diff --git a/Makefile b/Makefile
index 0a807e65da..6176f3a7bf 100644
--- a/Makefile
+++ b/Makefile
@@ -142,12 +142,12 @@ iwyu: build/.ran-cmake
 	cmake --preset iwyu
 	cmake --build build > build/iwyu.log
 	iwyu-fix-includes --only_re="src/nvim" --ignore_re="(src/nvim/eval/encode.c|src/nvim/auto/|src/nvim/os/lang.c|src/nvim/map.c\
-	|src/nvim/api/private/helpers.h\
 	|src/nvim/api/private/validate.h\
 	|src/nvim/assert_defs.h\
 	|src/nvim/buffer.h\
 	|src/nvim/buffer_defs.h\
 	|src/nvim/channel.h\
+	|src/nvim/channel_defs.h\
 	|src/nvim/charset.h\
 	|src/nvim/drawline.h\
 	|src/nvim/eval.h\
@@ -158,7 +158,6 @@ iwyu: build/.ran-cmake
 	|src/nvim/eval/window.h\
 	|src/nvim/event/libuv_process.h\
 	|src/nvim/event/loop.h\
-	|src/nvim/event/multiqueue.h\
 	|src/nvim/event/process.h\
 	|src/nvim/event/rstream.h\
 	|src/nvim/event/signal.h\
@@ -174,8 +173,6 @@ iwyu: build/.ran-cmake
 	|src/nvim/keycodes.h\
 	|src/nvim/lua/executor.h\
 	|src/nvim/main.h\
-	|src/nvim/mark.h\
-	|src/nvim/msgpack_rpc/channel.h\
 	|src/nvim/msgpack_rpc/channel_defs.h\
 	|src/nvim/msgpack_rpc/helpers.h\
 	|src/nvim/msgpack_rpc/unpacker.h\
diff --git a/cmake.config/iwyu/mapping.imp b/cmake.config/iwyu/mapping.imp
index 4056070958..f4559d9ea9 100644
--- a/cmake.config/iwyu/mapping.imp
+++ b/cmake.config/iwyu/mapping.imp
@@ -23,7 +23,6 @@
   { symbol: [ "extern_proc", private, '<uv.h>', public ] },
   { symbol: [ "iovec", private, '<sys/uio.h>', public ] },
 
-  { include: [ '"keysets_defs.generated.h"', private, '"nvim/api/private/dispatch.h"', public ] },
   { include: [ '<uv/unix.h>', private, '<uv.h>', public ] },
 ]
 
diff --git a/src/clint.py b/src/clint.py
index 021d6b0a16..537406cd24 100755
--- a/src/clint.py
+++ b/src/clint.py
@@ -900,12 +900,12 @@ def CheckIncludes(filename, lines, error):
     # These should be synced with the ignored headers in the `iwyu` target in
     # the Makefile.
     check_includes_ignore = [
-            "src/nvim/api/private/helpers.h",
             "src/nvim/api/private/validate.h",
             "src/nvim/assert_defs.h",
             "src/nvim/buffer.h",
             "src/nvim/buffer_defs.h",
             "src/nvim/channel.h",
+            "src/nvim/channel_defs.h",
             "src/nvim/charset.h",
             "src/nvim/drawline.h",
             "src/nvim/eval.h",
@@ -916,7 +916,6 @@ def CheckIncludes(filename, lines, error):
             "src/nvim/eval/window.h",
             "src/nvim/event/libuv_process.h",
             "src/nvim/event/loop.h",
-            "src/nvim/event/multiqueue.h",
             "src/nvim/event/process.h",
             "src/nvim/event/rstream.h",
             "src/nvim/event/signal.h",
@@ -932,8 +931,6 @@ def CheckIncludes(filename, lines, error):
             "src/nvim/keycodes.h",
             "src/nvim/lua/executor.h",
             "src/nvim/main.h",
-            "src/nvim/mark.h",
-            "src/nvim/msgpack_rpc/channel.h",
             "src/nvim/msgpack_rpc/channel_defs.h",
             "src/nvim/msgpack_rpc/helpers.h",
             "src/nvim/msgpack_rpc/unpacker.h",
@@ -949,10 +946,12 @@ def CheckIncludes(filename, lines, error):
                              ]
 
     skip_headers = [
-            "klib/kvec.h",
-            "klib/klist.h",
             "auto/config.h",
-            "nvim/func_attr.h"
+            "klib/klist.h",
+            "klib/kvec.h",
+            "nvim/func_attr.h",
+            "nvim/gettext.h",
+            "nvim/globals.h"
             ]
 
     for i in check_includes_ignore:
diff --git a/src/nvim/api/options.c b/src/nvim/api/options.c
index a3ea7d9d47..ea617dffaf 100644
--- a/src/nvim/api/options.c
+++ b/src/nvim/api/options.c
@@ -15,7 +15,6 @@
 #include "nvim/macros_defs.h"
 #include "nvim/memory.h"
 #include "nvim/option.h"
-#include "nvim/option_vars.h"
 #include "nvim/vim_defs.h"
 #include "nvim/window.h"
 
diff --git a/src/nvim/api/private/dispatch.h b/src/nvim/api/private/dispatch.h
index 88f846f813..b627db6b00 100644
--- a/src/nvim/api/private/dispatch.h
+++ b/src/nvim/api/private/dispatch.h
@@ -27,5 +27,5 @@ extern const MsgpackRpcRequestHandler method_handlers[];
 #ifdef INCLUDE_GENERATED_DECLARATIONS
 # include "api/private/dispatch.h.generated.h"
 # include "api/private/dispatch_wrappers.h.generated.h"  // IWYU pragma: export
-# include "keysets_defs.generated.h"
+# include "keysets_defs.generated.h"  // IWYU pragma: export
 #endif
diff --git a/src/nvim/api/private/helpers.c b/src/nvim/api/private/helpers.c
index 2772fa8b59..70e63d0ad5 100644
--- a/src/nvim/api/private/helpers.c
+++ b/src/nvim/api/private/helpers.c
@@ -17,7 +17,6 @@
 #include "nvim/ascii_defs.h"
 #include "nvim/buffer_defs.h"
 #include "nvim/eval/typval.h"
-#include "nvim/eval/typval_defs.h"
 #include "nvim/eval/vars.h"
 #include "nvim/ex_eval.h"
 #include "nvim/garray.h"
diff --git a/src/nvim/api/private/helpers.h b/src/nvim/api/private/helpers.h
index e61dd5f992..64558f0410 100644
--- a/src/nvim/api/private/helpers.h
+++ b/src/nvim/api/private/helpers.h
@@ -2,21 +2,15 @@
 
 #include <stdbool.h>
 #include <stddef.h>
-#include <stdint.h>
 
 #include "klib/kvec.h"
 #include "nvim/api/private/defs.h"
-#include "nvim/api/private/dispatch.h"
-#include "nvim/decoration.h"
-#include "nvim/eval/typval_defs.h"
 #include "nvim/ex_eval_defs.h"
-#include "nvim/getchar.h"
 #include "nvim/gettext.h"
 #include "nvim/globals.h"
 #include "nvim/macros_defs.h"
 #include "nvim/map_defs.h"
-#include "nvim/memory.h"
-#include "nvim/message.h"
+#include "nvim/message_defs.h"  // IWYU pragma: keep
 
 #define OBJECT_OBJ(o) o
 
diff --git a/src/nvim/api/ui.c b/src/nvim/api/ui.c
index b73c026d57..678d23fbeb 100644
--- a/src/nvim/api/ui.c
+++ b/src/nvim/api/ui.c
@@ -15,7 +15,7 @@
 #include "nvim/autocmd.h"
 #include "nvim/channel.h"
 #include "nvim/eval.h"
-#include "nvim/event/loop.h"
+#include "nvim/event/defs.h"
 #include "nvim/event/wstream.h"
 #include "nvim/globals.h"
 #include "nvim/grid.h"
diff --git a/src/nvim/api/vim.c b/src/nvim/api/vim.c
index 91f908bb88..70e6b840de 100644
--- a/src/nvim/api/vim.c
+++ b/src/nvim/api/vim.c
@@ -54,6 +54,7 @@
 #include "nvim/option_vars.h"
 #include "nvim/optionstr.h"
 #include "nvim/os/input.h"
+#include "nvim/os/os_defs.h"
 #include "nvim/os/process.h"
 #include "nvim/popupmenu.h"
 #include "nvim/pos_defs.h"
diff --git a/src/nvim/arglist.c b/src/nvim/arglist.c
index 064543b430..8bc8edb572 100644
--- a/src/nvim/arglist.c
+++ b/src/nvim/arglist.c
@@ -13,7 +13,6 @@
 #include "nvim/charset.h"
 #include "nvim/cmdexpand_defs.h"
 #include "nvim/eval/typval.h"
-#include "nvim/eval/typval_defs.h"
 #include "nvim/eval/window.h"
 #include "nvim/ex_cmds.h"
 #include "nvim/ex_cmds2.h"
diff --git a/src/nvim/arglist.h b/src/nvim/arglist.h
index 97729f466c..d117f6163b 100644
--- a/src/nvim/arglist.h
+++ b/src/nvim/arglist.h
@@ -2,9 +2,7 @@
 
 #include "nvim/arglist_defs.h"  // IWYU pragma: export
 #include "nvim/cmdexpand_defs.h"  // IWYU pragma: keep
-#include "nvim/eval/typval_defs.h"  // IWYU pragma: keep
 #include "nvim/ex_cmds_defs.h"  // IWYU pragma: keep
-#include "nvim/types_defs.h"  // IWYU pragma: keep
 
