diff --git a/ext/-test-/exception/enc_raise.c b/ext/-test-/exception/enc_raise.c
index 25410df205..dc8a42cf3f 100644
--- a/ext/-test-/exception/enc_raise.c
+++ b/ext/-test-/exception/enc_raise.c
@@ -5,6 +5,7 @@ static VALUE
 enc_raise(VALUE exc, VALUE encoding, VALUE mesg)
 {
     rb_enc_raise(rb_to_encoding(encoding), exc, "%s", StringValueCStr(mesg));
+    UNREACHABLE;
 }
 
 void