Incorrect Generic compatibility report

[zheeeng]

TypeScript Version: 3.2.2

Search Terms:

Code
It is a common situation that provides some default params to required options and make them be optional to bring convenient calling usage.

interface HasHeight { 
  height: number
}

type Omit<P, K extends keyof P> = Pick<P, Exclude<keyof P, K>>

function makeHeightOptional<P extends HasHeight>(heightRequired: (p: P) => number) {
  return function heightOptional(params: Omit<P, 'height'> & { height?: number }) {
    const height = params.height || 10
    const newParams = { ...params, height }

    // Argument of type 'Pick<P, Exclude<keyof P, "height">> & { height: number; }' is not assignable to parameter of type 'P'.
    return heightRequired(newParams)
  }
}

Expected behavior:

code works

Actual behavior:

TS report:

Argument of type 'Pick<P, Exclude<keyof P, "height">> & { height: number; }' is not assignable to parameter of type 'P'.

Playground Link: http://www.typescriptlang.org/play/index.html#src=interface%20HasHeight%20%7B%20%0A%20%20height%3A%20number%0A%7D%0A%0Atype%20Omit%3CP%2C%20K%20extends%20keyof%20P%3E%20%3D%20Pick%3CP%2C%20Exclude%3Ckeyof%20P%2C%20K%3E%3E%0A%0Afunction%20makeHeightOptional%3CP%20extends%20HasHeight%3E(heightRequired%3A%20(p%3A%20P)%20%3D%3E%20number)%20%7B%0A%20%20return%20function%20heightOptional(params%3A%20Omit%3CP%2C%20'height'%3E%20%26%20%7B%20height%3F%3A%20number%20%7D)%20%7B%0A%20%20%20%20const%20height%20%3D%20params.height%20%7C%7C%2010%0A%20%20%20%20const%20newParams%20%3D%20%7B%20...params%2C%20height%20%7D%0A%0A%20%20%20%20return%20heightRequired(newParams)%0A%20%20%7D%0A%7D%0A%0A

Related Issues:

[jack-williams]

Think this is a duplicate of #28884

[ahejlsberg]

Duplicate of #28884.

[typescript-bot]

This issue has been marked as a 'Duplicate' and has seen no recent activity. It has been automatically closed for house-keeping purposes.