CC1514

diff --git a/src/core/n-control.c b/src/core/n-control.c
index e927576..29acd80 100644
--- a/src/core/n-control.c
+++ b/src/core/n-control.c
@@ -764,6 +764,13 @@ got_err:
                        }
                        else { // do func[error] arg
                                REBVAL arg = *DS_NEXT; // will get overwritten
+                               REBSER *words = VAL_FUNC_WORDS(&value);
+                               REBVAL *args = BLK_SKIP(words, 1);
+                               if (SERIES_TAIL(words) != 2
+                                       || !TYPE_CHECK(args, VAL_TYPE(&value))) {
+                                       Trap_Arg(&value);
+                               }
+
                                Apply_Func(0, &value, &arg, 0);
                        }
                }