This module is entirely devoted to computing the variance of type parameters
in data types.
This module uses
Fix, which we bundle as part of Mezzo. See
val leq :
TypeCore.variance -> TypeCore.variance -> bool
Compare two variances and tell if the second one subsumes the first one.
val analyze_data_types :
TypeCore.env -> TypeCore.var list -> TypeCore.env
Perform variance computations on a set of data types, and return an
environment where variances have been updated.