This just says explicitly that foo takes an argument x of type int, an argument
y of type float, and returns a pair of type int\*float (that is, a pair whose
-first member is if type int and whose second member is of type float).
+first member is of type int and whose second member is of type float).
Type inference allows programmers to enjoy the benefits of strict compile-time
type-checking, which as we said, helps eliminate a large class of errors at a