diff --git a/py/objint_mpz.c b/py/objint_mpz.c
index 7b5cb0b9d4..808fae6e41 100644
--- a/py/objint_mpz.c
+++ b/py/objint_mpz.c
@@ -343,6 +343,10 @@ mp_obj_t mp_obj_int_pow3(mp_obj_t base, mp_obj_t exponent,  mp_obj_t modulus) {
         mpz_t *rhs = mp_mpz_for_int(exponent, &r_temp);
         mpz_t *mod = mp_mpz_for_int(modulus,  &m_temp);
 
+        if (mpz_is_zero(mod)) {
+            mp_raise_msg(&mp_type_ValueError, "pow() 3rd argument cannot be 0");
+        }
+
         mpz_pow3_inpl(&(res_p->mpz), lhs, rhs, mod);
 
         if (lhs == &l_temp) { mpz_deinit(lhs); }
diff --git a/py/objtype.c b/py/objtype.c
index 7262892bd8..5b70e8e489 100644
--- a/py/objtype.c
+++ b/py/objtype.c
@@ -981,8 +981,14 @@ const mp_obj_type_t mp_type_type = {
 };
 
 mp_obj_t mp_obj_new_type(qstr name, mp_obj_t bases_tuple, mp_obj_t locals_dict) {
-    assert(MP_OBJ_IS_TYPE(bases_tuple, &mp_type_tuple)); // MicroPython restriction, for now
-    assert(MP_OBJ_IS_TYPE(locals_dict, &mp_type_dict)); // MicroPython restriction, for now
+    if(!MP_OBJ_IS_TYPE(bases_tuple, &mp_type_tuple)) {
+        // MicroPython restriction, for now
+        mp_raise_TypeError("type() argument 2 must be tuple");
+    }
+    if(!MP_OBJ_IS_TYPE(locals_dict, &mp_type_dict)) {
+        // MicroPython restriction, for now
+        mp_raise_TypeError("type() argument 3 must be dict");
+    }
 
     // TODO might need to make a copy of locals_dict; at least that's how CPython does it
 
@@ -991,7 +997,9 @@ mp_obj_t mp_obj_new_type(qstr name, mp_obj_t bases_tuple, mp_obj_t locals_dict)
     mp_obj_t *items;
     mp_obj_tuple_get(bases_tuple, &len, &items);
     for (size_t i = 0; i < len; i++) {
-        assert(MP_OBJ_IS_TYPE(items[i], &mp_type_type));
+        if(!MP_OBJ_IS_TYPE(items[i], &mp_type_type)) {
+            mp_raise_TypeError("type is not an acceptable base type");
+        }
         mp_obj_type_t *t = MP_OBJ_TO_PTR(items[i]);
         // TODO: Verify with CPy, tested on function type
         if (t->make_new == NULL) {
@@ -1077,6 +1085,9 @@ STATIC mp_obj_t super_make_new(const mp_obj_type_t *type_in, size_t n_args, size
     // 0 arguments are turned into 2 in the compiler
     // 1 argument is not yet implemented
     mp_arg_check_num(n_args, n_kw, 2, 2, false);
+    if(!MP_OBJ_IS_TYPE(args[0], &mp_type_type)) {
+        mp_raise_TypeError("first argument to super() must be type");
+    }
     mp_obj_super_t *o = m_new_obj(mp_obj_super_t);
     *o = (mp_obj_super_t){{type_in}, args[0], args[1]};
     return MP_OBJ_FROM_PTR(o);
diff --git a/tests/basics/builtin_pow3.py b/tests/basics/builtin_pow3.py
index 69b57e5484..293a5acc9a 100644
--- a/tests/basics/builtin_pow3.py
+++ b/tests/basics/builtin_pow3.py
@@ -22,3 +22,8 @@ try:
     print(pow(4, 5, "z"))
 except TypeError:
     print("TypeError expected")
+
+try:
+    print(pow(4, 5, 0))
+except ValueError:
+    print("ValueError expected")
diff --git a/tests/basics/class_super.py b/tests/basics/class_super.py
index 1338ef4523..5a18017ac6 100644
--- a/tests/basics/class_super.py
+++ b/tests/basics/class_super.py
@@ -34,3 +34,10 @@ class B(A):
         print(super().bar) # accessing attribute after super()
         return super().foo().count(2) # calling a subsequent method
 print(B().foo())
+
+try:
+    super(1, 1).x
+except TypeError:
+    print(True)
+else:
+    print(False)
diff --git a/tests/basics/types3.py b/tests/basics/types3.py
new file mode 100644
index 0000000000..71f7906923
--- /dev/null
+++ b/tests/basics/types3.py
@@ -0,0 +1,20 @@
+try:
+    type('abc', None, None)
+except TypeError:
+    print(True)
+else:
+    print(False)
+
+try:
+    type('abc', (), None)
+except TypeError:
+    print(True)
+else:
+    print(False)
+
+try:
+    type('abc', (1,), {})
+except TypeError:
+    print(True)
+else:
+    print(False)