Add hover cards and jump to declaration / definition / reference for the
formatted SemIR that appears in check tests. This is done by adding a
heuristic "parser" for SemIR to the language server. The
cross-references are strictly best-effort, since this is just a tool for
Carbon developers, not a user-facing facility.
A couple of other changes made along the way:
* file_test tests with an AUTOUPDATE-SPLIT no longer look for CHECK:
lines outside that split. This was motivated by the tests for this new
facility including CHECK: lines as part of the test input.
* An agent skill for working on the language server, tracking some
things that cost Claude time when working on this.
Assisted-by: Claude via Antigravity
Instead of always printing types as canonical, attempt to find a sugared
type where possible, and include that type in the diagnostic. We can
only do this when given the instruction whose type is being printed
(`TypeOfInstId`) rather than the canonical type ID.
Initial support here is intentionally minimal: just looking through
calls to the callee's declared return type, and looking through pointer
dereferences and corresponding pointer types, to build out the initial
infrastructure. More cases can be added later; this degrades gracefully
to using the canonical type if a better type can't be found.
Assisted-by: Claude Opus 5 via 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
Richard Smith