 #ifdef INCLUDE_GENERATED_DECLARATIONS
 # include "arglist.h.generated.h"
diff --git a/src/nvim/autocmd.c b/src/nvim/autocmd.c
index 72b0852d8d..bfcf566fe3 100644
--- a/src/nvim/autocmd.c
+++ b/src/nvim/autocmd.c
@@ -19,7 +19,7 @@
 #include "nvim/eval/typval.h"
 #include "nvim/eval/userfunc.h"
 #include "nvim/eval/vars.h"
-#include "nvim/event/multiqueue.h"
+#include "nvim/event/defs.h"
 #include "nvim/ex_docmd.h"
 #include "nvim/ex_eval.h"
 #include "nvim/fileio.h"
diff --git a/src/nvim/buffer.c b/src/nvim/buffer.c
index 0392ff6ebd..75c6545c1d 100644
--- a/src/nvim/buffer.c
+++ b/src/nvim/buffer.c
@@ -39,7 +39,6 @@
 #include "nvim/charset.h"
 #include "nvim/cmdexpand.h"
 #include "nvim/cursor.h"
-#include "nvim/decoration.h"
 #include "nvim/diff.h"
 #include "nvim/digraph.h"
 #include "nvim/drawscreen.h"
diff --git a/src/nvim/bufwrite.c b/src/nvim/bufwrite.c
index 06bd05b11d..f8df273375 100644
--- a/src/nvim/bufwrite.c
+++ b/src/nvim/bufwrite.c
@@ -37,6 +37,7 @@
 #include "nvim/option_vars.h"
 #include "nvim/os/fs.h"
 #include "nvim/os/input.h"
+#include "nvim/os/os_defs.h"
 #include "nvim/path.h"
 #include "nvim/pos_defs.h"
 #include "nvim/sha256.h"
diff --git a/src/nvim/channel.c b/src/nvim/channel.c
index fb4711f7d9..42935933e0 100644
--- a/src/nvim/channel.c
+++ b/src/nvim/channel.c
@@ -15,8 +15,10 @@
 #include "nvim/eval.h"
 #include "nvim/eval/encode.h"
 #include "nvim/eval/typval.h"
+#include "nvim/event/multiqueue.h"
 #include "nvim/event/rstream.h"
 #include "nvim/event/socket.h"
+#include "nvim/event/stream.h"
 #include "nvim/event/wstream.h"
 #include "nvim/garray.h"
 #include "nvim/gettext.h"
@@ -32,6 +34,7 @@
 #include "nvim/os/shell.h"
 #include "nvim/path.h"
 #include "nvim/rbuffer.h"
+#include "nvim/types_defs.h"
 
 #ifdef MSWIN
 # include "nvim/os/fs.h"
diff --git a/src/nvim/channel.h b/src/nvim/channel.h
index 6deea08c83..2b6356b216 100644
--- a/src/nvim/channel.h
+++ b/src/nvim/channel.h
@@ -4,6 +4,7 @@
 #include <stdint.h>
 #include <stdlib.h>
 
+#include "nvim/channel_defs.h"  // IWYU pragma: export
 #include "nvim/eval/typval_defs.h"
 #include "nvim/event/libuv_process.h"
 #include "nvim/event/multiqueue.h"
@@ -19,60 +20,6 @@
 #include "nvim/terminal.h"
 #include "nvim/types_defs.h"
 
-#define CHAN_STDIO 1
-#define CHAN_STDERR 2
-
-typedef enum {
-  kChannelStreamProc,
-  kChannelStreamSocket,
-  kChannelStreamStdio,
-  kChannelStreamStderr,
-  kChannelStreamInternal,
-} ChannelStreamType;
-
-typedef enum {
-  kChannelPartStdin,
-  kChannelPartStdout,
-  kChannelPartStderr,
-  kChannelPartRpc,
-  kChannelPartAll,
-} ChannelPart;
-
-typedef enum {
-  kChannelStdinPipe,
-  kChannelStdinNull,
-} ChannelStdinMode;
-
-typedef struct {
-  Stream in;
-  Stream out;
-} StdioPair;
-
-typedef struct {
-  bool closed;
-} StderrState;
-
-typedef struct {
-  LuaRef cb;
-  bool closed;
-} InternalState;
-
-typedef struct {
-  Callback cb;
-  dict_T *self;
-  garray_T buffer;
-  bool eof;
-  bool buffered;
-  bool fwd_err;
-  const char *type;
-} CallbackReader;
-
-#define CALLBACK_READER_INIT ((CallbackReader){ .cb = CALLBACK_NONE, \
-                                                .self = NULL, \
-                                                .buffer = GA_EMPTY_INIT_VALUE, \
-                                                .buffered = false, \
-                                                .fwd_err = false, \
-                                                .type = NULL })
 static inline bool callback_reader_set(CallbackReader reader)
 {
   return reader.cb.type != kCallbackNone || reader.self;
diff --git a/src/nvim/channel_defs.h b/src/nvim/channel_defs.h
new file mode 100644
index 0000000000..1af4c2de59
--- /dev/null
+++ b/src/nvim/channel_defs.h
@@ -0,0 +1,74 @@
+#pragma once
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+#include "nvim/eval/typval_defs.h"
+#include "nvim/event/libuv_process.h"
+#include "nvim/event/multiqueue.h"
+#include "nvim/event/process.h"
+#include "nvim/event/socket.h"
+#include "nvim/event/stream.h"
+#include "nvim/garray_defs.h"
+#include "nvim/macros_defs.h"
+#include "nvim/main.h"
+#include "nvim/map_defs.h"
+#include "nvim/msgpack_rpc/channel_defs.h"
+#include "nvim/os/pty_process.h"
+#include "nvim/terminal.h"
+#include "nvim/types_defs.h"
+
+#define CHAN_STDIO 1
+#define CHAN_STDERR 2
+
+typedef enum {
+  kChannelStreamProc,
+  kChannelStreamSocket,
+  kChannelStreamStdio,
+  kChannelStreamStderr,
+  kChannelStreamInternal,
+} ChannelStreamType;
+
+typedef enum {
+  kChannelPartStdin,
+  kChannelPartStdout,
+  kChannelPartStderr,
+  kChannelPartRpc,
+  kChannelPartAll,
+} ChannelPart;
+
+typedef enum {
+  kChannelStdinPipe,
+  kChannelStdinNull,
+} ChannelStdinMode;
+
+typedef struct {
+  Stream in;
+  Stream out;
+} StdioPair;
+
+typedef struct {
+  bool closed;
+} StderrState;
+
+typedef struct {
+  LuaRef cb;
+  bool closed;
+} InternalState;
+
+typedef struct {
+  Callback cb;
+  dict_T *self;
+  garray_T buffer;
+  bool eof;
+  bool buffered;
+  bool fwd_err;
+  const char *type;
+} CallbackReader;
+
+#define CALLBACK_READER_INIT ((CallbackReader){ .cb = CALLBACK_NONE, \
+                                                .self = NULL, \
+                                                .buffer = GA_EMPTY_INIT_VALUE, \
+                                                .buffered = false, \
+                                                .fwd_err = false, \
+                                                .type = NULL })
diff --git a/src/nvim/decoration.c b/src/nvim/decoration.c
index 74056b7c26..b3fad78f84 100644
--- a/src/nvim/decoration.c
+++ b/src/nvim/decoration.c
@@ -6,7 +6,6 @@
 #include "nvim/api/extmark.h"
 #include "nvim/api/private/defs.h"
 #include "nvim/api/private/helpers.h"
-#include "nvim/buffer.h"
 #include "nvim/decoration.h"
 #include "nvim/drawscreen.h"
 #include "nvim/extmark.h"
@@ -14,6 +13,7 @@
 #include "nvim/grid.h"
 #include "nvim/highlight.h"
 #include "nvim/highlight_group.h"
+#include "nvim/map_defs.h"
 #include "nvim/marktree.h"
 #include "nvim/memory.h"
 #include "nvim/move.h"
diff --git a/src/nvim/drawscreen.c b/src/nvim/drawscreen.c
index 314764d117..09a0a43e2f 100644
--- a/src/nvim/drawscreen.c
+++ b/src/nvim/drawscreen.c
@@ -91,6 +91,7 @@
 #include "nvim/normal.h"
 #include "nvim/option.h"
 #include "nvim/option_vars.h"
+#include "nvim/os/os_defs.h"
 #include "nvim/plines.h"
 #include "nvim/popupmenu.h"
 #include "nvim/pos_defs.h"
diff --git a/src/nvim/eval.c b/src/nvim/eval.c
index 11c6034cc8..d8134c2360 100644
--- a/src/nvim/eval.c
+++ b/src/nvim/eval.c
@@ -32,6 +32,7 @@
 #include "nvim/eval/vars.h"
 #include "nvim/event/multiqueue.h"
 #include "nvim/event/process.h"
+#include "nvim/event/time.h"
 #include "nvim/ex_cmds.h"
 #include "nvim/ex_docmd.h"
 #include "nvim/ex_eval.h"
diff --git a/src/nvim/eval/funcs.c b/src/nvim/eval/funcs.c
index 1468c5564e..ea68c010d6 100644
--- a/src/nvim/eval/funcs.c
+++ b/src/nvim/eval/funcs.c
@@ -48,6 +48,7 @@
 #include "nvim/eval/userfunc.h"
 #include "nvim/eval/vars.h"
 #include "nvim/eval/window.h"
+#include "nvim/event/defs.h"
 #include "nvim/event/loop.h"
 #include "nvim/event/multiqueue.h"
 #include "nvim/event/process.h"
diff --git a/src/nvim/eval/gc.h b/src/nvim/eval/gc.h
index 36149ec060..ea91952fff 100644
--- a/src/nvim/eval/gc.h
+++ b/src/nvim/eval/gc.h
@@ -6,5 +6,5 @@ extern dict_T *gc_first_dict;
 extern list_T *gc_first_list;
 
 #ifdef INCLUDE_GENERATED_DECLARATIONS
-# include "eval/gc.h.generated.h"  // IWYU pragma: export
+# include "eval/gc.h.generated.h"
 #endif
diff --git a/src/nvim/event/defs.h b/src/nvim/event/defs.h
index 56e00171e2..ffea388b9b 100644
--- a/src/nvim/event/defs.h
+++ b/src/nvim/event/defs.h
@@ -2,6 +2,10 @@
 
