I'm one of the Hypothesis core developers, for which this will be very useful indeed - we have several decorators which modify the signature of the wrapped function, and currently we just check the return types.
I am also responsible for the `from_type()` strategy, which does runtime inspection of types (or type-annotated functions, classes, methods, ...) and works out how to call them. So I would really appreciate it if the implementation of ParameterSpecifications and the various type operators preserved enough information at runtime to reconstruct the semantics of that use!
Happy to review things, draft our implementation against a prototype, etc. - just let me know.
Best wishes from a continent literally on fire,