The `conv` tactic tries to close “trivial” goals after itself. As of
now, it uses
`try rfl`, which means it can close goals that are only trivial after
reducing with
default transparency. This is suboptimal
* this can require a fair amount of unfolding, and possibly slow down
the proof
a lot. And the user cannot even prevent it.
* it does not match what `rw` does, and a user might expect the two to
behave the
same.
So this PR changes it to `with_reducible rfl`, matching `rw`’s behavior.
I considered `with_reducible eq_refl` to only solve trivial goals that
involve equality,
but not other relations (e.g. `Perm xs xs`), but a discussion on mathlib
pointed out
that it’s expected and desirable to solve more general reflexive goals:
https://leanprover.zulipchat.com/#narrow/stream/270676-lean4/topic/Closing.20after.20.60rw.60.2C.20.60conv.60.3A.20.60eq_refl.60.20instead.20of.20.60rfl.60/near/429851605
Sets the default value to `pp.fieldNotation.generalized` to `true`.
Updates tests, and fixes some minor flaws in the implementation of the
generalized field notation pretty printer.
Now generalized field notation won't be used for any function that has a
`motive` argument. This is intended to prevent recursors from pretty
printing using it as (1) recursors are more like control flow structures
than actual functions and (2) generalized field notation tends to cause
elaboration problems for recursors.
Note: be sure functions that have an `@[app_unexpander]` use
`@[pp_nodot]` if applicable. For example, `List.toArray` needs
`@[pp_nodot]` to ensure the unexpander prints it using `#[...]`
notation.