 #include <assert.h>
 #include <stdarg.h>
+#include <stdbool.h>
+#include <uv.h>
+
+#include "nvim/rbuffer_defs.h"
 
 enum { EVENT_HANDLER_MAX_ARGC = 10, };
 
@@ -12,3 +16,165 @@ typedef struct {
 } Event;
 
 #define event_create(cb, ...) ((Event){ .handler = cb, .argv = { __VA_ARGS__ } })
+
+typedef struct multiqueue MultiQueue;
+typedef void (*PutCallback)(MultiQueue *multiq, void *data);
+
+#define multiqueue_put(q, h, ...) \
+  do { \
+    multiqueue_put_event(q, event_create(h, __VA_ARGS__)); \
+  } while (0)
+
+#define CREATE_EVENT(multiqueue, handler, ...) \
+  do { \
+    if (multiqueue) { \
+      multiqueue_put((multiqueue), (handler), __VA_ARGS__); \
+    } else { \
+      void *argv[] = { __VA_ARGS__ }; \
+      (handler)(argv); \
+    } \
+  } while (0)
+
+// Poll for events until a condition or timeout
+#define LOOP_PROCESS_EVENTS_UNTIL(loop, multiqueue, timeout, condition) \
+  do { \
+    int64_t remaining = timeout; \
+    uint64_t before = (remaining > 0) ? os_hrtime() : 0; \
+    while (!(condition)) { \
+      LOOP_PROCESS_EVENTS(loop, multiqueue, remaining); \
+      if (remaining == 0) { \
+        break; \
+      } else if (remaining > 0) { \
+        uint64_t now = os_hrtime(); \
+        remaining -= (int64_t)((now - before) / 1000000); \
+        before = now; \
+        if (remaining <= 0) { \
+          break; \
+        } \
+      } \
+    } \
+  } while (0)
+
+#define LOOP_PROCESS_EVENTS(loop, multiqueue, timeout) \
+  do { \
+    if (multiqueue && !multiqueue_empty(multiqueue)) { \
+      multiqueue_process_events(multiqueue); \
+    } else { \
+      loop_poll_events(loop, timeout); \
+    } \
+  } while (0)
+
+struct signal_watcher;
+
+typedef struct signal_watcher SignalWatcher;
+typedef void (*signal_cb)(SignalWatcher *watcher, int signum, void *data);
+typedef void (*signal_close_cb)(SignalWatcher *watcher, void *data);
+
+struct signal_watcher {
+  uv_signal_t uv;
+  void *data;
+  signal_cb cb;
+  signal_close_cb close_cb;
+  MultiQueue *events;
+};
+
+struct time_watcher;
+
+typedef struct time_watcher TimeWatcher;
+typedef void (*time_cb)(TimeWatcher *watcher, void *data);
+
+struct time_watcher {
+  uv_timer_t uv;
+  void *data;
+  time_cb cb, close_cb;
+  MultiQueue *events;
+  bool blockable;
+};
+
+struct wbuffer;
+
+typedef struct wbuffer WBuffer;
+typedef void (*wbuffer_data_finalizer)(void *data);
+
+struct wbuffer {
+  size_t size, refcount;
+  char *data;
+  wbuffer_data_finalizer cb;
+};
+
+struct stream;
+
+typedef struct stream Stream;
+/// Type of function called when the Stream buffer is filled with data
+///
+/// @param stream The Stream instance
+/// @param buf The associated RBuffer instance
+/// @param count Number of bytes that was read.
+/// @param data User-defined data
+/// @param eof If the stream reached EOF.
+typedef void (*stream_read_cb)(Stream *stream, RBuffer *buf, size_t count, void *data, bool eof);
+
+/// Type of function called when the Stream has information about a write
+/// request.
+///
+/// @param stream The Stream instance
+/// @param data User-defined data
+/// @param status 0 on success, anything else indicates failure
+typedef void (*stream_write_cb)(Stream *stream, void *data, int status);
+typedef void (*stream_close_cb)(Stream *stream, void *data);
+
+struct stream {
+  bool closed;
+  bool did_eof;
+  union {
+    uv_pipe_t pipe;
+    uv_tcp_t tcp;
+    uv_idle_t idle;
+#ifdef MSWIN
+    uv_tty_t tty;
+#endif
+  } uv;
+  uv_stream_t *uvstream;
+  uv_buf_t uvbuf;
+  RBuffer *buffer;
+  uv_file fd;
+  stream_read_cb read_cb;
+  stream_write_cb write_cb;
+  void *cb_data;
+  stream_close_cb close_cb, internal_close_cb;
+  void *close_cb_data, *internal_data;
+  size_t fpos;
+  size_t curmem;
+  size_t maxmem;
+  size_t pending_reqs;
+  size_t num_bytes;
+  MultiQueue *events;
+};
+
+struct socket_watcher;
+
+#define ADDRESS_MAX_SIZE 256
+
+typedef struct socket_watcher SocketWatcher;
+typedef void (*socket_cb)(SocketWatcher *watcher, int result, void *data);
+typedef void (*socket_close_cb)(SocketWatcher *watcher, void *data);
+
+struct socket_watcher {
+  // Pipe/socket path, or TCP address string
+  char addr[ADDRESS_MAX_SIZE];
+  // TCP server or unix socket (named pipe on Windows)
+  union {
+    struct {
+      uv_tcp_t handle;
+      struct addrinfo *addrinfo;
+    } tcp;
+    struct {
+      uv_pipe_t handle;
+    } pipe;
+  } uv;
+  uv_stream_t *stream;
+  void *data;
+  socket_cb cb;
+  socket_close_cb close_cb;
+  MultiQueue *events;
+};
diff --git a/src/nvim/event/libuv_process.c b/src/nvim/event/libuv_process.c
index 8264adb1fc..07c059423a 100644
--- a/src/nvim/event/libuv_process.c
+++ b/src/nvim/event/libuv_process.c
@@ -4,9 +4,9 @@
 #include <uv.h>
 
 #include "nvim/eval/typval.h"
+#include "nvim/event/defs.h"
 #include "nvim/event/libuv_process.h"
 #include "nvim/event/process.h"
-#include "nvim/event/stream.h"
 #include "nvim/log.h"
 #include "nvim/os/os.h"
 #include "nvim/ui_client.h"
diff --git a/src/nvim/event/loop.c b/src/nvim/event/loop.c
index 697bdb7aa8..a2cb72771c 100644
--- a/src/nvim/event/loop.c
+++ b/src/nvim/event/loop.c
@@ -5,6 +5,7 @@
 
 #include "nvim/event/defs.h"
 #include "nvim/event/loop.h"
+#include "nvim/event/multiqueue.h"
 #include "nvim/log.h"
 #include "nvim/memory.h"
 #include "nvim/os/time.h"
diff --git a/src/nvim/event/loop.h b/src/nvim/event/loop.h
index 442a159631..b567df5456 100644
--- a/src/nvim/event/loop.h
+++ b/src/nvim/event/loop.h
@@ -44,45 +44,6 @@ typedef struct loop {
   bool closing;  ///< Set to true if loop_close() has been called
 } Loop;
 
-#define CREATE_EVENT(multiqueue, handler, ...) \
-  do { \
-    if (multiqueue) { \
-      multiqueue_put((multiqueue), (handler), __VA_ARGS__); \
-    } else { \
-      void *argv[] = { __VA_ARGS__ }; \
-      (handler)(argv); \
-    } \
-  } while (0)
-
-// Poll for events until a condition or timeout
-#define LOOP_PROCESS_EVENTS_UNTIL(loop, multiqueue, timeout, condition) \
-  do { \
-    int64_t remaining = timeout; \
-    uint64_t before = (remaining > 0) ? os_hrtime() : 0; \
-    while (!(condition)) { \
-      LOOP_PROCESS_EVENTS(loop, multiqueue, remaining); \
-      if (remaining == 0) { \
-        break; \
-      } else if (remaining > 0) { \
-        uint64_t now = os_hrtime(); \
-        remaining -= (int64_t)((now - before) / 1000000); \
-        before = now; \
-        if (remaining <= 0) { \
-          break; \
-        } \
-      } \
-    } \
-  } while (0)
-
-#define LOOP_PROCESS_EVENTS(loop, multiqueue, timeout) \
-  do { \
-    if (multiqueue && !multiqueue_empty(multiqueue)) { \
-      multiqueue_process_events(multiqueue); \
-    } else { \
-      loop_poll_events(loop, timeout); \
-    } \
-  } while (0)
-
 #ifdef INCLUDE_GENERATED_DECLARATIONS
 # include "event/loop.h.generated.h"
 #endif
diff --git a/src/nvim/event/multiqueue.h b/src/nvim/event/multiqueue.h
index 7de307f77e..26e3bc1c30 100644
--- a/src/nvim/event/multiqueue.h
+++ b/src/nvim/event/multiqueue.h
@@ -1,17 +1,8 @@
 #pragma once
 
-#include <uv.h>
+#include <stddef.h>  // IWYU pragma: keep
 
-#include "nvim/event/defs.h"
-#include "nvim/lib/queue.h"
-
-typedef struct multiqueue MultiQueue;
-typedef void (*PutCallback)(MultiQueue *multiq, void *data);
-
-#define multiqueue_put(q, h, ...) \
-  do { \
-    multiqueue_put_event(q, event_create(h, __VA_ARGS__)); \
-  } while (0)
+#include "nvim/event/defs.h"  // IWYU pragma: keep
 
 #ifdef INCLUDE_GENERATED_DECLARATIONS
 # include "event/multiqueue.h.generated.h"
diff --git a/src/nvim/event/process.c b/src/nvim/event/process.c
index ac9c4973ce..3d9578936c 100644
--- a/src/nvim/event/process.c
+++ b/src/nvim/event/process.c
@@ -6,7 +6,9 @@
 #include "klib/klist.h"
 #include "nvim/event/libuv_process.h"
 #include "nvim/event/loop.h"
+#include "nvim/event/multiqueue.h"
 #include "nvim/event/process.h"
+#include "nvim/event/stream.h"
 #include "nvim/globals.h"
 #include "nvim/log.h"
 #include "nvim/main.h"
diff --git a/src/nvim/event/rstream.c b/src/nvim/event/rstream.c
index 130c080db5..df97b592e4 100644
--- a/src/nvim/event/rstream.c
+++ b/src/nvim/event/rstream.c
@@ -5,6 +5,7 @@
 #include <sys/types.h>
 #include <uv.h>
 
