(mobj.via.map.ptr[i].val, &val_tv) == FAIL) {
+          tv_clear(&val_tv);
           return FAIL;
         }
+        tv_list_append_owned_tv(kv_pair, val_tv);
       }
       break;
     }
     case MSGPACK_OBJECT_EXT: {
-      list_T *const list = tv_list_alloc();
-      list->lv_refcount++;
+      list_T *const list = tv_list_alloc(2);
+      tv_list_ref(list);
       tv_list_append_number(list, mobj.via.ext.type);
-      list_T *const ext_val_list = tv_list_alloc();
+      list_T *const ext_val_list = tv_list_alloc(kListLenMayKnow);
       tv_list_append_list(list, ext_val_list);
       create_special_dict(rettv, kMPExt, ((typval_T) {
         .v_type = VAR_LIST,
diff --git a/src/nvim/eval/encode.c b/src/nvim/eval/encode.c
index ef647b3ee4..9bae436e3d 100644
--- a/src/nvim/eval/encode.c
+++ b/src/nvim/eval/encode.c
@@ -28,6 +28,11 @@
 #include "nvim/lib/kvec.h"
 #include "nvim/eval/typval_encode.h"
 
+#ifdef __MINGW32__
+# undef fpclassify
+# define fpclassify __fpclassify
+#endif
+
 #define ga_concat(a, b) ga_concat(a, (char_u *)b)
 #define utf_ptr2char(b) utf_ptr2char((char_u *)b)
 #define utf_ptr2len(b) ((size_t)utf_ptr2len((char_u *)b))
@@ -53,17 +58,18 @@ int encode_list_write(void *const data, const char *const buf, const size_t len)
   list_T *const list = (list_T *) data;
   const char *const end = buf + len;
   const char *line_end = buf;
-  listitem_T *li = list->lv_last;
+  listitem_T *li = tv_list_last(list);
 
   // Continue the last list element
   if (li != NULL) {
     line_end = xmemscan(buf, NL, len);
     if (line_end != buf) {
       const size_t line_length = (size_t)(line_end - buf);
-      char *str = (char *)li->li_tv.vval.v_string;
+      char *str = (char *)TV_LIST_ITEM_TV(li)->vval.v_string;
       const size_t li_len = (str == NULL ? 0 : strlen(str));
-      li->li_tv.vval.v_string = xrealloc(str, li_len + line_length + 1);
-      str = (char *)li->li_tv.vval.v_string + li_len;
+      TV_LIST_ITEM_TV(li)->vval.v_string = xrealloc(
+          str, li_len + line_length + 1);
+      str = (char *)TV_LIST_ITEM_TV(li)->vval.v_string + li_len;
       memcpy(str, buf, line_length);
       str[line_length] = 0;
       memchrsub(str, NUL, NL, line_length);
@@ -135,21 +141,27 @@ static int conv_error(const char *const msg, const MPConvStack *const mpstack,
       }
       case kMPConvPairs:
       case kMPConvList: {
-        int idx = 0;
-        const listitem_T *li;
-        for (li = v.data.l.list->lv_first;
-             li != NULL && li->li_next != v.data.l.li;
-             li = li->li_next) {
-          idx++;
-        }
+        const int idx = (v.data.l.li == tv_list_first(v.data.l.list)
+                         ? 0
+                         : (v.data.l.li == NULL
+                            ? tv_list_len(v.data.l.list) - 1
+                            : (int)tv_list_idx_of_item(
+                                v.data.l.list,
+                                TV_LIST_ITEM_PREV(v.data.l.list,
+                                                  v.data.l.li))));
+        const listitem_T *const li = (v.data.l.li == NULL
+                                      ? tv_list_last(v.data.l.list)
+                                      : TV_LIST_ITEM_PREV(v.data.l.list,
+                                                          v.data.l.li));
         if (v.type == kMPConvList
             || li == NULL
-            || (li->li_tv.v_type != VAR_LIST
-                && li->li_tv.vval.v_list->lv_len <= 0)) {
-          vim_snprintf((char *) IObuff, IOSIZE, idx_msg, idx);
+            || (TV_LIST_ITEM_TV(li)->v_type != VAR_LIST
+                && tv_list_len(TV_LIST_ITEM_TV(li)->vval.v_list) <= 0)) {
+          vim_snprintf((char *)IObuff, IOSIZE, idx_msg, idx);
           ga_concat(&msg_ga, IObuff);
         } else {
-          typval_T key_tv = li->li_tv.vval.v_list->lv_first->li_tv;
+          typval_T key_tv = *TV_LIST_ITEM_TV(
+              tv_list_first(TV_LIST_ITEM_TV(li)->vval.v_list));
           char *const key = encode_tv2echo(&key_tv, NULL);
           vim_snprintf((char *) IObuff, IOSIZE, key_pair_msg, key, idx);
           xfree(key);
@@ -202,21 +214,17 @@ bool encode_vim_list_to_buf(const list_T *const list, size_t *const ret_len,
   FUNC_ATTR_NONNULL_ARG(2, 3) FUNC_ATTR_WARN_UNUSED_RESULT
 {
   size_t len = 0;
-  if (list != NULL) {
-    for (const listitem_T *li = list->lv_first;
-         li != NULL;
-         li = li->li_next) {
-      if (li->li_tv.v_type != VAR_STRING) {
-        return false;
-      }
-      len++;
-      if (li->li_tv.vval.v_string != 0) {
-        len += STRLEN(li->li_tv.vval.v_string);
-      }
+  TV_LIST_ITER_CONST(list, li, {
+    if (TV_LIST_ITEM_TV(li)->v_type != VAR_STRING) {
+      return false;
     }
-    if (len) {
-      len--;
+    len++;
+    if (TV_LIST_ITEM_TV(li)->vval.v_string != NULL) {
+      len += STRLEN(TV_LIST_ITEM_TV(li)->vval.v_string);
     }
+  });
+  if (len) {
+    len--;
   }
   *ret_len = len;
   if (len == 0) {
@@ -253,31 +261,34 @@ int encode_read_from_list(ListReaderState *const state, char *const buf,
   char *const buf_end = buf + nbuf;
   char *p = buf;
   while (p < buf_end) {
-    assert(state->li_length == 0 || state->li->li_tv.vval.v_string != NULL);
+    assert(state->li_length == 0
+           || TV_LIST_ITEM_TV(state->li)->vval.v_string != NULL);
     for (size_t i = state->offset; i < state->li_length && p < buf_end; i++) {
-      assert(state->li->li_tv.vval.v_string != NULL);
-      const char ch = (char)state->li->li_tv.vval.v_string[state->offset++];
+      assert(TV_LIST_ITEM_TV(state->li)->vval.v_string != NULL);
+      const char ch = (char)(
+          TV_LIST_ITEM_TV(state->li)->vval.v_string[state->offset++]);
       *p++ = (char)((char)ch == (char)NL ? (char)NUL : (char)ch);
     }
     if (p < buf_end) {
-      state->li = state->li->li_next;
+      state->li = TV_LIST_ITEM_NEXT(state->list, state->li);
       if (state->li == NULL) {
         *read_bytes = (size_t) (p - buf);
         return OK;
       }
       *p++ = NL;
-      if (state->li->li_tv.v_type != VAR_STRING) {
-        *read_bytes = (size_t) (p - buf);
+      if (TV_LIST_ITEM_TV(state->li)->v_type != VAR_STRING) {
+        *read_bytes = (size_t)(p - buf);
         return FAIL;
       }
       state->offset = 0;
-      state->li_length = (state->li->li_tv.vval.v_string == NULL
+      state->li_length = (TV_LIST_ITEM_TV(state->li)->vval.v_string == NULL
                           ? 0
-                          : STRLEN(state->li->li_tv.vval.v_string));
+                          : STRLEN(TV_LIST_ITEM_TV(state->li)->vval.v_string));
     }
   }
   *read_bytes = nbuf;
-  return (state->offset < state->li_length || state->li->li_next != NULL
+  return ((state->offset < state->li_length
+           || TV_LIST_ITEM_NEXT(state->list, state->li) != NULL)
           ? NOTDONE
           : OK);
 }
@@ -340,7 +351,7 @@ int encode_read_from_list(ListReaderState *const state, char *const buf,
     do { \
       const char *const fun_ = (const char *)(fun); \
       if (fun_ == NULL) { \
-        EMSG2(_(e_intern2), "string(): NULL function name"); \
+        internal_error("string(): NULL function name"); \
         ga_concat(gap, "function(NULL"); \
       } else { \
         ga_concat(gap, "function("); \
@@ -727,12 +738,11 @@ bool encode_check_json_key(const typval_T *const tv)
   if (val_di->di_tv.vval.v_list == NULL) {
     return true;
   }
-  for (const listitem_T *li = val_di->di_tv.vval.v_list->lv_first;
-       li != NULL; li = li->li_next) {
-    if (li->li_tv.v_type != VAR_STRING) {
+  TV_LIST_ITER_CONST(val_di->di_tv.vval.v_list, li, {
+    if (TV_LIST_ITEM_TV(li)->v_type != VAR_STRING) {
       return false;
     }
-  }
+  });
   return true;
 }
 
diff --git a/src/nvim/eval/encode.h b/src/nvim/eval/encode.h
index 9bc665253b..ccea245ab3 100644
--- a/src/nvim/eval/encode.h
+++ b/src/nvim/eval/encode.h
@@ -33,9 +33,10 @@ int encode_vim_to_echo(garray_T *const packer,
 
 /// Structure defining state for read_from_list()
 typedef struct {
+  const list_T *const list;  ///< List being currently read.
   const listitem_T *li;  ///< Item currently read.
-  size_t offset;         ///< Byte offset inside the read item.
-  size_t li_length;      ///< Length of the string inside the read item.
+  size_t offset;  ///< Byte offset inside the read item.
+  size_t li_length;  ///< Length of the string inside the read item.
 } ListReaderState;
 
