- Do not use the ? operator in the List factory.

runtime/lib/array.cc

Index: runtime/lib/array.cc
===================================================================
--- runtime/lib/array.cc	(revision 19164)
+++ runtime/lib/array.cc	(working copy)
@@ -14,20 +14,29 @@
 
 DEFINE_NATIVE_ENTRY(ObjectArray_allocate, 2) {
   const AbstractTypeArguments& type_arguments =
-      AbstractTypeArguments::CheckedHandle(arguments->NativeArgAt(0));
+      AbstractTypeArguments::CheckedHandle(isolate, arguments->NativeArgAt(0));
   ASSERT(type_arguments.IsNull() ||
          (type_arguments.IsInstantiated() && (type_arguments.Length() == 1)));
-  GET_NON_NULL_NATIVE_ARGUMENT(Smi, length, arguments->NativeArgAt(1));
-  intptr_t len = length.Value();
+  const Instance& length = Instance::CheckedHandle(
+      isolate, arguments->NativeArgAt(1));
+  if (!length.IsSmi()) {
+    const String& error = String::Handle(String::NewFormatted(
+        "Length must be an integer in the range [0..%"Pd"].",
+        Array::kMaxElements));
+    const Array& args = Array::Handle(Array::New(1));
+    args.SetAt(0, error);
+    Exceptions::ThrowByType(Exceptions::kArgument, args);
+  }
+  intptr_t len = Smi::Cast(length).Value();
   if (len < 0 || len > Array::kMaxElements) {
     const String& error = String::Handle(String::NewFormatted(
-        "length (%"Pd") must be in the range [0..%"Pd"]",
+        "Length (%"Pd") must be an integer in the range [0..%"Pd"].",
         len, Array::kMaxElements));
     const Array& args = Array::Handle(Array::New(1));
     args.SetAt(0, error);
     Exceptions::ThrowByType(Exceptions::kArgument, args);
   }
-  const Array& new_array = Array::Handle(Array::New(length.Value()));
+  const Array& new_array = Array::Handle(Array::New(len));
   new_array.SetTypeArguments(type_arguments);
   return new_array.raw();
 }