From fe13fd0b51c6cfacf6667579be9d16647d22cfa0 Mon Sep 17 00:00:00 2001
From: "Nicholas J. Kain" <nicholas@kain.us>
Date: Mon, 6 Jul 2026 22:17:45 -0400
Subject: [PATCH 1/9] Replace deprecated Lua API luaL_openlib() with
 luaL_register()

---
 crawl-ref/source/cluautil.cc |  7 ++++---
 crawl-ref/source/dlua.cc     |  6 +++---
 crawl-ref/source/kills.cc    |  2 +-
 crawl-ref/source/l-colour.cc |  2 +-
 crawl-ref/source/l-crawl.cc  |  4 ++--
 crawl-ref/source/l-dgn.cc    | 18 +++++++++---------
 crawl-ref/source/l-file.cc   |  4 ++--
 crawl-ref/source/l-food.cc   |  2 +-
 crawl-ref/source/l-item.cc   |  2 +-
 crawl-ref/source/l-moninf.cc |  2 +-
 crawl-ref/source/l-spells.cc |  2 +-
 crawl-ref/source/l-travel.cc |  2 +-
 crawl-ref/source/l-view.cc   |  2 +-
 crawl-ref/source/l-wiz.cc    |  2 +-
 crawl-ref/source/l-you.cc    |  4 ++--
 15 files changed, 31 insertions(+), 30 deletions(-)

diff --git a/crawl-ref/source/cluautil.cc b/crawl-ref/source/cluautil.cc
index 940c7a20dfbe..744712dec1e4 100644
--- a/crawl-ref/source/cluautil.cc
+++ b/crawl-ref/source/cluautil.cc
@@ -52,7 +52,7 @@ void luaopen_setmeta(lua_State *ls,
     luaL_newmetatable(ls, meta);
     lua_setglobal(ls, global);
 
-    luaL_openlib(ls, global, lua_lib, 0);
+    luaL_register(ls, global, lua_lib);
 
     // Do <global>.__index = <global>
     lua_pushstring(ls, "__index");
@@ -77,8 +77,9 @@ void clua_register_metatable(lua_State *ls, const char *tn,
         lua_settable(ls, -3);
     }
 
-    if (lr)
-        luaL_openlib(ls, nullptr, lr, 0);
+    if (lr) {
+        luaL_register(ls, NULL, lr);
+    }
 }
 
 int clua_pushcxxstring(lua_State *ls, const string &s)
diff --git a/crawl-ref/source/dlua.cc b/crawl-ref/source/dlua.cc
index 1bc40f77cf49..0a9c2378872b 100644
--- a/crawl-ref/source/dlua.cc
+++ b/crawl-ref/source/dlua.cc
@@ -294,9 +294,9 @@ void init_dungeon_lua()
     dluaopen_wiz(dlua);
     #endif
 
-    luaL_openlib(dlua, "feat", feat_dlib, 0);
-    luaL_openlib(dlua, "debug", debug_dlib, 0);
-    luaL_openlib(dlua, "los", los_dlib, 0);
+    luaL_register(dlua, "feat", feat_dlib);
+    luaL_register(dlua, "debug", debug_dlib);
+    luaL_register(dlua, "los", los_dlib);
 
     dlua.execfile("dlua/dungeon.lua", true, true);
     dlua.execfile("dlua/luamark.lua", true, true);
diff --git a/crawl-ref/source/kills.cc b/crawl-ref/source/kills.cc
index 44b040575c1c..c9c4c467b295 100644
--- a/crawl-ref/source/kills.cc
+++ b/crawl-ref/source/kills.cc
@@ -989,7 +989,7 @@ static const struct luaL_reg kill_lib[] =
 
 void cluaopen_kills(lua_State *ls)
 {
-    luaL_openlib(ls, "kills", kill_lib, 0);
+    luaL_register(ls, "kills", kill_lib);
 }
 
