* src/fns.c (Fmapconcat): Better empty-string-or-nil detection.

diff --git a/src/fns.c b/src/fns.c
index a6ceac293550b8cbe7b7e87a59804cfa9b99897f..4a9954ce9035c51e01ea202a85fdbfc02d913466 100644 (file)
--- a/src/fns.c
+++ b/src/fns.c
@@ -2836,7 +2836,7 @@ FUNCTION must be a function of one argument, and must return a value
   ptrdiff_t nargs = 2 * nmapped - 1;
   eassert (nmapped == leni);
 
-  if (!NILP (Fequal (separator, empty_multibyte_string)))
+  if (NILP (separator) || (STRINGP (separator) && SCHARS (separator) == 0))
     nargs = nmapped;
   else
     {