 /// Initialize ListReaderState structure
@@ -43,11 +44,13 @@ static inline ListReaderState encode_init_lrstate(const list_T *const list)
   FUNC_ATTR_NONNULL_ALL
 {
   return (ListReaderState) {
-    .li = list->lv_first,
+    .list = list,
+    .li = tv_list_first(list),
     .offset = 0,
-    .li_length = (list->lv_first->li_tv.vval.v_string == NULL
+    .li_length = (TV_LIST_ITEM_TV(tv_list_first(list))->vval.v_string == NULL
                   ? 0
-                  : STRLEN(list->lv_first->li_tv.vval.v_string)),
+                  : STRLEN(TV_LIST_ITEM_TV(
+                      tv_list_first(list))->vval.v_string)),
   };
 }
 
diff --git a/src/nvim/eval/typval.c b/src/nvim/eval/typval.c
index 4521085519..c8b550f902 100644
--- a/src/nvim/eval/typval.c
+++ b/src/nvim/eval/typval.c
@@ -3,6 +3,7 @@
 
 #include <stdio.h>
 #include <stddef.h>
+#include <stdlib.h>
 #include <string.h>
 #include <assert.h>
 #include <stdbool.h>
@@ -30,6 +31,7 @@
 #include "nvim/message.h"
 // TODO(ZyX-I): Move line_breakcheck out of misc1
 #include "nvim/misc1.h"  // For line_breakcheck
+#include "nvim/os/fileio.h"
 
 #ifdef INCLUDE_GENERATED_DECLARATIONS
 # include "eval/typval.c.generated.h"
@@ -44,6 +46,70 @@ bool tv_in_free_unref_items = false;
 const char *const tv_empty_string = "";
 
 //{{{1 Lists
+//{{{2 List log
+#ifdef LOG_LIST_ACTIONS
+ListLog *list_log_first = NULL;
+ListLog *list_log_last = NULL;
+
+/// Write list log to the given file
+///
+/// @param[in]  fname  File to write log to. Will be appended to if already
+///                    present.
+void list_write_log(const char *const fname)
+  FUNC_ATTR_NONNULL_ALL
+{
+  FileDescriptor fp;
+  const int fo_ret = file_open(&fp, fname, kFileCreate|kFileAppend, 0600);
+  if (fo_ret != 0) {
+    emsgf(_("E5142: Failed to open file %s: %s"), fname, os_strerror(fo_ret));
+    return;
+  }
+  for (ListLog *chunk = list_log_first; chunk != NULL;) {
+    for (size_t i = 0; i < chunk->size; i++) {
+      char buf[10 + 1 + ((16 + 3) * 3) + (8 + 2) + 2];
+      //       act  :     hex  " c:"      len "[]" "\n\0"
+      const ListLogEntry entry = chunk->entries[i];
+      const size_t snp_len = (size_t)snprintf(
+          buf, sizeof(buf),
+          "%-10.10s: l:%016" PRIxPTR "[%08d] 1:%016" PRIxPTR " 2:%016" PRIxPTR
+          "\n",
+          entry.action, entry.l, entry.len, entry.li1, entry.li2);
+      assert(snp_len + 1 == sizeof(buf));
+      const ptrdiff_t fw_ret = file_write(&fp, buf, snp_len);
+      if (fw_ret != (ptrdiff_t)snp_len) {
+        assert(fw_ret < 0);
+        if (i) {
+          memmove(chunk->entries, chunk->entries + i,
+                  sizeof(chunk->entries[0]) * (chunk->size - i));
+          chunk->size -= i;
+        }
+        emsgf(_("E5143: Failed to write to file %s: %s"),
+              fname, os_strerror((int)fw_ret));
+        return;
+      }
+    }
+    list_log_first = chunk->next;
+    xfree(chunk);
+    chunk = list_log_first;
+  }
+  const int fc_ret = file_close(&fp, true);
+  if (fc_ret != 0) {
+    emsgf(_("E5144: Failed to close file %s: %s"), fname, os_strerror(fc_ret));
+  }
+}
+
+#ifdef EXITFREE
+/// Free list log
+void list_free_log(void)
+{
+  for (ListLog *chunk = list_log_first; chunk != NULL;) {
+    list_log_first = chunk->next;
+    xfree(chunk);
+    chunk = list_log_first;
+  }
+}
+#endif
+#endif
 //{{{2 List item
 
 /// Allocate a list item
@@ -52,35 +118,29 @@ const char *const tv_empty_string = "";
 ///          and specifically set lv_lock.
 ///
 /// @return [allocated] new list item.
-listitem_T *tv_list_item_alloc(void)
+static listitem_T *tv_list_item_alloc(void)
   FUNC_ATTR_NONNULL_RET FUNC_ATTR_MALLOC
 {
   return xmalloc(sizeof(listitem_T));
 }
 
-/// Free a list item
-///
-/// Also clears the value. Does not touch watchers.
-///
-/// @param[out]  item  Item to free.
-void tv_list_item_free(listitem_T *const item)
-  FUNC_ATTR_NONNULL_ALL
-{
-  tv_clear(&item->li_tv);
-  xfree(item);
-}
-
 /// Remove a list item from a List and free it
 ///
 /// Also clears the value.
 ///
 /// @param[out]  l  List to remove item from.
 /// @param[in,out]  item  Item to remove.
-void tv_list_item_remove(list_T *const l, listitem_T *const item)
+///
+/// @return Pointer to the list item just after removed one, NULL if removed
+///         item was the last one.
+listitem_T *tv_list_item_remove(list_T *const l, listitem_T *const item)
   FUNC_ATTR_NONNULL_ALL
 {
-  tv_list_remove_items(l, item, item);
-  tv_list_item_free(item);
+  listitem_T *const next_item = TV_LIST_ITEM_NEXT(l, item);
+  tv_list_drop_items(l, item, item);
+  tv_clear(TV_LIST_ITEM_TV(item));
+  xfree(item);
+  return next_item;
 }
 
 //{{{2 List watchers
@@ -137,8 +197,14 @@ void tv_list_watch_fix(list_T *const l, const listitem_T *const item)
 ///
 /// Caller should take care of the reference count.
 ///
+/// @param[in]  len  Expected number of items to be populated before list
+///                  becomes accessible from VimL. It is still valid to
+///                  underpopulate a list, value only controls how many elements
+///                  will be allocated in advance. Currently does nothing.
+///                  @see ListLenSpecials.
+///
 /// @return [allocated] new list.
-list_T *tv_list_alloc(void)
+list_T *tv_list_alloc(const ptrdiff_t len)
   FUNC_ATTR_NONNULL_RET
 {
   list_T *const list = xcalloc(1, sizeof(list_T));
@@ -150,15 +216,59 @@ list_T *tv_list_alloc(void)
   list->lv_used_prev = NULL;
   list->lv_used_next = gc_first_list;
   gc_first_list = list;
+  list_log(list, NULL, (void *)(uintptr_t)len, "alloc");
   return list;
 }
 
+/// Initialize a static list with 10 items
+///
+/// @param[out]  sl  Static list to initialize.
+void tv_list_init_static10(staticList10_T *const sl)
+  FUNC_ATTR_NONNULL_ALL
+{
+#define SL_SIZE ARRAY_SIZE(sl->sl_items)
+  list_T *const l = &sl->sl_list;
+
+  memset(sl, 0, sizeof(staticList10_T));
+  l->lv_first = &sl->sl_items[0];
+  l->lv_last = &sl->sl_items[SL_SIZE - 1];
+  l->lv_refcount = DO_NOT_FREE_CNT;
+  tv_list_set_lock(l, VAR_FIXED);
+  sl->sl_list.lv_len = 10;
+
+  sl->sl_items[0].li_prev = NULL;
+  sl->sl_items[0].li_next = &sl->sl_items[1];
+  sl->sl_items[SL_SIZE - 1].li_prev = &sl->sl_items[SL_SIZE - 2];
+  sl->sl_items[SL_SIZE - 1].li_next = NULL;
+
+  for (size_t i = 1; i < SL_SIZE - 1; i++) {
+    listitem_T *const li = &sl->sl_items[i];
+    li->li_prev = li - 1;
+    li->li_next = li + 1;
+  }
+  list_log((const list_T *)sl, &sl->sl_items[0], &sl->sl_items[SL_SIZE - 1],
+           "s10init");
+#undef SL_SIZE
+}
+
+/// Initialize static list with undefined number of elements
+///
+/// @param[out]  l  List to initialize.
+void tv_list_init_static(list_T *const l)
+  FUNC_ATTR_NONNULL_ALL
+{
+  memset(l, 0, sizeof(*l));
+  l->lv_refcount = DO_NOT_FREE_CNT;
+  list_log(l, NULL, NULL, "sinit");
+}
+
 /// Free items contained in a list
 ///
 /// @param[in,out]  l  List to clear.
 void tv_list_free_contents(list_T *const l)
   FUNC_ATTR_NONNULL_ALL
 {
+  list_log(l, NULL, NULL, "freecont");
   for (listitem_T *item = l->lv_first; item != NULL; item = l->lv_first) {
     // Remove the item before deleting it.
     l->lv_first = item->li_next;
@@ -188,6 +298,7 @@ void tv_list_free_list(list_T *const l)
   if (l->lv_used_next != NULL) {
     l->lv_used_next->lv_used_prev = l->lv_used_prev;
   }
+  list_log(l, NULL, NULL, "freelist");
 
   xfree(l);
 }
@@ -221,17 +332,18 @@ void tv_list_unref(list_T *const l)
 
