16 files changed, 675 insertions, 673 deletions

diff --git a/src/job.c b/src/job.c
index ba5eec0f10..ddfc8ef3c8 100644
--- a/src/job.c
+++ b/src/job.c
@@ -793,11 +793,11 @@ job_free_job(job_T *job)
     static void
 job_free(job_T *job)
 {
-    if (!in_free_unref_items)
-    {
-	job_free_contents(job);
-	job_free_job(job);
-    }
+    if (in_free_unref_items)
+	return;
+
+    job_free_contents(job);
+    job_free_job(job);
 }
 
 static job_T *jobs_to_free = NULL;
@@ -1087,28 +1087,28 @@ set_ref_in_job(int copyID)
     void
 job_unref(job_T *job)
 {
-    if (job != NULL && --job->jv_refcount <= 0)
+    if (job == NULL || --job->jv_refcount > 0)
+	return;
+
+    // Do not free the job if there is a channel where the close callback
+    // may get the job info.
+    if (job_channel_still_useful(job))
+	return;
+
+    // Do not free the job when it has not ended yet and there is a
+    // "stoponexit" flag or an exit callback.
+    if (!job_need_end_check(job))
     {
-	// Do not free the job if there is a channel where the close callback
-	// may get the job info.
-	if (!job_channel_still_useful(job))
-	{
-	    // Do not free the job when it has not ended yet and there is a
-	    // "stoponexit" flag or an exit callback.
-	    if (!job_need_end_check(job))
-	    {
-		job_free(job);
-	    }
-	    else if (job->jv_channel != NULL)
-	    {
-		// Do remove the link to the channel, otherwise it hangs
-		// around until Vim exits. See job_free() for refcount.
-		ch_log(job->jv_channel, "detaching channel from job");
-		job->jv_channel->ch_job = NULL;
-		channel_unref(job->jv_channel);
-		job->jv_channel = NULL;
-	    }
-	}
+	job_free(job);
+    }
+    else if (job->jv_channel != NULL)
+    {
+	// Do remove the link to the channel, otherwise it hangs
+	// around until Vim exits. See job_free() for refcount.
+	ch_log(job->jv_channel, "detaching channel from job");
+	job->jv_channel->ch_job = NULL;
+	channel_unref(job->jv_channel);
+	job->jv_channel = NULL;
     }
 }
 
@@ -1157,18 +1157,18 @@ job_alloc(void)
     job_T *job;
 
     job = ALLOC_CLEAR_ONE(job_T);
-    if (job != NULL)
-    {
-	job->jv_refcount = 1;
-	job->jv_stoponexit = vim_strsave((char_u *)"term");
+    if (job == NULL)
+	return NULL;
 
-	if (first_job != NULL)
-	{
-	    first_job->jv_prev = job;
-	    job->jv_next = first_job;
-	}
-	first_job = job;
+    job->jv_refcount = 1;
+    job->jv_stoponexit = vim_strsave((char_u *)"term");
+
+    if (first_job != NULL)
+    {
+	first_job->jv_prev = job;
+	job->jv_next = first_job;
     }
+    first_job = job;
     return job;
 }
 
@@ -1803,13 +1803,13 @@ f_job_getchannel(typval_T *argvars, typval_T *rettv)
 	return;
 
     job = get_job_arg(&argvars[0]);
-    if (job != NULL)
-    {
-	rettv->v_type = VAR_CHANNEL;
-	rettv->vval.v_channel = job->jv_channel;
-	if (job->jv_channel != NULL)
-	    ++job->jv_channel->ch_refcount;
-    }
+    if (job == NULL)
+	return;
+
+    rettv->v_type = VAR_CHANNEL;
+    rettv->vval.v_channel = job->jv_channel;
+    if (job->jv_channel != NULL)
+	++job->jv_channel->ch_refcount;
 }
 
 /*
@@ -1855,13 +1855,13 @@ job_info(job_T *job, dict_T *dict)
 #endif
 
     l = list_alloc();
-    if (l != NULL)
-    {
-	dict_add_list(dict, "cmd", l);
-	if (job->jv_argv != NULL)
-	    for (i = 0; job->jv_argv[i] != NULL; i++)
-		list_append_string(l, (char_u *)job->jv_argv[i], -1);
-    }
+    if (l == NULL)
+	return;
+
+    dict_add_list(dict, "cmd", l);
+    if (job->jv_argv != NULL)
+	for (i = 0; job->jv_argv[i] != NULL; i++)
+	    list_append_string(l, (char_u *)job->jv_argv[i], -1);
 }
 
 /*
diff --git a/src/list.c b/src/list.c
index 8f228a1aeb..71184547ef 100644
--- a/src/list.c
+++ b/src/list.c
@@ -124,27 +124,27 @@ list_alloc_with_items(int count)
 
     list_init(l);
 
-    if (count > 0)
-    {
-	listitem_T	*li = (listitem_T *)(l + 1);
-	int		i;
+    if (count <= 0)
+	return l;
 
