Port call hierarchy, fourslash tests

[jakebailey]

This is all very well tested; fourslash tests use baseline diffs, and the only diffs are ones related to the fact that tsserver differed from LSP, and so the code here is once again sort of a hybrid of the old code plus the post-processing steps VS Code does on top of tsserver, with the difference that I made script files not report themselves as variable, which VS Code happened to do because of its fallback condition (now, file).

[Copilot]

Pull request overview

Ports call hierarchy support into the language server and adds comprehensive fourslash baseline tests, aligning outputs with LSP/VS Code expectations (e.g., mapping script to file and getter to property). Also improves baseline diff handling and introduces a new fourslash verification path for call hierarchy.

• Add call hierarchy handlers to the LSP server (prepare, incoming, outgoing) and declare capability.
• Implement call hierarchy analysis in the language service, including item creation, incoming/outgoing call site collection, and formatting for baseline outputs.
• Add extensive fourslash tests and reference baselines; adjust baseline utilities to handle call-hierarchy outputs and TypeScript path normalizations; minor fixes in references and AST utilities.

Reviewed changes

Copilot reviewed 68 out of 68 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
internal/lsp/server.go	Registers call hierarchy handlers and advertises capability; enables prepare/incoming/outgoing requests.
internal/ls/callhierarchy.go	New implementation for resolving declarations, building CallHierarchyItems, and computing incoming/outgoing call sites; adds formatting helpers for baselines.
internal/fourslash/fourslash.go	Adds VerifyBaselineCallHierarchy with formatting of spans; special-cases test name normalization; utilities for line starts and caret rendering.
internal/fourslash/baselineutil.go	Adds Call Hierarchy baseline command and path normalization to match TypeScript baseline formats.
internal/fourslash/_scripts/convertFourslash.mts	Parses and generates call hierarchy baseline commands from fourslash specs.
internal/ls/symbols.go	Adjusts SymbolKind mapping (e.g., source files to file/module; accessors to property; adds more kinds).
internal/ls/findallreferences.go	Uses entryKindNode for constructor and default export references; replaces local helpers with AST utilities.
internal/ast/utilities.go	Exports GetAssignedName; adds helpers for call/new/element access target detection and property/element climb functions.
internal/testutil/baseline/baseline.go	Returns NoContent for empty diffs (no hunks) to reduce noise.
testdata/baselines/reference/...	Adds multiple call hierarchy baseline files and diffs; changes “script” kind to “file” and “getter” to “property” where applicable.
internal/fourslash/tests/gen/...	Adds numerous fourslash tests covering functions, classes, static blocks, decorators, JSX, tagged templates, cross-file, ambiguity cases, and accessors.
testdata/baselines/reference/fourslash/findAllReferences/findAllReferencesOfConstructor.baseline.jsonc	Updates references baseline to include constructor symbol ranges for “new a.C()”.

[jakebailey]

really annoying but these tests had dots in their names ☹️

[jakebailey]

Yeesh, either our tests are bad or I did something very wrong (well, I'm wrong either way); this does not seem to work in the editor past a single resolve.

[jakebailey]

I'm apparently very silly and chose a test func that has no callers... 🤦

Choosing a better func like assert...

[gabritto]

Couldn't we also fix this kind of diff (and same for script -> file below) in the baseline process so we get rid of these diff files?

[jakebailey]

Oh, great idea.

[jakebailey]

Done!