Extends Lean's incremental reporting and reuse between commands into
various steps inside declarations:
* headers and bodies of each (mutual) definition/theorem
* `theorem ... := by` for each contained tactic step, including
recursively inside supported combinators currently consisting of
* `·` (cdot), `case`, `next`
* `induction`, `cases`
* macros such as `next` unfolding to the above

*Incremental reuse* means not recomputing any such steps if they are not
affected by a document change. *Incremental reporting* includes the
parts seen in the recording above: the progress bar and messages. Other
language server features such as hover etc. are *not yet* supported
incrementally, i.e. they are shown only when the declaration has been
fully processed as before.
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Co-authored-by: Scott Morrison <scott.morrison@gmail.com>
As [reported on
Zulip](https://leanprover.zulipchat.com/#narrow/stream/341532-lean4-dev/topic/Find.20references.20broken.20in.20lean.20core/near/437051935).
The `mainModuleName` was being set incorrectly when browsing lean core
sources, resulting in failure of cross-file server requests like "Find
References". Because the `srcSearchPath` is generated asynchronously, we
store it as a `Task Name` which is resolved some time before the header
is finished parsing. (I don't think the `.get` here will ever block,
because the srcSearchPath will be ready by the time the initial command
snap is requested.)
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Co-authored-by: Sebastian Ullrich <sebasti@nullri.ch>
Adds a `--json` option to the `lean` CLI. When used, the Lean frontend
will print messages as JSON objects using the default `ToJson` encoding
for the `Message` structure. This allows consumers (such as Lake) to
handle Lean output in a more intelligent, well-structured way.
`Message` has been refactored into `BaseMessage`, `Message`, and
`SerialMessage` to enable deriving `ToJson`/ `FromJson` instances
automatically for `BaseMessage` / `SerialMessage`. `SerialMessage` is a
`Message` with its `MessageData` eagerly serialized to a `String`.
This lead to incorrect diagnostic spans in the editor and resulted in
header errors that did not show up under "Messages" everywhere in the
file because the `fullRange?` property was missing.
Also changes the "Import out of date" warning diagnostic severity to
"Hint" so that it doesn't show up in the "Problems" view.