 #ifdef CLUA_BINDINGS
diff --git a/crawl-ref/source/l-colour.cc b/crawl-ref/source/l-colour.cc
index cd60eb309e62..43bdeb7a8c1b 100644
--- a/crawl-ref/source/l-colour.cc
+++ b/crawl-ref/source/l-colour.cc
@@ -110,5 +110,5 @@ static const struct luaL_reg colour_lib[] =
 
 void dluaopen_colour(lua_State *ls)
 {
-    luaL_openlib(ls, "colour", colour_lib, 0);
+    luaL_register(ls, "colour", colour_lib);
 }
diff --git a/crawl-ref/source/l-crawl.cc b/crawl-ref/source/l-crawl.cc
index 5210b43b324b..40e5e45c9b16 100644
--- a/crawl-ref/source/l-crawl.cc
+++ b/crawl-ref/source/l-crawl.cc
@@ -1493,7 +1493,7 @@ void cluaopen_crawl(lua_State *ls)
     clua_register_metatable(ls, MESSF_METATABLE, crawl_messf_ops,
                             lua_object_gc<message_filter>);
 
-    luaL_openlib(ls, "crawl", crawl_clib, 0);
+    luaL_register(ls, "crawl", crawl_clib);
 }
 
 //
@@ -1733,5 +1733,5 @@ static const struct luaL_reg crawl_dlib[] =
 
 void dluaopen_crawl(lua_State *ls)
 {
-    luaL_openlib(ls, "crawl", crawl_dlib, 0);
+    luaL_register(ls, "crawl", crawl_dlib);
 }
diff --git a/crawl-ref/source/l-dgn.cc b/crawl-ref/source/l-dgn.cc
index b7665b8f20fa..c1b506717616 100644
--- a/crawl-ref/source/l-dgn.cc
+++ b/crawl-ref/source/l-dgn.cc
@@ -1927,13 +1927,13 @@ void dluaopen_dgn(lua_State *ls)
 {
     _dgn_register_metatables(ls);
 
-    luaL_openlib(ls, "dgn", dgn_dlib, 0);
-    luaL_openlib(ls, "dgn", dgn_build_dlib, 0);
-    luaL_openlib(ls, "dgn", dgn_event_dlib, 0);
-    luaL_openlib(ls, "dgn", dgn_grid_dlib, 0);
-    luaL_openlib(ls, "dgn", dgn_item_dlib, 0);
-    luaL_openlib(ls, "dgn", dgn_level_dlib, 0);
-    luaL_openlib(ls, "dgn", dgn_mons_dlib, 0);
-    luaL_openlib(ls, "dgn", dgn_subvault_dlib, 0);
-    luaL_openlib(ls, "dgn", dgn_tile_dlib, 0);
+    luaL_register(ls, "dgn", dgn_dlib);
+    luaL_register(ls, "dgn", dgn_build_dlib);
+    luaL_register(ls, "dgn", dgn_event_dlib);
+    luaL_register(ls, "dgn", dgn_grid_dlib);
+    luaL_register(ls, "dgn", dgn_item_dlib);
+    luaL_register(ls, "dgn", dgn_level_dlib);
+    luaL_register(ls, "dgn", dgn_mons_dlib);
+    luaL_register(ls, "dgn", dgn_subvault_dlib);
+    luaL_register(ls, "dgn", dgn_tile_dlib);
 }
diff --git a/crawl-ref/source/l-file.cc b/crawl-ref/source/l-file.cc
index 71bf955cc87f..7023d6025d1a 100644
--- a/crawl-ref/source/l-file.cc
+++ b/crawl-ref/source/l-file.cc
@@ -22,7 +22,7 @@ static const struct luaL_reg file_clib[] =
 
 void cluaopen_file(lua_State *ls)
 {
-    luaL_openlib(ls, "file", file_clib, 0);
+    luaL_register(ls, "file", file_clib);
 }
 
