diff --git a/src/hb-ot-hdmx-table.hh b/src/hb-ot-hdmx-table.hh
index 8582dbe27..5c187ebbb 100644
--- a/src/hb-ot-hdmx-table.hh
+++ b/src/hb-ot-hdmx-table.hh
@@ -95,7 +95,7 @@ struct hdmx
   bool serialize (hb_serialize_context_t *c,
 		  unsigned version,
 		  Iterator it,
-		  const hb_vector_t<hb_codepoint_pair_t> &new_to_old_gid_list,
+		  hb_array_t<const hb_codepoint_pair_t> new_to_old_gid_list,
 		  unsigned num_glyphs)
   {
     TRACE_SERIALIZE (this);
diff --git a/src/hb-ot-hmtx-table.hh b/src/hb-ot-hmtx-table.hh
index 493bc6e7a..8e44f143b 100644
--- a/src/hb-ot-hmtx-table.hh
+++ b/src/hb-ot-hmtx-table.hh
@@ -182,7 +182,7 @@ struct hmtxvmtx
 	   hb_requires (hb_is_iterator (Iterator))>
   void serialize (hb_serialize_context_t *c,
 		  Iterator it,
-		  const hb_vector_t<hb_codepoint_pair_t> new_to_old_gid_list,
+		  hb_array_t<const hb_codepoint_pair_t> new_to_old_gid_list,
 		  unsigned num_long_metrics,
                   unsigned total_num_metrics)
   {
diff --git a/src/hb-ot-var-common.hh b/src/hb-ot-var-common.hh
index 3ab58ae30..2e02f9a99 100644
--- a/src/hb-ot-var-common.hh
+++ b/src/hb-ot-var-common.hh
@@ -231,9 +231,9 @@ struct tuple_delta_t
   /* indices_length = point_count, indice[i] = 1 means point i is referenced */
   hb_vector_t<bool> indices;
 
-  hb_vector_t<double> deltas_x;
+  hb_vector_t<float> deltas_x;
   /* empty for cvar tuples */
-  hb_vector_t<double> deltas_y;
+  hb_vector_t<float> deltas_y;
 
   /* compiled data: header and deltas
    * compiled point data is saved in a hashmap within tuple_variations_t cause
@@ -299,9 +299,9 @@ struct tuple_delta_t
     return *this;
   }
 
-  tuple_delta_t& operator *= (double scalar)
+  tuple_delta_t& operator *= (float scalar)
   {
-    if (scalar == 1.0)
+    if (scalar == 1.0f)
       return *this;
 
     unsigned num = indices.length;
@@ -514,9 +514,9 @@ struct tuple_delta_t
   bool compile_deltas ()
   { return compile_deltas (indices, deltas_x, deltas_y, compiled_deltas); }
 
-  static bool compile_deltas (const hb_vector_t<bool> &point_indices,
-			      const hb_vector_t<double> &x_deltas,
-			      const hb_vector_t<double> &y_deltas,
+  static bool compile_deltas (hb_array_t<const bool> point_indices,
+			      hb_array_t<const float> x_deltas,
+			      hb_array_t<const float> y_deltas,
 			      hb_vector_t<unsigned char> &compiled_deltas /* OUT */)
   {
     hb_vector_t<int> rounded_deltas;
@@ -692,7 +692,7 @@ struct tuple_delta_t
 
     if (ref_count == count) return true;
 
-    hb_vector_t<double> opt_deltas_x, opt_deltas_y;
+    hb_vector_t<float> opt_deltas_x, opt_deltas_y;
     bool is_comp_glyph_wo_deltas = (is_composite && ref_count == 0);
     if (is_comp_glyph_wo_deltas)
     {
@@ -875,7 +875,7 @@ struct TupleVariationData
 
     private:
     /* referenced point set->compiled point data map */
-    hb_hashmap_t<const hb_vector_t<bool>*, hb_vector_t<char>> point_data_map;
+    hb_hashmap_t<const hb_vector_t<bool>*, hb_vector_t<unsigned char>> point_data_map;
     /* referenced point set-> count map, used in finding shared points */
     hb_hashmap_t<const hb_vector_t<bool>*, unsigned> point_set_count_map;
 