 //{{{2 Add/remove
 
-/// Remove items "item" to "item2" from list "l".
+/// Remove items "item" to "item2" from list "l"
 ///
 /// @warning Does not free the listitem or the value!
 ///
 /// @param[out]  l  List to remove from.
 /// @param[in]  item  First item to remove.
 /// @param[in]  item2  Last item to remove.
-void tv_list_remove_items(list_T *const l, listitem_T *const item,
-                          listitem_T *const item2)
+void tv_list_drop_items(list_T *const l, listitem_T *const item,
+                        listitem_T *const item2)
   FUNC_ATTR_NONNULL_ALL
 {
+  list_log(l, item, item2, "drop");
   // Notify watchers.
   for (listitem_T *ip = item; ip != item2->li_next; ip = ip->li_next) {
     l->lv_len--;
@@ -249,6 +361,51 @@ void tv_list_remove_items(list_T *const l, listitem_T *const item,
     item->li_prev->li_next = item2->li_next;
   }
   l->lv_idx_item = NULL;
+  list_log(l, l->lv_first, l->lv_last, "afterdrop");
+}
+
+/// Like tv_list_drop_items, but also frees all removed items
+void tv_list_remove_items(list_T *const l, listitem_T *const item,
+                          listitem_T *const item2)
+  FUNC_ATTR_NONNULL_ALL
+{
+  list_log(l, item, item2, "remove");
+  tv_list_drop_items(l, item, item2);
+  for (listitem_T *li = item;;) {
+    tv_clear(TV_LIST_ITEM_TV(li));
+    listitem_T *const nli = li->li_next;
+    xfree(li);
+    if (li == item2) {
+      break;
+    }
+    li = nli;
+  }
+}
+
+/// Move items "item" to "item2" from list "l" to the end of the list "tgt_l"
+///
+/// @param[out]  l  List to move from.
+/// @param[in]  item  First item to move.
+/// @param[in]  item2  Last item to move.
+/// @param[out]  tgt_l  List to move to.
+/// @param[in]  cnt  Number of items moved.
+void tv_list_move_items(list_T *const l, listitem_T *const item,
+                        listitem_T *const item2, list_T *const tgt_l,
+                        const int cnt)
+  FUNC_ATTR_NONNULL_ALL
+{
+  list_log(l, item, item2, "move");
+  tv_list_drop_items(l, item, item2);
+  item->li_prev = tgt_l->lv_last;
+  item2->li_next = NULL;
+  if (tgt_l->lv_last == NULL) {
+    tgt_l->lv_first = item;
+  } else {
+    tgt_l->lv_last->li_next = item;
+  }
+  tgt_l->lv_last = item2;
+  tgt_l->lv_len += cnt;
+  list_log(tgt_l, tgt_l->lv_first, tgt_l->lv_last, "movetgt");
 }
 
 /// Insert list item
@@ -277,6 +434,7 @@ void tv_list_insert(list_T *const l, listitem_T *const ni,
     }
     item->li_prev = ni;
     l->lv_len++;
+    list_log(l, ni, item, "insert");
   }
 }
 
@@ -303,6 +461,7 @@ void tv_list_insert_tv(list_T *const l, typval_T *const tv,
 void tv_list_append(list_T *const l, listitem_T *const item)
   FUNC_ATTR_NONNULL_ALL
 {
+  list_log(l, item, NULL, "append");
   if (l->lv_last == NULL) {
     // empty list
     l->lv_first = item;
@@ -326,7 +485,19 @@ void tv_list_append_tv(list_T *const l, typval_T *const tv)
   FUNC_ATTR_NONNULL_ALL
 {
   listitem_T *const li = tv_list_item_alloc();
-  tv_copy(tv, &li->li_tv);
+  tv_copy(tv, TV_LIST_ITEM_TV(li));
+  tv_list_append(l, li);
+}
+
+/// Like tv_list_append_tv(), but tv is moved to a list
+///
+/// This means that it is no longer valid to use contents of the typval_T after
+/// function exits.
+void tv_list_append_owned_tv(list_T *const l, typval_T tv)
+  FUNC_ATTR_NONNULL_ALL
+{
+  listitem_T *const li = tv_list_item_alloc();
+  *TV_LIST_ITEM_TV(li) = tv;
   tv_list_append(l, li);
 }
 
@@ -334,33 +505,29 @@ void tv_list_append_tv(list_T *const l, typval_T *const tv)
 ///
 /// @param[out]  l  List to append to.
 /// @param[in,out]  itemlist  List to append. Reference count is increased.
-void tv_list_append_list(list_T *const list, list_T *const itemlist)
+void tv_list_append_list(list_T *const l, list_T *const itemlist)
   FUNC_ATTR_NONNULL_ARG(1)
 {
-  listitem_T *const li = tv_list_item_alloc();
-
-  li->li_tv.v_type = VAR_LIST;
-  li->li_tv.v_lock = VAR_UNLOCKED;
-  li->li_tv.vval.v_list = itemlist;
-  tv_list_append(list, li);
-  if (itemlist != NULL) {
-    itemlist->lv_refcount++;
-  }
+  tv_list_append_owned_tv(l, (typval_T) {
+    .v_type = VAR_LIST,
+    .v_lock = VAR_UNLOCKED,
+    .vval.v_list = itemlist,
+  });
+  tv_list_ref(itemlist);
 }
 
 /// Append a dictionary to a list
 ///
 /// @param[out]  l  List to append to.
 /// @param[in,out]  dict  Dictionary to append. Reference count is increased.
-void tv_list_append_dict(list_T *const list, dict_T *const dict)
+void tv_list_append_dict(list_T *const l, dict_T *const dict)
   FUNC_ATTR_NONNULL_ARG(1)
 {
-  listitem_T *const li = tv_list_item_alloc();
-
-  li->li_tv.v_type = VAR_DICT;
-  li->li_tv.v_lock = VAR_UNLOCKED;
-  li->li_tv.vval.v_dict = dict;
-  tv_list_append(list, li);
+  tv_list_append_owned_tv(l, (typval_T) {
+    .v_type = VAR_DICT,
+    .v_lock = VAR_UNLOCKED,
+    .vval.v_dict = dict,
+  });
   if (dict != NULL) {
     dict->dv_refcount++;
   }
@@ -374,17 +541,18 @@ void tv_list_append_dict(list_T *const list, dict_T *const dict)
 ///                  case string is considered to be usual zero-terminated
 ///                  string or NULL “empty” string.
 void tv_list_append_string(list_T *const l, const char *const str,
-                           const ptrdiff_t len)
+                           const ssize_t len)
   FUNC_ATTR_NONNULL_ARG(1)
 {
-  if (str == NULL) {
-    assert(len == 0 || len == -1);
-    tv_list_append_allocated_string(l, NULL);
-  } else {
-    tv_list_append_allocated_string(l, (len >= 0
-                                        ? xmemdupz(str, (size_t)len)
-                                        : xstrdup(str)));
-  }
+  tv_list_append_owned_tv(l, (typval_T) {
+    .v_type = VAR_STRING,
+    .v_lock = VAR_UNLOCKED,
+    .vval.v_string = (str == NULL
+                      ? NULL
+                      : (len >= 0
+                         ? xmemdupz(str, (size_t)len)
+                         : xstrdup(str))),
+  });
 }
 
 /// Append given string to the list
@@ -396,12 +564,11 @@ void tv_list_append_string(list_T *const l, const char *const str,
 void tv_list_append_allocated_string(list_T *const l, char *const str)
   FUNC_ATTR_NONNULL_ARG(1)
 {
-  listitem_T *const li = tv_list_item_alloc();
-
-  tv_list_append(l, li);
-  li->li_tv.v_type = VAR_STRING;
-  li->li_tv.v_lock = VAR_UNLOCKED;
-  li->li_tv.vval.v_string = (char_u *)str;
+  tv_list_append_owned_tv(l, (typval_T) {
+    .v_type = VAR_STRING,
+    .v_lock = VAR_UNLOCKED,
+    .vval.v_string = (char_u *)str,
+  });
 }
 
 /// Append number to the list
@@ -411,11 +578,11 @@ void tv_list_append_allocated_string(list_T *const l, char *const str)
 ///                listitem_T.
 void tv_list_append_number(list_T *const l, const varnumber_T n)
 {
-  listitem_T *const li = tv_list_item_alloc();
-  li->li_tv.v_type = VAR_NUMBER;
-  li->li_tv.v_lock = VAR_UNLOCKED;
-  li->li_tv.vval.v_number = n;
-  tv_list_append(l, li);
+  tv_list_append_owned_tv(l, (typval_T) {
+    .v_type = VAR_NUMBER,
+    .v_lock = VAR_UNLOCKED,
+    .vval.v_number = n,
+  });
 }
 
 //{{{2 Operations on the whole list
@@ -438,34 +605,36 @@ list_T *tv_list_copy(const vimconv_T *const conv, list_T *const orig,
     return NULL;
   }
 
