diff --git a/src/getchar.c b/src/getchar.c
index 80e98ec..f6734a7 100644
--- a/src/getchar.c
+++ b/src/getchar.c
@@ -2540,13 +2540,18 @@
 			 */
 			if (mp->m_expr)
 			{
-			    int		save_vgetc_busy = vgetc_busy;
+			    int save_vgetc_busy = vgetc_busy;
+			    int save_may_garbage_collect = may_garbage_collect;
 
 			    vgetc_busy = 0;
+			    may_garbage_collect = FALSE;
+
 			    save_m_keys = vim_strsave(mp->m_keys);
 			    save_m_str = vim_strsave(mp->m_str);
 			    s = eval_map_expr(save_m_str, NUL);
+
 			    vgetc_busy = save_vgetc_busy;
+			    may_garbage_collect = save_may_garbage_collect;
 			}
 			else
 #endif