--- src/hb-object-private.hh
+++ src/hb-object-private.hh
@@ -131,7 +131,7 @@
   }
 
   inline bool destroy (void) {
-    if (unlikely (!this || this->is_inert ()))
+    if (unlikely (is_inert ()))
       return false;
     if (ref_count.dec () != 1)
       return false;
@@ -160,13 +160,12 @@
   }
 
   inline void trace (const char *function) const {
-    if (unlikely (!this)) return;
     /* TODO We cannot use DEBUG_MSG_FUNC here since that one currently only
      * prints the class name and throws away the template info. */
     DEBUG_MSG (OBJECT, (void *) this,
 	       "%s refcount=%d",
 	       function,
-	       this ? ref_count.ref_count : 0);
+	       ref_count.ref_count);
   }
 
   private:
@@ -179,7 +179,7 @@
 template <typename Type>
 static inline void hb_object_trace (const Type *obj, const char *function)
 {
-  obj->header.trace (function);
+  if (likely (obj)) obj->header.trace (function);
 }
 template <typename Type>
 static inline Type *hb_object_create (void)
@@ -204,7 +204,7 @@
 static inline bool hb_object_destroy (Type *obj)
 {
   hb_object_trace (obj, HB_FUNC);
-  return obj->header.destroy ();
+  return likely (obj) && obj->header.destroy ();
 }
 template <typename Type>
 static inline bool hb_object_set_user_data (Type               *obj,
--- src/hb-ot-map-private.hh
+++ src/hb-ot-map-private.hh
@@ -52,8 +52,12 @@
     unsigned int needs_fallback : 1;
     unsigned int auto_zwj : 1;
 
-    static int cmp (const feature_map_t *a, const feature_map_t *b)
-    { return a->tag < b->tag ? -1 : a->tag > b->tag ? 1 : 0; }
+    static int cmp (const void *va, const void *vb)
+    {
+      const feature_map_t *a = static_cast<const feature_map_t *>(va);
+      const feature_map_t *b = static_cast<const feature_map_t *>(vb);
+      return a->tag < b->tag ? -1 : a->tag > b->tag ? 1 : 0;
+    }
   };
 
   struct lookup_map_t {
--- src/hb-ot-tag.cc
+++ src/hb-ot-tag.cc
@@ -591,9 +591,11 @@
 };
 
 static int
-lang_compare_first_component (const char *a,
-			      const char *b)
+lang_compare_first_component (const void *va,
+			      const void *vb)
 {
+  const char *a = static_cast<const char *>(va);
+  const char *b = static_cast<const char *>(vb);
   unsigned int da, db;
   const char *p;
 
@@ -641,7 +643,7 @@
   /* Find a language matching in the first component */
   lang_tag = (LangTag *) bsearch (lang_str, ot_languages,
 				  ARRAY_LENGTH (ot_languages), sizeof (LangTag),
-				  (hb_compare_func_t) lang_compare_first_component);
+				  lang_compare_first_component);
   if (lang_tag)
     return lang_tag->tag;