-  list_T *copy = tv_list_alloc();
+  list_T *copy = tv_list_alloc(tv_list_len(orig));
+  tv_list_ref(copy);
   if (copyID != 0) {
     // Do this before adding the items, because one of the items may
     // refer back to this list.
     orig->lv_copyID = copyID;
     orig->lv_copylist = copy;
   }
-  listitem_T *item;
-  for (item = orig->lv_first; item != NULL && !got_int;
-       item = item->li_next) {
+  TV_LIST_ITER(orig, item, {
+    if (got_int) {
+      break;
+    }
     listitem_T *const ni = tv_list_item_alloc();
     if (deep) {
-      if (var_item_copy(conv, &item->li_tv, &ni->li_tv, deep, copyID) == FAIL) {
+      if (var_item_copy(conv, TV_LIST_ITEM_TV(item), TV_LIST_ITEM_TV(ni),
+                        deep, copyID) == FAIL) {
         xfree(ni);
-        break;
+        goto tv_list_copy_error;
       }
     } else {
-      tv_copy(&item->li_tv, &ni->li_tv);
+      tv_copy(TV_LIST_ITEM_TV(item), TV_LIST_ITEM_TV(ni));
     }
     tv_list_append(copy, ni);
-  }
-  copy->lv_refcount++;
-  if (item != NULL) {
-    tv_list_unref(copy);
-    copy = NULL;
-  }
+  });
 
   return copy;
+
+tv_list_copy_error:
+  tv_list_unref(copy);
+  return NULL;
 }
 
 /// Extend first list with the second
@@ -475,17 +644,17 @@ list_T *tv_list_copy(const vimconv_T *const conv, list_T *const orig,
 /// @param[in]  bef  If not NULL, extends before this item.
 void tv_list_extend(list_T *const l1, list_T *const l2,
                     listitem_T *const bef)
-  FUNC_ATTR_NONNULL_ARG(1, 2)
+  FUNC_ATTR_NONNULL_ARG(1)
 {
-  int todo = l2->lv_len;
+  int todo = tv_list_len(l2);
   listitem_T *const befbef = (bef == NULL ? NULL : bef->li_prev);
   listitem_T *const saved_next = (befbef == NULL ? NULL : befbef->li_next);
   // We also quit the loop when we have inserted the original item count of
   // the list, avoid a hang when we extend a list with itself.
-  for (listitem_T *item = l2->lv_first
-       ; item != NULL && --todo >= 0
+  for (listitem_T *item = tv_list_first(l2)
+       ; item != NULL && todo--
        ; item = (item == befbef ? saved_next : item->li_next)) {
-    tv_list_insert_tv(l1, &item->li_tv, bef);
+    tv_list_insert_tv(l1, TV_LIST_ITEM_TV(item), bef);
   }
 }
 
@@ -540,13 +709,15 @@ static int list_join_inner(garray_T *const gap, list_T *const l,
 {
   size_t sumlen = 0;
   bool first = true;
-  listitem_T  *item;
 
   // Stringify each item in the list.
-  for (item = l->lv_first; item != NULL && !got_int; item = item->li_next) {
+  TV_LIST_ITER(l, item, {
+    if (got_int) {
+      break;
+    }
     char *s;
     size_t len;
-    s = encode_tv2echo(&item->li_tv, &len);
+    s = encode_tv2echo(TV_LIST_ITEM_TV(item), &len);
     if (s == NULL) {
       return FAIL;
     }
@@ -557,7 +728,7 @@ static int list_join_inner(garray_T *const gap, list_T *const l,
     p->tofree = p->s = (char_u *)s;
 
     line_breakcheck();
-  }
+  });
 
   // Allocate result buffer with its total size, avoid re-allocation and
   // multiple copy operations.  Add 2 for a tailing ']' and NUL.
@@ -591,16 +762,16 @@ static int list_join_inner(garray_T *const gap, list_T *const l,
 ///
 /// @return OK in case of success, FAIL otherwise.
 int tv_list_join(garray_T *const gap, list_T *const l, const char *const sep)
-  FUNC_ATTR_NONNULL_ALL
+  FUNC_ATTR_NONNULL_ARG(1)
 {
-  if (l->lv_len < 1) {
+  if (!tv_list_len(l)) {
     return OK;
   }
 
   garray_T join_ga;
   int retval;
 
-  ga_init(&join_ga, (int)sizeof(Join), l->lv_len);
+  ga_init(&join_ga, (int)sizeof(Join), tv_list_len(l));
   retval = list_join_inner(gap, l, sep, &join_ga);
 
 #define FREE_JOIN_TOFREE(join) xfree((join)->tofree)
@@ -632,11 +803,13 @@ bool tv_list_equal(list_T *const l1, list_T *const l2, const bool ic,
     return false;
   }
 
-  listitem_T *item1 = l1->lv_first;
-  listitem_T *item2 = l2->lv_first;
+  listitem_T *item1 = tv_list_first(l1);
+  listitem_T *item2 = tv_list_first(l2);
   for (; item1 != NULL && item2 != NULL
-       ; item1 = item1->li_next, item2 = item2->li_next) {
-    if (!tv_equal(&item1->li_tv, &item2->li_tv, ic, recursive)) {
+       ; (item1 = TV_LIST_ITEM_NEXT(l1, item1),
+          item2 = TV_LIST_ITEM_NEXT(l2, item2))) {
+    if (!tv_equal(TV_LIST_ITEM_TV(item1), TV_LIST_ITEM_TV(item2), ic,
+                  recursive)) {
       return false;
     }
   }
@@ -644,6 +817,74 @@ bool tv_list_equal(list_T *const l1, list_T *const l2, const bool ic,
   return true;
 }
 
+/// Reverse list in-place
+///
+/// @param[in,out]  l  List to reverse.
+void tv_list_reverse(list_T *const l)
+{
+  if (tv_list_len(l) <= 1) {
+    return;
+  }
+  list_log(l, NULL, NULL, "reverse");
+#define SWAP(a, b) \
+  do { \
+    tmp = a; \
+    a = b; \
+    b = tmp; \
+  } while (0)
+  listitem_T *tmp;
+
+  SWAP(l->lv_first, l->lv_last);
+  for (listitem_T *li = l->lv_first; li != NULL; li = li->li_next) {
+    SWAP(li->li_next, li->li_prev);
+  }
+#undef SWAP
+
+  l->lv_idx = l->lv_len - l->lv_idx - 1;
+}
+
+// FIXME Add unit tests for tv_list_item_sort().
+
+/// Sort list using libc qsort
+///
+/// @param[in,out]  l  List to sort, will be sorted in-place.
+/// @param  ptrs  Preallocated array of items to sort, must have at least
+///               tv_list_len(l) entries. Should not be initialized.
+/// @param[in]  item_compare_func  Function used to compare list items.
+/// @param  errp  Location where information about whether error occurred is
+///               saved by item_compare_func. If boolean there appears to be
+///               true list will not be modified. Must be initialized to false
+///               by the caller.
+void tv_list_item_sort(list_T *const l, ListSortItem *const ptrs,
+                       const ListSorter item_compare_func,
+                       bool *errp)
+  FUNC_ATTR_NONNULL_ARG(3, 4)
+{
+  const int len = tv_list_len(l);
+  if (len <= 1) {
+    return;
+  }
+  list_log(l, NULL, NULL, "sort");
+  int i = 0;
+  TV_LIST_ITER(l, li, {
+    ptrs[i].item = li;
+    ptrs[i].idx = i;
+    i++;
+  });
+  // Sort the array with item pointers.
+  qsort(ptrs, (size_t)len, sizeof(ListSortItem), item_compare_func);
+  if (!(*errp)) {
+    // Clear the list and append the items in the sorted order.
+    l->lv_first    = NULL;
+    l->lv_last     = NULL;
+    l->lv_idx_item = NULL;
+    l->lv_len      = 0;
+    for (i = 0; i < len; i++) {
+      tv_list_append(l, ptrs[i].item);
+    }
+  }
+}
+
 //{{{2 Indexing/searching
 
 /// Locate item with a given index in a list and return it
@@ -662,13 +903,8 @@ listitem_T *tv_list_find(list_T *const l, int n)
     return NULL;
   }
 
-  // Negative index is relative to the end.
-  if (n < 0) {
-    n = l->lv_len + n;
-  }
-
-  // Check for index out of range.
-  if (n < 0 || n >= l->lv_len) {
+  n = tv_list_uidx(l, n);
+  if (n == -1) {
     return NULL;
   }
 
@@ -717,6 +953,7 @@ listitem_T *tv_list_find(list_T *const l, int n)
   // Cache the used index.
   l->lv_idx = idx;
   l->lv_idx_item = item;
+  list_log(l, l->lv_idx_item, (void *)(uintptr_t)l->lv_idx, "find");
 
   return item;
 }
@@ -740,7 +977,7 @@ varnumber_T tv_list_find_nr(list_T *const l, const int n, bool *const ret_error)
     }
     return -1;
   }
-  return tv_get_number_chk(&li->li_tv, ret_error);
+  return tv_get_number_chk(TV_LIST_ITEM_TV(li), ret_error);
 }
 
 /// Get list item l[n] as a string
@@ -757,7 +994,7 @@ const char *tv_list_find_str(list_T *const l, const int n)
     emsgf(_(e_listidx), (int64_t)n);
     return NULL;
   }
-  return tv_get_string(&li->li_tv);
+  return tv_get_string(TV_LIST_ITEM_TV(li));
 }
 
 /// Locate item in a list and return its index
@@ -772,15 +1009,14 @@ long tv_list_idx_of_item(const list_T *const l, const listitem_T *const item)
   if (l == NULL) {
     return -1;
   }
-  long idx = 0;
-  const listitem_T *li;
-  for (li = l->lv_first; li != NULL && li != item; li = li->li_next) {
+  int idx = 0;
+  TV_LIST_ITER_CONST(l, li, {
+    if (li == item) {
+      return idx;
+    }
     idx++;
-  }
-  if (li == NULL) {
-    return -1;
-  }
-  return idx;
+  });
+  return -1;
 }
 
 //{{{1 Dictionaries
@@ -824,7 +1060,7 @@ void tv_dict_watcher_add(dict_T *const dict, const char *const key_pattern,
 /// @param[in]  cb2  Second callback to check.
 ///
 /// @return True if they are equal, false otherwise.
-bool tv_callback_equal(const Callback *const cb1, const Callback *const cb2)
+bool tv_callback_equal(const Callback *cb1, const Callback *cb2)
   FUNC_ATTR_NONNULL_ALL FUNC_ATTR_WARN_UNUSED_RESULT
 {
   if (cb1->type != cb2->type) {
@@ -843,10 +1079,31 @@ bool tv_callback_equal(const Callback *const cb1, const Callback *const cb2)
       return true;
     }
   }
-  assert(false);
+  abort();
   return false;
 }
 
