patch 8.0.0074
Problem:    Cannot make Vim fail on an internal error.
Solution:   Add IEMSG() and IEMSG2(). (Domenique Pelle)  Avoid reporting an
            internal error without mentioning where.
diff --git a/src/globals.h b/src/globals.h
index fea9543..c15e4f9 100644
--- a/src/globals.h
+++ b/src/globals.h
@@ -1440,6 +1440,7 @@
 EXTERN char_u e_fontwidth[]	INIT(= N_("E236: Font \"%s\" is not fixed-width"));
 #endif
 EXTERN char_u e_internal[]	INIT(= N_("E473: Internal error"));
+EXTERN char_u e_intern2[]	INIT(= N_("E685: Internal error: %s"));
 EXTERN char_u e_interr[]	INIT(= N_("Interrupted"));
 EXTERN char_u e_invaddr[]	INIT(= N_("E14: Invalid address"));
 EXTERN char_u e_invarg[]	INIT(= N_("E474: Invalid argument"));
@@ -1589,7 +1590,6 @@
 EXTERN char_u e_guarded[]	INIT(= N_("E463: Region is guarded, cannot modify"));
 EXTERN char_u e_nbreadonly[]	INIT(= N_("E744: NetBeans does not allow changes in read-only files"));
 #endif
-EXTERN char_u e_intern2[]	INIT(= N_("E685: Internal error: %s"));
 EXTERN char_u e_maxmempat[]	INIT(= N_("E363: pattern uses more memory than 'maxmempattern'"));
 EXTERN char_u e_emptybuf[]	INIT(= N_("E749: empty buffer"));
 EXTERN char_u e_nobufnr[]	INIT(= N_("E86: Buffer %ld does not exist"));