path-cat: error if arguments are not strings.

* stream.c (path_cat): Use length_str to enforce a type check.
Otherwise, for instance, (path-cat #() "foo") will return "foo".

1 files changed, 2 insertions, 2 deletions

diff --git a/stream.c b/stream.c
index e4670e10..cb853d98 100644
--- a/stream.c
+++ b/stream.c
@@ -5079,8 +5079,8 @@ val long_suffix(val name, val alt_in)
 
 val path_cat(val dir_name, val base_name)
 {
-  val dl = length(dir_name);
-  val bl = length(base_name);
+  val dl = length_str(dir_name);
+  val bl = length_str(base_name);
   val ps = static_str(path_sep_chars);
 
   if (dl == zero)