@@ -883,7 +883,7 @@ struct TupleVariationData
      * shared_points_bytes is a pointer to some value in the point_data_map,
      * which will be freed during map destruction. Save it for serialization, so
      * no need to do find_shared_points () again */
-    hb_vector_t<char> *shared_points_bytes = nullptr;
+    hb_vector_t<unsigned char> *shared_points_bytes = nullptr;
 
     /* total compiled byte size as TupleVariationData format, initialized to 0 */
     unsigned compiled_byte_size = 0;
@@ -1244,7 +1244,7 @@ struct TupleVariationData
       for (auto& tuple: tuple_vars)
       {
         const hb_vector_t<bool>* points_set = &(tuple.indices);
-        hb_vector_t<char> *points_data;
+        hb_vector_t<unsigned char> *points_data;
         if (unlikely (!point_data_map.has (points_set, &points_data)))
           return false;
 
@@ -1289,20 +1289,20 @@ struct TupleVariationData
       TRACE_SERIALIZE (this);
       if (is_gvar && shared_points_bytes)
       {
-        hb_bytes_t s (shared_points_bytes->arrayZ, shared_points_bytes->length);
+        hb_ubytes_t s (shared_points_bytes->arrayZ, shared_points_bytes->length);
         s.copy (c);
       }
 
       for (const auto& tuple: tuple_vars)
       {
         const hb_vector_t<bool>* points_set = &(tuple.indices);
-        hb_vector_t<char> *point_data;
+        hb_vector_t<unsigned char> *point_data;
         if (!point_data_map.has (points_set, &point_data))
           return_trace (false);
 
         if (!is_gvar || point_data != shared_points_bytes)
         {
-          hb_bytes_t s (point_data->arrayZ, point_data->length);
+          hb_ubytes_t s (point_data->arrayZ, point_data->length);
           s.copy (c);
         }
 
diff --git a/src/hb-subset-plan.hh b/src/hb-subset-plan.hh
index fe80c08bc..2d1bea231 100644
--- a/src/hb-subset-plan.hh
+++ b/src/hb-subset-plan.hh
@@ -114,9 +114,9 @@ struct contour_point_vector_t : hb_vector_t<contour_point_t>
     hb_memcpy (arrayZ, a.arrayZ, count * sizeof (arrayZ[0]));
   }
 
-  bool add_deltas (const hb_vector_t<float> deltas_x,
-                   const hb_vector_t<float> deltas_y,
-                   const hb_vector_t<bool> indices)
+  bool add_deltas (hb_array_t<const float> deltas_x,
+                   hb_array_t<const float> deltas_y,
+                   hb_array_t<const bool> indices)
   {
     if (indices.length != deltas_x.length ||
         indices.length != deltas_y.length)
diff --git a/src/hb-vector.hh b/src/hb-vector.hh
index 679c92151..89e4cd337 100644
--- a/src/hb-vector.hh
+++ b/src/hb-vector.hh
@@ -53,7 +53,7 @@ struct hb_vector_t
   }
   template <typename Iterable,
 	    hb_requires (hb_is_iterable (Iterable))>
-  hb_vector_t (const Iterable &o) : hb_vector_t ()
+  explicit hb_vector_t (const Iterable &o) : hb_vector_t ()
   {
     extend (o);
   }
diff --git a/src/test-tuple-varstore.cc b/src/test-tuple-varstore.cc
index 1e07d27d3..afba20f28 100644
--- a/src/test-tuple-varstore.cc
+++ b/src/test-tuple-varstore.cc
@@ -66,7 +66,7 @@ test_decompile_cvar ()
   assert (tuple_variations.tuple_vars[0].axis_tuples.get (axis_tag) == Triple (-1.0, -1.0, 0.0));
   assert (tuple_variations.tuple_vars[1].axis_tuples.get (axis_tag) == Triple (0.0, 1.0, 1.0));
 
