diff --git a/src/nvim/autocmd.c b/src/nvim/autocmd.c
index 0300b760a6..152184e75c 100644
--- a/src/nvim/autocmd.c
+++ b/src/nvim/autocmd.c
@@ -1669,6 +1669,7 @@ bool apply_autocmds_group(event_T event, char *fname, char *fname_io, bool force
   bool did_save_redobuff = false;
   save_redo_T save_redo;
   const bool save_KeyTyped = KeyTyped;
+  ESTACK_CHECK_DECLARATION;
 
   // Quickly return if there are no autocommands for this event or
   // autocommands are blocked.
@@ -1853,6 +1854,7 @@ bool apply_autocmds_group(event_T event, char *fname, char *fname_io, bool force
 
   // name and lnum are filled in later
   estack_push(ETYPE_AUCMD, NULL, 0);
+  ESTACK_CHECK_SETUP;
 
   const sctx_T save_current_sctx = current_sctx;
 
@@ -1962,6 +1964,7 @@ bool apply_autocmds_group(event_T event, char *fname, char *fname_io, bool force
   filechangeshell_busy = false;
   autocmd_nested = save_autocmd_nested;
   xfree(SOURCING_NAME);
+  ESTACK_CHECK_NOW;
   estack_pop();
   xfree(afile_orig);
   xfree(autocmd_fname);
diff --git a/src/nvim/buffer.c b/src/nvim/buffer.c
index e246c3b5d6..0494ff9c9c 100644
--- a/src/nvim/buffer.c
+++ b/src/nvim/buffer.c
@@ -3788,6 +3788,7 @@ static int chk_modeline(linenr_T lnum, int flags)
 {
   char *e;
   int retval = OK;
+  ESTACK_CHECK_DECLARATION;
 
   int prev = -1;
   char *s = ml_get(lnum);
@@ -3843,6 +3844,7 @@ static int chk_modeline(linenr_T lnum, int flags)
 
   // prepare for emsg()
   estack_push(ETYPE_MODELINE, "modelines", lnum);
+  ESTACK_CHECK_SETUP;
 
   bool end = false;
   while (end == false) {
@@ -3899,6 +3901,7 @@ static int chk_modeline(linenr_T lnum, int flags)
                                       // careful not to go off the end
   }
 
+  ESTACK_CHECK_NOW;
   estack_pop();
   xfree(linecopy);
 
diff --git a/src/nvim/eval/userfunc.c b/src/nvim/eval/userfunc.c
index e9289489bb..745d697828 100644
--- a/src/nvim/eval/userfunc.c
+++ b/src/nvim/eval/userfunc.c
@@ -1010,6 +1010,7 @@ void call_user_func(ufunc_T *fp, int argcount, typval_T *argvars, typval_T *rett
   bool started_profiling = false;
   bool did_save_redo = false;
   save_redo_T save_redo;
+  ESTACK_CHECK_DECLARATION;
 
   // If depth of calling is getting too high, don't execute the function
   if (depth >= p_mfd) {
@@ -1181,6 +1182,7 @@ void call_user_func(ufunc_T *fp, int argcount, typval_T *argvars, typval_T *rett
   }
 
   estack_push_ufunc(fp, 1);
+  ESTACK_CHECK_SETUP;
   if (p_verbose >= 12) {
     no_wait_return++;
     verbose_enter_scroll();
@@ -1332,6 +1334,7 @@ void call_user_func(ufunc_T *fp, int argcount, typval_T *argvars, typval_T *rett
     no_wait_return--;
   }
 
+  ESTACK_CHECK_NOW;
   estack_pop();
   current_sctx = save_current_sctx;
   if (do_profiling_yes) {
diff --git a/src/nvim/ex_docmd.c b/src/nvim/ex_docmd.c
index 7eb05a2383..d692c3e10b 100644
--- a/src/nvim/ex_docmd.c
+++ b/src/nvim/ex_docmd.c
@@ -964,6 +964,7 @@ void handle_did_throw(void)
   assert(current_exception != NULL);
   char *p = NULL;
   msglist_T *messages = NULL;
+  ESTACK_CHECK_DECLARATION;
 
   // If the uncaught exception is a user exception, report it as an
   // error.  If it is an error exception, display the saved error
@@ -985,6 +986,7 @@ void handle_did_throw(void)
   }
 
   estack_push(ETYPE_EXCEPT, current_exception->throw_name, current_exception->throw_lnum);
+  ESTACK_CHECK_SETUP;
   current_exception->throw_name = NULL;
 
   discard_current_exception();              // uses IObuff if 'verbose'
@@ -1009,6 +1011,7 @@ void handle_did_throw(void)
     xfree(p);
   }
   xfree(SOURCING_NAME);
+  ESTACK_CHECK_NOW;
   estack_pop();
 }
 
diff --git a/src/nvim/main.c b/src/nvim/main.c
index 65ad96f4e3..dfe30b5dbe 100644
--- a/src/nvim/main.c
+++ b/src/nvim/main.c
@@ -1918,6 +1918,7 @@ static void exe_pre_commands(mparm_T *parmp)
 {
   char **cmds = parmp->pre_commands;
   int cnt = parmp->n_pre_commands;
+  ESTACK_CHECK_DECLARATION;
 
   if (cnt <= 0) {
     return;
@@ -1925,10 +1926,12 @@ static void exe_pre_commands(mparm_T *parmp)
 
