Error message in find_data.default is not helpful

[kent37]

The error message in find_data.default gives no clue about where the error occurred or what the unknown data type is. To a user of a lazyeval client package it is quite mysterious and hard to debug.

Something like

stop("lazyeval::find_data does not know how to find data associated with an object of class ", class(x), call. = FALSE)

would be more helpful.