Unexpected Type Error

The simulator/VM error isn't especially helpful here. Any suggestions?

var lat = info.currentLocation.toRadians()[0].toDouble();

Connecting to device...
Device Version 0.32.-Device id 0 name "A garmin device"
Shell Version -13348Failed invoking <symbol>
Unexpected Type Error
in compute (/Users/Nick/Software/workspace/testing/source/testingView.mc:56)
Unexpected Type Error
Unexpected Type Error