toke.c: Assert that we don’t overflow token stack

With this assertion, the test case from #123743 fails sooner.

1 files changed, 1 insertions, 0 deletions

diff --git a/toke.c b/toke.c
index 388b272442..2df773299e 100644
--- a/toke.c
+++ b/toke.c
@@ -1907,6 +1907,7 @@ S_force_next(pTHX_ I32 type)
 	tokereport(type, &NEXTVAL_NEXTTOKE);
     }
 #endif
+    assert(PL_nexttoke < C_ARRAY_LENGTH(PL_nexttype));
     PL_nexttype[PL_nexttoke] = type;
     PL_nexttoke++;
     if (PL_lex_state != LEX_KNOWNEXT) {