Doesn't work as written when int != intptr_t.

runtime/vm/parser.cc

Index: runtime/vm/parser.cc
diff --git a/runtime/vm/parser.cc b/runtime/vm/parser.cc
index d1121036d50e44d0c22064997c914b99d6949400..67aaf4763dd4543882d3fb0bc34a7f3465cfbd9b 100644
--- a/runtime/vm/parser.cc
+++ b/runtime/vm/parser.cc
@@ -5347,8 +5347,8 @@ void Parser::ParseNativeFunctionBlock(const ParamList* params,
   NativeFunction native_function = NativeEntry::ResolveNative(
       library, native_name, num_params, &auto_setup_scope);
   if (native_function == NULL) {
-    ErrorMsg(native_pos, "native function '%s' (%d arguments) cannot be found",
-        native_name.ToCString(), func.NumParameters());
+    ErrorMsg(native_pos, "native function '%s' cannot be found",
+        native_name.ToCString());
   }
   func.SetIsNativeAutoSetupScope(auto_setup_scope);