-	l->lv_len = count;
-	l->lv_with_items = count;
-	l->lv_first = li;
-	l->lv_u.mat.lv_last = li + count - 1;
-	for (i = 0; i < count; ++i)
-	{
-	    if (i == 0)
-		li->li_prev = NULL;
-	    else
-		li->li_prev = li - 1;
-	    if (i == count - 1)
-		li->li_next = NULL;
-	    else
-		li->li_next = li + 1;
-	    ++li;
-	}
+    listitem_T	*li = (listitem_T *)(l + 1);
+    int		i;
+
+    l->lv_len = count;
+    l->lv_with_items = count;
+    l->lv_first = li;
+    l->lv_u.mat.lv_last = li + count - 1;
+    for (i = 0; i < count; ++i)
+    {
+	if (i == 0)
+	    li->li_prev = NULL;
+	else
+	    li->li_prev = li - 1;
+	if (i == count - 1)
+	    li->li_next = NULL;
+	else
+	    li->li_next = li + 1;
+	++li;
     }
 
     return l;
@@ -297,11 +297,11 @@ list_free_items(int copyID)
     void
 list_free(list_T *l)
 {
-    if (!in_free_unref_items)
-    {
-	list_free_contents(l);
-	list_free_list(l);
-    }
+    if (in_free_unref_items)
+	return;
+
+    list_free_contents(l);
+    list_free_list(l);
 }
 
 /*
@@ -540,13 +540,13 @@ list_find_index(list_T *l, long *idx)
 {
     listitem_T *li = list_find(l, *idx);
 
-    if (li == NULL)
+    if (li != NULL)
+	return li;
+
+    if (*idx < 0)
     {
-	if (*idx < 0)
-	{
-	    *idx = 0;
-	    li = list_find(l, *idx);
-	}
+	*idx = 0;
+	li = list_find(l, *idx);
     }
     return li;
 }
@@ -772,21 +772,21 @@ check_range_index_one(list_T *l, long *n1, int can_append, int quiet)
     long	orig_n1 = *n1;
     listitem_T	*li = list_find_index(l, n1);
 
+    if (li != NULL)
+	return li;
+
+    // Vim9: Allow for adding an item at the end.
+    if (can_append && in_vim9script()
+	    && *n1 == l->lv_len && l->lv_lock == 0)
+    {
+	list_append_number(l, 0);
+	li = list_find_index(l, n1);
+    }
     if (li == NULL)
     {
-	// Vim9: Allow for adding an item at the end.
-	if (can_append && in_vim9script()
-					&& *n1 == l->lv_len && l->lv_lock == 0)
-	{
-	    list_append_number(l, 0);
-	    li = list_find_index(l, n1);
-	}
-	if (li == NULL)
-	{
-	    if (!quiet)
-		semsg(_(e_list_index_out_of_range_nr), orig_n1);
-	    return NULL;
-	}
+	if (!quiet)
+	    semsg(_(e_list_index_out_of_range_nr), orig_n1);
+	return NULL;
     }
     return li;
 }
@@ -1286,45 +1286,45 @@ list_copy(list_T *orig, int deep, int top, int copyID)
 	return NULL;
 
     copy = list_alloc();
-    if (copy != NULL)
+    if (copy == NULL)
+	return NULL;
+
+    if (orig->lv_type == NULL || top || deep)
+	copy->lv_type = NULL;
+    else
+	copy->lv_type = alloc_type(orig->lv_type);
+    if (copyID != 0)
     {
-	if (orig->lv_type == NULL || top || deep)
-	    copy->lv_type = NULL;
-	else
-	    copy->lv_type = alloc_type(orig->lv_type);
-	if (copyID != 0)
-	{
-	    // Do this before adding the items, because one of the items may
-	    // refer back to this list.
-	    orig->lv_copyID = copyID;
-	    orig->lv_copylist = copy;
-	}
-	CHECK_LIST_MATERIALIZE(orig);
-	for (item = orig->lv_first; item != NULL && !got_int;
-							 item = item->li_next)
+	// Do this before adding the items, because one of the items may
+	// refer back to this list.
+	orig->lv_copyID = copyID;
+	orig->lv_copylist = copy;
+    }
+    CHECK_LIST_MATERIALIZE(orig);
+    for (item = orig->lv_first; item != NULL && !got_int;
+	    item = item->li_next)
+    {
+	ni = listitem_alloc();
+	if (ni == NULL)
+	    break;
+	if (deep)
 	{
-	    ni = listitem_alloc();
-	    if (ni == NULL)
-		break;
-	    if (deep)
+	    if (item_copy(&item->li_tv, &ni->li_tv,
+			deep, FALSE, copyID) == FAIL)
 	    {
-		if (item_copy(&item->li_tv, &ni->li_tv,
-						  deep, FALSE, copyID) == FAIL)
-		{
-		    vim_free(ni);
-		    break;
-		}
+		vim_free(ni);
+		break;
 	    }
-	    else
-		copy_tv(&item->li_tv, &ni->li_tv);
-	    list_append(copy, ni);
-	}
-	++copy->lv_refcount;
-	if (item != NULL)
-	{
-	    list_unref(copy);
-	    copy = NULL;
 	}
+	else
+	    copy_tv(&item->li_tv, &ni->li_tv);
+	list_append(copy, ni);
+    }
+    ++copy->lv_refcount;
+    if (item != NULL)
+    {
+	list_unref(copy);
+	copy = NULL;
     }
 
