diff --git a/src/insexpand.c b/src/insexpand.c
index 3cfdfac..b767b4e 100644
--- a/src/insexpand.c
+++ b/src/insexpand.c
@@ -3850,7 +3850,7 @@
 	else
 	{
 	    // Mark a buffer scanned when it has been scanned completely
-	    if (type == 0 || type == CTRL_X_PATH_PATTERNS)
+	    if (buf_valid(st.ins_buf) && (type == 0 || type == CTRL_X_PATH_PATTERNS))
 		st.ins_buf->b_scanned = TRUE;
 
 	    compl_started = FALSE;
diff --git a/src/testdir/crash/poc_tagfunc.vim b/src/testdir/crash/poc_tagfunc.vim
new file mode 100644
index 0000000..49d9b6f
--- /dev/null
+++ b/src/testdir/crash/poc_tagfunc.vim
@@ -0,0 +1,6 @@
+fu Tagfunc(t,f,o)
+  bw
+endf
+set tagfunc=Tagfunc
+n0
+sil0norm0i
diff --git a/src/testdir/test_crash.vim b/src/testdir/test_crash.vim
index 516d991..27bf7b5 100644
--- a/src/testdir/test_crash.vim
+++ b/src/testdir/test_crash.vim
@@ -39,12 +39,17 @@
     \ '  && echo "crash 4: [OK]" >> X_crash1_result.txt' .. "\<cr>")
   " clean up
   call delete('Xerr')
-
   " This test takes a bit longer
   call TermWait(buf, 200)
 
+  let file = 'crash/poc_tagfunc.vim'
+  let args = printf(cmn_args, vim, file)
+  call term_sendkeys(buf, args ..
+    \ '  || echo "crash 5: [OK]" >> X_crash1_result.txt' .. "\<cr>")
+
+  call TermWait(buf, 100)
+
   " clean up
-  call delete('Xerr')
   exe buf .. "bw!"
 
   sp X_crash1_result.txt
@@ -54,6 +59,7 @@
       \ 'crash 2: [OK]',
       \ 'crash 3: [OK]',
       \ 'crash 4: [OK]',
+      \ 'crash 5: [OK]',
       \ ]
 
   call assert_equal(expected, getline(1, '$'))
diff --git a/src/version.c b/src/version.c
index 13d5d69..b604b57 100644
--- a/src/version.c
+++ b/src/version.c
@@ -700,6 +700,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1858,
+/**/
     1857,
 /**/
     1856,