+#include "nvim/event/defs.h"
 #include "nvim/event/loop.h"
 #include "nvim/event/rstream.h"
 #include "nvim/event/stream.h"
diff --git a/src/nvim/event/signal.c b/src/nvim/event/signal.c
index 2d6cccf53a..3a100812cf 100644
--- a/src/nvim/event/signal.c
+++ b/src/nvim/event/signal.c
@@ -1,6 +1,7 @@
 #include <stddef.h>
 #include <uv.h>
 
+#include "nvim/event/defs.h"
 #include "nvim/event/loop.h"
 #include "nvim/event/signal.h"
 
diff --git a/src/nvim/event/signal.h b/src/nvim/event/signal.h
index 946de1b4f0..711797ca71 100644
--- a/src/nvim/event/signal.h
+++ b/src/nvim/event/signal.h
@@ -2,23 +2,10 @@
 
 #include <uv.h>
 
+#include "nvim/event/defs.h"
 #include "nvim/event/loop.h"
 #include "nvim/event/multiqueue.h"
 
-struct signal_watcher;
-
-typedef struct signal_watcher SignalWatcher;
-typedef void (*signal_cb)(SignalWatcher *watcher, int signum, void *data);
-typedef void (*signal_close_cb)(SignalWatcher *watcher, void *data);
-
-struct signal_watcher {
-  uv_signal_t uv;
-  void *data;
-  signal_cb cb;
-  signal_close_cb close_cb;
-  MultiQueue *events;
-};
-
 #ifdef INCLUDE_GENERATED_DECLARATIONS
 # include "event/signal.h.generated.h"
 #endif
diff --git a/src/nvim/event/socket.c b/src/nvim/event/socket.c
index cde53a00e1..3c7b98bfe7 100644
--- a/src/nvim/event/socket.c
+++ b/src/nvim/event/socket.c
@@ -7,6 +7,7 @@
 
 #include "nvim/ascii_defs.h"
 #include "nvim/charset.h"
+#include "nvim/event/defs.h"
 #include "nvim/event/loop.h"
 #include "nvim/event/socket.h"
 #include "nvim/event/stream.h"
diff --git a/src/nvim/event/socket.h b/src/nvim/event/socket.h
index 504af3c7a8..24ba361efa 100644
--- a/src/nvim/event/socket.h
+++ b/src/nvim/event/socket.h
@@ -2,39 +2,12 @@
 
 #include <uv.h>
 
+#include "nvim/event/defs.h"
 #include "nvim/event/loop.h"
 #include "nvim/event/multiqueue.h"
 #include "nvim/event/rstream.h"
 #include "nvim/event/wstream.h"
 
-struct socket_watcher;
-
-#define ADDRESS_MAX_SIZE 256
-
-typedef struct socket_watcher SocketWatcher;
-typedef void (*socket_cb)(SocketWatcher *watcher, int result, void *data);
-typedef void (*socket_close_cb)(SocketWatcher *watcher, void *data);
-
-struct socket_watcher {
-  // Pipe/socket path, or TCP address string
-  char addr[ADDRESS_MAX_SIZE];
-  // TCP server or unix socket (named pipe on Windows)
-  union {
-    struct {
-      uv_tcp_t handle;
-      struct addrinfo *addrinfo;
-    } tcp;
-    struct {
-      uv_pipe_t handle;
-    } pipe;
-  } uv;
-  uv_stream_t *stream;
-  void *data;
-  socket_cb cb;
-  socket_close_cb close_cb;
-  MultiQueue *events;
-};
-
 #ifdef INCLUDE_GENERATED_DECLARATIONS
 # include "event/socket.h.generated.h"
 #endif
diff --git a/src/nvim/event/stream.c b/src/nvim/event/stream.c
index 8baecbbb31..886e93931b 100644
--- a/src/nvim/event/stream.c
+++ b/src/nvim/event/stream.c
@@ -4,6 +4,7 @@
 #include <uv.h>
 #include <uv/version.h>
 
+#include "nvim/event/defs.h"
 #include "nvim/event/loop.h"
 #include "nvim/event/stream.h"
 #include "nvim/log.h"
diff --git a/src/nvim/event/stream.h b/src/nvim/event/stream.h
index ab694e2247..588aab12b0 100644
--- a/src/nvim/event/stream.h
+++ b/src/nvim/event/stream.h
@@ -4,59 +4,11 @@
 #include <stddef.h>
 #include <uv.h>
 
+#include "nvim/event/defs.h"
 #include "nvim/event/loop.h"
 #include "nvim/event/multiqueue.h"
 #include "nvim/rbuffer_defs.h"
 
-struct stream;
-
-typedef struct stream Stream;
-/// Type of function called when the Stream buffer is filled with data
-///
-/// @param stream The Stream instance
-/// @param buf The associated RBuffer instance
-/// @param count Number of bytes that was read.
-/// @param data User-defined data
-/// @param eof If the stream reached EOF.
-typedef void (*stream_read_cb)(Stream *stream, RBuffer *buf, size_t count, void *data, bool eof);
-
-/// Type of function called when the Stream has information about a write
-/// request.
-///
-/// @param stream The Stream instance
-/// @param data User-defined data
-/// @param status 0 on success, anything else indicates failure
-typedef void (*stream_write_cb)(Stream *stream, void *data, int status);
-typedef void (*stream_close_cb)(Stream *stream, void *data);
-
-struct stream {
-  bool closed;
-  bool did_eof;
-  union {
-    uv_pipe_t pipe;
-    uv_tcp_t tcp;
-    uv_idle_t idle;
-#ifdef MSWIN
-    uv_tty_t tty;
-#endif
-  } uv;
-  uv_stream_t *uvstream;
-  uv_buf_t uvbuf;
-  RBuffer *buffer;
-  uv_file fd;
-  stream_read_cb read_cb;
-  stream_write_cb write_cb;
-  void *cb_data;
-  stream_close_cb close_cb, internal_close_cb;
-  void *close_cb_data, *internal_data;
-  size_t fpos;
-  size_t curmem;
-  size_t maxmem;
-  size_t pending_reqs;
-  size_t num_bytes;
-  MultiQueue *events;
-};
-
 #ifdef INCLUDE_GENERATED_DECLARATIONS
 # include "event/stream.h.generated.h"
 #endif
diff --git a/src/nvim/event/time.c b/src/nvim/event/time.c
index 7206d74176..de837fd278 100644
--- a/src/nvim/event/time.c
+++ b/src/nvim/event/time.c
@@ -1,7 +1,10 @@
+#include <stdbool.h>
 #include <stdint.h>
 #include <uv.h>
 
+#include "nvim/event/defs.h"
 #include "nvim/event/loop.h"
+#include "nvim/event/multiqueue.h"
 #include "nvim/event/time.h"
 
 #ifdef INCLUDE_GENERATED_DECLARATIONS
diff --git a/src/nvim/event/time.h b/src/nvim/event/time.h
index 3514566901..85171f315a 100644
--- a/src/nvim/event/time.h
+++ b/src/nvim/event/time.h
@@ -3,22 +3,10 @@
 #include <stdbool.h>
 #include <uv.h>
 
+#include "nvim/event/defs.h"
 #include "nvim/event/loop.h"
 #include "nvim/event/multiqueue.h"
 
-struct time_watcher;
-
-typedef struct time_watcher TimeWatcher;
-typedef void (*time_cb)(TimeWatcher *watcher, void *data);
-
-struct time_watcher {
-  uv_timer_t uv;
-  void *data;
-  time_cb cb, close_cb;
-  MultiQueue *events;
-  bool blockable;
-};
-
 #ifdef INCLUDE_GENERATED_DECLARATIONS
 # include "event/time.h.generated.h"
 #endif
diff --git a/src/nvim/event/wstream.c b/src/nvim/event/wstream.c
index 239f64c013..70cc5b6547 100644
--- a/src/nvim/event/wstream.c
+++ b/src/nvim/event/wstream.c
@@ -1,7 +1,9 @@
 #include <assert.h>
 #include <stdbool.h>
+#include <stddef.h>
 #include <uv.h>
 
+#include "nvim/event/defs.h"
 #include "nvim/event/loop.h"
 #include "nvim/event/stream.h"
 #include "nvim/event/wstream.h"
diff --git a/src/nvim/event/wstream.h b/src/nvim/event/wstream.h
index 4cba7bde8f..d61ab644f4 100644
--- a/src/nvim/event/wstream.h
+++ b/src/nvim/event/wstream.h
@@ -5,20 +5,10 @@
 #include <stdint.h>
 #include <uv.h>
 
+#include "nvim/event/defs.h"
 #include "nvim/event/loop.h"
 #include "nvim/event/stream.h"
 
-struct wbuffer;
-
-typedef struct wbuffer WBuffer;
-typedef void (*wbuffer_data_finalizer)(void *data);
-
-struct wbuffer {
-  size_t size, refcount;
-  char *data;
-  wbuffer_data_finalizer cb;
-};
-
 #ifdef INCLUDE_GENERATED_DECLARATIONS
 # include "event/wstream.h.generated.h"
 #endif
diff --git a/src/nvim/ex_cmds.c b/src/nvim/ex_cmds.c
index 786612070e..96429c96f7 100644
--- a/src/nvim/ex_cmds.c
+++ b/src/nvim/ex_cmds.c
@@ -19,7 +19,6 @@
 #include "nvim/ascii_defs.h"
 #include "nvim/autocmd.h"
 #include "nvim/buffer.h"
-#include "nvim/buffer_defs.h"
 #include "nvim/buffer_updates.h"
 #include "nvim/bufwrite.h"
 #include "nvim/change.h"
diff --git a/src/nvim/ex_cmds.h b/src/nvim/ex_cmds.h
index 011d42c6d9..2f576731f4 100644
--- a/src/nvim/ex_cmds.h
+++ b/src/nvim/ex_cmds.h
@@ -1,35 +1,6 @@
 #pragma once
 
