The Verifier Got Cheap: What TypeScript 7 Actually Changes for Coding Agents
I measured TypeScript 7 against 6.0.3 and 5.9.3 on two real repos: 8.0x on a small Astro blog, 9.8x on a 159,000-line Next.js app. The speed is real, but the interesting part is what a sub-second full type-check does to an agent's verify loop, and the fact that the painful part of the migration is TypeScript 6, not 7.
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