+/// Unref/free callback
+void callback_free(Callback *callback)
+  FUNC_ATTR_NONNULL_ALL
+{
+  switch (callback->type) {
+    case kCallbackFuncref: {
+      func_unref(callback->data.funcref);
+      xfree(callback->data.funcref);
+      break;
+    }
+    case kCallbackPartial: {
+      partial_unref(callback->data.partial);
+      break;
+    }
+    case kCallbackNone: {
+      break;
+    }
+  }
+  callback->type = kCallbackNone;
+}
+
 /// Remove watcher from a dictionary
 ///
 /// @param  dict  Dictionary to remove watcher from.
@@ -1318,7 +1575,7 @@ int tv_dict_add_list(dict_T *const d, const char *const key,
   item->di_tv.v_lock = VAR_UNLOCKED;
   item->di_tv.v_type = VAR_LIST;
   item->di_tv.vval.v_list = list;
-  list->lv_refcount++;
+  tv_list_ref(list);
   if (tv_dict_add(d, item) == FAIL) {
     tv_dict_item_free(item);
     return FAIL;
@@ -1374,6 +1631,29 @@ int tv_dict_add_nr(dict_T *const d, const char *const key,
   return OK;
 }
 
+/// Add a special entry to dictionary
+///
+/// @param[out]  d  Dictionary to add entry to.
+/// @param[in]  key  Key to add.
+/// @param[in]  key_len  Key length.
+/// @param[in]  val SpecialVarValue to add.
+///
+/// @return OK in case of success, FAIL when key already exists.
+int tv_dict_add_special(dict_T *const d, const char *const key,
+                        const size_t key_len, SpecialVarValue val)
+{
+  dictitem_T *const item = tv_dict_item_alloc_len(key, key_len);
+
+  item->di_tv.v_lock = VAR_UNLOCKED;
+  item->di_tv.v_type = VAR_SPECIAL;
+  item->di_tv.vval.v_special = val;
+  if (tv_dict_add(d, item) == FAIL) {
+    tv_dict_item_free(item);
+    return FAIL;
+  }
+  return OK;
+}
+
 /// Add a string entry to dictionary
 ///
 /// @param[out]  d  Dictionary to add entry to.
@@ -1387,11 +1667,32 @@ int tv_dict_add_str(dict_T *const d,
                     const char *const val)
   FUNC_ATTR_NONNULL_ALL
 {
+  return tv_dict_add_allocated_str(d, key, key_len, xstrdup(val));
+}
+
+/// Add a string entry to dictionary
+///
+/// Unlike tv_dict_add_str() saves val to the new dictionary item in place of
+/// creating a new copy.
+///
+/// @warning String will be freed even in case addition fails.
+///
+/// @param[out]  d  Dictionary to add entry to.
+/// @param[in]  key  Key to add.
+/// @param[in]  key_len  Key length.
+/// @param[in]  val  String to add.
+///
+/// @return OK in case of success, FAIL when key already exists.
+int tv_dict_add_allocated_str(dict_T *const d,
+                              const char *const key, const size_t key_len,
+                              char *const val)
+  FUNC_ATTR_NONNULL_ALL
+{
   dictitem_T *const item = tv_dict_item_alloc_len(key, key_len);
 
   item->di_tv.v_lock = VAR_UNLOCKED;
   item->di_tv.v_type = VAR_STRING;
-  item->di_tv.vval.v_string = (char_u *)xstrdup(val);
+  item->di_tv.vval.v_string = (char_u *)val;
   if (tv_dict_add(d, item) == FAIL) {
     tv_dict_item_free(item);
     return FAIL;
@@ -1603,16 +1904,20 @@ void tv_dict_set_keys_readonly(dict_T *const dict)
 /// Also sets reference count.
 ///
 /// @param[out]  ret_tv  Structure where list is saved.
+/// @param[in]  len  Expected number of items to be populated before list
+///                  becomes accessible from VimL. It is still valid to
+///                  underpopulate a list, value only controls how many elements
+///                  will be allocated in advance. @see ListLenSpecials.
 ///
 /// @return [allocated] pointer to the created list.
-list_T *tv_list_alloc_ret(typval_T *const ret_tv)
+list_T *tv_list_alloc_ret(typval_T *const ret_tv, const ptrdiff_t len)
   FUNC_ATTR_NONNULL_ALL
 {
-  list_T *const l = tv_list_alloc();
+  list_T *const l = tv_list_alloc(len);
   ret_tv->vval.v_list = l;
   ret_tv->v_type = VAR_LIST;
   ret_tv->v_lock = VAR_UNLOCKED;
-  l->lv_refcount++;
+  tv_list_ref(l);
   return l;
 }
 
@@ -1729,14 +2034,20 @@ static inline void _nothing_conv_func_end(typval_T *const tv, const int copyID)
       tv->v_lock = VAR_UNLOCKED; \
     } while (0)
 
+static inline void _nothing_conv_empty_dict(typval_T *const tv,
+                                            dict_T **const dictp)
+  FUNC_ATTR_ALWAYS_INLINE FUNC_ATTR_NONNULL_ARG(2)
+{
+  tv_dict_unref(*dictp);
+  *dictp = NULL;
+  if (tv != NULL) {
+    tv->v_lock = VAR_UNLOCKED;
+  }
+}
 #define TYPVAL_ENCODE_CONV_EMPTY_DICT(tv, dict) \
     do { \
       assert((void *)&dict != (void *)&TYPVAL_ENCODE_NODICT_VAR); \
-      tv_dict_unref((dict_T *)dict); \
-      *((dict_T **)&dict) = NULL; \
-      if (tv != NULL) { \
-        ((typval_T *)tv)->v_lock = VAR_UNLOCKED; \
-      } \
+      _nothing_conv_empty_dict(tv, ((dict_T **)&dict)); \
     } while (0)
 
 static inline int _nothing_conv_real_list_after_start(
@@ -1933,7 +2244,7 @@ void tv_free(typval_T *tv)
 ///
 /// @param[in]  from  Location to copy from.
 /// @param[out]  to  Location to copy to.
-void tv_copy(typval_T *const from, typval_T *const to)
+void tv_copy(const typval_T *const from, typval_T *const to)
 {
   to->v_type = from->v_type;
   to->v_lock = VAR_UNLOCKED;
@@ -1961,9 +2272,7 @@ void tv_copy(typval_T *const from, typval_T *const to)
       break;
     }
     case VAR_LIST: {
-      if (from->vval.v_list != NULL) {
-        to->vval.v_list->lv_refcount++;
-      }
+      tv_list_ref(to->vval.v_list);
       break;
     }
     case VAR_DICT: {
@@ -2019,9 +2328,9 @@ void tv_item_lock(typval_T *const tv, const int deep, const bool lock)
         CHANGE_LOCK(lock, l->lv_lock);
         if (deep < 0 || deep > 1) {
           // Recursive: lock/unlock the items the List contains.
-          for (listitem_T *li = l->lv_first; li != NULL; li = li->li_next) {
-            tv_item_lock(&li->li_tv, deep - 1, lock);
-          }
+          TV_LIST_ITER(l, li, {
+            tv_item_lock(TV_LIST_ITEM_TV(li), deep - 1, lock);
+          });
         }
       }
       break;
@@ -2057,6 +2366,8 @@ void tv_item_lock(typval_T *const tv, const int deep, const bool lock)
 
 /// Check whether VimL value is locked itself or refers to a locked container
 ///
+/// @warning Fixed container is not the same as locked.
+///
 /// @param[in]  tv  Value to check.
 ///
 /// @return True if value is locked, false otherwise.
@@ -2065,8 +2376,7 @@ bool tv_islocked(const typval_T *const tv)
 {
   return ((tv->v_lock == VAR_LOCKED)
           || (tv->v_type == VAR_LIST
-              && tv->vval.v_list != NULL
-              && (tv->vval.v_list->lv_lock == VAR_LOCKED))
+              && (tv_list_locked(tv->vval.v_list) == VAR_LOCKED))
           || (tv->v_type == VAR_DICT
               && tv->vval.v_dict != NULL
               && (tv->vval.v_dict->dv_lock == VAR_LOCKED)));
diff --git a/src/nvim/eval/typval.h b/src/nvim/eval/typval.h
index 3f8ed3b3f9..2272a580d6 100644
--- a/src/nvim/eval/typval.h
+++ b/src/nvim/eval/typval.h
@@ -6,6 +6,8 @@
 #include <stdint.h>
 #include <string.h>
 #include <stdbool.h>
+#include <assert.h>
+#include <limits.h>
 
 #include "nvim/types.h"
 #include "nvim/hashtab.h"
@@ -18,6 +20,9 @@
 #include "nvim/gettext.h"
 #include "nvim/message.h"
 #include "nvim/macros.h"
+#ifdef LOG_LIST_ACTIONS
+# include "nvim/memory.h"
+#endif
 
 /// Type used for VimL VAR_NUMBER values
 typedef int64_t varnumber_T;
@@ -26,6 +31,28 @@ typedef uint64_t uvarnumber_T;
 /// Type used for VimL VAR_FLOAT values
 typedef double float_T;
 