-#include "nvim/buffer_defs.h"  // IWYU pragma: keep
-#include "nvim/eval/typval_defs.h"
 #include "nvim/ex_cmds_defs.h"  // IWYU pragma: export
-#include "nvim/os/time_defs.h"
-#include "nvim/pos_defs.h"  // IWYU pragma: keep
-
-/// flags for do_ecmd()
-enum {
-  ECMD_HIDE       = 0x01,  ///< don't free the current buffer
-  ECMD_SET_HELP   = 0x02,  ///< set b_help flag of (new) buffer before opening file
-  ECMD_OLDBUF     = 0x04,  ///< use existing buffer if it exists
-  ECMD_FORCEIT    = 0x08,  ///< ! used in Ex command
-  ECMD_ADDBUF     = 0x10,  ///< don't edit, just add to buffer list
-  ECMD_ALTBUF     = 0x20,  ///< like ECMD_ADDBUF and set the alternate file
-  ECMD_NOWINENTER = 0x40,  ///< do not trigger BufWinEnter
-};
-
-/// for lnum argument in do_ecmd()
-enum {
-  ECMD_LASTL = 0,   ///< use last position in loaded file
-  ECMD_LAST  = -1,  ///< use last position in all files
-  ECMD_ONE   = 1,   ///< use first line
-};
-
-/// Previous :substitute replacement string definition
-typedef struct {
-  char *sub;            ///< Previous replacement string.
-  Timestamp timestamp;  ///< Time when it was last set.
-  list_T *additional_elements;  ///< Additional data left from ShaDa file.
-} SubReplacementString;
 
 #ifdef INCLUDE_GENERATED_DECLARATIONS
 # include "ex_cmds.h.generated.h"
diff --git a/src/nvim/ex_cmds_defs.h b/src/nvim/ex_cmds_defs.h
index 00363884ec..5ece6db8e9 100644
--- a/src/nvim/ex_cmds_defs.h
+++ b/src/nvim/ex_cmds_defs.h
@@ -229,3 +229,28 @@ typedef struct {
     bool bar;
   } magic;
 } CmdParseInfo;
+
+/// flags for do_ecmd()
+enum {
+  ECMD_HIDE       = 0x01,  ///< don't free the current buffer
+  ECMD_SET_HELP   = 0x02,  ///< set b_help flag of (new) buffer before opening file
+  ECMD_OLDBUF     = 0x04,  ///< use existing buffer if it exists
+  ECMD_FORCEIT    = 0x08,  ///< ! used in Ex command
+  ECMD_ADDBUF     = 0x10,  ///< don't edit, just add to buffer list
+  ECMD_ALTBUF     = 0x20,  ///< like ECMD_ADDBUF and set the alternate file
+  ECMD_NOWINENTER = 0x40,  ///< do not trigger BufWinEnter
+};
+
+/// for lnum argument in do_ecmd()
+enum {
+  ECMD_LASTL = 0,   ///< use last position in loaded file
+  ECMD_LAST  = -1,  ///< use last position in all files
+  ECMD_ONE   = 1,   ///< use first line
+};
+
+/// Previous :substitute replacement string definition
+typedef struct {
+  char *sub;            ///< Previous replacement string.
+  Timestamp timestamp;  ///< Time when it was last set.
+  list_T *additional_elements;  ///< Additional data left from ShaDa file.
+} SubReplacementString;
diff --git a/src/nvim/ex_docmd.c b/src/nvim/ex_docmd.c
index ff80ee9e54..d8e2c54efa 100644
--- a/src/nvim/ex_docmd.c
+++ b/src/nvim/ex_docmd.c
@@ -29,7 +29,7 @@
 #include "nvim/eval.h"
 #include "nvim/eval/typval.h"
 #include "nvim/eval/userfunc.h"
-#include "nvim/event/loop.h"
+#include "nvim/event/defs.h"
 #include "nvim/ex_cmds.h"
 #include "nvim/ex_cmds2.h"
 #include "nvim/ex_cmds_defs.h"
diff --git a/src/nvim/extmark.h b/src/nvim/extmark.h
index 5ba079bd12..e83c8d1257 100644
--- a/src/nvim/extmark.h
+++ b/src/nvim/extmark.h
@@ -5,10 +5,9 @@
 
 #include "klib/kvec.h"
 #include "nvim/buffer_defs.h"  // IWYU pragma: keep
-#include "nvim/decoration_defs.h"  // IWYU pragma: keep
 #include "nvim/extmark_defs.h"  // IWYU pragma: export
 #include "nvim/macros_defs.h"
-#include "nvim/marktree_defs.h"  // IWYU pragma: keep
+#include "nvim/marktree_defs.h"
 #include "nvim/pos_defs.h"
 
 EXTERN int curbuf_splice_pending INIT( = 0);
diff --git a/src/nvim/input.c b/src/nvim/input.c
index fb25968071..a2a9692cb4 100644
--- a/src/nvim/input.c
+++ b/src/nvim/input.c
@@ -7,7 +7,7 @@
 #include <string.h>
 
 #include "nvim/ascii_defs.h"
-#include "nvim/event/multiqueue.h"
+#include "nvim/event/defs.h"
 #include "nvim/getchar.h"
 #include "nvim/gettext.h"
 #include "nvim/globals.h"
diff --git a/src/nvim/log.h b/src/nvim/log.h
index b277e09a0f..0a9a86c905 100644
--- a/src/nvim/log.h
+++ b/src/nvim/log.h
@@ -1,50 +1,18 @@
 #pragma once
 
-#include <stdbool.h>
-#include <stdio.h>
-
-#include "auto/config.h"
+#include "nvim/log_defs.h"  // IWYU pragma: export
 #include "nvim/macros_defs.h"
 
 // USDT probes. Example invocation:
 //     NVIM_PROBE(nvim_foo_bar, 1, string.data);
 #if defined(HAVE_SYS_SDT_H)
-# include <sys/sdt.h>  // NOLINT
+# include <sys/sdt.h>  // IWYU pragma: keep
 
 # define NVIM_PROBE(name, n, ...) STAP_PROBE##n(neovim, name, __VA_ARGS__)
 #else
 # define NVIM_PROBE(name, n, ...)
 #endif
 
-#define LOGLVL_DBG 1
-#define LOGLVL_INF 2
-#define LOGLVL_WRN 3
-#define LOGLVL_ERR 4
-
-#define LOG(level, ...) logmsg((level), NULL, __func__, __LINE__, true, __VA_ARGS__)
-
-#ifdef NVIM_LOG_DEBUG
-# define DLOG(...) logmsg(LOGLVL_DBG, NULL, __func__, __LINE__, true, __VA_ARGS__)
-# define DLOGN(...) logmsg(LOGLVL_DBG, NULL, __func__, __LINE__, false, __VA_ARGS__)
-# define ILOG(...) logmsg(LOGLVL_INF, NULL, __func__, __LINE__, true, __VA_ARGS__)
-# define ILOGN(...) logmsg(LOGLVL_INF, NULL, __func__, __LINE__, false, __VA_ARGS__)
-#else
-# define DLOG(...)
-# define DLOGN(...)
-# define ILOG(...)
-# define ILOGN(...)
-#endif
-
-#define WLOG(...) logmsg(LOGLVL_WRN, NULL, __func__, __LINE__, true, __VA_ARGS__)
-#define WLOGN(...) logmsg(LOGLVL_WRN, NULL, __func__, __LINE__, false, __VA_ARGS__)
-#define ELOG(...) logmsg(LOGLVL_ERR, NULL, __func__, __LINE__, true, __VA_ARGS__)
-#define ELOGN(...) logmsg(LOGLVL_ERR, NULL, __func__, __LINE__, false, __VA_ARGS__)
-
-#ifdef HAVE_EXECINFO_BACKTRACE
-# define LOG_CALLSTACK() log_callstack(__func__, __LINE__)
-# define LOG_CALLSTACK_TO_FILE(fp) log_callstack_to_file(fp, __func__, __LINE__)
-#endif
-
 // uncrustify:off
 #if NVIM_HAS_INCLUDE(<sanitizer/asan_interface.h>)
 # include <sanitizer/asan_interface.h>  // IWYU pragma: keep
diff --git a/src/nvim/log_defs.h b/src/nvim/log_defs.h
new file mode 100644
index 0000000000..1b666720fc
--- /dev/null
+++ b/src/nvim/log_defs.h
@@ -0,0 +1,36 @@
+#pragma once
+
+#include <stdbool.h>
+#include <stdio.h>
+
+#include "auto/config.h"
+#include "nvim/macros_defs.h"
+
+#define LOGLVL_DBG 1
+#define LOGLVL_INF 2
+#define LOGLVL_WRN 3
+#define LOGLVL_ERR 4
+
+#define LOG(level, ...) logmsg((level), NULL, __func__, __LINE__, true, __VA_ARGS__)
+
+#ifdef NVIM_LOG_DEBUG
+# define DLOG(...) logmsg(LOGLVL_DBG, NULL, __func__, __LINE__, true, __VA_ARGS__)
+# define DLOGN(...) logmsg(LOGLVL_DBG, NULL, __func__, __LINE__, false, __VA_ARGS__)
+# define ILOG(...) logmsg(LOGLVL_INF, NULL, __func__, __LINE__, true, __VA_ARGS__)
+# define ILOGN(...) logmsg(LOGLVL_INF, NULL, __func__, __LINE__, false, __VA_ARGS__)
+#else
+# define DLOG(...)
+# define DLOGN(...)
+# define ILOG(...)
+# define ILOGN(...)
+#endif
+
+#define WLOG(...) logmsg(LOGLVL_WRN, NULL, __func__, __LINE__, true, __VA_ARGS__)
+#define WLOGN(...) logmsg(LOGLVL_WRN, NULL, __func__, __LINE__, false, __VA_ARGS__)
+#define ELOG(...) logmsg(LOGLVL_ERR, NULL, __func__, __LINE__, true, __VA_ARGS__)
+#define ELOGN(...) logmsg(LOGLVL_ERR, NULL, __func__, __LINE__, false, __VA_ARGS__)
+
+#ifdef HAVE_EXECINFO_BACKTRACE
+# define LOG_CALLSTACK() log_callstack(__func__, __LINE__)
+# define LOG_CALLSTACK_TO_FILE(fp) log_callstack_to_file(fp, __func__, __LINE__)
+#endif
diff --git a/src/nvim/lua/executor.c b/src/nvim/lua/executor.c
index 0763bbd329..77c3f22da8 100644
--- a/src/nvim/lua/executor.c
+++ b/src/nvim/lua/executor.c
@@ -27,7 +27,6 @@
 #include "nvim/eval/userfunc.h"
 #include "nvim/event/defs.h"
 #include "nvim/event/loop.h"
-#include "nvim/event/multiqueue.h"
 #include "nvim/event/time.h"
 #include "nvim/ex_cmds.h"
 #include "nvim/ex_cmds_defs.h"
diff --git a/src/nvim/mark.c b/src/nvim/mark.c
index 1e2462970f..54b1df99a2 100644
--- a/src/nvim/mark.c
+++ b/src/nvim/mark.c
@@ -2,13 +2,13 @@
 
