regcomp.c: Add assert

The code's proper functioning currently depends on bracketed character
classes not returning a sequence of characters to the regex sets feature
(?[...])

Add an assert to validate that.

1 files changed, 1 insertions, 0 deletions

diff --git a/regcomp.c b/regcomp.c
index 8e109b5c72..1c45413e61 100644
--- a/regcomp.c
+++ b/regcomp.c
@@ -17371,6 +17371,7 @@ S_regclass(pTHX_ RExC_state_t *pRExC_state, I32 *flagp, U32 depth,
     PERL_UNUSED_ARG(depth);
 #endif
 
+    assert(! (ret_invlist && allow_mutiple_chars));
 
     /* If wants an inversion list returned, we can't optimize to something
      * else. */