angular.copy([], obj) will make obj un-clear-able

[codeachange]

var arr = []; // got from php like: json_encode(array())
var obj = {};
angular.copy(arr, obj);

after that, both angular.copy([], obj) and angular.copy({}, obj) will not clear the properties of obj. I know that the doc says the destination object should be same type as the source object, but there is no check on that.
It'll be good for debugging if an error would be thrown when the types dose not match.

[jbedard]

This probably changed a bit after 33c67ce (will be in next 1.5 release). Now the destination object will be cleared correctly, but copying to it will fail in some cases (same cases as before the change).

This could be enhanced a bit to either a) throw an error when isArray(source) != isArray(destination) or b) allow copying from an array into object (just like object into array works today - which is kind of weird)...