REBOL 3 Errors: invalid-arg

This is a generic error for handling values that were used improperly. For instance, when a set-word is used inside of a function's specification block.

Message:

["Invalid argument:" :arg1]

Example:

filter-error try [f: func [word:][probe word]]
** Script Error: Invalid argument: word
** Where: func [word:] [probe word]