TypeScript Version: 4.1.2

Search Terms:

Code

type BuildTuple<L extends number, T extends any[] = [any]> = 
    T['length'] extends L ? T : BuildTuple<L, [...T, ...T]>;

type A = BuildTuple<3>

Expected behavior:

The type checker completes in a reasonable time, either by succeeding or by reporting "Type instantiation is excessively deep and possibly infinite".

Actual behavior:

The type checker just hangs.

Playground Link:

https://www.typescriptlang.org/play?ts=4.1.2#code/C4TwDgpgBAQgrgSwDYBMAqcxIgHgDJQQAewEAdigM5RlwC2ARhAE4A0UahJ5VUAhmRABtALpQAvFCECQIgHwSoAKCiqOQgOTYyAc2AALDWOKkK1AgH4OUAFyxEqDFlx52QgHSe07T+7TyAbiUlUEgoAEFFeGR0TGwcAGY5JSA