     return copy;
@@ -1491,17 +1491,17 @@ list_join(
     retval = list_join_inner(gap, l, sep, echo_style, restore_copyID,
 							    copyID, &join_ga);
 
+    if (join_ga.ga_data == NULL)
+	return retval;
+
     // Dispose each item in join_ga.
-    if (join_ga.ga_data != NULL)
+    p = (join_T *)join_ga.ga_data;
+    for (i = 0; i < join_ga.ga_len; ++i)
     {
-	p = (join_T *)join_ga.ga_data;
-	for (i = 0; i < join_ga.ga_len; ++i)
-	{
-	    vim_free(p->tofree);
-	    ++p;
-	}
-	ga_clear(&join_ga);
+	vim_free(p->tofree);
+	++p;
     }
+    ga_clear(&join_ga);
 
     return retval;
 }
@@ -2560,36 +2560,36 @@ filter_map(typval_T *argvars, typval_T *rettv, filtermap_T filtermap)
     // message.  Avoid a misleading error message for an empty string that
     // was not passed as argument.
     expr = &argvars[1];
-    if (expr->v_type != VAR_UNKNOWN)
-    {
-	typval_T	save_val;
-	typval_T	save_key;
+    if (expr->v_type == VAR_UNKNOWN)
+	return;
+
+    typval_T	save_val;
+    typval_T	save_key;
 
-	prepare_vimvar(VV_VAL, &save_val);
-	prepare_vimvar(VV_KEY, &save_key);
+    prepare_vimvar(VV_VAL, &save_val);
+    prepare_vimvar(VV_KEY, &save_key);
 
-	// We reset "did_emsg" to be able to detect whether an error
-	// occurred during evaluation of the expression.
-	save_did_emsg = did_emsg;
-	did_emsg = FALSE;
+    // We reset "did_emsg" to be able to detect whether an error
+    // occurred during evaluation of the expression.
+    save_did_emsg = did_emsg;
+    did_emsg = FALSE;
 
-	if (argvars[0].v_type == VAR_DICT)
-	    dict_filter_map(argvars[0].vval.v_dict, filtermap, type, func_name,
-		    arg_errmsg, expr, rettv);
-	else if (argvars[0].v_type == VAR_BLOB)
-	    blob_filter_map(argvars[0].vval.v_blob, filtermap, expr, rettv);
-	else if (argvars[0].v_type == VAR_STRING)
-	    string_filter_map(tv_get_string(&argvars[0]), filtermap, expr,
-		    rettv);
-	else // argvars[0].v_type == VAR_LIST
-	    list_filter_map(argvars[0].vval.v_list, filtermap, type, func_name,
-		    arg_errmsg, expr, rettv);
+    if (argvars[0].v_type == VAR_DICT)
+	dict_filter_map(argvars[0].vval.v_dict, filtermap, type, func_name,
+		arg_errmsg, expr, rettv);
+    else if (argvars[0].v_type == VAR_BLOB)
+	blob_filter_map(argvars[0].vval.v_blob, filtermap, expr, rettv);
+    else if (argvars[0].v_type == VAR_STRING)
+	string_filter_map(tv_get_string(&argvars[0]), filtermap, expr,
+		rettv);
+    else // argvars[0].v_type == VAR_LIST
+	list_filter_map(argvars[0].vval.v_list, filtermap, type, func_name,
+		arg_errmsg, expr, rettv);
 
-	restore_vimvar(VV_KEY, &save_key);
-	restore_vimvar(VV_VAL, &save_val);
+    restore_vimvar(VV_KEY, &save_key);
+    restore_vimvar(VV_VAL, &save_val);
 
