Major platform and editor/server changes
LSP plumbing got a major concurrency cleanup — The server switched to a dynamic, cancellable message queue and also added fire-and-forget request paths to reduce deadlocks and shutdown races. Experimental capabilities were moved under capabilities.experimental, logs now funnel into a single pane, and the generated protocol types were simplified for VS clients.
A new file-watching subsystem landed — The new internal/fswatch package arrived with tests, docs, support code, and cross-OS CI coverage, marking a substantial step toward more robust watch-mode behavior.
native-preview and extension integration expanded — Snapshot IDs moved to integers, profiling APIs were added, and WebStorm-facing checker/type APIs were filled in. The VS Code extension also improved tsdk selection/persistence and workspace handling.
Compiler correctness and emit fixes
Declaration emit and checker stability improved across several crash paths — Fixes landed for constructor-type declaration emit, internal expando stripping, skipped diagnostics during declaration emit, this-parameter comparison in pseudotype signatures, and multiple crash cases in declaration emit, inference, and control-flow analysis.
Parser and transform bugs were tightened up — The parser now stops on uneraseable as/satisfies chains, JSDoc @template and constructor modifiers are handled more reliably, async super in default parameters is emitted correctly, and in/out variance modifiers are stripped from JS output.
Resolution and config handling got more robust — The week fixed a concurrent module-resolution cache mismatch, a nil dereference in node_modules lookup, empty tsconfig.json handling, invalid include patterns, and command-line reset crashes in project rebuilding.
Diagnostics and language-service improvements
Better error messages and suggestions — Exact-optional-property diagnostics are clearer, Unicode spelling suggestions now handle multibyte identifiers properly, and computed-name errors point at the correct late-bound symbol.
Navigation and quick info got a few useful fixes — Go-to-implementation now finds typed object-literal implementations, hover can use contextual JSDoc, and JSDoc-related parsing and quick-info scenarios were expanded with new tests.
Other misc changes
Smaller fixes and housekeeping — Included assorted baseline updates, dependency bumps, CI workflow tweaks, JSX/entity and emit edge cases, source-map and formatting fixes, and various test additions across parser, resolver, and LSP internals.