+/// Refcount for dict or list that should not be freed
+enum { DO_NOT_FREE_CNT = (INT_MAX / 2) };
+
+/// Additional values for tv_list_alloc() len argument
+enum {
+  /// List length is not known in advance
+  ///
+  /// To be used when there is neither a way to know how many elements will be
+  /// needed nor are any educated guesses.
+  kListLenUnknown = -1,
+  /// List length *should* be known, but is actually not
+  ///
+  /// All occurrences of this value should be eventually removed. This is for
+  /// the case when the only reason why list length is not known is that it
+  /// would be hard to code without refactoring, but refactoring is needed.
+  kListLenShouldKnow = -2,
+  /// List length may be known in advance, but it requires too much effort
+  ///
+  /// To be used when it looks impractical to determine list length.
+  kListLenMayKnow = -3,
+} ListLenSpecials;
+
 /// Maximal possible value of varnumber_T variable
 #define VARNUMBER_MAX INT64_MAX
 #define UVARNUMBER_MAX UINT64_MAX
@@ -43,7 +70,7 @@ typedef struct partial_S partial_T;
 typedef struct ufunc ufunc_T;
 
 typedef enum {
-  kCallbackNone,
+  kCallbackNone = 0,
   kCallbackFuncref,
   kCallbackPartial,
 } CallbackType;
@@ -150,12 +177,26 @@ struct listvar_S {
   list_T *lv_used_prev;  ///< Previous list in used lists list.
 };
 
-// Static list with 10 items. Use init_static_list() to initialize.
+// Static list with 10 items. Use tv_list_init_static10() to initialize.
 typedef struct {
   list_T sl_list;  // must be first
   listitem_T sl_items[10];
 } staticList10_T;
 
+#define TV_LIST_STATIC10_INIT { \
+    .sl_list = { \
+      .lv_first = NULL, \
+      .lv_last = NULL, \
+      .lv_refcount = 0, \
+      .lv_len = 0, \
+      .lv_watch = NULL, \
+      .lv_idx_item = NULL, \
+      .lv_lock = VAR_FIXED, \
+      .lv_used_next = NULL, \
+      .lv_used_prev = NULL, \
+    }, \
+  }
+
 // Structure to hold an item of a Dictionary.
 // Also used for a variable.
 // The key is copied into "di_key" to avoid an extra alloc/free for it.
@@ -165,11 +206,11 @@ struct dictitem_S {
   char_u di_key[1];             ///< key (actually longer!)
 };
 
-#define TV_DICTITEM_STRUCT(KEY_LEN) \
+#define TV_DICTITEM_STRUCT(...) \
     struct { \
       typval_T di_tv;  /* Structure that holds scope dictionary itself. */ \
       uint8_t di_flags;  /* Flags. */ \
-      char_u di_key[KEY_LEN];  /* Key value. */ \
+      char_u di_key[__VA_ARGS__];  /* Key value. */ \
     }
 
 /// Structure to hold a scope dictionary
@@ -277,6 +318,104 @@ typedef struct list_stack_S {
   struct list_stack_S *prev;
 } list_stack_T;
 
+/// Structure representing one list item, used for sort array.
+typedef struct {
+  listitem_T *item;  ///< Sorted list item.
+  int idx;  ///< Sorted list item index.
+} ListSortItem;
+
+typedef int (*ListSorter)(const void *, const void *);
+
+#ifdef LOG_LIST_ACTIONS
+
+/// List actions log entry
+typedef struct {
+  uintptr_t l;  ///< List log entry belongs to.
+  uintptr_t li1;  ///< First list item log entry belongs to, if applicable.
+  uintptr_t li2;  ///< Second list item log entry belongs to, if applicable.
+  int len;  ///< List length when log entry was created.
+  const char *action;  ///< Logged action.
+} ListLogEntry;
+
+typedef struct list_log ListLog;
+
+/// List actions log
+struct list_log {
+  ListLog *next;  ///< Next chunk or NULL.
+  size_t capacity;  ///< Number of entries in current chunk.
+  size_t size;  ///< Current chunk size.
+  ListLogEntry entries[];  ///< Actual log entries.
+};
+
+extern ListLog *list_log_first;  ///< First list log chunk, NULL if missing
+extern ListLog *list_log_last;  ///< Last list log chunk
+
+static inline ListLog *list_log_alloc(const size_t size)
+  REAL_FATTR_ALWAYS_INLINE REAL_FATTR_WARN_UNUSED_RESULT;
+
+/// Allocate a new log chunk and update globals
+///
+/// @param[in]  size  Number of entries in a new chunk.
+///
+/// @return [allocated] Newly allocated chunk.
+static inline ListLog *list_log_new(const size_t size)
+{
+  ListLog *ret = xmalloc(offsetof(ListLog, entries)
+                         + size * sizeof(ret->entries[0]));
+  ret->size = 0;
+  ret->capacity = size;
+  ret->next = NULL;
+  if (list_log_first == NULL) {
+    list_log_first = ret;
+  } else {
+    list_log_last->next = ret;
+  }
+  list_log_last = ret;
+  return ret;
+}
+
+static inline void list_log(const list_T *const l,
+                            const listitem_T *const li1,
+                            const listitem_T *const li2,
+                            const char *const action)
+  REAL_FATTR_ALWAYS_INLINE;
+
+/// Add new entry to log
+///
+/// If last chunk was filled it uses twice as much memory to allocate the next
+/// chunk.
+///
+/// @param[in]  l  List to which entry belongs.
+/// @param[in]  li1  List item 1.
+/// @param[in]  li2  List item 2, often used for integers and not list items.
+/// @param[in]  action  Logged action.
+static inline void list_log(const list_T *const l,
+                            const listitem_T *const li1,
+                            const listitem_T *const li2,
+                            const char *const action)
+{
+  ListLog *tgt;
+  if (list_log_first == NULL) {
+    tgt = list_log_new(128);
+  } else if (list_log_last->size == list_log_last->capacity) {
+    tgt = list_log_new(list_log_last->capacity * 2);
+  } else {
+    tgt = list_log_last;
+  }
+  tgt->entries[tgt->size++] = (ListLogEntry) {
+    .l = (uintptr_t)l,
+    .li1 = (uintptr_t)li1,
+    .li2 = (uintptr_t)li2,
+    .len = (l == NULL ? 0 : l->lv_len),
+    .action = action,
+  };
+}
+#else
+# define list_log(...)
+# define list_write_log(...)
+# define list_free_log()
+#endif
+
 // In a hashtab item "hi_key" points to "di_key" in a dictitem.
 // This avoids adding a pointer to the hashtab item.
 
@@ -284,20 +423,181 @@ typedef struct list_stack_S {
 #define TV_DICT_HI2DI(hi) \
     ((dictitem_T *)((hi)->hi_key - offsetof(dictitem_T, di_key)))
 
-static inline long tv_list_len(const list_T *const l)
+/// Increase reference count for a given list
+///
+/// Does nothing for NULL lists.
+///
+/// @param[in]  l  List to modify.
+static inline void tv_list_ref(list_T *const l)
+{
+  if (l == NULL) {
+    return;
+  }
+  l->lv_refcount++;
+}
+
+static inline VarLockStatus tv_list_locked(const list_T *const l)
+  REAL_FATTR_PURE REAL_FATTR_WARN_UNUSED_RESULT;
+
+/// Get list lock status
+///
+/// Returns VAR_FIXED for NULL lists.
+///
+/// @param[in]  l  List to check.
+static inline VarLockStatus tv_list_locked(const list_T *const l)
+{
+  if (l == NULL) {
+    return VAR_FIXED;
+  }
+  return l->lv_lock;
+}
+
+/// Set list lock status
+///
+/// May only “set” VAR_FIXED for NULL lists.
+///
+/// @param[out]  l  List to modify.
+/// @param[in]  lock  New lock status.
+static inline void tv_list_set_lock(list_T *const l,
+                                    const VarLockStatus lock)
+{
+  if (l == NULL) {
+    assert(lock == VAR_FIXED);
+    return;
+  }
+  l->lv_lock = lock;
+}
+
+/// Set list copyID
+///
+/// Does not expect NULL list, be careful.
+///
+/// @param[out]  l  List to modify.
+/// @param[in]  copyid  New copyID.
+static inline void tv_list_set_copyid(list_T *const l,
+                                      const int copyid)
+  FUNC_ATTR_NONNULL_ALL
+{
+  l->lv_copyID = copyid;
+}
+
+static inline int tv_list_len(const list_T *const l)
   REAL_FATTR_PURE REAL_FATTR_WARN_UNUSED_RESULT;
 
 /// Get the number of items in a list
 ///
 /// @param[in]  l  List to check.
-static inline long tv_list_len(const list_T *const l)
+static inline int tv_list_len(const list_T *const l)
 {
+  list_log(l, NULL, NULL, "len");
   if (l == NULL) {
     return 0;
   }
   return l->lv_len;
 }
 
