XMLSimplifyTypes is an optimization pass for the XML IntermediateLanguage, invoked from XMLSimplify.
Description
This pass simplifies types in an XML program, eliminating all unused type arguments.
Implementation
Details and Notes
It first computes a simple fixpoint on all the datatype declarations
to determine which datatype tycon args are actually used. Then it
does a single pass over the program to determine which polymorphic
declaration type variables are used, and rewrites types to eliminate
unused type arguments.
This pass should eliminate any spurious duplication that the Monomorphise pass might perform due to phantom types.