This PR refines the new wording of the "application type mismatch" error
message to avoid ambiguity in references to the "final" argument in a
subexpression that may be followed by additional arguments.
It does so by replacing "final" with "last," rephrasing the message so
that this adjective modifies the argument itself rather than the word
"argument," and only displaying this wording when two arguments could be
confused (determined by expression equality).
These changes were motivated by a report that in cases where a function
application `f a b c` fails to elaborate because `b` is incorrectly
typed, the existing error message's reference to `b` being the "final"
argument in the application `f a b` may create confusion because it is
not the final argument in the full application expression.
This PR rewords the `application type mismatch` error message by more
specifically mentioning that the problem is with the final argument.
This is useful when the same argument is passed to the function multiple
times.
We decided against using a wording which specifically mentions the
"function expression", because users who are not used to currying might
not think of the `f a` in `f a b` as a function.
New behavior: when in recovery mode, if any tactic fails in `all_goals`
then the metacontext is restored and all goals are admitted.
Without this, it can leave partially-solved metavariables and incomplete
goal lists.
Modifies `simp` to elaborate all simp arguments without disabling error
recovery. Like in #4177, simp arguments with elaboration errors are not
added to the simp set. Error recovery is still disabled when `simp` is
used in combinators such as `first`.
This enables better term info and features like tab completion when
there are elaboration errors.
Also included is a fix to the `all_goals` and `<;>` tactic combinators.
Recall that `try`/`catch` for the Tactic monad restores the state on
failure. This meant that all messages were being cleared on tactic
failure. The fix is to use `Tactic.tryCatch` instead, which doesn't
restore state.
Part of addressing #3831Closes#4888
