diff --git a/src/vim9expr.c b/src/vim9expr.c
index 8cd095c..370dce3 100644
--- a/src/vim9expr.c
+++ b/src/vim9expr.c
@@ -975,6 +975,7 @@
     int		count = 0;
     int		is_const;
     int		is_all_const = TRUE;	// reset when non-const encountered
+    int		must_end = FALSE;
 
     for (;;)
     {
@@ -993,6 +994,11 @@
 	    ++p;
 	    break;
 	}
+	if (must_end)
+	{
+	    semsg(_(e_missing_comma_in_list_str), p);
+	    return FAIL;
+	}
 	if (compile_expr0_ext(&p, cctx, &is_const) == FAIL)
 	    return FAIL;
 	if (!is_const)
@@ -1007,6 +1013,8 @@
 		return FAIL;
 	    }
 	}
+	else
+	    must_end = TRUE;
 	whitep = p;
 	p = skipwhite(p);
     }