diff --git a/src/runtime/runtime-collections.cc b/src/runtime/runtime-collections.cc
index 65690df..b25a5ef 100644
--- a/src/runtime/runtime-collections.cc
+++ b/src/runtime/runtime-collections.cc
@@ -31,7 +31,7 @@
   SealHandleScope shs(isolate);
   DCHECK(args.length() == 1);
   CONVERT_ARG_CHECKED(JSObject, object, 0);
-  RUNTIME_ASSERT(object->IsJSSet() || object->IsJSMap());
+  CHECK(object->IsJSSet() || object->IsJSMap());
   return static_cast<JSCollection*>(object)->table();
 }
 
@@ -40,8 +40,8 @@
   HandleScope scope(isolate);
   DCHECK(args.length() == 1);
   CONVERT_ARG_HANDLE_CHECKED(Object, object, 0);
-  Handle<Smi> hash = Object::GetOrCreateHash(isolate, object);
-  return *hash;
+  Smi* hash = Object::GetOrCreateHash(isolate, object);
+  return hash;
 }
 
 
@@ -91,8 +91,8 @@
   CONVERT_ARG_HANDLE_CHECKED(JSSetIterator, holder, 0);
   CONVERT_ARG_HANDLE_CHECKED(JSSet, set, 1);
   CONVERT_SMI_ARG_CHECKED(kind, 2)
-  RUNTIME_ASSERT(kind == JSSetIterator::kKindValues ||
-                 kind == JSSetIterator::kKindEntries);
+  CHECK(kind == JSSetIterator::kKindValues ||
+        kind == JSSetIterator::kKindEntries);
   Handle<OrderedHashSet> table(OrderedHashSet::cast(set->table()));
   holder->set_table(*table);
   holder->set_index(Smi::FromInt(0));
@@ -186,9 +186,9 @@
   CONVERT_ARG_HANDLE_CHECKED(JSMapIterator, holder, 0);
   CONVERT_ARG_HANDLE_CHECKED(JSMap, map, 1);
   CONVERT_SMI_ARG_CHECKED(kind, 2)
-  RUNTIME_ASSERT(kind == JSMapIterator::kKindKeys ||
-                 kind == JSMapIterator::kKindValues ||
-                 kind == JSMapIterator::kKindEntries);
+  CHECK(kind == JSMapIterator::kKindKeys ||
+        kind == JSMapIterator::kKindValues ||
+        kind == JSMapIterator::kKindEntries);
   Handle<OrderedHashMap> table(OrderedHashMap::cast(map->table()));
   holder->set_table(*table);
   holder->set_index(Smi::FromInt(0));
@@ -232,7 +232,7 @@
   DCHECK(args.length() == 2);
   CONVERT_ARG_HANDLE_CHECKED(JSWeakCollection, holder, 0);
   CONVERT_NUMBER_CHECKED(int, max_entries, Int32, args[1]);
-  RUNTIME_ASSERT(max_entries >= 0);
+  CHECK(max_entries >= 0);
 
   Handle<ObjectHashTable> table(ObjectHashTable::cast(holder->table()));
   if (max_entries == 0 || max_entries > table->NumberOfElements()) {
@@ -250,7 +250,7 @@
     int count = 0;
     for (int i = 0; count / 2 < max_entries && i < table->Capacity(); i++) {
       Handle<Object> key(table->KeyAt(i), isolate);
-      if (table->IsKey(*key)) {
+      if (table->IsKey(isolate, *key)) {
         entries->set(count++, *key);
         Object* value = table->Lookup(key);
         entries->set(count++, value);
@@ -286,12 +286,13 @@
   CONVERT_ARG_HANDLE_CHECKED(JSWeakCollection, weak_collection, 0);
   CONVERT_ARG_HANDLE_CHECKED(Object, key, 1);
   CONVERT_SMI_ARG_CHECKED(hash, 2)
-  RUNTIME_ASSERT(key->IsJSReceiver() || key->IsSymbol());
+  CHECK(key->IsJSReceiver() || key->IsSymbol());
   Handle<ObjectHashTable> table(
       ObjectHashTable::cast(weak_collection->table()));
-  RUNTIME_ASSERT(table->IsKey(*key));
+  CHECK(table->IsKey(isolate, *key));
   Handle<Object> lookup(table->Lookup(key, hash), isolate);
-  return lookup->IsTheHole() ? isolate->heap()->undefined_value() : *lookup;
+  return lookup->IsTheHole(isolate) ? isolate->heap()->undefined_value()
+                                    : *lookup;
 }
 