-	did_emsg |= save_did_emsg;
-    }
+    did_emsg |= save_did_emsg;
 }
 
 /*
diff --git a/src/locale.c b/src/locale.c
index d0378ffb50..ccdb479a8e 100644
--- a/src/locale.c
+++ b/src/locale.c
@@ -151,20 +151,20 @@ get_mess_env(void)
     char_u	*p;
 
     p = mch_getenv((char_u *)"LC_ALL");
-    if (p == NULL || *p == NUL)
-    {
-	p = mch_getenv((char_u *)"LC_MESSAGES");
-	if (p == NULL || *p == NUL)
-	{
-	    p = mch_getenv((char_u *)"LANG");
-	    if (p != NULL && VIM_ISDIGIT(*p))
-		p = NULL;		// ignore something like "1043"
+    if (p != NULL && *p != NUL)
+	return p;
+
+    p = mch_getenv((char_u *)"LC_MESSAGES");
+    if (p != NULL && *p != NUL)
+	return p;
+
+    p = mch_getenv((char_u *)"LANG");
+    if (p != NULL && VIM_ISDIGIT(*p))
+	p = NULL;		// ignore something like "1043"
 # ifdef HAVE_GET_LOCALE_VAL
-	    if (p == NULL || *p == NUL)
-		p = get_locale_val(LC_CTYPE);
+    if (p == NULL || *p == NUL)
+	p = get_locale_val(LC_CTYPE);
 # endif
-	}
-    }
     return p;
 }
 #endif
@@ -504,11 +504,11 @@ find_locales(void)
     static void
 init_locales(void)
 {
-    if (!did_init_locales)
-    {
-	did_init_locales = TRUE;
-	locales = find_locales();
-    }
+    if (did_init_locales)
+	return;
+
+    did_init_locales = TRUE;
+    locales = find_locales();
 }
 
 # if defined(EXITFREE) || defined(PROTO)
@@ -516,12 +516,13 @@ init_locales(void)
 free_locales(void)
 {
     int			i;
-    if (locales != NULL)
-    {
-	for (i = 0; locales[i] != NULL; i++)
-	    vim_free(locales[i]);
-	VIM_CLEAR(locales);
-    }
+
+    if (locales == NULL)
+	return;
+
+    for (i = 0; locales[i] != NULL; i++)
+	vim_free(locales[i]);
+    VIM_CLEAR(locales);
 }
 # endif
 
diff --git a/src/main.c b/src/main.c
index 0299c61a79..d1c42ed120 100644
--- a/src/main.c
+++ b/src/main.c
@@ -3099,23 +3099,23 @@ exe_pre_commands(mparm_T *parmp)
     int		i;
     ESTACK_CHECK_DECLARATION
 
-    if (cnt > 0)
-    {
-	curwin->w_cursor.lnum = 0; // just in case..
-	estack_push(ETYPE_ARGS, (char_u *)_("pre-vimrc command line"), 0);
-	ESTACK_CHECK_SETUP
+    if (cnt <= 0)
+	return;
+
+    curwin->w_cursor.lnum = 0; // just in case..
+    estack_push(ETYPE_ARGS, (char_u *)_("pre-vimrc command line"), 0);
+    ESTACK_CHECK_SETUP
 # ifdef FEAT_EVAL
 	current_sctx.sc_sid = SID_CMDARG;
 # endif
 	for (i = 0; i < cnt; ++i)
 	    do_cmdline_cmd(cmds[i]);
-	ESTACK_CHECK_NOW
+    ESTACK_CHECK_NOW
 	estack_pop();
 # ifdef FEAT_EVAL
-	current_sctx.sc_sid = 0;
+    current_sctx.sc_sid = 0;
 # endif
-	TIME_MSG("--cmd commands");
-    }
+    TIME_MSG("--cmd commands");
 }
 
 /*
@@ -3369,28 +3369,27 @@ process_env(
 
     ESTACK_CHECK_DECLARATION
 
-    if ((initstr = mch_getenv(env)) != NULL && *initstr != NUL)
-    {
-	if (is_viminit)
-	    vimrc_found(NULL, NULL);
-	estack_push(ETYPE_ENV, env, 0);
-	ESTACK_CHECK_SETUP
+    if ((initstr = mch_getenv(env)) == NULL || *initstr == NUL)
+	return FAIL;
+
+    if (is_viminit)
+	vimrc_found(NULL, NULL);
+    estack_push(ETYPE_ENV, env, 0);
+    ESTACK_CHECK_SETUP
 	save_current_sctx = current_sctx;
-	current_sctx.sc_version = 1;
+    current_sctx.sc_version = 1;
 #ifdef FEAT_EVAL
-	current_sctx.sc_sid = SID_ENV;
-	current_sctx.sc_seq = 0;
-	current_sctx.sc_lnum = 0;
+    current_sctx.sc_sid = SID_ENV;
+    current_sctx.sc_seq = 0;
+    current_sctx.sc_lnum = 0;
 #endif
 
-	do_cmdline_cmd(initstr);
+    do_cmdline_cmd(initstr);
 
-	ESTACK_CHECK_NOW
+    ESTACK_CHECK_NOW
 	estack_pop();
-	current_sctx = save_current_sctx;
-	return OK;
-    }
-    return FAIL;
+    current_sctx = save_current_sctx;
+    return OK;
 }
 
