fails:Array#concat tries to convert the passed argument to an Array using #to_ary
fails:Array#concat does not call #to_ary on Array subclasses
fails:Array#concat raises a RuntimeError when Array is frozen and modification occurs
fails:Array#concat raises a RuntimeError when Array is frozen and no modification occurs
fails:Array#concat keeps tainted status
fails:Array#concat is not infected by the other
fails:Array#concat keeps the tainted status of elements
fails:Array#concat keeps untrusted status
fails:Array#concat is not infected untrustedness by the other
fails:Array#concat keeps the untrusted status of elements
