diff --git a/src/indent.c b/src/indent.c

index e1c6f52..a002b4b 100644

--- a/src/indent.c

+++ b/src/indent.c

@@ -18,18 +18,19 @@

 /*

  * Set the integer values corresponding to the string setting of 'vartabstop'.

  * "array" will be set, caller must free it if needed.

+ * Return FAIL for an error.

  */

     int

 tabstop_set(char_u *var, int **array)

 {

-    int valcount = 1;

-    int t;

-    char_u *cp;

+    int	    valcount = 1;

+    int	    t;

+    char_u  *cp;

     if (var[0] == NUL || (var[0] == '0' && var[1] == NUL))

     {

 	*array = NULL;

-	return TRUE;

+	return OK;

     }

     for (cp = var; *cp != NUL; ++cp)

@@ -43,8 +44,8 @@ tabstop_set(char_u *var, int **array)

 		if (cp != end)

 		    emsg(_(e_positive));

 		else

-		    emsg(_(e_invarg));

-		return FALSE;

+		    semsg(_(e_invarg2), cp);

+		return FAIL;

 	    }

 	}

@@ -55,26 +56,36 @@ tabstop_set(char_u *var, int **array)

 	    ++valcount;

 	    continue;

 	}

-	emsg(_(e_invarg));

-	return FALSE;

+	semsg(_(e_invarg2), var);

+	return FAIL;

     }

     *array = ALLOC_MULT(int, valcount + 1);

     if (*array == NULL)

-	return FALSE;

+	return FAIL;

     (*array)[0] = valcount;

     t = 1;

     for (cp = var; *cp != NUL;)

     {

-	(*array)[t++] = atoi((char *)cp);

-	while (*cp  != NUL && *cp != ',')

+	int n = atoi((char *)cp);

+

+	// Catch negative values, overflow and ridiculous big values.

+	if (n < 0 || n > 9999)

+	{

+	    semsg(_(e_invarg2), cp);

+	    vim_free(*array);

+	    *array = NULL;

+	    return FAIL;

+	}

+	(*array)[t++] = n;

+	while (*cp != NUL && *cp != ',')

 	    ++cp;

 	if (*cp != NUL)

 	    ++cp;

     }

-    return TRUE;

+    return OK;

 }

 /*

@@ -1561,7 +1572,7 @@ ex_retab(exarg_T *eap)

 #ifdef FEAT_VARTABS

     new_ts_str = eap->arg;

-    if (!tabstop_set(eap->arg, &new_vts_array))

+    if (tabstop_set(eap->arg, &new_vts_array) == FAIL)

 	return;

     while (vim_isdigit(*(eap->arg)) || *(eap->arg) == ',')

 	++(eap->arg);

@@ -1577,12 +1588,18 @@ ex_retab(exarg_T *eap)

     else

 	new_ts_str = vim_strnsave(new_ts_str, eap->arg - new_ts_str);

 #else

-    new_ts = getdigits(&(eap->arg));

-    if (new_ts < 0)

+    ptr = eap->arg;

+    new_ts = getdigits(&ptr);

+    if (new_ts < 0 && *eap->arg == '-')

     {

 	emsg(_(e_positive));

 	return;

     }

+    if (new_ts < 0 || new_ts > 9999)

+    {

+	semsg(_(e_invarg2), eap->arg);

+	return;

+    }

     if (new_ts == 0)

 	new_ts = curbuf->b_p_ts;

 #endif

diff --git a/src/option.c b/src/option.c

index b9d7edb..9a3b71e 100644

--- a/src/option.c

+++ b/src/option.c

@@ -2349,9 +2349,9 @@ didset_options2(void)

 #endif

 #ifdef FEAT_VARTABS

     vim_free(curbuf->b_p_vsts_array);

-    tabstop_set(curbuf->b_p_vsts, &curbuf->b_p_vsts_array);

+    (void)tabstop_set(curbuf->b_p_vsts, &curbuf->b_p_vsts_array);

     vim_free(curbuf->b_p_vts_array);

