diff --git a/src/regexp.c b/src/regexp.c
index 6a62b28..69acb69 100644
--- a/src/regexp.c
+++ b/src/regexp.c
@@ -325,8 +325,8 @@
 
 /* Used for an error (down from) vim_regcomp(): give the error message, set
  * rc_did_emsg and return NULL */
-#define EMSG_RET_NULL(m) return (EMSG(m), rc_did_emsg = TRUE, NULL)
-#define EMSG_M_RET_NULL(m, c) return (EMSG2((m), (c) ? "" : "\\"), rc_did_emsg = TRUE, NULL)
+#define EMSG_RET_NULL(m) return (EMSG(m), rc_did_emsg = TRUE, (void *)NULL)
+#define EMSG_M_RET_NULL(m, c) return (EMSG2((m), (c) ? "" : "\\"), rc_did_emsg = TRUE, (void *)NULL)
 #define EMSG_RET_FAIL(m) return (EMSG(m), rc_did_emsg = TRUE, FAIL)
 #define EMSG_ONE_RET_NULL EMSG_M_RET_NULL(_("E369: invalid item in %s%%[]"), reg_magic == MAGIC_ALL)