Yeah, the new method is the wrong thing, I need to revert this change.  When foreign-funcall-form is called and fsbvp=T, it calls translate-objects with indirect=T, which in turn calls #'expand-to-foreign-dyn-indirect on each of the arguments.  When an argument is a foreign-string-type, the trouble begins.   The foreign string is represented by a pointer, as indicated by the (:actual-type :pointer) in the define-foreign-type.  All libffi really needs is a pointer to the pointer, and there is a method for expand-to-foreign-dyn-indirect for foreign-pointer-type, but foreign-string-type is not a subclass of foreign-pointer-type.

It seems like the resolution is to define a method for expand-to-foreign-dyn-indirect for the foreign-type-alias class that does a recursive call using the actual-type.  Does that make sense?  As a side point, expand-to-foreign-dyn has a similar method but it is defined for enhanced-typedef (subclass chain: enhanced-typedef < foreign-typedef < foreign-type-alias); is there any reason why that method shouldn't be defined for foreign-type-alias instead?

Liam