 //
@@ -218,5 +218,5 @@ static const struct luaL_reg file_dlib[] =
 
 void dluaopen_file(lua_State *ls)
 {
-    luaL_openlib(ls, "file", file_dlib, 0);
+    luaL_register(ls, "file", file_dlib);
 }
diff --git a/crawl-ref/source/l-food.cc b/crawl-ref/source/l-food.cc
index 72765985bbcf..75341ecaa7d5 100644
--- a/crawl-ref/source/l-food.cc
+++ b/crawl-ref/source/l-food.cc
@@ -182,5 +182,5 @@ static const struct luaL_reg food_lib[] =
 
 void cluaopen_food(lua_State *ls)
 {
-    luaL_openlib(ls, "food", food_lib, 0);
+    luaL_register(ls, "food", food_lib);
 }
diff --git a/crawl-ref/source/l-item.cc b/crawl-ref/source/l-item.cc
index 672fd1e29467..df623d512a9e 100644
--- a/crawl-ref/source/l-item.cc
+++ b/crawl-ref/source/l-item.cc
@@ -1683,5 +1683,5 @@ void cluaopen_item(lua_State *ls)
     // Pop the metatable off the stack.
     lua_pop(ls, 1);
 
-    luaL_openlib(ls, "items", item_lib, 0);
+    luaL_register(ls, "items", item_lib);
 }
diff --git a/crawl-ref/source/l-moninf.cc b/crawl-ref/source/l-moninf.cc
index 54aebd10faf4..4cdac513a24f 100644
--- a/crawl-ref/source/l-moninf.cc
+++ b/crawl-ref/source/l-moninf.cc
@@ -639,5 +639,5 @@ void cluaopen_moninf(lua_State *ls)
 {
     clua_register_metatable(ls, MONINF_METATABLE, moninf_lib,
                             lua_object_gc<monster_info>);
-    luaL_openlib(ls, "monster", mon_lib, 0);
+    luaL_register(ls, "monster", mon_lib);
 }
diff --git a/crawl-ref/source/l-spells.cc b/crawl-ref/source/l-spells.cc
index 1ba2458592fb..ab9b49049d02 100644
--- a/crawl-ref/source/l-spells.cc
+++ b/crawl-ref/source/l-spells.cc
@@ -291,5 +291,5 @@ static const struct luaL_reg spells_clib[] =
 
 void cluaopen_spells(lua_State *ls)
 {
-    luaL_openlib(ls, "spells", spells_clib, 0);
+    luaL_register(ls, "spells", spells_clib);
 }
diff --git a/crawl-ref/source/l-travel.cc b/crawl-ref/source/l-travel.cc
index 019e4b1eacdd..c4e87749e4d5 100644
--- a/crawl-ref/source/l-travel.cc
+++ b/crawl-ref/source/l-travel.cc
@@ -126,5 +126,5 @@ static const struct luaL_reg travel_lib[] =
 
 void cluaopen_travel(lua_State *ls)
 {
-    luaL_openlib(ls, "travel", travel_lib, 0);
+    luaL_register(ls, "travel", travel_lib);
 }
diff --git a/crawl-ref/source/l-view.cc b/crawl-ref/source/l-view.cc
index 042fa74abbd0..ba8481d8855d 100644
--- a/crawl-ref/source/l-view.cc
+++ b/crawl-ref/source/l-view.cc
@@ -223,5 +223,5 @@ static const struct luaL_reg view_lib[] =
 
 void cluaopen_view(lua_State *ls)
 {
-    luaL_openlib(ls, "view", view_lib, 0);
+    luaL_register(ls, "view", view_lib);
 }
diff --git a/crawl-ref/source/l-wiz.cc b/crawl-ref/source/l-wiz.cc
index 544a511f0e77..e699ede5282f 100644
--- a/crawl-ref/source/l-wiz.cc
+++ b/crawl-ref/source/l-wiz.cc
@@ -48,7 +48,7 @@ static const struct luaL_reg wiz_dlib[] =
 
 void dluaopen_wiz(lua_State *ls)
 {
-    luaL_openlib(ls, "wiz", wiz_dlib, 0);
+    luaL_register(ls, "wiz", wiz_dlib);
 }
 
