for a nested function 'fd' return the type of the closure
of an outer function or aggregate. If the function is a member function
the 'this' type is expected to be stored in 'sthis.Sthis'.
It is always returned if it is not a void pointer.
buildClosure() must have been called on the outer function before.
for a nested function 'fd' return the type of the closure of an outer function or aggregate. If the function is a member function the 'this' type is expected to be stored in 'sthis.Sthis'. It is always returned if it is not a void pointer. buildClosure() must have been called on the outer function before.