Bug Report

🕗 Version & Regression Information

• This is the behavior in every version I tried, starting from 4.1 where recursive conditional types were added

⏯ Playground Link

Playground link with relevant code

💻 Code

export type ComputeRangeLoose<
  N extends number,
  Result extends Array<number> = [],
> = Result['length'] extends N ? Result : ComputeRangeLoose<N, [...Result, Result['length']]>

type A = ComputeRangeLoose<{ foo: true }>

export type ComputeRangeStrict<
  N extends number,
  Result extends Array<number> = [],
> = N extends number
  ? Result['length'] extends N ? Result : ComputeRangeStrict<N, [...Result, Result['length']]>
  : never

type B = ComputeRangeStrict<{ foo: true }>

🙁 Actual behavior

ComputeRangeLoose<{ foo: true }> allows to pass a type that is not related to number, throwing Type instantiation is excessively deep and possibly infinite.

ComputeRangeStrict<{ foo: true }> throws an expected Type '{ foo: true; }' does not satisfy the constraint 'number'

🙂 Expected behavior

Both ComputeRangeLoose and ComputeRangeStrict throw Type '{ foo: true; }' does not satisfy the constraint 'number'

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As the issue is reproducible since 4.1, I'm pretty sure it was already mentioned somewhere however I failed to find a suitable issue