This PR makes the logic and tactics of `Std.Do` universe polymorphic, at
the cost of a few definitional properties arising from the switch from
`Prop` to `ULift Prop` in the base case `SPred []`.
Co-authored-by: Sebastian Graf <sg@lean-fro.org>
This PR introduces a Hoare logic for monadic programs in
`Std.Do.Triple`, and assorted tactics:
* `mspec` for applying Hoare triple specifications
* `mvcgen` to turn a Hoare triple proof obligation `⦃P⦄ prog ⦃Q⦄` into
pure verification conditoins (i.e., without any traces of Hoare triples
or weakest preconditions reminiscent of `prog`). The resulting
verification conditions in the stateful logic of `Std.Do.SPred` can be
discharged manually with the tactics coming with its custom proof mode
or with automation such as `simp` and `grind`.
This is pre-release of a planned feature and not yet intended for
production use. We are grateful for feedback of early adopters, though.
Co-authored-by: Sebastian Graf <sg@lean-fro.org>