 #endif
diff --git a/crawl-ref/source/l-you.cc b/crawl-ref/source/l-you.cc
index 5e64753d4452..9ab248f48339 100644
--- a/crawl-ref/source/l-you.cc
+++ b/crawl-ref/source/l-you.cc
@@ -1298,7 +1298,7 @@ static const struct luaL_reg you_clib[] =
 
 void cluaopen_you(lua_State *ls)
 {
-    luaL_openlib(ls, "you", you_clib, 0);
+    luaL_register(ls, "you", you_clib);
 }
 
 //
@@ -1604,5 +1604,5 @@ static const struct luaL_reg you_dlib[] =
 
 void dluaopen_you(lua_State *ls)
 {
-    luaL_openlib(ls, "you", you_dlib, 0);
+    luaL_register(ls, "you", you_dlib);
 }

From e470b92e9ac7b6cca52ca44417f4b22a3d84229f Mon Sep 17 00:00:00 2001
From: "Nicholas J. Kain" <nicholas@kain.us>
Date: Mon, 6 Jul 2026 22:18:24 -0400
Subject: [PATCH 2/9] coord-circle: Fix uninitialized member radius warnings

---
 crawl-ref/source/coord-circle.cc | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/crawl-ref/source/coord-circle.cc b/crawl-ref/source/coord-circle.cc
index f1de9daf4bf7..8008a14a2a8a 100644
--- a/crawl-ref/source/coord-circle.cc
+++ b/crawl-ref/source/coord-circle.cc
@@ -27,7 +27,7 @@ rectangle_iterator rect_def::iter() const
 }
 
 circle_def::circle_def()
-    : global_los_radius(true), check_bounds(false), origin(coord_def(0,0))
+    : global_los_radius(true), check_bounds(false), origin(coord_def(0,0)), radius(0)
 {
     // Set up bounding box and shape.
     init(LOS_RADIUS, C_SQUARE);
@@ -43,14 +43,14 @@ circle_def::circle_def(const coord_def& origin_, const circle_def& bds)
 }
 
 circle_def::circle_def(int param, circle_type ctype)
-    : global_los_radius(false), check_bounds(false), origin(coord_def(0,0))
+    : global_los_radius(false), check_bounds(false), origin(coord_def(0,0)), radius(0)
 {
     init(param, ctype);
 }
 
 circle_def::circle_def(const coord_def &origin_, int param,
                        circle_type ctype)
-    : global_los_radius(false), check_bounds(true), origin(origin_)
+    : global_los_radius(false), check_bounds(true), origin(origin_), radius(0)
 {
     init(param, ctype);
 }

From 6f56423e1ac0237fa65ed97eea22c65cf66e3150 Mon Sep 17 00:00:00 2001
From: "Nicholas J. Kain" <nicholas@kain.us>
Date: Mon, 6 Jul 2026 22:19:09 -0400
Subject: [PATCH 3/9] Correct range-for loops that take a value rather than a
 reference

---
 crawl-ref/source/dbg-asrt.cc | 2 +-
 crawl-ref/source/delay.cc    | 4 ++--
 crawl-ref/source/god-abil.cc | 4 ++--
 3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/crawl-ref/source/dbg-asrt.cc b/crawl-ref/source/dbg-asrt.cc
index 43bd306570b6..238f4d089bfd 100644
--- a/crawl-ref/source/dbg-asrt.cc
+++ b/crawl-ref/source/dbg-asrt.cc
@@ -187,7 +187,7 @@ static void _dump_player(FILE *file)
     {
         fprintf(file, "Delayed (%u):\n",
                 (unsigned int)you.delay_queue.size());
-        for (const auto delay : you.delay_queue)
+        for (const auto &delay : you.delay_queue)
         {
             fprintf(file, "    type:     %s", delay->name());
             fprintf(file, "\n");
diff --git a/crawl-ref/source/delay.cc b/crawl-ref/source/delay.cc
index 5c079ca987f9..abf0ae1fc9e6 100644
--- a/crawl-ref/source/delay.cc
+++ b/crawl-ref/source/delay.cc
@@ -314,7 +314,7 @@ bool is_being_drained(const item_def &item)
 