 #if (defined(UNIX) || defined(VMS)) && !defined(NO_VIM_MAIN)
diff --git a/src/map.c b/src/map.c
index a856b88e7c..244636fdc8 100644
--- a/src/map.c
+++ b/src/map.c
@@ -67,11 +67,11 @@ is_maphash_valid(void)
     static void
 validate_maphash(void)
 {
-    if (!maphash_valid)
-    {
-	CLEAR_FIELD(maphash);
-	maphash_valid = TRUE;
-    }
+    if (maphash_valid)
+	return;
+
+    CLEAR_FIELD(maphash);
+    maphash_valid = TRUE;
 }
 
 /*
@@ -581,8 +581,8 @@ do_map(
     // needs to be freed later (*keys_buf and *arg_buf).
     // replace_termcodes() also removes CTRL-Vs and sometimes backslashes.
     // If something like <C-H> is simplified to 0x08 then mark it as simplified
-    // and also add a n entry with a modifier, which will work when
-    // modifyOtherKeys is working.
+    // and also add an entry with a modifier, which will work when using a key
+    // protocol.
     if (haskey)
     {
 	char_u	*new_keys;
@@ -1843,32 +1843,33 @@ vim_strsave_escape_csi(char_u *p)
     // illegal utf-8 byte:
     // 0xc0 -> 0xc3 0x80 -> 0xc3 K_SPECIAL KS_SPECIAL KE_FILLER
     res = alloc(STRLEN(p) * 4 + 1);
-    if (res != NULL)
+    if (res == NULL)
+	return NULL;
+
+    d = res;
+    for (s = p; *s != NUL; )
     {
-	d = res;
-	for (s = p; *s != NUL; )
-	{
-	    if ((s[0] == K_SPECIAL
+	if ((s[0] == K_SPECIAL
 #ifdef FEAT_GUI
 		    || (gui.in_use && s[0] == CSI)
 #endif
-		) && s[1] != NUL && s[2] != NUL)
-	    {
-		// Copy special key unmodified.
-		*d++ = *s++;
-		*d++ = *s++;
-		*d++ = *s++;
-	    }
-	    else
-	    {
-		// Add character, possibly multi-byte to destination, escaping
-		// CSI and K_SPECIAL. Be careful, it can be an illegal byte!
-		d = add_char2buf(PTR2CHAR(s), d);
-		s += MB_CPTR2LEN(s);
-	    }
+	    ) && s[1] != NUL && s[2] != NUL)
+	{
+	    // Copy special key unmodified.
+	    *d++ = *s++;
+	    *d++ = *s++;
+	    *d++ = *s++;
+	}
+	else
+	{
+	    // Add character, possibly multi-byte to destination, escaping
+	    // CSI and K_SPECIAL. Be careful, it can be an illegal byte!
+	    d = add_char2buf(PTR2CHAR(s), d);
+	    s += MB_CPTR2LEN(s);
 	}
-	*d = NUL;
     }
+    *d = NUL;
+
     return res;
 }
 
diff --git a/src/mark.c b/src/mark.c
index 584db033d3..a7592e6077 100644
--- a/src/mark.c
+++ b/src/mark.c
@@ -485,34 +485,34 @@ fname2fnum(xfmark_T *fm)
 {
     char_u	*p;
 
-    if (fm->fname != NULL)
-    {
-	/*
-	 * First expand "~/" in the file name to the home directory.
-	 * Don't expand the whole name, it may contain other '~' chars.
-	 */
-	if (fm->fname[0] == '~' && (fm->fname[1] == '/'
+    if (fm->fname == NULL)
+	return;
+
+    /*
+     * First expand "~/" in the file name to the home directory.
+     * Don't expand the whole name, it may contain other '~' chars.
+     */
+    if (fm->fname[0] == '~' && (fm->fname[1] == '/'
 #ifdef BACKSLASH_IN_FILENAME
-		    || fm->fname[1] == '\\'
+		|| fm->fname[1] == '\\'
 #endif
-		    ))
-	{
-	    int len;
+		))
+    {
+	int len;
 
-	    expand_env((char_u *)"~/", NameBuff, MAXPATHL);
-	    len = (int)STRLEN(NameBuff);
-	    vim_strncpy(NameBuff + len, fm->fname + 2, MAXPATHL - len - 1);
-	}
-	else
-	    vim_strncpy(NameBuff, fm->fname, MAXPATHL - 1);
+	expand_env((char_u *)"~/", NameBuff, MAXPATHL);
+	len = (int)STRLEN(NameBuff);
+	vim_strncpy(NameBuff + len, fm->fname + 2, MAXPATHL - len - 1);
+    }
+    else
+	vim_strncpy(NameBuff, fm->fname, MAXPATHL - 1);
 
-	// Try to shorten the file name.
-	mch_dirname(IObuff, IOSIZE);
-	p = shorten_fname(NameBuff, IObuff);
+    // Try to shorten the file name.
+    mch_dirname(IObuff, IOSIZE);
+    p = shorten_fname(NameBuff, IObuff);
 
-	// buflist_new() will call fmarks_check_names()
-	(void)buflist_new(NameBuff, p, (linenr_T)1, 0);
-    }
+    // buflist_new() will call fmarks_check_names()
+    (void)buflist_new(NameBuff, p, (linenr_T)1, 0);
 }
 
