=== modified file 'src/font.c'
--- src/font.c	2014-04-05 19:30:36 +0000
+++ src/font.c	2014-05-18 16:11:09 +0000
@@ -2803,10 +2803,16 @@
 	ASET (work, FONT_TYPE_INDEX, driver_list->driver->type);
 	entity = assoc_no_quit (work, XCDR (cache));
 	if (CONSP (entity))
-	  entity = XCDR (entity);
+	  {
+	    entity = XCDR (entity);
+	    fprintf (stderr, "%s: cached entity ", __func__);
+	    debug_print (entity);
+	  }
 	else
 	  {
 	    entity = driver_list->driver->match (f, work);
+	    fprintf (stderr, "%s: matched entity ", __func__);
+	    debug_print (entity);
 	    if (!NILP (entity))
 	      {
 		Lisp_Object copy = copy_font_spec (work);
@@ -3299,6 +3305,7 @@
   Lisp_Object entity, name;
 
   entity = font_find_for_lface (f, attrs, spec, -1);
+  eassert (NILP (entity) || FONT_ENTITY_P (entity));  
   if (NILP (entity))
     {
       /* No font is listed for SPEC, but each font-backend may have
@@ -3307,6 +3314,7 @@
       if (NILP (entity))
 	return Qnil;
     }
+  eassert (NILP (entity) || FONT_ENTITY_P (entity));
   /* Don't lose the original name that was put in initially.  We need
      it to re-apply the font when font parameters (like hinting or dpi) have
      changed.  */