Annotations/IntelliSense gets lost with simple `&` and `|` joins or utilities

[jjeff]

🔎 Search Terms

IntelliSense, comments, annotations, symbol annotation, utilities, utility, union, intersection

🕗 Version & Regression Information

• This is the behavior in every version I tried, and I reviewed the FAQ for entries about annotations

⏯ Playground Link

https://www.typescriptlang.org/play?#code/KYDwDg9gTgLgBASwHY2FAZgQwMbDgMQgjgG8AoOOAegCoa4BBJOTJJCGTGBCZ9aOOgRQAzvDBQIYNDACecGlQqDhYgAqTpsWQC44AIyIAbYK2W16TFmw5cefASODZeAEzgSpM+YuVOXSK4aXtp6SACuALb6aGQAvmRkoJCwiChoWLhwAEKYUKTmdIzMrOyc3LyCAjAAFni1wu6eWnIKSpQNUEGa3npiUMgA5vGJAWJVEHqExAC8BZRUVHCSRkZwEABuaHAwxIPA8KW2FUjKQqIwwS26gphGTgA05ksra5vbu3D7hzbl9n7ONxXXpwAAsACYRklwNB4HJpAQiExXAB5KC5fJzAAU0zgADIcnkAJRwAA+iOI5Ixo14434EGRGKmSMCaIxcDm5AWLwgq3e+SOf1pcFcvAA5PAAO7QADWcDqUGAZ1Ulx6oVu92AT0o-iBarkenB2p2NUawPVACI6nyLVDFnBItA8C5ImATCA4KBMK6THAALQBwNB4OBxLwvAAJWAAEdwsJgAwYAAZUxiFFIYAAHgAKg84ABpYCyESekCoQIlmVFiDoODZjlwKuyGt1gB8DbUCGwMszylzygAoiBsEZwq4s02W7mC0WRK2yO28couZQ4ABtfNpGfFgC6foA-Hoo7H465M53uzm8-nW4u4Go8tw7ueuz3p0OR2Os4Xi9fb-PKDiDdZx3MNZARRMU0wNMM1xOZjzjRVINTGB0yzaY8zFc51H1WQxTJOAxV1QJzTkMV5zIMZ4AAK3CGDgGmPRkOg1DYKIBsV3tV5+WsMo7GFO4RGIUUkAlOBpSgOUFSVShsNVEIDQ1Jx4iAA

💻 Code

// follow Playground link to see behavior

export interface Foo {
  /** An annotation for first property */
  firstProperty: boolean
  /** An annotation for second property */
  secondProperty: number
}

export interface Bar {
  /** An annotation for the third property */
  thirdProperty: string
}

const foo: Foo = {
  // roll over to get annotation
  firstProperty: false,
  // roll over to get annotation
  secondProperty: 42
}

export type FooAndOrBar = (Foo & Bar) | Foo | Bar

const fooAndBar: FooAndOrBar = {
  // rollover annotations don't work here
  firstProperty: true,
  secondProperty: 2,
  thirdProperty: "hello"
}

🙁 Actual behavior

IntelliSense doesn't work on properties after running through & (intersections) with | (unions) or more complex type manipulation.

🙂 Expected behavior

I expected the annotation to "come along" with the symbol and appear in IntelliSense.

Additional information about the issue

No response

[fatcerberus]

fwiw: (Foo & Bar) | Foo | Bar and Foo | Bar are completely equivalent¹, but you get annotations for the latter. Union types are not mutually exclusive

Footnotes

1. In fact subtype reduction will probably reduce the former to the latter if it kicks in. ↩

[jjeff]

fwiw: (Foo & Bar) | Foo | Bar and Foo | Bar are completely equivalent

Hmm… Yeah. I was trying to come up with a more simplified example of this happening. My actual issue is more similar to the second example in the Playground link:

type RequireAtLeastOne<T, Keys extends keyof T = keyof T> = Pick<
  T,
  Exclude<keyof T, Keys>
> &
  {
    [K in Keys]-?: Required<Pick<T, K>> & Partial<Pick<T, Exclude<Keys, K>>>
  }[Keys]

type AtLeastOneFoo = RequireAtLeastOne<Foo, 'firstProperty' | 'secondProperty'>

const justOneFoo: AtLeastOneFoo = {
  // rollover annotations also don't work here
  firstProperty: false
}

Either way, it's frustrating to lose the annotations… even if you're a sloppy coder like me.