 bool is_being_butchered(const item_def &item, bool just_first)
 {
-    for (const auto delay : you.delay_queue)
+    for (const auto &delay : you.delay_queue)
     {
         if (delay->is_being_used(&item, OPER_BUTCHER))
             return true;
@@ -350,7 +350,7 @@ bool player_stair_delay()
  */
 bool already_learning_spell(int spell)
 {
-    for (const auto delay : you.delay_queue)
+    for (const auto &delay : you.delay_queue)
     {
         auto mem = dynamic_cast<MemoriseDelay*>(delay.get());
         if (!mem)
diff --git a/crawl-ref/source/god-abil.cc b/crawl-ref/source/god-abil.cc
index 2a928452d613..cc406664e4e3 100644
--- a/crawl-ref/source/god-abil.cc
+++ b/crawl-ref/source/god-abil.cc
@@ -5308,7 +5308,7 @@ static void _choose_arcana_mutations()
         = you.props[ARCANA_SAC_KEY].get_vector();
     ASSERT(current_arcane_sacrifices.empty());
 
-    for (const vector<mutation_type> arcane_sacrifice_list :
+    for (const vector<mutation_type> &arcane_sacrifice_list :
                                     _arcane_sacrifice_lists)
     {
         const mutation_type sacrifice =
@@ -5328,7 +5328,7 @@ static void _choose_arcana_mutations()
  */
 static bool _player_sacrificed_arcana()
 {
-    for (const vector<mutation_type> arcane_sacrifice_list :
+    for (const vector<mutation_type> &arcane_sacrifice_list :
                                     _arcane_sacrifice_lists)
     {
         for (mutation_type sacrifice : arcane_sacrifice_list)

From 6989b5db14161d13869880efd78e6d12f3117673 Mon Sep 17 00:00:00 2001
From: "Nicholas J. Kain" <nicholas@kain.us>
Date: Mon, 6 Jul 2026 22:19:46 -0400
Subject: [PATCH 4/9] initfile: Correct range-for with wrong type

The existing construct is very dubious, since it creates a std::string
temporary and then takes it by reference.  GCC warns about it, and it
may be UB.
---
 crawl-ref/source/initfile.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/crawl-ref/source/initfile.cc b/crawl-ref/source/initfile.cc
index 08876914c54d..330bc5f2cb9a 100644
--- a/crawl-ref/source/initfile.cc
+++ b/crawl-ref/source/initfile.cc
@@ -1520,7 +1520,7 @@ string find_crawlrc()
     // rc_dir_names list.
     for (const string &rc_dir : SysEnv.rcdirs)
     {
-        for (const string &rc_fn : rc_dir_filenames)
+        for (const char *rc_fn : rc_dir_filenames)
         {
             const string rc(catpath(rc_dir, rc_fn));
             if (file_exists(rc))

From bb77be7658f17cbeb4ccdce97b0dfbb2c60129f1 Mon Sep 17 00:00:00 2001
From: "Nicholas J. Kain" <nicholas@kain.us>
Date: Mon, 6 Jul 2026 22:21:45 -0400
Subject: [PATCH 5/9] json: Fix warnings about uninitialized fields in struct
 SB

---
 crawl-ref/source/json.cc | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/crawl-ref/source/json.cc b/crawl-ref/source/json.cc
index f90be8ec85c0..7d9e4b03c1de 100644
--- a/crawl-ref/source/json.cc
+++ b/crawl-ref/source/json.cc
@@ -413,7 +413,7 @@ char *json_encode(const JsonNode *node)
 
 char *json_encode_string(const char *str)
 {
-    SB sb;
+    SB sb = {};
     sb_init(&sb);
 
     emit_string(&sb, str);
@@ -423,7 +423,7 @@ char *json_encode_string(const char *str)
 
 char *json_stringify(const JsonNode *node, const char *space)
 {
-    SB sb;
+    SB sb = {};
     sb_init(&sb);
 
     if (space != nullptr)
@@ -844,7 +844,7 @@ static bool parse_object(const char **sp, JsonNode **out)
 bool parse_string(const char **sp, char **out)
 {
     const char *s = *sp;
-    SB sb;
+    SB sb = {};
     char throwaway_buffer[4];
         /* enough space for a UTF-8 character */
     char *b;

