This PR filters out all declarations from `Lean.*`, `*.Tactic.*`, and
`*.Linter.*` from the results of `exact?` and `rw?`.
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Co-authored-by: damiano <adomani@gmail.com>
Co-authored-by: Markus Himmel <markus@lean-fro.org>
This PR changes the behaviour of `apply?` so that the `sorry` it uses to
close the goal is non-synthetic. (Recall that correct use of synthetic
sorries requires that the tactic also generates an error message, which
we don't want to do in this situation.) Either this PR or #8230 are
sufficient to defend against the problem reported in #8212.