# [racket] TR error message

I have a function that consumes two Number's and tries to compare them
using <=. Rightfully, TR gives a type error. The message says:
Type Checker: No function domains matched in function application:
Domains: Fixnum Zero
Integer Zero
Positive-Fixnum Fixnum
Nonnegative-Fixnum Fixnum
Exact-Positive-Integer Fixnum
Exact-Nonnegative-Integer Fixnum
Exact-Positive-Integer Integer
Exact-Nonnegative-Integer Integer
Nonnegative-Float Float
Float Nonnegative-Float
Real Real Real *
Arguments: Complex Complex
I've never tried to look closely at the "not a comparable number"
error message before (which, btw, would be a really awesome error
message to give for <, <=, etc.), but now that I do do so, I don't
quite understand it.
Are the two things on each line meant to be possible argument types
for each position of <=? If so why are many of the combinations
missing? If not, why do some (eg, "Fixnum") appear so many times?
I just don't know how to read the above error.
Shriram