diff --git a/src/OT/Layout/Common/Coverage.hh b/src/OT/Layout/Common/Coverage.hh
index 000e78146..fbd7c642a 100644
--- a/src/OT/Layout/Common/Coverage.hh
+++ b/src/OT/Layout/Common/Coverage.hh
@@ -74,10 +74,8 @@ struct Coverage
   }
 
   /* Has interface. */
-  static constexpr unsigned SENTINEL = NOT_COVERED;
-  typedef unsigned int value_t;
-  value_t operator [] (hb_codepoint_t k) const { return get (k); }
-  bool has (hb_codepoint_t k) const { return (*this)[k] != SENTINEL; }
+  unsigned operator [] (hb_codepoint_t k) const { return get (k); }
+  bool has (hb_codepoint_t k) const { return (*this)[k] != NOT_COVERED; }
   /* Predicate. */
   bool operator () (hb_codepoint_t k) const { return has (k); }
 
diff --git a/src/hb-bit-set-invertible.hh b/src/hb-bit-set-invertible.hh
index 27fb0732e..ff8aecc60 100644
--- a/src/hb-bit-set-invertible.hh
+++ b/src/hb-bit-set-invertible.hh
@@ -123,10 +123,8 @@ struct hb_bit_set_invertible_t
   bool get (hb_codepoint_t g) const { return s.get (g) ^ inverted; }
 
   /* Has interface. */
-  static constexpr bool SENTINEL = false;
-  typedef bool value_t;
-  value_t operator [] (hb_codepoint_t k) const { return get (k); }
-  bool has (hb_codepoint_t k) const { return (*this)[k] != SENTINEL; }
+  bool operator [] (hb_codepoint_t k) const { return get (k); }
+  bool has (hb_codepoint_t k) const { return (*this)[k]; }
   /* Predicate. */
   bool operator () (hb_codepoint_t k) const { return has (k); }
 
diff --git a/src/hb-bit-set.hh b/src/hb-bit-set.hh
index d615408e8..6c4df79c4 100644
--- a/src/hb-bit-set.hh
+++ b/src/hb-bit-set.hh
@@ -330,10 +330,8 @@ struct hb_bit_set_t
   }
 
   /* Has interface. */
-  static constexpr bool SENTINEL = false;
-  typedef bool value_t;
-  value_t operator [] (hb_codepoint_t k) const { return get (k); }
-  bool has (hb_codepoint_t k) const { return (*this)[k] != SENTINEL; }
+  bool operator [] (hb_codepoint_t k) const { return get (k); }
+  bool has (hb_codepoint_t k) const { return (*this)[k]; }
   /* Predicate. */
   bool operator () (hb_codepoint_t k) const { return has (k); }
 
diff --git a/src/hb-map.hh b/src/hb-map.hh
index f9c7b3d3f..bfb1b3f76 100644
--- a/src/hb-map.hh
+++ b/src/hb-map.hh
@@ -248,8 +248,7 @@ struct hb_hashmap_t
   void del (const K &key) { set_with_hash (key, hb_hash (key), item_t::default_value (), true); }
 
   /* Has interface. */
-  typedef const V& value_t;
-  value_t operator [] (K k) const { return get (k); }
+  const V& operator [] (K k) const { return get (k); }
   template <typename VV=V>
   bool has (K key, VV **vp = nullptr) const
   {
diff --git a/src/hb-ot-layout-common.hh b/src/hb-ot-layout-common.hh
index 3410b01bb..fda3f3121 100644
--- a/src/hb-ot-layout-common.hh
+++ b/src/hb-ot-layout-common.hh
@@ -1999,10 +1999,8 @@ struct ClassDefFormat2_4
 struct ClassDef
 {
   /* Has interface. */
-  static constexpr unsigned SENTINEL = 0;
-  typedef unsigned int value_t;
-  value_t operator [] (hb_codepoint_t k) const { return get (k); }
-  bool has (hb_codepoint_t k) const { return (*this)[k] != SENTINEL; }
+  unsigned operator [] (hb_codepoint_t k) const { return get (k); }
+  bool has (hb_codepoint_t k) const { return (*this)[k]; }
   /* Projection. */
   hb_codepoint_t operator () (hb_codepoint_t k) const { return get (k); }
 
diff --git a/src/hb-set.hh b/src/hb-set.hh
index 5d5576cb9..f958a081f 100644
--- a/src/hb-set.hh
+++ b/src/hb-set.hh
@@ -105,10 +105,8 @@ struct hb_sparseset_t
   bool get (hb_codepoint_t g) const { return s.get (g); }
 
   /* Has interface. */
-  static constexpr bool SENTINEL = false;
-  typedef bool value_t;
-  value_t operator [] (hb_codepoint_t k) const { return get (k); }
-  bool has (hb_codepoint_t k) const { return (*this)[k] != SENTINEL; }
+  bool operator [] (hb_codepoint_t k) const { return get (k); }
+  bool has (hb_codepoint_t k) const { return (*this)[k]; }
 
   /* Predicate. */
   bool operator () (hb_codepoint_t k) const { return has (k); }