This PR adds support for interactivity to the combined "try this"
messages that were introduced in #9966. In doing so, it moves the link
to apply a suggestion to a separate `[apply]` button in front of the
suggestion. Hints with diffs remain unchanged, as they did not
previously support interacting with terms in the diff, either.
<img width="379" height="256" alt="Suggestion with interactive message"
src="https://github.com/user-attachments/assets/7838ebf6-0613-46e7-bc88-468a05acbf51"
/>
This PR adjusts the "try this" widget to be rendered as a widget message
under 'Messages', not a separate widget under a 'Suggestions' section.
The main benefit of this is that the message of the widget is not
duplicated between 'Messages' and 'Suggestions'.
Since widget message suggestions were already implemented by @jrr6 for
the new hint infrastructure, this PR replaces the old "try this"
implementation with the new hint infrastructure. In doing so, the
`style?` field of suggestions is deprecated, since the hint
infrastructure highlights hints using diff colors, and `style?` also
never saw much use downstream. Additionally, since the message and the
suggestion are now the same component, the `messageData?` field of
suggestions is deprecated as well. Notably, the "Try this:" message
string now also contains a newline and indentation to separate the
suggestion from the rest of the message more clearly and the `postInfo?`
field of the suggestion is now part of the message.
Finally, this PR changes the diff colors used by the hint infrastructure
to be more color-blindness-friendly (insertions are now blue, not green,
and text that remains unchanged is now using the editor foreground color
instead of blue).
### Breaking changes
Tests that use `#guard_msgs` to test the "Try this:" message may need to
be adjusted for the new formatting of the message.
This PR eliminates uses of `intros x y z` (with arguments) and updates
the `intros` docstring to suggest that `intro x y z` should be used
instead. The `intros` tactic is historical, and can be traced all the
way back to Lean 2, when `intro` could only introduce a single
hypothesis. Since 2020, the `intro` tactic has superceded it. The
`intros` tactic (without arguments) is currently still useful.
This PR updates `rw?`, `show_term`, and other tactic-suggesting tactics
to suggest `expose_names` when necessary and validate tactics prior to
suggesting them, as `exact?` already did, and it also ensures all such
tactics produce hover info in the messages showing tactic suggestions.
This introduces a breaking change in the `TryThis` API: the `type?`
parameter of `addRewriteSuggestion` is now an `LOption`, not an
`Option`, to obviate the need for a hack we previously used to indicate
that a rewrite closed the goal.
Closes#7350
* Replaces the unused `Lean.PrettyPrinter.ppConst` with
`MessageData.ofConst` (which similarly avoids an unnecessary `@`) and
that further generates a hover for the constant
* Uses this in `TryThis.addRewriteSuggestion`, so that `rw?` suggestions
don't have unnecessary `@`s.
* Add `MessageData.signature`, as a wrapper around
`PrettyPrinter.signature`, using the same machinery to generate hovers
for constants, improving the hover behaviour in #check so that we get
second order pop-up for constants in the signature. (Not sure how to
write tests for second order hovers, so there is no test for this.)
Previously:
If the `rfl` macro was going to fail, it would:
1. expand to `eq_refl`, which is implemented by
`Lean.Elab.Tactic.evalRefl`, and call `Lean.MVarId.refl` which would:
* either try kernel defeq (if in `.default` or `.all` transparency mode)
* otherwise try `IsDefEq`
* then fail.
2. Next expand to the `apply_rfl` tactic, which is implemented by
`Lean.Elab.Tactic.Rfl.evalApplyRfl`, and call `Lean.MVarId.applyRefl`
which would look for lemmas labelled `@[refl]`, and unfortunately in
Mathlib find `Eq.refl`, so try applying that (resulting in another
`IsDefEq`)
3. Because of an accidental duplication, if `Lean.Elab.Tactic.Rfl` was
imported, it would *again* expand to `apply_rfl`.
Now:
1. Same behaviour in `eq_refl`.
2. The `@[refl]` attribute will reject `Eq.refl`, and `MVarId.applyRefl`
will fail when applied to equality goals.
3. The duplication has been removed.
This updates the rw? tactic from Mathlib to use lazy discriminator trees
and upstreams it.
---------
Co-authored-by: Scott Morrison <scott.morrison@gmail.com>