 /*
diff --git a/src/match.c b/src/match.c
index 6ac6513ca8..f59c2066a1 100644
--- a/src/match.c
+++ b/src/match.c
@@ -978,14 +978,14 @@ matchadd_dict_arg(typval_T *tv, char_u **conceal_char, win_T **win)
     if (dict_has_key(tv->vval.v_dict, "conceal"))
 	*conceal_char = dict_get_string(tv->vval.v_dict, "conceal", FALSE);
 
-    if ((di = dict_find(tv->vval.v_dict, (char_u *)"window", -1)) != NULL)
+    if ((di = dict_find(tv->vval.v_dict, (char_u *)"window", -1)) == NULL)
+	return OK;
+
+    *win = find_win_by_nr_or_id(&di->di_tv);
+    if (*win == NULL)
     {
-	*win = find_win_by_nr_or_id(&di->di_tv);
-	if (*win == NULL)
-	{
-	    emsg(_(e_invalid_window_number));
-	    return FAIL;
-	}
+	emsg(_(e_invalid_window_number));
+	return FAIL;
     }
 
     return OK;
@@ -1330,32 +1330,32 @@ f_matchaddpos(typval_T *argvars UNUSED, typval_T *rettv UNUSED)
     void
 f_matcharg(typval_T *argvars UNUSED, typval_T *rettv)
 {
-    if (rettv_list_alloc(rettv) == OK)
-    {
+    if (rettv_list_alloc(rettv) != OK)
+	return;
+
 # ifdef FEAT_SEARCH_EXTRA
-	int	    id;
-	matchitem_T *m;
+    int	    id;
+    matchitem_T *m;
 
-	if (in_vim9script() && check_for_number_arg(argvars, 0) == FAIL)
-	    return;
+    if (in_vim9script() && check_for_number_arg(argvars, 0) == FAIL)
+	return;
 
-	id = (int)tv_get_number(&argvars[0]);
-	if (id >= 1 && id <= 3)
+    id = (int)tv_get_number(&argvars[0]);
+    if (id >= 1 && id <= 3)
+    {
+	if ((m = get_match(curwin, id)) != NULL)
 	{
-	    if ((m = get_match(curwin, id)) != NULL)
-	    {
-		list_append_string(rettv->vval.v_list,
-					       syn_id2name(m->mit_hlg_id), -1);
-		list_append_string(rettv->vval.v_list, m->mit_pattern, -1);
-	    }
-	    else
-	    {
-		list_append_string(rettv->vval.v_list, NULL, -1);
-		list_append_string(rettv->vval.v_list, NULL, -1);
-	    }
+	    list_append_string(rettv->vval.v_list,
+		    syn_id2name(m->mit_hlg_id), -1);
+	    list_append_string(rettv->vval.v_list, m->mit_pattern, -1);
+	}
+	else
+	{
+	    list_append_string(rettv->vval.v_list, NULL, -1);
+	    list_append_string(rettv->vval.v_list, NULL, -1);
 	}
-# endif
     }
+# endif
 }
 
 /*
diff --git a/src/mbyte.c b/src/mbyte.c
index 1570cef231..07cd9c6e64 100644
--- a/src/mbyte.c
+++ b/src/mbyte.c
@@ -809,17 +809,17 @@ bomb_size(void)
     void
 remove_bom(char_u *s)
 {
-    if (enc_utf8)
-    {
-	char_u *p = s;
+    if (!enc_utf8)
+	return;
 
-	while ((p = vim_strbyte(p, 0xef)) != NULL)
-	{
-	    if (p[1] == 0xbb && p[2] == 0xbf)
-		STRMOVE(p, p + 3);
-	    else
-		++p;
-	}
+    char_u *p = s;
+
+    while ((p = vim_strbyte(p, 0xef)) != NULL)
+    {
+	if (p[1] == 0xbb && p[2] == 0xbf)
+	    STRMOVE(p, p + 3);
+	else
+	    ++p;
     }
 }
 #endif
@@ -4590,56 +4590,56 @@ enc_canonize(char_u *enc)
 
     // copy "enc" to allocated memory, with room for two '-'
     r = alloc(STRLEN(enc) + 3);
-    if (r != NULL)
+    if (r == NULL)
+	return NULL;
+
+    // Make it all lower case and replace '_' with '-'.
+    p = r;
+    for (s = enc; *s != NUL; ++s)
     {
-	// Make it all lower case and replace '_' with '-'.
-	p = r;
-	for (s = enc; *s != NUL; ++s)
-	{
-	    if (*s == '_')
-		*p++ = '-';
-	    else
-		*p++ = TOLOWER_ASC(*s);
-	}
-	*p = NUL;
+	if (*s == '_')
+	    *p++ = '-';
+	else
+	    *p++ = TOLOWER_ASC(*s);
+    }
+    *p = NUL;
 