 
@@ -301,12 +302,12 @@
   CONVERT_ARG_HANDLE_CHECKED(JSWeakCollection, weak_collection, 0);
   CONVERT_ARG_HANDLE_CHECKED(Object, key, 1);
   CONVERT_SMI_ARG_CHECKED(hash, 2)
-  RUNTIME_ASSERT(key->IsJSReceiver() || key->IsSymbol());
+  CHECK(key->IsJSReceiver() || key->IsSymbol());
   Handle<ObjectHashTable> table(
       ObjectHashTable::cast(weak_collection->table()));
-  RUNTIME_ASSERT(table->IsKey(*key));
+  CHECK(table->IsKey(isolate, *key));
   Handle<Object> lookup(table->Lookup(key, hash), isolate);
-  return isolate->heap()->ToBoolean(!lookup->IsTheHole());
+  return isolate->heap()->ToBoolean(!lookup->IsTheHole(isolate));
 }
 
 
@@ -316,10 +317,10 @@
   CONVERT_ARG_HANDLE_CHECKED(JSWeakCollection, weak_collection, 0);
   CONVERT_ARG_HANDLE_CHECKED(Object, key, 1);
   CONVERT_SMI_ARG_CHECKED(hash, 2)
-  RUNTIME_ASSERT(key->IsJSReceiver() || key->IsSymbol());
+  CHECK(key->IsJSReceiver() || key->IsSymbol());
   Handle<ObjectHashTable> table(
       ObjectHashTable::cast(weak_collection->table()));
-  RUNTIME_ASSERT(table->IsKey(*key));
+  CHECK(table->IsKey(isolate, *key));
   bool was_present = JSWeakCollection::Delete(weak_collection, key, hash);
   return isolate->heap()->ToBoolean(was_present);
 }
@@ -330,12 +331,12 @@
   DCHECK(args.length() == 4);
   CONVERT_ARG_HANDLE_CHECKED(JSWeakCollection, weak_collection, 0);
   CONVERT_ARG_HANDLE_CHECKED(Object, key, 1);
-  RUNTIME_ASSERT(key->IsJSReceiver() || key->IsSymbol());
+  CHECK(key->IsJSReceiver() || key->IsSymbol());
   CONVERT_ARG_HANDLE_CHECKED(Object, value, 2);
   CONVERT_SMI_ARG_CHECKED(hash, 3)
   Handle<ObjectHashTable> table(
       ObjectHashTable::cast(weak_collection->table()));
-  RUNTIME_ASSERT(table->IsKey(*key));
+  CHECK(table->IsKey(isolate, *key));
   JSWeakCollection::Set(weak_collection, key, value, hash);
   return *weak_collection;
 }
@@ -346,7 +347,7 @@
   DCHECK(args.length() == 2);
   CONVERT_ARG_HANDLE_CHECKED(JSWeakCollection, holder, 0);
   CONVERT_NUMBER_CHECKED(int, max_values, Int32, args[1]);
-  RUNTIME_ASSERT(max_values >= 0);
+  CHECK(max_values >= 0);
 
   Handle<ObjectHashTable> table(ObjectHashTable::cast(holder->table()));
   if (max_values == 0 || max_values > table->NumberOfElements()) {
@@ -361,8 +362,8 @@
     DisallowHeapAllocation no_gc;
     int count = 0;
     for (int i = 0; count < max_values && i < table->Capacity(); i++) {
-      Handle<Object> key(table->KeyAt(i), isolate);
-      if (table->IsKey(*key)) values->set(count++, *key);
+      Object* key = table->KeyAt(i);
+      if (table->IsKey(isolate, key)) values->set(count++, key);
     }
     DCHECK_EQ(max_values, count);
   }