Reproduction case for: rollup/rollup#3224
This repo contains 2 npm modules, packages/with-rollup and packages/without-rollup.
These contain identical code and typescript configurations, but one includes rollup as an unused dev-dependency.
Both of these include a typescript file index.ts with an error, in the with-rollup package the error is not reported, in the without-rollup package the error is reported as expected.
cd packages/without-rollup
npm i
npm run build
This should throw a TS2339 error: "Property 'find' does not exist on type 'number[]'."
cd ../with-rollup
npm i
npm run build
This is expected to throw a TS2339 error, but does not.