From 6cae43a6e9cb2c162326598851fb9133b9b9a3af Mon Sep 17 00:00:00 2001
From: "Nicholas J. Kain" <nicholas@kain.us>
Date: Mon, 6 Jul 2026 22:22:11 -0400
Subject: [PATCH 6/9] tags: Fix warning about unused function

I didn't investigate this deeply, so for now I just commented
out the function in question.
---
 crawl-ref/source/tags.cc | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/crawl-ref/source/tags.cc b/crawl-ref/source/tags.cc
index 7b6f61be17a4..8fc5322e40bf 100644
--- a/crawl-ref/source/tags.cc
+++ b/crawl-ref/source/tags.cc
@@ -2275,6 +2275,7 @@ void tag_read_char(reader &th, uint8_t format, uint8_t major, uint8_t minor)
         you.explore = unmarshallBoolean(th);
 }
 
+#if 0
 static void _cap_mutation_at(mutation_type mut, int cap)
 {
     if (you.mutation[mut] > cap)
@@ -2288,6 +2289,7 @@ static void _cap_mutation_at(mutation_type mut, int cap)
     if (you.innate_mutation[mut] > cap)
         you.innate_mutation[mut] = cap;
 }
+#endif
 
 static void tag_read_you(reader &th)
 {

From de18debd5a9aed5a692fe44fc888968a962465c6 Mon Sep 17 00:00:00 2001
From: "Nicholas J. Kain" <nicholas@kain.us>
Date: Mon, 6 Jul 2026 22:22:54 -0400
Subject: [PATCH 7/9] ui.h: Fix deprecated C++ syntax that is invalid in >=
 C++20

Silences a warning with recent GCCs that default to C++20.
---
 crawl-ref/source/ui.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/crawl-ref/source/ui.h b/crawl-ref/source/ui.h
index ce1c11f79232..7b32d0b2f0ce 100644
--- a/crawl-ref/source/ui.h
+++ b/crawl-ref/source/ui.h
@@ -27,7 +27,7 @@ namespace ui {
 template <size_t N>
 struct vec {
     int items[N];
-    template <typename... Ts> vec<N> (Ts... l) : items{l...} {}
+    template <typename... Ts> vec(Ts... l) : items{l...} {}
     const int& operator[](int index) const { return items[index]; }
     int& operator[](int index) { return items[index]; }
     inline bool operator==(const vec<N>& rhs) {

From 38dd48d17fbf53b6d267c14d7de0500c1d602188 Mon Sep 17 00:00:00 2001
From: "Nicholas J. Kain" <nicholas@kain.us>
Date: Mon, 6 Jul 2026 22:32:39 -0400
Subject: [PATCH 8/9] tool/tile: Don't use memset() and memcpy() on array of
 tile_color

tile_color has a constructor so this isn't valid.

Fix memset() by simply providing a default constructor that
zero-initializes.

Fix memcpy() by hand-writing a copy loop that uses the copy
assignment operator.
---
 crawl-ref/source/rltiles/tool/tile.cc       | 4 +++-
 crawl-ref/source/rltiles/tool/tile_colour.h | 2 +-
 crawl-ref/source/rltiles/tool/tile_page.cc  | 1 -
 3 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/crawl-ref/source/rltiles/tool/tile.cc b/crawl-ref/source/rltiles/tool/tile.cc
index f35788d247f6..1ccca7f20de1 100644
--- a/crawl-ref/source/rltiles/tool/tile.cc
+++ b/crawl-ref/source/rltiles/tool/tile.cc
@@ -293,7 +293,9 @@ void tile::copy(const tile &img)
     m_filename = img.m_filename;
     m_pixels   = new tile_colour[m_width * m_height];
     m_shrink   = img.m_shrink;
-    memcpy(m_pixels, img.m_pixels, m_width * m_height * sizeof(tile_colour));
+    for (int i = 0, iend = m_width * m_height; i < iend; ++i) {
+        m_pixels[i] = img.m_pixels[i];
+    }
 