-	// Skip "2byte-" and "8bit-".
-	p = enc_skip(r);
+    // Skip "2byte-" and "8bit-".
+    p = enc_skip(r);
 
-	// Change "microsoft-cp" to "cp".  Used in some spell files.
-	if (STRNCMP(p, "microsoft-cp", 12) == 0)
-	    STRMOVE(p, p + 10);
+    // Change "microsoft-cp" to "cp".  Used in some spell files.
+    if (STRNCMP(p, "microsoft-cp", 12) == 0)
+	STRMOVE(p, p + 10);
 
-	// "iso8859" -> "iso-8859"
-	if (STRNCMP(p, "iso8859", 7) == 0)
-	{
-	    STRMOVE(p + 4, p + 3);
-	    p[3] = '-';
-	}
+    // "iso8859" -> "iso-8859"
+    if (STRNCMP(p, "iso8859", 7) == 0)
+    {
+	STRMOVE(p + 4, p + 3);
+	p[3] = '-';
+    }
 
-	// "iso-8859n" -> "iso-8859-n"
-	if (STRNCMP(p, "iso-8859", 8) == 0 && isdigit(p[8]))
-	{
-	    STRMOVE(p + 9, p + 8);
-	    p[8] = '-';
-	}
+    // "iso-8859n" -> "iso-8859-n"
+    if (STRNCMP(p, "iso-8859", 8) == 0 && isdigit(p[8]))
+    {
+	STRMOVE(p + 9, p + 8);
+	p[8] = '-';
+    }
 
-	// "latin-N" -> "latinN"
-	if (STRNCMP(p, "latin-", 6) == 0)
-	    STRMOVE(p + 5, p + 6);
+    // "latin-N" -> "latinN"
+    if (STRNCMP(p, "latin-", 6) == 0)
+	STRMOVE(p + 5, p + 6);
 
-	if (enc_canon_search(p) >= 0)
-	{
-	    // canonical name can be used unmodified
-	    if (p != r)
-		STRMOVE(r, p);
-	}
-	else if ((i = enc_alias_search(p)) >= 0)
-	{
-	    // alias recognized, get canonical name
-	    vim_free(r);
-	    r = vim_strsave((char_u *)enc_canon_table[i].name);
-	}
+    if (enc_canon_search(p) >= 0)
+    {
+	// canonical name can be used unmodified
+	if (p != r)
+	    STRMOVE(r, p);
+    }
+    else if ((i = enc_alias_search(p)) >= 0)
+    {
+	// alias recognized, get canonical name
+	vim_free(r);
+	r = vim_strsave((char_u *)enc_canon_table[i].name);
     }
     return r;
 }
@@ -5269,26 +5269,26 @@ convert_input_safe(
 
     d = string_convert_ext(&input_conv, ptr, &dlen,
 					restp == NULL ? NULL : &unconvertlen);
-    if (d != NULL)
+    if (d == NULL)
+	return dlen;
+
+    if (dlen <= maxlen)
     {
-	if (dlen <= maxlen)
+	if (unconvertlen > 0)
 	{
-	    if (unconvertlen > 0)
-	    {
-		// Move the unconverted characters to allocated memory.
-		*restp = alloc(unconvertlen);
-		if (*restp != NULL)
-		    mch_memmove(*restp, ptr + len - unconvertlen, unconvertlen);
-		*restlenp = unconvertlen;
-	    }
-	    mch_memmove(ptr, d, dlen);
+	    // Move the unconverted characters to allocated memory.
+	    *restp = alloc(unconvertlen);
+	    if (*restp != NULL)
+		mch_memmove(*restp, ptr + len - unconvertlen, unconvertlen);
+	    *restlenp = unconvertlen;
 	}
-	else
-	    // result is too long, keep the unconverted text (the caller must
-	    // have done something wrong!)
-	    dlen = len;
-	vim_free(d);
+	mch_memmove(ptr, d, dlen);
     }
+    else
+	// result is too long, keep the unconverted text (the caller must
+	// have done something wrong!)
+	dlen = len;
+    vim_free(d);
     return dlen;
 }
 
diff --git a/src/memfile.c b/src/memfile.c
index 0d816f36d3..e8cbe31696 100644
--- a/src/memfile.c
+++ b/src/memfile.c
@@ -879,16 +879,16 @@ mf_alloc_bhdr(memfile_T *mfp, int page_count)
 {
     bhdr_T	*hp;
 
-    if ((hp = ALLOC_ONE(bhdr_T)) != NULL)
+    if ((hp = ALLOC_ONE(bhdr_T)) == NULL)
+	return NULL;
+
+    if ((hp->bh_data = alloc((size_t)mfp->mf_page_size * page_count))
+	    == NULL)
     {
-	if ((hp->bh_data = alloc((size_t)mfp->mf_page_size * page_count))
-								       == NULL)
-	{
-	    vim_free(hp);	    // not enough memory
-	    return NULL;
-	}
-	hp->bh_page_count = page_count;
+	vim_free(hp);	    // not enough memory
+	return NULL;
     }
+    hp->bh_page_count = page_count;
     return hp;
 }
 
