fix(puppeteer-core): avoid type instantiation errors #9370
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Using the accumulator allows enabling the tail-recursion optimization in the TypeScript compiler. Closes #9369
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Lightning00Blade
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🤖 I have created a release *beep* *boop* --- <details><summary>puppeteer: 19.4.0</summary> ## [19.4.0](puppeteer-v19.3.0...puppeteer-v19.4.0) (2022-12-07) ### Features * **chromium:** roll to Chromium 109.0.5412.0 (r1069273) ([#9364](#9364)) ([1875da6](1875da6)), closes [#9233](#9233) ### Dependencies * The following workspace dependencies were updated * dependencies * puppeteer-core bumped from 19.3.0 to 19.4.0 </details> <details><summary>puppeteer-core: 19.4.0</summary> ## [19.4.0](puppeteer-core-v19.3.0...puppeteer-core-v19.4.0) (2022-12-07) ### Features * ability to send headers via ws connection to browser in node.js environment ([#9314](#9314)) ([937fffa](937fffa)), closes [#7218](#7218) * **chromium:** roll to Chromium 109.0.5412.0 (r1069273) ([#9364](#9364)) ([1875da6](1875da6)), closes [#9233](#9233) * **puppeteer-core:** keydown supports commands ([#9357](#9357)) ([b7ebc5d](b7ebc5d)) ### Bug Fixes * **puppeteer-core:** avoid type instantiation errors ([#9370](#9370)) ([17f31a9](17f31a9)), closes [#9369](#9369) </details> --- This PR was generated with [Release Please](https://github.com/googleapis/release-please). See [documentation](https://github.com/googleapis/release-please#release-please). Co-authored-by: release-please[bot] <55107282+release-please[bot]@users.noreply.github.com>
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A bit late to the party, but here goes...
Spotted a minor imperfection, where a couple evaluation branches should be marked as never.
The Acc trick does not allow tail recursion optimization (I believe there is no such optimization). It does allow intermediate thunks to be evaluated before the recursive call. This hugely reduces the (virtual) stack size. There still exists a limit on how many tokens the input string can contain before instantiation depth exceeds the limit. From trial and error investigation it seems the recursion depth limit is about 1000 (typescript v4.5.4).
Practically, a selector string with multiple compound selectors with explicit combinators (i.e. not space), such as "div > div > div > ..." would be limited to ~500 compound selectors. We could probably live with that.
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These two branches are never taken.
Using the accumulator allows enabling the tail-recursion optimization in the TypeScript compiler.
Closes #9369