 #include <assert.h>
 #include <limits.h>
+#include <stdbool.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <string.h>
 
 #include "nvim/ascii_defs.h"
 #include "nvim/buffer.h"
-#include "nvim/buffer_defs.h"
 #include "nvim/charset.h"
 #include "nvim/cursor.h"
 #include "nvim/diff.h"
@@ -16,7 +16,6 @@
 #include "nvim/eval/typval.h"
 #include "nvim/ex_cmds_defs.h"
 #include "nvim/extmark.h"
-#include "nvim/extmark_defs.h"
 #include "nvim/fold.h"
 #include "nvim/gettext.h"
 #include "nvim/globals.h"
@@ -32,7 +31,9 @@
 #include "nvim/os/fs.h"
 #include "nvim/os/input.h"
 #include "nvim/os/os.h"
+#include "nvim/os/time.h"
 #include "nvim/path.h"
+#include "nvim/pos_defs.h"
 #include "nvim/quickfix.h"
 #include "nvim/strings.h"
 #include "nvim/textobject.h"
diff --git a/src/nvim/mark.h b/src/nvim/mark.h
index 990be69028..b1a093bee0 100644
--- a/src/nvim/mark.h
+++ b/src/nvim/mark.h
@@ -1,54 +1,10 @@
 #pragma once
 
-#include <stdbool.h>
-#include <stddef.h>
-
 #include "nvim/ascii_defs.h"
-#include "nvim/buffer_defs.h"
-#include "nvim/ex_cmds_defs.h"
-#include "nvim/extmark_defs.h"
+#include "nvim/ex_cmds_defs.h"  // IWYU pragma: keep
 #include "nvim/func_attr.h"
 #include "nvim/macros_defs.h"
 #include "nvim/mark_defs.h"  // IWYU pragma: export
-#include "nvim/memory.h"
-#include "nvim/os/time.h"
-#include "nvim/pos_defs.h"
-
-/// Set fmark using given value
-#define SET_FMARK(fmarkp_, mark_, fnum_, view_) \
-  do { \
-    fmark_T *const fmarkp__ = fmarkp_; \
-    fmarkp__->mark = mark_; \
-    fmarkp__->fnum = fnum_; \
-    fmarkp__->timestamp = os_time(); \
-    fmarkp__->view = view_; \
-    fmarkp__->additional_data = NULL; \
-  } while (0)
-
-/// Free and set fmark using given value
-#define RESET_FMARK(fmarkp_, mark_, fnum_, view_) \
-  do { \
-    fmark_T *const fmarkp___ = fmarkp_; \
-    free_fmark(*fmarkp___); \
-    SET_FMARK(fmarkp___, mark_, fnum_, view_); \
-  } while (0)
-
-/// Set given extended mark (regular mark + file name)
-#define SET_XFMARK(xfmarkp_, mark_, fnum_, view_, fname_) \
-  do { \
-    xfmark_T *const xfmarkp__ = xfmarkp_; \
-    xfmarkp__->fname = fname_; \
-    SET_FMARK(&(xfmarkp__->fmark), mark_, fnum_, view_); \
-  } while (0)
-
-/// Free and set given extended mark (regular mark + file name)
-#define RESET_XFMARK(xfmarkp_, mark_, fnum_, view_, fname_) \
-  do { \
-    xfmark_T *const xfmarkp__ = xfmarkp_; \
-    free_xfmark(*xfmarkp__); \
-    xfmarkp__->fname = fname_; \
-    SET_FMARK(&(xfmarkp__->fmark), mark_, fnum_, view_); \
-  } while (0)
 
 static inline int mark_global_index(char name)
   REAL_FATTR_CONST;
@@ -80,47 +36,6 @@ static inline int mark_local_index(const char name)
                    : -1))));
 }
 
-static inline bool lt(pos_T a, pos_T b)
-  REAL_FATTR_CONST REAL_FATTR_ALWAYS_INLINE;
-static inline bool equalpos(pos_T a, pos_T b)
-  REAL_FATTR_CONST REAL_FATTR_ALWAYS_INLINE;
-static inline bool ltoreq(pos_T a, pos_T b)
-  REAL_FATTR_CONST REAL_FATTR_ALWAYS_INLINE;
-static inline void clearpos(pos_T *a)
-  REAL_FATTR_ALWAYS_INLINE;
-
-/// Return true if position a is before (less than) position b.
-static inline bool lt(pos_T a, pos_T b)
-{
-  if (a.lnum != b.lnum) {
-    return a.lnum < b.lnum;
-  } else if (a.col != b.col) {
-    return a.col < b.col;
-  } else {
-    return a.coladd < b.coladd;
-  }
-}
-
-/// Return true if position a and b are equal.
-static inline bool equalpos(pos_T a, pos_T b)
-{
-  return (a.lnum == b.lnum) && (a.col == b.col) && (a.coladd == b.coladd);
-}
-
-/// Return true if position a is less than or equal to b.
-static inline bool ltoreq(pos_T a, pos_T b)
-{
-  return lt(a, b) || equalpos(a, b);
-}
-
-/// Clear the pos_T structure pointed to by a.
-static inline void clearpos(pos_T *a)
-{
-  a->lnum = 0;
-  a->col = 0;
-  a->coladd = 0;
-}
-
 /// Global marks (marks with file number or name)
 EXTERN xfmark_T namedfm[NGLOBALMARKS] INIT( = { 0 });
 
diff --git a/src/nvim/mark_defs.h b/src/nvim/mark_defs.h
index 04672a5c52..a98a741363 100644
--- a/src/nvim/mark_defs.h
+++ b/src/nvim/mark_defs.h
@@ -84,3 +84,79 @@ typedef struct xfilemark {
 } xfmark_T;
 
 #define INIT_XFMARK { INIT_FMARK, NULL }
+
+/// Set fmark using given value
+#define SET_FMARK(fmarkp_, mark_, fnum_, view_) \
+  do { \
+    fmark_T *const fmarkp__ = fmarkp_; \
+    fmarkp__->mark = mark_; \
+    fmarkp__->fnum = fnum_; \
+    fmarkp__->timestamp = os_time(); \
+    fmarkp__->view = view_; \
+    fmarkp__->additional_data = NULL; \
+  } while (0)
+
+/// Free and set fmark using given value
+#define RESET_FMARK(fmarkp_, mark_, fnum_, view_) \
+  do { \
+    fmark_T *const fmarkp___ = fmarkp_; \
+    free_fmark(*fmarkp___); \
+    SET_FMARK(fmarkp___, mark_, fnum_, view_); \
+  } while (0)
+
+/// Set given extended mark (regular mark + file name)
+#define SET_XFMARK(xfmarkp_, mark_, fnum_, view_, fname_) \
+  do { \
+    xfmark_T *const xfmarkp__ = xfmarkp_; \
+    xfmarkp__->fname = fname_; \
+    SET_FMARK(&(xfmarkp__->fmark), mark_, fnum_, view_); \
+  } while (0)
+
+/// Free and set given extended mark (regular mark + file name)
+#define RESET_XFMARK(xfmarkp_, mark_, fnum_, view_, fname_) \
+  do { \
+    xfmark_T *const xfmarkp__ = xfmarkp_; \
+    free_xfmark(*xfmarkp__); \
+    xfmarkp__->fname = fname_; \
+    SET_FMARK(&(xfmarkp__->fmark), mark_, fnum_, view_); \
+  } while (0)
+
+static inline bool lt(pos_T a, pos_T b)
+  REAL_FATTR_CONST REAL_FATTR_ALWAYS_INLINE;
+/// Return true if position a is before (less than) position b.
+static inline bool lt(pos_T a, pos_T b)
+{
+  if (a.lnum != b.lnum) {
+    return a.lnum < b.lnum;
+  } else if (a.col != b.col) {
+    return a.col < b.col;
+  } else {
+    return a.coladd < b.coladd;
+  }
+}
+
+static inline bool equalpos(pos_T a, pos_T b)
+  REAL_FATTR_CONST REAL_FATTR_ALWAYS_INLINE;
+/// Return true if position a and b are equal.
+static inline bool equalpos(pos_T a, pos_T b)
+{
+  return (a.lnum == b.lnum) && (a.col == b.col) && (a.coladd == b.coladd);
+}
+
+static inline bool ltoreq(pos_T a, pos_T b)
+  REAL_FATTR_CONST REAL_FATTR_ALWAYS_INLINE;
+/// Return true if position a is less than or equal to b.
+static inline bool ltoreq(pos_T a, pos_T b)
+{
+  return lt(a, b) || equalpos(a, b);
+}
+
+static inline void clearpos(pos_T *a)
+  REAL_FATTR_ALWAYS_INLINE;
+/// Clear the pos_T structure pointed to by a.
+static inline void clearpos(pos_T *a)
+{
+  a->lnum = 0;
+  a->col = 0;
+  a->coladd = 0;
+}
diff --git a/src/nvim/mbyte.h b/src/nvim/mbyte.h
index 49c323282d..bae60185e2 100644
--- a/src/nvim/mbyte.h
+++ b/src/nvim/mbyte.h
@@ -3,12 +3,12 @@
 #include <stdbool.h>
 #include <stdint.h>
 #include <string.h>
+#include <sys/types.h>  // IWYU pragma: keep
 