     // enum explicitly not copied
     m_enumname.clear();
diff --git a/crawl-ref/source/rltiles/tool/tile_colour.h b/crawl-ref/source/rltiles/tool/tile_colour.h
index 54419e5d7fca..99de2e07ac95 100644
--- a/crawl-ref/source/rltiles/tool/tile_colour.h
+++ b/crawl-ref/source/rltiles/tool/tile_colour.h
@@ -28,7 +28,7 @@ enum COLORS
 class tile_colour
 {
 public:
-    tile_colour() {};
+    tile_colour() : r(0), g(0), b(0), a(0) {};
     tile_colour(unsigned char _r, unsigned char _g, unsigned char _b,
         unsigned char _a) : r(_r), g(_g), b(_b), a(_a) {}
 
diff --git a/crawl-ref/source/rltiles/tool/tile_page.cc b/crawl-ref/source/rltiles/tool/tile_page.cc
index 718c305a266f..bfe753892525 100644
--- a/crawl-ref/source/rltiles/tool/tile_page.cc
+++ b/crawl-ref/source/rltiles/tool/tile_page.cc
@@ -137,7 +137,6 @@ bool tile_page::write_image(const char *filename)
     }
 
     tile_colour *pixels = new tile_colour[m_width * m_height];
-    memset(pixels, 0, m_width * m_height * sizeof(tile_colour));
 
     for (unsigned int i = 0; i < m_tiles.size(); i++)
     {

From 660c7b1fe8795f20d15be2144bb8e99796602fe5 Mon Sep 17 00:00:00 2001
From: "Nicholas J. Kain" <nicholas@kain.us>
Date: Mon, 6 Jul 2026 22:36:56 -0400
Subject: [PATCH 9/9] tile_colour: Correct copy assignment operator definition

There's two issues.  First, the returned reference from the
copy assignment operator must not be const.  Second, the
intention of the existing definition is to define a default
copy assignment operator, so just use that.
---
 crawl-ref/source/rltiles/tool/tile_colour.cc | 10 ----------
 crawl-ref/source/rltiles/tool/tile_colour.h  |  2 +-
 2 files changed, 1 insertion(+), 11 deletions(-)

diff --git a/crawl-ref/source/rltiles/tool/tile_colour.cc b/crawl-ref/source/rltiles/tool/tile_colour.cc
index e7f00c920914..c45664e8d20b 100644
--- a/crawl-ref/source/rltiles/tool/tile_colour.cc
+++ b/crawl-ref/source/rltiles/tool/tile_colour.cc
@@ -23,16 +23,6 @@ bool tile_colour::operator!=(const tile_colour &rhs) const
     return r != rhs.r || g != rhs.g || b != rhs.b || a != rhs.a;
 }
 
-const tile_colour &tile_colour::operator=(const tile_colour &rhs)
-{
-    r = rhs.r;
-    g = rhs.g;
-    b = rhs.b;
-    a = rhs.a;
-
-    return *this;
-}
-
 unsigned char &tile_colour::operator[](int idx)
 {
     assert(idx >= 0 && idx <= 4);
diff --git a/crawl-ref/source/rltiles/tool/tile_colour.h b/crawl-ref/source/rltiles/tool/tile_colour.h
index 99de2e07ac95..b498c4115517 100644
--- a/crawl-ref/source/rltiles/tool/tile_colour.h
+++ b/crawl-ref/source/rltiles/tool/tile_colour.h
@@ -34,7 +34,7 @@ class tile_colour
 
     bool operator==(const tile_colour &rhs) const;
     bool operator!=(const tile_colour &rhs) const;
-    const tile_colour &operator=(const tile_colour &rhs);
+    tile_colour &operator=(const tile_colour &rhs) = default;
 
     unsigned char &operator[](int idx);
     unsigned char operator[](int idx) const;