The rewrite that's been in preview is now stable. The Go compiler cuts type-checking times by an order of magnitude — cold builds that took seconds now take fractions of one, and incremental checks in large monorepos drop proportionally. Language server latency drops with it, which means hover types, go-to-definition, and diagnostic squiggles in VS Code and JetBrains IDEs respond closer to instantly than to "give it a moment." The behavioral contract is unchanged: type semantics match the prior compiler, so existing code doesn't break. The practical question is toolchain integration — build pipelines running `tsc` via ts-node, ts-jest, or custom wrappers should be tested before upgrading, since performance assumptions in those layers may need revisiting.