+static inline int tv_list_copyid(const list_T *const l)
+  REAL_FATTR_PURE REAL_FATTR_WARN_UNUSED_RESULT REAL_FATTR_NONNULL_ALL;
+
+/// Get list copyID
+///
+/// Does not expect NULL list, be careful.
+///
+/// @param[in]  l  List to check.
+static inline int tv_list_copyid(const list_T *const l)
+{
+  return l->lv_copyID;
+}
+
+static inline list_T *tv_list_latest_copy(const list_T *const l)
+  REAL_FATTR_PURE REAL_FATTR_WARN_UNUSED_RESULT REAL_FATTR_NONNULL_ALL;
+
+/// Get latest list copy
+///
+/// Gets lv_copylist field assigned by tv_list_copy() earlier.
+///
+/// Does not expect NULL list, be careful.
+///
+/// @param[in]  l  List to check.
+static inline list_T *tv_list_latest_copy(const list_T *const l)
+{
+  return l->lv_copylist;
+}
+
+static inline int tv_list_uidx(const list_T *const l, int n)
+  REAL_FATTR_PURE REAL_FATTR_WARN_UNUSED_RESULT;
+
+/// Normalize index: that is, return either -1 or non-negative index
+///
+/// @param[in]  l  List to index. Used to get length.
+/// @param[in]  n  List index, possibly negative.
+///
+/// @return -1 or list index in range [0, tv_list_len(l)).
+static inline int tv_list_uidx(const list_T *const l, int n)
+{
+  // Negative index is relative to the end.
+  if (n < 0) {
+    n += tv_list_len(l);
+  }
+
+  // Check for index out of range.
+  if (n < 0 || n >= tv_list_len(l)) {
+    return -1;
+  }
+  return n;
+}
+
+static inline bool tv_list_has_watchers(const list_T *const l)
+  REAL_FATTR_PURE REAL_FATTR_WARN_UNUSED_RESULT;
+
+/// Check whether list has watchers
+///
+/// E.g. is referenced by a :for loop.
+///
+/// @param[in]  l  List to check.
+///
+/// @return true if there are watchers, false otherwise.
+static inline bool tv_list_has_watchers(const list_T *const l)
+{
+  return l && l->lv_watch;
+}
+
+static inline listitem_T *tv_list_first(const list_T *const l)
+  REAL_FATTR_PURE REAL_FATTR_WARN_UNUSED_RESULT;
+
+/// Get first list item
+///
+/// @param[in]  l  List to get item from.
+///
+/// @return List item or NULL in case of an empty list.
+static inline listitem_T *tv_list_first(const list_T *const l)
+{
+  if (l == NULL) {
+    list_log(l, NULL, NULL, "first");
+    return NULL;
+  }
+  list_log(l, l->lv_first, NULL, "first");
+  return l->lv_first;
+}
+
+static inline listitem_T *tv_list_last(const list_T *const l)
+  REAL_FATTR_PURE REAL_FATTR_WARN_UNUSED_RESULT;
+
+/// Get last list item
+///
+/// @param[in]  l  List to get item from.
+///
+/// @return List item or NULL in case of an empty list.
+static inline listitem_T *tv_list_last(const list_T *const l)
+{
+  if (l == NULL) {
+    list_log(l, NULL, NULL, "last");
+    return NULL;
+  }
+  list_log(l, l->lv_last, NULL, "last");
+  return l->lv_last;
+}
+
 static inline long tv_dict_len(const dict_T *const d)
   REAL_FATTR_PURE REAL_FATTR_WARN_UNUSED_RESULT;
 
@@ -352,6 +652,76 @@ extern const char *const tv_empty_string;
 /// Specifies that free_unref_items() function has (not) been entered
 extern bool tv_in_free_unref_items;
 
