diff --git a/src/hb-common.cc b/src/hb-common.cc
index 176da8d..710b36e 100644
--- a/src/hb-common.cc
+++ b/src/hb-common.cc
@@ -521,7 +521,7 @@
     }
   }
   hb_user_data_item_t item = {key, data, destroy};
-  bool ret = !!items.replace_or_insert (item, lock, replace != 0);
+  bool ret = !!items.replace_or_insert (item, lock, (bool) replace);
 
   return ret;
 }
diff --git a/src/hb-fallback-shape.cc b/src/hb-fallback-shape.cc
index 0cd623e..b5ebfc0 100644
--- a/src/hb-fallback-shape.cc
+++ b/src/hb-fallback-shape.cc
@@ -106,7 +106,7 @@
    */
 
   hb_codepoint_t space;
-  bool has_space = font->get_glyph (' ', 0, &space) != 0;
+  bool has_space = (bool) font->get_glyph (' ', 0, &space);
 
   buffer->clear_positions ();
 
diff --git a/src/hb-font-private.hh b/src/hb-font-private.hh
index c45258b..7255cb9 100644
--- a/src/hb-font-private.hh
+++ b/src/hb-font-private.hh
@@ -160,7 +160,7 @@
   HB_FONT_FUNCS_IMPLEMENT_CALLBACKS
 #undef HB_FONT_FUNC_IMPLEMENT
 
-  inline hb_bool_t has_glyph (hb_codepoint_t unicode)
+  inline bool has_glyph (hb_codepoint_t unicode)
   {
     hb_codepoint_t glyph;
     return get_glyph (unicode, 0, &glyph);
diff --git a/src/hb-ot-layout.cc b/src/hb-ot-layout.cc
index fbc5d51..3d4ee16 100644
--- a/src/hb-ot-layout.cc
+++ b/src/hb-ot-layout.cc
@@ -742,7 +742,7 @@
 					   hb_bool_t             zero_context)
 {
   if (unlikely (lookup_index >= hb_ot_layout_from_face (face)->gsub_lookup_count)) return false;
-  OT::hb_would_apply_context_t c (face, glyphs, glyphs_length, zero_context != 0);
+  OT::hb_would_apply_context_t c (face, glyphs, glyphs_length, (bool) zero_context);
 
   const OT::SubstLookup& l = hb_ot_layout_from_face (face)->gsub->get_lookup (lookup_index);
 
diff --git a/src/hb-ot-map.cc b/src/hb-ot-map.cc
index 1b8a3ac..7bdeddb 100644
--- a/src/hb-ot-map.cc
+++ b/src/hb-ot-map.cc
@@ -89,7 +89,7 @@
 
   for (unsigned int table_index = 0; table_index < 2; table_index++) {
     hb_tag_t table_tag = table_tags[table_index];
-    found_script[table_index] = hb_ot_layout_table_choose_script (face, table_tag, script_tags, &script_index[table_index], &chosen_script[table_index]) != 0;
+    found_script[table_index] = (bool) hb_ot_layout_table_choose_script (face, table_tag, script_tags, &script_index[table_index], &chosen_script[table_index]);
     hb_ot_layout_script_find_language (face, table_tag, script_index[table_index], language_tag, &language_index[table_index]);
   }
 }
diff --git a/src/hb-ot-shape-complex-hangul.cc b/src/hb-ot-shape-complex-hangul.cc
index 52080a1..5f4d98b 100644
--- a/src/hb-ot-shape-complex-hangul.cc
+++ b/src/hb-ot-shape-complex-hangul.cc
@@ -301,7 +301,7 @@
     {
       /* Have <LV>, <LVT>, or <LV,T> */
       hb_codepoint_t s = u;
-      bool has_glyph = font->has_glyph (s) != 0;
+      bool has_glyph = font->has_glyph (s);
       unsigned int lindex = (s - SBase) / NCount;
       unsigned int nindex = (s - SBase) % NCount;
       unsigned int vindex = nindex / TCount;
diff --git a/src/hb-ot-shape-complex-hebrew.cc b/src/hb-ot-shape-complex-hebrew.cc
index 2e29bdd..3215900 100644
--- a/src/hb-ot-shape-complex-hebrew.cc
+++ b/src/hb-ot-shape-complex-hebrew.cc
@@ -68,7 +68,7 @@
     0xFB4Au /* TAV */
   };
 
-  bool found = c->unicode->compose (a, b, ab) != 0;
+  bool found = (bool) c->unicode->compose (a, b, ab);
 
   if (!found && !c->plan->has_mark)
   {
diff --git a/src/hb-ot-shape-complex-indic.cc b/src/hb-ot-shape-complex-indic.cc
index 72b621e..5354897 100644
--- a/src/hb-ot-shape-complex-indic.cc
+++ b/src/hb-ot-shape-complex-indic.cc
@@ -1806,7 +1806,7 @@
     }
   }
 
-  return c->unicode->decompose (ab, a, b) != 0;
+  return (bool) c->unicode->decompose (ab, a, b);
 }
 
 static bool
@@ -1822,7 +1822,7 @@
   /* Composition-exclusion exceptions that we want to recompose. */
   if (a == 0x09AFu && b == 0x09BCu) { *ab = 0x09DFu; return true; }
 
-  return c->unicode->compose (a, b, ab) != 0;
+  return (bool) c->unicode->compose (a, b, ab);
 }
 
 
diff --git a/src/hb-ot-shape-normalize.cc b/src/hb-ot-shape-normalize.cc
index f6a655d..3f00b8e 100644
--- a/src/hb-ot-shape-normalize.cc
+++ b/src/hb-ot-shape-normalize.cc
@@ -76,7 +76,7 @@
 		   hb_codepoint_t *a,
 		   hb_codepoint_t *b)
 {
-  return c->unicode->decompose (ab, a, b) != 0;
+  return (bool) c->unicode->decompose (ab, a, b);
 }
 
 static bool
@@ -85,7 +85,7 @@
 		 hb_codepoint_t  b,
 		 hb_codepoint_t *ab)
 {
-  return c->unicode->compose (a, b, ab) != 0;
+  return (bool) c->unicode->compose (a, b, ab);
 }
 
 static inline void
@@ -127,7 +127,7 @@
       (b && !font->get_glyph (b, 0, &b_glyph)))
     return 0;
 
-  bool has_a = font->get_glyph (a, 0, &a_glyph) != 0;
+  bool has_a = (bool) font->get_glyph (a, 0, &a_glyph);
   if (shortest && has_a) {
     /* Output a and b */
     output_char (buffer, a, a_glyph);
diff --git a/src/hb-ot-shape.cc b/src/hb-ot-shape.cc
index bfbd533..7a93c62 100644
--- a/src/hb-ot-shape.cc
+++ b/src/hb-ot-shape.cc
@@ -688,7 +688,7 @@
 {
   bool ret = false;
   unsigned int count = c->buffer->len;
-  bool has_positioning = hb_ot_layout_has_positioning (c->face) != 0;
+  bool has_positioning = (bool) hb_ot_layout_has_positioning (c->face);
   /* If the font has no GPOS, AND, no fallback positioning will
    * happen, AND, direction is forward, then when zeroing mark
    * widths, we shift the mark with it, such that the mark