[stack] Type for row based languages

I think that functions on rows can be given types using type constraints - even the weird ones like bi@.
A type can be given to the composition of functions f g h that is equivalent whether f g or g h are taken first.

Let f : ( A -> B ) where P
Let g : ( C -> D ) where Q
In a type system that does not have ad-hoc polymorphism, then
  f g : ( A -> D ) where P and Q and B = C
For example:
bi@ : ( A B (B -> C d) -> E C d d) where A C = E B

And in a type system that does have it,
 then  f g : ( A -> D ) where P and Q and B < C

I wrote more details about such a system at
http://www.nothingontelly.com/RowTypes.txt

Is there pre-existing work on this?
Have I made a mistake? Missed something?
Is there a book I should have read?