-  hb_vector_t<double> deltas_1 {0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, -1.0, 0.0, -3.0, 1.0, 0.0, -1.0, 0.0, -3.0, 1.0, 0.0, -37.0, -37.0, -26.0, -26.0, 0.0, 0.0, 0.0, -3.0, 0.0, 0.0, 0.0, 0.0, 0.0, -3.0, 0.0, 2.0, -29.0, -29.0, -20.0, -20.0, 0.0, 0.0, 0.0, 1.0, -29.0, -29.0, -20.0, -20.0, 0.0, 0.0, 0.0, 1.0};
+  hb_vector_t<float> deltas_1 {0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, -1.0, 0.0, -3.0, 1.0, 0.0, -1.0, 0.0, -3.0, 1.0, 0.0, -37.0, -37.0, -26.0, -26.0, 0.0, 0.0, 0.0, -3.0, 0.0, 0.0, 0.0, 0.0, 0.0, -3.0, 0.0, 2.0, -29.0, -29.0, -20.0, -20.0, 0.0, 0.0, 0.0, 1.0, -29.0, -29.0, -20.0, -20.0, 0.0, 0.0, 0.0, 1.0};
   for (unsigned i = 0; i < 65; i++)
   {
     if (i < 23)
@@ -78,7 +78,7 @@ test_decompile_cvar ()
     }
   }
 
-  hb_vector_t<double> deltas_2 {0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 5.0, -3.0, 0.0, 1.0, 0.0, 5.0, -3.0, 0.0, 97.0, 97.0, 68.0, 68.0, 0.0, 0.0, 0.0, 5.0, 0.0, 0.0, 1.0, -1.0, 1.0, 7.0, -1.0, -5.0, 73.0, 73.0, 53.0, 53.0, 0.0, 0.0, 0.0, -1.0, 73.0, 73.0, 53.0, 53.0, 0.0, 0.0, 0.0, -1.0};
+  hb_vector_t<float> deltas_2 {0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 5.0, -3.0, 0.0, 1.0, 0.0, 5.0, -3.0, 0.0, 97.0, 97.0, 68.0, 68.0, 0.0, 0.0, 0.0, 5.0, 0.0, 0.0, 1.0, -1.0, 1.0, 7.0, -1.0, -5.0, 73.0, 73.0, 53.0, 53.0, 0.0, 0.0, 0.0, -1.0, 73.0, 73.0, 53.0, 53.0, 0.0, 0.0, 0.0, -1.0};
   for (unsigned i = 0 ; i < 65; i++)
   {
     if (i < 23)
@@ -106,9 +106,9 @@ test_decompile_cvar ()
   assert (tuple_variations.tuple_vars[0].axis_tuples.get (axis_tag) == Triple (-1.0, -1.0, 0.0));
   assert (tuple_variations.tuple_vars[1].axis_tuples.get (axis_tag) == Triple (0.0, 1.0, 1.0));
 
-  hb_vector_t<double> rounded_deltas_1 {0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, -1, 0.0, -2, 1, 0.0, -1, 0.0, -2, 1, 0.0, -19, -19, -13, -13, 0.0, 0.0, 0.0, -2, 0.0, 0.0, 0.0, 0.0, 0.0, -2, 0.0, 1, -15, -15, -10.0, -10.0, 0.0, 0.0, 0.0, 1, -15, -15, -10.0, -10.0, 0.0, 0.0, 0.0, 1};
+  hb_vector_t<float> rounded_deltas_1 {0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, -1, 0.0, -2, 1, 0.0, -1, 0.0, -2, 1, 0.0, -19, -19, -13, -13, 0.0, 0.0, 0.0, -2, 0.0, 0.0, 0.0, 0.0, 0.0, -2, 0.0, 1, -15, -15, -10.0, -10.0, 0.0, 0.0, 0.0, 1, -15, -15, -10.0, -10.0, 0.0, 0.0, 0.0, 1};
 
-  hb_vector_t<double> rounded_deltas_2 {0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 1, 0.0, 4, -2, 0.0, 1, 0.0, 4, -2, 0.0, 68, 68, 48, 48, 0.0, 0.0, 0.0, 4, 0.0, 0.0, 1, -1, 1, 5, -1, -4, 51, 51, 37, 37, 0.0, 0.0, 0.0, -1, 51, 51, 37, 37, 0.0, 0.0, 0.0, -1};
+  hb_vector_t<float> rounded_deltas_2 {0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 1, 0.0, 4, -2, 0.0, 1, 0.0, 4, -2, 0.0, 68, 68, 48, 48, 0.0, 0.0, 0.0, 4, 0.0, 0.0, 1, -1, 1, 5, -1, -4, 51, 51, 37, 37, 0.0, 0.0, 0.0, -1, 51, 51, 37, 37, 0.0, 0.0, 0.0, -1};
 
   for (unsigned i = 0; i < 65; i++)
   {