diff --git a/src/hb-ot-shape-complex-arabic-win1256.hh b/src/hb-ot-shape-complex-arabic-win1256.hh
index b15e145f2..41e3dd38a 100644
--- a/src/hb-ot-shape-complex-arabic-win1256.hh
+++ b/src/hb-ot-shape-complex-arabic-win1256.hh
@@ -142,7 +142,7 @@
 		OT_UARRAY(Name##Substitute, OT_LIST(ToGlyphs)) \
 	) \
 	OT_COVERAGE1(Name##Coverage, OT_LIST(FromGlyphs)) \
-	/* ASSERT_STATIC_EXPR_ZERO (len(FromGlyphs) == len(ToGlyphs)) */
+	/* static_assert_expr (len(FromGlyphs) == len(ToGlyphs)) */
 
 #define OT_SUBLOOKUP_LIGATURE_SUBST_FORMAT1(Name, FirstGlyphs, LigatureSetOffsets) \
 	OT_SUBLOOKUP(Name, 1, \
@@ -151,7 +151,7 @@
 		OT_UARRAY(Name##LigatureSetOffsetsArray, OT_LIST(LigatureSetOffsets)) \
 	) \
 	OT_COVERAGE1(Name##Coverage, OT_LIST(FirstGlyphs)) \
-	/* ASSERT_STATIC_EXPR_ZERO (len(FirstGlyphs) == len(LigatureSetOffsets)) */
+	/* static_assert_expr (len(FirstGlyphs) == len(LigatureSetOffsets)) */
 
 #define OT_LIGATURE_SET(Name, LigatureSetOffsets) \
 	OT_UARRAY(Name, OT_LIST(LigatureSetOffsets))
diff --git a/src/hb-ot-shape-complex-indic.hh b/src/hb-ot-shape-complex-indic.hh
index 63dc93ea9..dcb28a4e8 100644
--- a/src/hb-ot-shape-complex-indic.hh
+++ b/src/hb-ot-shape-complex-indic.hh
@@ -175,7 +175,7 @@ enum indic_matra_category_t {
 
 #define INDIC_COMBINE_CATEGORIES(S,M) \
   ( \
-    ASSERT_STATIC_EXPR_ZERO (S < 255 && M < 255) + \
+    static_assert_expr (S < 255 && M < 255) + \
     ( S | \
      ( \
       ( \
diff --git a/src/hb.hh b/src/hb.hh
index f567f26a1..e4abc7c9e 100644
--- a/src/hb.hh
+++ b/src/hb.hh
@@ -444,7 +444,7 @@ static int HB_UNUSED _hb_errno = 0;
 /* Static-assert as expression. */
 template <bool cond> class hb_assert_constant_t;
 template <> class hb_assert_constant_t<true> {};
-#define ASSERT_STATIC_EXPR_ZERO(_cond) (0u * (unsigned int) sizeof (hb_assert_constant_t<_cond>))
+#define static_assert_expr(_cond) (bool (0u * (unsigned int) sizeof (hb_assert_constant_t<_cond>)))
 
 /* Lets assert int types.  Saves trouble down the road. */
 static_assert ((sizeof (int8_t) == 1), "");
@@ -498,10 +498,10 @@ static_assert ((sizeof (hb_var_int_t) == 4), "");
  * For example, for testing "x ∈ {x1, x2, x3}" use:
  * (FLAG_UNSAFE(x) & (FLAG(x1) | FLAG(x2) | FLAG(x3)))
  */
-#define FLAG(x) (ASSERT_STATIC_EXPR_ZERO ((unsigned)(x) < 32) + (((uint32_t) 1U) << (unsigned)(x)))
+#define FLAG(x) (static_assert_expr ((unsigned)(x) < 32) + (((uint32_t) 1U) << (unsigned)(x)))
 #define FLAG_UNSAFE(x) ((unsigned)(x) < 32 ? (((uint32_t) 1U) << (unsigned)(x)) : 0)
-#define FLAG_RANGE(x,y) (ASSERT_STATIC_EXPR_ZERO ((x) < (y)) + FLAG(y+1) - FLAG(x))
-#define FLAG64(x) (ASSERT_STATIC_EXPR_ZERO ((unsigned)(x) < 64) + (((uint64_t) 1ULL) << (unsigned)(x)))
+#define FLAG_RANGE(x,y) (static_assert_expr ((x) < (y)) + FLAG(y+1) - FLAG(x))
+#define FLAG64(x) (static_assert_expr ((unsigned)(x) < 64) + (((uint64_t) 1ULL) << (unsigned)(x)))
 #define FLAG64_UNSAFE(x) ((unsigned)(x) < 64 ? (((uint64_t) 1ULL) << (unsigned)(x)) : 0)