The extra work done in #33252 is valuable, but maybe it doesn't need to be so expensive. Setup: 1. Clone https://github.com/amcasey/material-ui.git 2. Check out Benchmark 3. `yarn` to restore packages 4. `yarn typescript` to prebuild and run some TS tests Repro 1. `tsc -p docs` On a random Mac Mini: - 10-run avg on https://github.com/microsoft/TypeScript/commit/72bb4c2bdcb0cb245c397cd9a8f1f0d1158c6a5d: 30,872ms - 10-run avg on https://github.com/microsoft/TypeScript/commit/c5e6d95e930048a033868d72440a9296904a33ec: 33,268ms (8% slower) _Note_: to build old TS commits, you probably need to change `const { default: chalk }` to `const chalk` in `scripts/build/utils.js`.