-    tabstop_set(curbuf->b_p_vts,  &curbuf->b_p_vts_array);

+    (void)tabstop_set(curbuf->b_p_vts,  &curbuf->b_p_vts_array);

 #endif

 }

@@ -5828,7 +5828,7 @@ buf_copy_options(buf_T *buf, int flags)

 	    buf->b_p_vsts = vim_strsave(p_vsts);

 	    COPY_OPT_SCTX(buf, BV_VSTS);

 	    if (p_vsts && p_vsts != empty_option)

-		tabstop_set(p_vsts, &buf->b_p_vsts_array);

+		(void)tabstop_set(p_vsts, &buf->b_p_vsts_array);

 	    else

 		buf->b_p_vsts_array = 0;

 	    buf->b_p_vsts_nopaste = p_vsts_nopaste

@@ -5988,7 +5988,7 @@ buf_copy_options(buf_T *buf, int flags)

 		buf->b_p_isk = save_p_isk;

 #ifdef FEAT_VARTABS

 		if (p_vts && p_vts != empty_option && !buf->b_p_vts_array)

-		    tabstop_set(p_vts, &buf->b_p_vts_array);

+		    (void)tabstop_set(p_vts, &buf->b_p_vts_array);

 		else

 		    buf->b_p_vts_array = NULL;

 #endif

@@ -6003,7 +6003,7 @@ buf_copy_options(buf_T *buf, int flags)

 		buf->b_p_vts = vim_strsave(p_vts);

 		COPY_OPT_SCTX(buf, BV_VTS);

 		if (p_vts && p_vts != empty_option && !buf->b_p_vts_array)

-		    tabstop_set(p_vts, &buf->b_p_vts_array);

+		    (void)tabstop_set(p_vts, &buf->b_p_vts_array);

 		else

 		    buf->b_p_vts_array = NULL;

 #endif

@@ -6700,7 +6700,7 @@ paste_option_changed(void)

 	    if (buf->b_p_vsts_array)

 		vim_free(buf->b_p_vsts_array);

 	    if (buf->b_p_vsts && buf->b_p_vsts != empty_option)

-		tabstop_set(buf->b_p_vsts, &buf->b_p_vsts_array);

+		(void)tabstop_set(buf->b_p_vsts, &buf->b_p_vsts_array);

 	    else

 		buf->b_p_vsts_array = 0;

 #endif

diff --git a/src/optionstr.c b/src/optionstr.c

index 521242d..db015e8 100644

--- a/src/optionstr.c

+++ b/src/optionstr.c

@@ -2215,7 +2215,7 @@ ambw_end:

 	    if (errmsg == NULL)

 	    {

 		int *oldarray = curbuf->b_p_vsts_array;

-		if (tabstop_set(*varp, &(curbuf->b_p_vsts_array)))

+		if (tabstop_set(*varp, &(curbuf->b_p_vsts_array)) == OK)

 		{

 		    if (oldarray)

 			vim_free(oldarray);

@@ -2254,7 +2254,7 @@ ambw_end:

 	    {

 		int *oldarray = curbuf->b_p_vts_array;

-		if (tabstop_set(*varp, &(curbuf->b_p_vts_array)))

+		if (tabstop_set(*varp, &(curbuf->b_p_vts_array)) == OK)

 		{

 		    vim_free(oldarray);

 #ifdef FEAT_FOLDING

diff --git a/src/testdir/test_retab.vim b/src/testdir/test_retab.vim

index b792da5..c7190aa 100644

--- a/src/testdir/test_retab.vim

+++ b/src/testdir/test_retab.vim

@@ -75,6 +75,9 @@ endfunc

 func Test_retab_error()

   call assert_fails('retab -1',  'E487:')

   call assert_fails('retab! -1', 'E487:')

+  call assert_fails('ret -1000', 'E487:')

+  call assert_fails('ret 10000', 'E475:')

+  call assert_fails('ret 80000000000000000000', 'E475:')

 endfunc

 " vim: shiftwidth=2 sts=2 expandtab