patch 7.4.1866
Problem:    Invalid memory access when exiting with EXITFREE defined.
            (Dominique Pelle)
Solution:   Set "really_exiting" and skip error messages.
diff --git a/src/eval.c b/src/eval.c
index 3d0abf3..a49d54b 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -25348,7 +25348,11 @@
     {
 	fp = find_func(name);
 	if (fp == NULL)
-	    EMSG2(_(e_intern2), "func_unref()");
+	{
+	    /* Ignore when invoked through free_all_mem(). */
+	    if (!really_exiting)
+		EMSG2(_(e_intern2), "func_unref()");
+	}
 	else if (--fp->uf_refcount <= 0)
 	{
 	    /* Only delete it when it's not being used.  Otherwise it's done
diff --git a/src/misc2.c b/src/misc2.c
index b4e9479..f7b1de3 100644
--- a/src/misc2.c
+++ b/src/misc2.c
@@ -1044,6 +1044,9 @@
 	return;
     entered = TRUE;
 
+    /* Set this flag to indicate some errors can be ignored. */
+    really_exiting = TRUE;
+
 # ifdef FEAT_AUTOCMD
     /* Don't want to trigger autocommands from here on. */
     block_autocmds();
diff --git a/src/version.c b/src/version.c
index 7952a14..f9305d5 100644
--- a/src/version.c
+++ b/src/version.c
@@ -754,6 +754,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1866,
+/**/
     1865,
 /**/
     1864,