diff --git a/src/hb-open-type-private.hh b/src/hb-open-type-private.hh
index f4a2ba9..5d90e5b 100644
--- a/src/hb-open-type-private.hh
+++ b/src/hb-open-type-private.hh
@@ -80,17 +80,25 @@
  */
 
 /* Check _assertion in a method environment */
-#define _DEFINE_SIZE_ASSERTION(_assertion) \
-  inline void _size_assertion (void) const \
-  { ASSERT_STATIC (_assertion); }
+#define _DEFINE_INSTANCE_ASSERTION1(_line, _assertion) \
+  inline void _instance_assertion_on_line_##_line (void) const \
+  { \
+    ASSERT_STATIC (_assertion); \
+    ASSERT_INSTANCE_POD (*this); /* Make sure it's POD. */ \
+  }
+# define _DEFINE_INSTANCE_ASSERTION0(_line, _assertion) _DEFINE_INSTANCE_ASSERTION1 (_line, _assertion)
+# define DEFINE_INSTANCE_ASSERTION(_assertion) _DEFINE_INSTANCE_ASSERTION0 (__LINE__, _assertion)
+
 /* Check that _code compiles in a method environment */
-#define _DEFINE_COMPILES_ASSERTION(_code) \
-  inline void _compiles_assertion (void) const \
+#define _DEFINE_COMPILES_ASSERTION1(_line, _code) \
+  inline void _compiles_assertion_on_line_##_line (void) const \
   { _code; }
+# define _DEFINE_COMPILES_ASSERTION0(_line, _code) _DEFINE_COMPILES_ASSERTION1 (_line, _code)
+# define DEFINE_COMPILES_ASSERTION(_code) _DEFINE_COMPILES_ASSERTION0 (__LINE__, _code)
 
 
 #define DEFINE_SIZE_STATIC(size) \
-  _DEFINE_SIZE_ASSERTION (sizeof (*this) == (size)); \
+  DEFINE_INSTANCE_ASSERTION (sizeof (*this) == (size)); \
   static const unsigned int static_size = (size); \
   static const unsigned int min_size = (size)
 
@@ -98,21 +106,21 @@
 #define VAR 1
 
 #define DEFINE_SIZE_UNION(size, _member) \
-  _DEFINE_SIZE_ASSERTION (this->u._member.static_size == (size)); \
+  DEFINE_INSTANCE_ASSERTION (this->u._member.static_size == (size)); \
   static const unsigned int min_size = (size)
 
 #define DEFINE_SIZE_MIN(size) \
-  _DEFINE_SIZE_ASSERTION (sizeof (*this) >= (size)); \
+  DEFINE_INSTANCE_ASSERTION (sizeof (*this) >= (size)); \
   static const unsigned int min_size = (size)
 
 #define DEFINE_SIZE_ARRAY(size, array) \
-  _DEFINE_SIZE_ASSERTION (sizeof (*this) == (size) + sizeof (array[0])); \
-  _DEFINE_COMPILES_ASSERTION ((void) array[0].static_size) \
+  DEFINE_INSTANCE_ASSERTION (sizeof (*this) == (size) + sizeof (array[0])); \
+  DEFINE_COMPILES_ASSERTION ((void) array[0].static_size) \
   static const unsigned int min_size = (size)
 
 #define DEFINE_SIZE_ARRAY2(size, array1, array2) \
-  _DEFINE_SIZE_ASSERTION (sizeof (*this) == (size) + sizeof (this->array1[0]) + sizeof (this->array2[0])); \
-  _DEFINE_COMPILES_ASSERTION ((void) array1[0].static_size; (void) array2[0].static_size) \
+  DEFINE_INSTANCE_ASSERTION (sizeof (*this) == (size) + sizeof (this->array1[0]) + sizeof (this->array2[0])); \
+  DEFINE_COMPILES_ASSERTION ((void) array1[0].static_size; (void) array2[0].static_size) \
   static const unsigned int min_size = (size)
 
 
diff --git a/src/hb-private.hh b/src/hb-private.hh
index 44b7314..8f821f2 100644
--- a/src/hb-private.hh
+++ b/src/hb-private.hh
@@ -104,6 +104,30 @@
 ASSERT_STATIC (sizeof (hb_mask_t) == 4);
 ASSERT_STATIC (sizeof (hb_var_int_t) == 4);
 
+
+/* We like our types POD */
+
+#define _ASSERT_TYPE_POD1(_line, _type) union _type_##_type##_on_line_##_line##_is_not_POD { _type instance; }
+#define _ASSERT_TYPE_POD0(_line, _type) _ASSERT_TYPE_POD1 (_line, _type)
+#define ASSERT_TYPE_POD(_type) _ASSERT_TYPE_POD0 (__LINE__, _type)
+
+#ifdef __GNUC__
+# define _ASSERT_INSTANCE_POD1(_line, _instance) union _type_of_instance_on_line_##_line##_is_not_POD { __typeof__(_instance) instance; }
+#else
+# define _ASSERT_INSTANCE_POD1(_line, _instance) typedef int _assertion_on_line_##_line##_not_tested
+#endif
+# define _ASSERT_INSTANCE_POD0(_line, _instance) _ASSERT_INSTANCE_POD1 (_line, _instance)
+# define ASSERT_INSTANCE_POD(_instance) _ASSERT_INSTANCE_POD0 (__LINE__, _instance)
+
+/* Check _assertion in a method environment */
+#define _ASSERT_POD1(_line) \
+  inline void _static_assertion_on_line_##_line (void) const \
+  { _ASSERT_INSTANCE_POD1 (*this); /* Make sure it's POD. */ }
+# define _ASSERT_POD0(_line) _ASSERT_POD1 (_line)
+# define ASSERT_POD() _ASSERT_POD0 (__LINE__)
+
+
+
 /* Misc */