Specializes the congr lemma generated for the `arg` conv tactic to only
rewrite the chosen argument. This makes it much more likely that the
chosen argument is able to be accessed.
Lets `arg` access the domain and codomain of pi types via `arg 1` and
`arg 2` in more situations. Upstreams `pi_congr` for this from mathlib.
Adds a negative indexing option, where `arg -2` accesses the
second-to-last argument for example, making the behavior of `lhs`
available to `arg`. This works for `enter` as well.
Other improvement: when there is an error in the `enter [...]` tactic,
individual locations get underlined with the error. The tactic info now
also is like `rw`, so you can see the intermediate conv states.
Closes#5871
Previously the `ac_rfl` tactic was only really usable when depending on
mathlib. With these instances, `ac_rfl` can deal with the various
operations defined in Lean.
---------
Co-authored-by: Scott Morrison <scott.morrison@gmail.com>
This adds a number of lemmas for simplification of `Bool` and `Prop`
terms. It pulls lemmas from Mathlib and adds additional lemmas where
confluence or consistency suggested they are needed.
It has been tested against Mathlib using some automated test
infrastructure.
That testing module is not yet included in this PR, but will be included
as part of this.
Note. There are currently some comments saying the origin of the simp
rule. These will be removed prior to merging, but are added to clarify
where the rule came from during review.
---------
Co-authored-by: Scott Morrison <scott.morrison@gmail.com>
This will collect definitions from Std.Logic
---------
Co-authored-by: David Thrane Christiansen <david@davidchristiansen.dk>
Co-authored-by: Scott Morrison <scott.morrison@gmail.com>
See new test for example that takes exponential time without new simp
theorems.
TODO: replace auxiliary theorems with simprocs as soon as we implement them.
Because `Decidable` carries data,
when writing `@[simp]` lemmas which include a `Decidable` instance on the LHS,
it is best to use `{_ : Decidable p}` rather than `[Decidable p]`
so that non-canonical instances can be found via unification rather than
typeclass search.
(Previously this behaviour was often being hidden by the default `decide :=
true` in `simp`.)