   curwin->w_cursor.lnum = 0;     // just in case..
   estack_push(ETYPE_ARGS, _("pre-vimrc command line"), 0);
+  ESTACK_CHECK_SETUP;
   current_sctx.sc_sid = SID_CMDARG;
   for (int i = 0; i < cnt; i++) {
     do_cmdline_cmd(cmds[i]);
   }
+  ESTACK_CHECK_NOW;
   estack_pop();
   current_sctx.sc_sid = 0;
   TIME_MSG("--cmd commands");
@@ -1937,6 +1940,8 @@ static void exe_pre_commands(mparm_T *parmp)
 // Execute "+", "-c" and "-S" arguments.
 static void exe_commands(mparm_T *parmp)
 {
+  ESTACK_CHECK_DECLARATION;
+
   // We start commands on line 0, make "vim +/pat file" match a
   // pattern on line 1.  But don't move the cursor when an autocommand
   // with g`" was used.
@@ -1945,6 +1950,7 @@ static void exe_commands(mparm_T *parmp)
     curwin->w_cursor.lnum = 0;
   }
   estack_push(ETYPE_ARGS, "command line", 0);
+  ESTACK_CHECK_SETUP;
   current_sctx.sc_sid = SID_CARG;
   current_sctx.sc_seq = 0;
   for (int i = 0; i < parmp->n_commands; i++) {
@@ -1953,6 +1959,7 @@ static void exe_commands(mparm_T *parmp)
       xfree(parmp->commands[i]);
     }
   }
+  ESTACK_CHECK_NOW;
   estack_pop();
   current_sctx.sc_sid = 0;
   if (curwin->w_cursor.lnum == 0) {
@@ -2149,18 +2156,21 @@ static void source_startup_scripts(const mparm_T *const parmp)
 static int execute_env(char *env)
   FUNC_ATTR_NONNULL_ALL
 {
+  ESTACK_CHECK_DECLARATION;
   char *initstr = os_getenv(env);
   if (initstr == NULL) {
     return FAIL;
   }
 
   estack_push(ETYPE_ENV, env, 0);
+  ESTACK_CHECK_SETUP;
   const sctx_T save_current_sctx = current_sctx;
   current_sctx.sc_sid = SID_ENV;
   current_sctx.sc_seq = 0;
   current_sctx.sc_lnum = 0;
   do_cmdline_cmd(initstr);
 
+  ESTACK_CHECK_NOW;
   estack_pop();
   current_sctx = save_current_sctx;
 
diff --git a/src/nvim/runtime.c b/src/nvim/runtime.c
index 9152f132ce..9bc9ddcac3 100644
--- a/src/nvim/runtime.c
+++ b/src/nvim/runtime.c
@@ -2092,6 +2092,7 @@ static int do_source_ext(char *const fname, const bool check_other, const int is
   scriptitem_T *si = NULL;
   proftime_T wait_start;
   bool trigger_source_post = false;
+  ESTACK_CHECK_DECLARATION;
 
   CLEAR_FIELD(cookie);
   char *fname_exp = NULL;
@@ -2255,6 +2256,7 @@ static int do_source_ext(char *const fname, const bool check_other, const int is
 
   // Keep the sourcing name/lnum, for recursive calls.
   estack_push(ETYPE_SCRIPT, si != NULL ? si->sn_name : fname_exp, 0);
+  ESTACK_CHECK_SETUP;
 
   if (l_do_profiling == PROF_YES && si != NULL) {
     bool forceit = false;
@@ -2316,6 +2318,7 @@ static int do_source_ext(char *const fname, const bool check_other, const int is
   if (got_int) {
     emsg(_(e_interr));
   }
+  ESTACK_CHECK_NOW;
   estack_pop();
   if (p_verbose > 1) {
     verbose_enter();
diff --git a/src/nvim/runtime.h b/src/nvim/runtime.h
index 43cdbd20dd..8a1d2dadd9 100644
--- a/src/nvim/runtime.h
+++ b/src/nvim/runtime.h
@@ -45,4 +45,19 @@ enum {
   DIP_DIRFILE = 0x200,  ///< find both files and directories
 };
 
+#ifdef ABORT_ON_INTERNAL_ERROR
+# define ESTACK_CHECK_DECLARATION int estack_len_before
+# define ESTACK_CHECK_SETUP do { estack_len_before = exestack.ga_len; } while (0)
+# define ESTACK_CHECK_NOW \
+  do { \
+    if (estack_len_before != exestack.ga_len) { \
+      siemsg("Exestack length expected: %d, actual: %d", estack_len_before, exestack.ga_len); \
+    } \
+  } while (0)
+#else
+# define ESTACK_CHECK_DECLARATION do {} while (0)
+# define ESTACK_CHECK_SETUP do {} while (0)
+# define ESTACK_CHECK_NOW do {} while (0)
+#endif
+
 #include "runtime.h.generated.h"
diff --git a/src/nvim/spellfile.c b/src/nvim/spellfile.c
index bd63b3b3e2..87cf6e55c4 100644
--- a/src/nvim/spellfile.c
+++ b/src/nvim/spellfile.c
@@ -608,6 +608,7 @@ slang_T *spell_load_file(char *fname, char *lang, slang_T *old_lp, bool silent)
   slang_T *lp = NULL;
   int res;
   bool did_estack_push = false;
+  ESTACK_CHECK_DECLARATION;
 
   FILE *fd = os_fopen(fname, "r");
   if (fd == NULL) {
@@ -640,6 +641,7 @@ slang_T *spell_load_file(char *fname, char *lang, slang_T *old_lp, bool silent)
 
   // Set sourcing_name, so that error messages mention the file name.
   estack_push(ETYPE_SPELL, fname, 0);
+  ESTACK_CHECK_SETUP;
   did_estack_push = true;
 
   // <HEADER>: <fileID>
@@ -838,6 +840,7 @@ endOK:
     fclose(fd);
   }
   if (did_estack_push) {
+    ESTACK_CHECK_NOW;
     estack_pop();
   }