@@ -1209,12 +1209,12 @@ mf_set_ffname(memfile_T *mfp)
     void
 mf_fullname(memfile_T *mfp)
 {
-    if (mfp != NULL && mfp->mf_fname != NULL && mfp->mf_ffname != NULL)
-    {
-	vim_free(mfp->mf_fname);
-	mfp->mf_fname = mfp->mf_ffname;
-	mfp->mf_ffname = NULL;
-    }
+    if (mfp == NULL || mfp->mf_fname == NULL || mfp->mf_ffname == NULL)
+	return;
+
+    vim_free(mfp->mf_fname);
+    mfp->mf_fname = mfp->mf_ffname;
+    mfp->mf_ffname = NULL;
 }
 
 /*
diff --git a/src/memline.c b/src/memline.c
index 48b17f5589..7cbe559e65 100644
--- a/src/memline.c
+++ b/src/memline.c
@@ -422,21 +422,21 @@ error:
     static void
 ml_set_mfp_crypt(buf_T *buf)
 {
-    if (*buf->b_p_key != NUL)
-    {
-	int method_nr = crypt_get_method_nr(buf);
+    if (*buf->b_p_key == NUL)
+	return;
 
-	if (method_nr > CRYPT_M_ZIP && method_nr < CRYPT_M_SOD)
-	{
-	    // Generate a seed and store it in the memfile.
-	    sha2_seed(buf->b_ml.ml_mfp->mf_seed, MF_SEED_LEN, NULL, 0);
-	}
-#ifdef FEAT_SODIUM
-	else if (method_nr == CRYPT_M_SOD)
-	    crypt_sodium_randombytes_buf(buf->b_ml.ml_mfp->mf_seed,
-							    MF_SEED_LEN);
- #endif
+    int method_nr = crypt_get_method_nr(buf);
+
+    if (method_nr > CRYPT_M_ZIP && method_nr < CRYPT_M_SOD)
+    {
+	// Generate a seed and store it in the memfile.
+	sha2_seed(buf->b_ml.ml_mfp->mf_seed, MF_SEED_LEN, NULL, 0);
     }
+#ifdef FEAT_SODIUM
+    else if (method_nr == CRYPT_M_SOD)
+	crypt_sodium_randombytes_buf(buf->b_ml.ml_mfp->mf_seed,
+		MF_SEED_LEN);
+#endif
 }
 
 /*
@@ -2090,22 +2090,22 @@ make_percent_swname(char_u *dir, char_u *name)
     char_u *d = NULL, *s, *f;
 
     f = fix_fname(name != NULL ? name : (char_u *)"");
-    if (f != NULL)
-    {
-	s = alloc(STRLEN(f) + 1);
-	if (s != NULL)
-	{
-	    STRCPY(s, f);
-	    for (d = s; *d != NUL; MB_PTR_ADV(d))
-		if (vim_ispathsep(*d))
-		    *d = '%';
+    if (f == NULL)
+	return NULL;
 
-	    dir[STRLEN(dir) - 1] = NUL;  // remove one trailing slash
-	    d = concat_fnames(dir, s, TRUE);
-	    vim_free(s);
-	}
-	vim_free(f);
+    s = alloc(STRLEN(f) + 1);
+    if (s != NULL)
+    {
+	STRCPY(s, f);
+	for (d = s; *d != NUL; MB_PTR_ADV(d))
+	    if (vim_ispathsep(*d))
+		*d = '%';
+
+	dir[STRLEN(dir) - 1] = NUL;  // remove one trailing slash
+	d = concat_fnames(dir, s, TRUE);
+	vim_free(s);
     }
+    vim_free(f);
     return d;
 }
 #endif
@@ -5473,24 +5473,24 @@ ml_decrypt_data(
     int		text_len;
     cryptstate_T *state;
 
-    if (dp->db_id == DATA_ID)
-    {
-	head_end = (char_u *)(&dp->db_index[dp->db_line_count]);
-	text_start = (char_u *)dp + dp->db_txt_start;
-	text_len = dp->db_txt_end - dp->db_txt_start;
+    if (dp->db_id != DATA_ID)
+	return;
+
+    head_end = (char_u *)(&dp->db_index[dp->db_line_count]);
+    text_start = (char_u *)dp + dp->db_txt_start;
+    text_len = dp->db_txt_end - dp->db_txt_start;
 
-	if (head_end > text_start || dp->db_txt_start > size
-						     || dp->db_txt_end > size)
-	    return;  // data was messed up
+    if (head_end > text_start || dp->db_txt_start > size
+	    || dp->db_txt_end > size)
+	return;  // data was messed up
 
-	state = ml_crypt_prepare(mfp, offset, TRUE);
-	if (state != NULL)
-	{
-	    // Decry