Implements formatting support within LSP. Current implementation
performs while file formatting, we just replace file with output of
Carbon::Format()
https://github.com/carbon-language/carbon-lang/pull/7687 independently
improves formatting so that this output is somewhat decent.
Assisted-With: Gemini / Antigravity
Add support for "jump to declaration", "find references", type
information on hover. This support is strictly single-file for now; only
references and declarations within the same file are found. We could go
a bit beyond that, but to properly handle cross-file references we'll
need to build an index and a compilation database, which is beyond the
scope of this change.
On hover, we provide the type information for the instruction under the
cursor as-is. This is frequently not very useful, as the type of a
function F is simply "<type of F>", but is a starting point for richer
information.
Assisted-by: Claude Code
We currently provide UTF-8 positions, since our source representation is
UTF-8 and we use byte offsets as column numbers, but the LSP protocol
default is UTF-16 column positions. Negotiate UTF-8 positions where
possible; this is supported by essentially every LSP client other than
VS Code.
In the case where we select a UTF-16 position, we continue to not do any
actual conversions, so our column offsets in such cases will continue to
be wrong on non-ASCII source files in VS Code.
Assisted by: Claude Code
LSP assumes lines are index 0 to n-1, but Carbon Locs are index from 1
to n. We had the logic for this correct for the start of range but not
for the end of range (inclusive range).
Before this was the diagnostic span we would produce:
```carbon
fn F() {
return ();
<~~~~~~~~>
}
<~~~~~~~~~~~>
```
after:
```carbon
fn F() {
return ();
<~~~~~~~~>
}
```
The language server is now able to subscribe to and apply incremental
changes to the document. Source code is assumed to be utf-8. It does not
currently handle utf-16 code points.
---------
Co-authored-by: Carbon Infra Bot <carbon-external-infra@google.com>
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
Without this, diagnostics will linger after closing a file.
This refactors towards a pattern of putting outgoing calls as methods on
`Context`. I'm mixed on this, mainly thinking it's an improvement on
using `outgoing` directly (because it shares the name and structure),
might want to move it to a side-class later that is _only_ LSP wrappers.
I could also make inheritance private on OutgoingMessages and these
kinds of methods public there, but I'm hesitant to adopt that approach
versus a type separation.
This PR adds a new command to the Carbon VSCode extension "carbon:
Restart language server" which acts similar to clangd / bazel
extensions. While not useful during regular working of the extension
this helps when LSP either crashes or the toolchain is updated.
In order to support graceful restart, I needed to add a Call handler for
"shutdown" which is noop for now. Lsp clients always call shutdown
before sending exit.
---------
Co-authored-by: jonmeow <jperkins@google.com>
DavidLoftus
Richard Smith