+/// Iterate over a list
+///
+/// @param  modifier  Modifier: expected to be const or nothing, volatile should
+///                   also work if you have any uses for the volatile list.
+/// @param[in]  l  List to iterate over.
+/// @param  li  Name of the variable with current listitem_T entry.
+/// @param  code  Cycle body.
+#define _TV_LIST_ITER_MOD(modifier, l, li, code) \
+    do { \
+      modifier list_T *const l_ = (l); \
+      list_log(l_, NULL, NULL, "iter" #modifier); \
+      if (l_ != NULL) { \
+        for (modifier listitem_T *li = l_->lv_first; \
+             li != NULL; li = li->li_next) { \
+          code \
+        } \
+      } \
+    } while (0)
+
+/// Iterate over a list
+///
+/// To be used when you need to modify list or values you iterate over, use
+/// #TV_LIST_ITER_CONST if you don’t.
+///
+/// @param[in]  l  List to iterate over.
+/// @param  li  Name of the variable with current listitem_T entry.
+/// @param  code  Cycle body.
+#define TV_LIST_ITER(l, li, code) \
+    _TV_LIST_ITER_MOD(, l, li, code)
+
+/// Iterate over a list
+///
+/// To be used when you don’t need to modify list or values you iterate over,
+/// use #TV_LIST_ITER if you do.
+///
+/// @param[in]  l  List to iterate over.
+/// @param  li  Name of the variable with current listitem_T entry.
+/// @param  code  Cycle body.
+#define TV_LIST_ITER_CONST(l, li, code) \
+    _TV_LIST_ITER_MOD(const, l, li, code)
+
+// Below macros are macros to avoid duplicating code for functionally identical
+// const and non-const function variants.
+
+/// Get typval_T out of list item
+///
+/// @param[in]  li  List item to get typval_T from, must not be NULL.
+///
+/// @return Pointer to typval_T.
+#define TV_LIST_ITEM_TV(li) (&(li)->li_tv)
+
+/// Get next list item given the current one
+///
+/// @param[in]  l  List to get item from.
+/// @param[in]  li  List item to get typval_T from.
+///
+/// @return Pointer to the next item or NULL.
+#define TV_LIST_ITEM_NEXT(l, li) ((li)->li_next)
+
+/// Get previous list item given the current one
+///
+/// @param[in]  l  List to get item from.
+/// @param[in]  li  List item to get typval_T from.
+///
+/// @return Pointer to the previous item or NULL.
+#define TV_LIST_ITEM_PREV(l, li) ((li)->li_prev)
+// List argument is not used currently, but it is a must for lists implemented
+// as a pair (size(in list), array) without terminator - basically for lists on
+// top of kvec.
+
 /// Iterate over a dictionary
 ///
 /// @param[in]  d  Dictionary to iterate over.
diff --git a/src/nvim/eval/typval_encode.c.h b/src/nvim/eval/typval_encode.c.h
index a93ad2dbba..f2d0d7265f 100644
--- a/src/nvim/eval/typval_encode.c.h
+++ b/src/nvim/eval/typval_encode.c.h
@@ -355,14 +355,14 @@ static int _TYPVAL_ENCODE_CONVERT_ONE_VALUE(
       break;
     }
     case VAR_LIST: {
-      if (tv->vval.v_list == NULL || tv->vval.v_list->lv_len == 0) {
+      if (tv->vval.v_list == NULL || tv_list_len(tv->vval.v_list) == 0) {
         TYPVAL_ENCODE_CONV_EMPTY_LIST(tv);
         break;
       }
-      const int saved_copyID = tv->vval.v_list->lv_copyID;
+      const int saved_copyID = tv_list_copyid(tv->vval.v_list);
       _TYPVAL_ENCODE_DO_CHECK_SELF_REFERENCE(tv->vval.v_list, lv_copyID, copyID,
                                              kMPConvList);
-      TYPVAL_ENCODE_CONV_LIST_START(tv, tv->vval.v_list->lv_len);
+      TYPVAL_ENCODE_CONV_LIST_START(tv, tv_list_len(tv->vval.v_list));
       assert(saved_copyID != copyID && saved_copyID != copyID - 1);
       _mp_push(*mpstack, ((MPConvStackVal) {
         .type = kMPConvList,
@@ -371,7 +371,7 @@ static int _TYPVAL_ENCODE_CONVERT_ONE_VALUE(
         .data = {
           .l = {
             .list = tv->vval.v_list,
-            .li = tv->vval.v_list->lv_first,
+            .li = tv_list_first(tv->vval.v_list),
           },
         },
       }));
@@ -440,23 +440,43 @@ static int _TYPVAL_ENCODE_CONVERT_ONE_VALUE(
             // bits is not checked), other unsigned and have at most 31
             // non-zero bits (number of bits is not checked).
             if (val_di->di_tv.v_type != VAR_LIST
-                || (val_list = val_di->di_tv.vval.v_list) == NULL
-                || val_list->lv_len != 4
-                || val_list->lv_first->li_tv.v_type != VAR_NUMBER
-                || (sign = val_list->lv_first->li_tv.vval.v_number) == 0
-                || val_list->lv_first->li_next->li_tv.v_type != VAR_NUMBER
-                || (highest_bits =
-                    val_list->lv_first->li_next->li_tv.vval.v_number) < 0
-                || val_list->lv_last->li_prev->li_tv.v_type != VAR_NUMBER
-                || (high_bits =
-                    val_list->lv_last->li_prev->li_tv.vval.v_number) < 0
-                || val_list->lv_last->li_tv.v_type != VAR_NUMBER
-                || (low_bits = val_list->lv_last->li_tv.vval.v_number) < 0) {
+                || tv_list_len(val_list = val_di->di_tv.vval.v_list) != 4) {
               goto _convert_one_value_regular_dict;
             }
-            uint64_t number = ((uint64_t)(((uint64_t)highest_bits) << 62)
-                               | (uint64_t)(((uint64_t)high_bits) << 31)
-                               | (uint64_t)low_bits);
+
+            const listitem_T *const sign_li = tv_list_first(val_list);
+            if (TV_LIST_ITEM_TV(sign_li)->v_type != VAR_NUMBER
+                || (sign = TV_LIST_ITEM_TV(sign_li)->vval.v_number) == 0) {
+              goto _convert_one_value_regular_dict;
+            }
+
+            const listitem_T *const highest_bits_li = (
+                TV_LIST_ITEM_NEXT(val_list, sign_li));
+            if (TV_LIST_ITEM_TV(highest_bits_li)->v_type != VAR_NUMBER
+                || ((highest_bits
+                     = TV_LIST_ITEM_TV(highest_bits_li)->vval.v_number)
+                    < 0)) {
+              goto _convert_one_value_regular_dict;
+            }
+
+            const listitem_T *const high_bits_li =  (
+                TV_LIST_ITEM_NEXT(val_list, highest_bits_li));
+            if (TV_LIST_ITEM_TV(high_bits_li)->v_type != VAR_NUMBER
+                || ((high_bits = TV_LIST_ITEM_TV(high_bits_li)->vval.v_number)
+                    < 0)) {
+              goto _convert_one_value_regular_dict;
+            }
+
+            const listitem_T *const low_bits_li = tv_list_last(val_list);
+            if (TV_LIST_ITEM_TV(low_bits_li)->v_type != VAR_NUMBER
+                || ((low_bits = TV_LIST_ITEM_TV(low_bits_li)->vval.v_number)
+                    < 0)) {
+              goto _convert_one_value_regular_dict;
+            }
+
+            const uint64_t number = ((uint64_t)(((uint64_t)highest_bits) << 62)
+                                     | (uint64_t)(((uint64_t)high_bits) << 31)
+                                     | (uint64_t)low_bits);
             if (sign > 0) {
               TYPVAL_ENCODE_CONV_UNSIGNED_NUMBER(tv, number);
             } else {
@@ -495,12 +515,12 @@ static int _TYPVAL_ENCODE_CONVERT_ONE_VALUE(
             if (val_di->di_tv.v_type != VAR_LIST) {
               goto _convert_one_value_regular_dict;
             }
-            const int saved_copyID = val_di->di_tv.vval.v_list->lv_copyID;
+            const int saved_copyID = tv_list_copyid(val_di->di_tv.vval.v_list);
             _TYPVAL_ENCODE_DO_CHECK_SELF_REFERENCE(val_di->di_tv.vval.v_list,
                                                    lv_copyID, copyID,
                                                    kMPConvList);
-            TYPVAL_ENCODE_CONV_LIST_START(tv,
-                                          val_di->di_tv.vval.v_list->lv_len);
+            TYPVAL_ENCODE_CONV_LIST_START(
+                tv, tv_list_len(val_di->di_tv.vval.v_list));
             assert(saved_copyID != copyID && saved_copyID != copyID - 1);
             _mp_push(*mpstack, ((MPConvStackVal) {
               .tv = tv,
@@ -509,7 +529,7 @@ static int _TYPVAL_ENCODE_CONVERT_ONE_VALUE(
               .data = {
                 .l = {
                   .list = val_di->di_tv.vval.v_list,
-                  .li = val_di->di_tv.vval.v_list->lv_first,
+                  .li = tv_list_first(val_di->di_tv.vval.v_list),
                 },
               },
             }));
@@ -520,22 +540,21 @@ static int _TYPVAL_ENCODE_CONVERT_ONE_VALUE(
               goto _convert_one_value_regular_dict;
             }
             list_T *const val_list = val_di->di_tv.vval.v_list;
-            if (val_list == NULL || val_list->lv_len == 0) {
+            if (val_list == NULL || tv_list_len(val_list) == 0) {
               TYPVAL_ENCODE_CONV_EMPTY_DICT(tv, TYPVAL_ENCODE_NODICT_VAR);
               break;
             }
-            for (const listitem_T *li = val_list->lv_first; li != NULL;
-                 li = li->li_next) {
-              if (li->li_tv.v_type != VAR_LIST
-                  || li->li_tv.vval.v_list->lv_len != 2) {
+            TV_LIST_ITER_CONST(val_list, li, {
+              if (TV_LIST_ITEM_TV(li)->v_type != VAR_LIST
+                  || tv_list_len(TV_LIST_ITEM_TV(li)->vval.v_list) != 2) {
                 goto _convert_one_value_regular_dict;
               }
-            }
-            const int saved_copyID = val_di->di_tv.vval.v_list->lv_copyID;
+            });
+            const int saved_copyID = tv_list_copyid(val_di->di_tv.vval.v_list);
             _TYPVAL_ENCODE_DO_CHECK_SELF_REFERENCE(val_list, lv_copyID, copyID,
                                                    kMPConvPairs);
             TYPVAL_ENCODE_CONV_DICT_START(tv, TYPVAL_ENCODE_NODICT_VAR,
-                                          val_list->lv_len);
+                                          tv_list_len(val_list));
             assert(saved_copyID != copyID && saved_copyID != copyID - 1);
             _mp_push(*mpstack, ((MPConvStackVal) {
               .tv = tv,
@@ -544,7 +563,7 @@ static int _TYPVAL_ENCODE_CONVERT_ONE_VALUE(
               .data = {
                 .l = {
                   .list = val_list,
-                  .li = val_list->lv_first,
+                  .li = tv_list_first(val_list),
                 },
               },
             }));
@@ -554,18 +573,23 @@ static int _TYPVAL_ENCODE_CONVERT_ONE_VALUE(
             const list_T *val_list;
             varnumber_T type;
             if (val_di->di_tv.v_type != VAR_LIST
-                || (val_list = val_di->di_tv.vval.v_list) == NULL
-                || val_list->lv_len != 2
-                || (val_list->lv_first->li_tv.v_type != VAR_NUMBER)
-                || (type = val_list->lv_first->li_tv.vval.v_number) > INT8_MAX
+                || tv_list_len((val_list = val_di->di_tv.vval.v_list)) != 2
+                || (TV_LIST_ITEM_TV(tv_list_first(val_list))->v_type
+                    != VAR_NUMBER)
+                || ((type
+                     = TV_LIST_ITEM_TV(tv_list_first(val_list))->vval.v_number)
+                    > INT8_MAX)
                 || type < INT8_MIN
-                || (val_list->lv_last->li_tv.v_type != VAR_LIST)) {
+                || (TV_LIST_ITEM_TV(tv_list_last(val_list))->v_type
+                    != VAR_LIST)) {
               goto _convert_one_value_regular_dict;
             }
             size_t len;
             char *buf;
-            if (!encode_vim_list_to_buf(val_list->lv_last->li_tv.vval.v_list,
-                                        &len, &buf)) {
+            if (!(
+                encode_vim_list_to_buf(
+                    TV_LIST_ITEM_TV(tv_list_last(val_list))->vval.v_list, &len,
+                    &buf))) {
               goto _convert_one_value_regular_dict;
             }
             TYPVAL_ENCODE_CONV_EXT_STRING(tv, buf, len, type);
@@ -600,7 +624,7 @@ _convert_one_value_regular_dict: {}
       break;
     }
     case VAR_UNKNOWN: {
-      EMSG2(_(e_intern2), STR(_TYPVAL_ENCODE_CONVERT_ONE_VALUE) "()");
+      internal_error(STR(_TYPVAL_ENCODE_CONVERT_ONE_VALUE) "()");
       return FAIL;
     }
   }
@@ -671,40 +695,45 @@ typval_encode_stop_converting_one_item:
       case kMPConvList: {
         if (cur_mpsv->data.l.li == NULL) {
           (void)_mp_pop(mpstack);
-          cur_mpsv->data.l.list->lv_copyID = cur_mpsv->saved_copyID;
+          tv_list_set_copyid(cur_mpsv->data.l.list, cur_mpsv->saved_copyID);
           TYPVAL_ENCODE_CONV_LIST_END(cur_mpsv->tv);
           continue;
-        } else if (cur_mpsv->data.l.li != cur_mpsv->data.l.list->lv_first) {
+        } else if (cur_mpsv->data.l.li
+                   != tv_list_first(cur_mpsv->data.l.list)) {
           TYPVAL_ENCODE_CONV_LIST_BETWEEN_ITEMS(cur_mpsv->tv);
         }
-        tv = &cur_mpsv->data.l.li->li_tv;
-        cur_mpsv->data.l.li = cur_mpsv->data.l.li->li_next;
+        tv = TV_LIST_ITEM_TV(cur_mpsv->data.l.li);
+        cur_mpsv->data.l.li = TV_LIST_ITEM_NEXT(cur_mpsv->data.l.list,
+                                                cur_mpsv->data.l.li);
         break;
       }
       case kMPConvPairs: {
         if (cur_mpsv->data.l.li == NULL) {
           (void)_mp_pop(mpstack);
-          cur_mpsv->data.l.list->lv_copyID = cur_mpsv->saved_copyID;
+          tv_list_set_copyid(cur_mpsv->data.l.list, cur_mpsv->saved_copyID);
           TYPVAL_ENCODE_CONV_DICT_END(cur_mpsv->tv, TYPVAL_ENCODE_NODICT_VAR);
           continue;
-        } else if (cur_mpsv->data.l.li != cur_mpsv->data.l.list->lv_first) {
+        } else if (cur_mpsv->data.l.li
+                   != tv_list_first(cur_mpsv->data.l.list)) {
           TYPVAL_ENCODE_CONV_DICT_BETWEEN_ITEMS(
               cur_mpsv->tv, TYPVAL_ENCODE_NODICT_VAR);
         }
-        const list_T *const kv_pair = cur_mpsv->data.l.li->li_tv.vval.v_list;
+        const list_T *const kv_pair = (
+            TV_LIST_ITEM_TV(cur_mpsv->data.l.li)->vval.v_list);
         TYPVAL_ENCODE_SPECIAL_DICT_KEY_CHECK(
-            encode_vim_to__error_ret, kv_pair->lv_first->li_tv);
-        if (_TYPVAL_ENCODE_CONVERT_ONE_VALUE(TYPVAL_ENCODE_FIRST_ARG_NAME,
-                                             &mpstack, cur_mpsv,
-                                             &kv_pair->lv_first->li_tv,
-                                             copyID,
-                                             objname) == FAIL) {
+            encode_vim_to__error_ret, *TV_LIST_ITEM_TV(tv_list_first(kv_pair)));
+        if (
+            _TYPVAL_ENCODE_CONVERT_ONE_VALUE(
+                TYPVAL_ENCODE_FIRST_ARG_NAME, &mpstack, cur_mpsv,
+                TV_LIST_ITEM_TV(tv_list_first(kv_pair)), copyID, objname)
+            == FAIL) {
           goto encode_vim_to__error_ret;
         }
         TYPVAL_ENCODE_CONV_DICT_AFTER_KEY(cur_mpsv->tv,
                                           TYPVAL_ENCODE_NODICT_VAR);
-        tv = &kv_pair->lv_last->li_tv;
-        cur_mpsv->data.l.li = cur_mpsv->data.l.li->li_next;
+        tv = TV_LIST_ITEM_TV(tv_list_last(kv_pair));
+        cur_mpsv->data.l.li = TV_LIST_ITEM_NEXT(cur_mpsv->data.l.list,
+                                                cur_mpsv->data.l.li);
         break;
       }
       case kMPConvPartial: {