 #include "nvim/cmdexpand_defs.h"  // IWYU pragma: keep
 #include "nvim/eval/typval_defs.h"  // IWYU pragma: keep
 #include "nvim/func_attr.h"
 #include "nvim/mbyte_defs.h"  // IWYU pragma: export
-#include "nvim/os/os_defs.h"  // IWYU pragma: export
 #include "nvim/types_defs.h"  // IWYU pragma: keep
 
 // Return byte length of character that starts with byte "b".
diff --git a/src/nvim/message.c b/src/nvim/message.c
index b9935d5b5d..6aaa00cee9 100644
--- a/src/nvim/message.c
+++ b/src/nvim/message.c
@@ -10,6 +10,8 @@
 #include <string.h>
 #include <sys/types.h>
 
+#include "klib/kvec.h"
+#include "nvim/api/private/defs.h"
 #include "nvim/api/private/helpers.h"
 #include "nvim/ascii_defs.h"
 #include "nvim/buffer_defs.h"
diff --git a/src/nvim/message.h b/src/nvim/message.h
index 904fb2d3ad..15a83fca2c 100644
--- a/src/nvim/message.h
+++ b/src/nvim/message.h
@@ -1,53 +1,12 @@
 #pragma once
 
-#include <errno.h>
 #include <stdbool.h>
 #include <stddef.h>  // IWYU pragma: keep
-#include <stdio.h>
 
-#include "klib/kvec.h"
-#include "nvim/api/private/defs.h"
 #include "nvim/ex_cmds_defs.h"  // IWYU pragma: keep
 #include "nvim/grid_defs.h"
 #include "nvim/macros_defs.h"
-
-/// Types of dialogs passed to do_dialog().
-enum {
-  VIM_GENERIC   = 0,
-  VIM_ERROR     = 1,
-  VIM_WARNING   = 2,
-  VIM_INFO      = 3,
-  VIM_QUESTION  = 4,
-  VIM_LAST_TYPE = 4,  ///< sentinel value
-};
-
-/// Return values for functions like vim_dialogyesno()
-enum {
-  VIM_YES        = 2,
-  VIM_NO         = 3,
-  VIM_CANCEL     = 4,
-  VIM_ALL        = 5,
-  VIM_DISCARDALL = 6,
-};
-
-enum { MSG_HIST = 0x1000, };  ///< special attribute addition: Put message in history
-
-typedef struct {
-  String text;
-  int attr;
-} HlMessageChunk;
-
-typedef kvec_t(HlMessageChunk) HlMessage;
-
-/// Message history for `:messages`
-typedef struct msg_hist {
-  struct msg_hist *next;  ///< Next message.
-  char *msg;              ///< Message text.
-  const char *kind;       ///< Message kind (for msg_ext)
-  int attr;               ///< Message highlighting.
-  bool multiline;         ///< Multiline message.
-  HlMessage multiattr;    ///< multiattr message.
-} MessageHistoryEntry;
+#include "nvim/message_defs.h"  // IWYU pragma: export
 
 /// First message
 extern MessageHistoryEntry *first_msg_hist;
@@ -79,14 +38,3 @@ EXTERN int msg_listdo_overwrite INIT( = 0);
 #ifdef INCLUDE_GENERATED_DECLARATIONS
 # include "message.h.generated.h"
 #endif
-
-// Prefer using semsg(), because perror() may send the output to the wrong
-// destination and mess up the screen.
-#define PERROR(msg) (void)semsg("%s: %s", (msg), strerror(errno))
-
-#ifndef MSWIN
-/// Headless (no UI) error message handler.
-# define os_errmsg(str)        fprintf(stderr, "%s", (str))
-/// Headless (no UI) message handler.
-# define os_msg(str)           printf("%s", (str))
-#endif
diff --git a/src/nvim/message_defs.h b/src/nvim/message_defs.h
new file mode 100644
index 0000000000..a0237ea78f
--- /dev/null
+++ b/src/nvim/message_defs.h
@@ -0,0 +1,59 @@
+#pragma once
+
+#include <errno.h>
+#include <stdbool.h>
+#include <stdio.h>
+
+#include "klib/kvec.h"
+#include "nvim/api/private/defs.h"
+#include "nvim/grid_defs.h"
+#include "nvim/macros_defs.h"
+
+/// Types of dialogs passed to do_dialog().
+enum {
+  VIM_GENERIC   = 0,
+  VIM_ERROR     = 1,
+  VIM_WARNING   = 2,
+  VIM_INFO      = 3,
+  VIM_QUESTION  = 4,
+  VIM_LAST_TYPE = 4,  ///< sentinel value
+};
+
+/// Return values for functions like vim_dialogyesno()
+enum {
+  VIM_YES        = 2,
+  VIM_NO         = 3,
+  VIM_CANCEL     = 4,
+  VIM_ALL        = 5,
+  VIM_DISCARDALL = 6,
+};
+
+enum { MSG_HIST = 0x1000, };  ///< special attribute addition: Put message in history
+
+typedef struct {
+  String text;
+  int attr;
+} HlMessageChunk;
+
+typedef kvec_t(HlMessageChunk) HlMessage;
+
+/// Message history for `:messages`
+typedef struct msg_hist {
+  struct msg_hist *next;  ///< Next message.
+  char *msg;              ///< Message text.
+  const char *kind;       ///< Message kind (for msg_ext)
+  int attr;               ///< Message highlighting.
+  bool multiline;         ///< Multiline message.
+  HlMessage multiattr;    ///< multiattr message.
+} MessageHistoryEntry;
+
+// Prefer using semsg(), because perror() may send the output to the wrong
+// destination and mess up the screen.
+#define PERROR(msg) (void)semsg("%s: %s", (msg), strerror(errno))
+
+#ifndef MSWIN
+/// Headless (no UI) error message handler.
+# define os_errmsg(str)        fprintf(stderr, "%s", (str))
+/// Headless (no UI) message handler.
+# define os_msg(str)           printf("%s", (str))
+#endif
diff --git a/src/nvim/msgpack_rpc/channel.c b/src/nvim/msgpack_rpc/channel.c
index 2336853609..c9139f5f93 100644
--- a/src/nvim/msgpack_rpc/channel.c
+++ b/src/nvim/msgpack_rpc/channel.c
@@ -15,10 +15,9 @@
 #include "nvim/api/ui.h"
 #include "nvim/channel.h"
 #include "nvim/event/defs.h"
-#include "nvim/event/loop.h"
+#include "nvim/event/multiqueue.h"
 #include "nvim/event/process.h"
 #include "nvim/event/rstream.h"
-#include "nvim/event/stream.h"
 #include "nvim/event/wstream.h"
 #include "nvim/globals.h"
 #include "nvim/log.h"
diff --git a/src/nvim/msgpack_rpc/channel.h b/src/nvim/msgpack_rpc/channel.h
index 818bee8318..a33081eadc 100644
--- a/src/nvim/msgpack_rpc/channel.h
+++ b/src/nvim/msgpack_rpc/channel.h
@@ -3,11 +3,7 @@
 #include <stdint.h>  // IWYU pragma: keep
 
 #include "nvim/api/private/defs.h"  // IWYU pragma: keep
-#include "nvim/channel.h"
-#include "nvim/event/multiqueue.h"
-#include "nvim/event/process.h"
-#include "nvim/event/socket.h"
-#include "nvim/event/wstream.h"
+#include "nvim/event/defs.h"
 #include "nvim/macros_defs.h"
 #include "nvim/memory_defs.h"  // IWYU pragma: keep
 #include "nvim/msgpack_rpc/channel_defs.h"  // IWYU pragma: export
diff --git a/src/nvim/msgpack_rpc/server.c b/src/nvim/msgpack_rpc/server.c
index e60c1b88a5..0cc249b2b8 100644
--- a/src/nvim/msgpack_rpc/server.c
+++ b/src/nvim/msgpack_rpc/server.c
@@ -6,6 +6,7 @@
 
 #include "nvim/channel.h"
 #include "nvim/eval.h"
+#include "nvim/event/defs.h"
 #include "nvim/event/socket.h"
 #include "nvim/garray.h"
 #include "nvim/log.h"
diff --git a/src/nvim/option.c b/src/nvim/option.c
index 0d0437d45f..6237b11de2 100644
--- a/src/nvim/option.c
+++ b/src/nvim/option.c
@@ -84,7 +84,6 @@
 #include "nvim/regexp.h"
 #include "nvim/runtime.h"
 #include "nvim/search.h"
-#include "nvim/sign_defs.h"
 #include "nvim/spell.h"
 #include "nvim/spellfile.h"
 #include "nvim/spellsuggest.h"
diff --git a/src/nvim/option_defs.h b/src/nvim/option_defs.h
index 7ccf09b934..62c02989a2 100644
--- a/src/nvim/option_defs.h
+++ b/src/nvim/option_defs.h
@@ -131,6 +131,5 @@ typedef enum {
 } OptReqScope;
 
 #ifdef INCLUDE_GENERATED_DECLARATIONS
-// Initialize the OptIndex enum.
-# include "options_enum.generated.h"
+# include "options_enum.generated.h"  // IWYU pragma: export
 #endif
diff --git a/src/nvim/os/input.c b/src/nvim/os/input.c
index 69d328754b..e096749ce3 100644
--- a/src/nvim/os/input.c
+++ b/src/nvim/os/input.c
@@ -8,6 +8,7 @@
 #include "nvim/api/private/defs.h"
 #include "nvim/ascii_defs.h"
 #include "nvim/autocmd.h"
+#include "nvim/event/defs.h"
 #include "nvim/event/loop.h"
 #include "nvim/event/multiqueue.h"
 #include "nvim/event/rstream.h"
diff --git a/src/nvim/os/pty_process_unix.c b/src/nvim/os/pty_process_unix.c
index d4be3086ea..4478d9d7bd 100644
--- a/src/nvim/os/pty_process_unix.c
+++ b/src/nvim/os/pty_process_unix.c
@@ -32,9 +32,9 @@
 #include "auto/config.h"
 #include "klib/klist.h"
 #include "nvim/eval/typval.h"
+#include "nvim/event/defs.h"
 #include "nvim/event/loop.h"
 #include "nvim/event/process.h"
-#include "nvim/event/stream.h"
 #include "nvim/log.h"
 #include "nvim/os/fs.h"
 #include "nvim/os/os_defs.h"
diff --git a/src/nvim/os/shell.c b/src/nvim/os/shell.c
index cb8066a62d..a0401f3a24 100644
--- a/src/nvim/os/shell.c
+++ b/src/nvim/os/shell.c
@@ -11,6 +11,7 @@
 #include "nvim/charset.h"
 #include "nvim/eval.h"
 #include "nvim/eval/typval_defs.h"
+#include "nvim/event/defs.h"
 #include "nvim/event/libuv_process.h"
 #include "nvim/event/loop.h"
 #include "nvim/event/multiqueue.h"
@@ -30,6 +31,7 @@
 #include "nvim/message.h"
 #include "nvim/option_vars.h"
 #include "nvim/os/fs.h"
+#include "nvim/os/os_defs.h"
 #include "nvim/os/shell.h"
 #include "nvim/os/signal.h"
 #include "nvim/os/time.h"
diff --git a/src/nvim/os/signal.c b/src/nvim/os/signal.c
index 3a861b87b4..4960fa6a19 100644
--- a/src/nvim/os/signal.c
+++ b/src/nvim/os/signal.c
@@ -8,6 +8,7 @@
 
 #include "nvim/autocmd.h"
 #include "nvim/eval.h"
+#include "nvim/event/defs.h"
 #include "nvim/event/signal.h"
 #include "nvim/globals.h"
 #include "nvim/log.h"
diff --git a/src/nvim/os/time.c b/src/nvim/os/time.c
index 7f3e44f680..f842bb0ab8 100644
--- a/src/nvim/os/time.c
+++ b/src/nvim/os/time.c
@@ -7,7 +7,7 @@
 #include <uv.h>
 
 #include "auto/config.h"
-#include "nvim/event/loop.h"
+#include "nvim/event/defs.h"
 #include "nvim/gettext.h"
 #include "nvim/globals.h"
 #include "nvim/log.h"
diff --git a/src/nvim/os/tty.h b/src/nvim/os/tty.h
index a24d875c05..3a78573189 100644
--- a/src/nvim/os/tty.h
+++ b/src/nvim/os/tty.h
@@ -1,5 +1,5 @@
 #pragma once
 
 #ifdef INCLUDE_GENERATED_DECLARATIONS
-# include "os/tty.h.generated.h"  // IWYU pragma: export
+# include "os/tty.h.generated.h"
 #endif
diff --git a/src/nvim/popupmenu.h b/src/nvim/popupmenu.h
index dc741d1b77..1e4a1584ea 100644
--- a/src/nvim/popupmenu.h
+++ b/src/nvim/popupmenu.h
@@ -2,7 +2,7 @@
 
 #include <stdbool.h>
 
-#include "nvim/buffer_defs.h"
+#include "nvim/buffer_defs.h"  // IWYU pragma: keep
 #include "nvim/eval/typval_defs.h"  // IWYU pragma: keep
 #include "nvim/grid_defs.h"
 #include "nvim/macros_defs.h"
diff --git a/src/nvim/spell.c b/src/nvim/spell.c
index d20d113d9c..c322621038 100644
--- a/src/nvim/spell.c
+++ b/src/nvim/spell.c
@@ -90,6 +90,7 @@
 #include "nvim/option_vars.h"
 #include "nvim/os/fs.h"
 #include "nvim/os/input.h"
+#include "nvim/os/os_defs.h"
 #include "nvim/path.h"
 #include "nvim/pos_defs.h"
 #include "nvim/regexp.h"
diff --git a/src/nvim/spellsuggest.c b/src/nvim/spellsuggest.c
index efd647a5c3..c4be6f2ec7 100644
--- a/src/nvim/spellsuggest.c
+++ b/src/nvim/spellsuggest.c
@@ -35,6 +35,7 @@
 #include "nvim/option_vars.h"
 #include "nvim/os/fs.h"
 #include "nvim/os/input.h"
+#include "nvim/os/os_defs.h"
 #include "nvim/pos_defs.h"
 #include "nvim/profile.h"
 #include "nvim/spell.h"
diff --git a/src/nvim/statusline.h b/src/nvim/statusline.h
index 59a900d566..e1038ef2ca 100644
--- a/src/nvim/statusline.h
+++ b/src/nvim/statusline.h
@@ -4,7 +4,7 @@
 
 #include "nvim/buffer_defs.h"  // IWYU pragma: keep
 #include "nvim/macros_defs.h"
-#include "nvim/option_defs.h"
+#include "nvim/option_defs.h"  // IWYU pragma: keep
 #include "nvim/statusline_defs.h"  // IWYU pragma: export
 
 /// Array defining what should be done when tabline is clicked
diff --git a/src/nvim/tag.c b/src/nvim/tag.c
index 7fa02d2e0a..e67fa337b3 100644
--- a/src/nvim/tag.c
+++ b/src/nvim/tag.c
@@ -43,6 +43,7 @@
 #include "nvim/optionstr.h"
 #include "nvim/os/fs.h"
 #include "nvim/os/input.h"
+#include "nvim/os/os_defs.h"
 #include "nvim/os/time.h"
 #include "nvim/path.h"
 #include "nvim/pos_defs.h"
diff --git a/src/nvim/terminal.c b/src/nvim/terminal.c
index 3b70ee922a..c26e2a2259 100644
--- a/src/nvim/terminal.c
+++ b/src/nvim/terminal.c
@@ -57,6 +57,7 @@
 #include "nvim/drawscreen.h"
 #include "nvim/eval.h"
 #include "nvim/eval/typval.h"
+#include "nvim/event/defs.h"
 #include "nvim/event/multiqueue.h"
 #include "nvim/event/time.h"
 #include "nvim/ex_docmd.h"
diff --git a/src/nvim/terminal.h b/src/nvim/terminal.h
index ffa97f17b2..dd0ef3f47c 100644
--- a/src/nvim/terminal.h
+++ b/src/nvim/terminal.h
@@ -1,5 +1,6 @@
 #pragma once
 
+#include <stdbool.h>
 #include <stddef.h>
 #include <stdint.h>
 
diff --git a/src/nvim/tui/input.c b/src/nvim/tui/input.c
index 6c47d1b5c7..9ba21a6afd 100644
--- a/src/nvim/tui/input.c
+++ b/src/nvim/tui/input.c
@@ -7,6 +7,7 @@
 #include "nvim/api/private/defs.h"
 #include "nvim/api/private/helpers.h"
 #include "nvim/event/defs.h"
+#include "nvim/event/stream.h"
 #include "nvim/macros_defs.h"
 #include "nvim/main.h"
 #include "nvim/map_defs.h"
diff --git a/src/nvim/tui/tui.c b/src/nvim/tui/tui.c
index f084ab212b..496c192b95 100644
--- a/src/nvim/tui/tui.c
+++ b/src/nvim/tui/tui.c
@@ -15,6 +15,7 @@
 #include "nvim/api/private/helpers.h"
 #include "nvim/ascii_defs.h"
 #include "nvim/cursor_shape.h"
+#include "nvim/event/defs.h"
 #include "nvim/event/loop.h"
 #include "nvim/event/signal.h"
 #include "nvim/event/stream.h"
diff --git a/src/nvim/ui.c b/src/nvim/ui.c
index 0fc0c5bf86..1f94e4da63 100644
--- a/src/nvim/ui.c
+++ b/src/nvim/ui.c
@@ -14,6 +14,7 @@
 #include "nvim/buffer.h"
 #include "nvim/cursor_shape.h"
 #include "nvim/drawscreen.h"
+#include "nvim/event/multiqueue.h"
 #include "nvim/ex_getln.h"
 #include "nvim/gettext.h"
 #include "nvim/globals.h"
diff --git a/src/nvim/ui_client.c b/src/nvim/ui_client.c
index d744560a86..5c9eeaabdf 100644
--- a/src/nvim/ui_client.c
+++ b/src/nvim/ui_client.c
@@ -10,7 +10,7 @@
 #include "nvim/channel.h"
 #include "nvim/eval.h"
 #include "nvim/eval/typval_defs.h"
-#include "nvim/event/loop.h"
+#include "nvim/event/defs.h"
 #include "nvim/globals.h"
 #include "nvim/highlight.h"
 #include "nvim/log.h"
diff --git a/src/nvim/vim_defs.h b/src/nvim/vim_defs.h
index b408eb2fd7..b6cf402b02 100644
--- a/src/nvim/vim_defs.h
+++ b/src/nvim/vim_defs.h
@@ -56,7 +56,6 @@ typedef enum {
   kCdCauseAuto,    ///< On 'autochdir'.
 } CdCause;
 
-// bring lots of system header files
 #include "nvim/os/os_defs.h"  // IWYU pragma: keep
 
 // return values for functions
diff --git a/src/nvim/window.c b/src/nvim/window.c
index 0a09d8e27d..fe9509548f 100644
--- a/src/nvim/window.c
+++ b/src/nvim/window.c
@@ -56,6 +56,7 @@
 #include "nvim/option_defs.h"
 #include "nvim/option_vars.h"
 #include "nvim/os/fs.h"
+#include "nvim/os/os_defs.h"
 #include "nvim/path.h"
 #include "nvim/plines.h"
 #include "nvim/pos_defs.h"