Polymorphism not working correctly with union types

[hgl]

TypeScript Version: 4.1.2

Search Terms: polymorphism union

Code

abstract class Person {
  name: [string, string]

  constructor(p: Person)
  constructor(p: {name: string})
  constructor(p: Person | {name: string}) {
    if (p instanceof Person) {
      this.name = p.name
    } else {
      let parts = p.name.split(/\s+/)
      this.name = [parts[0] || "", parts[1] || ""]
    }
  }
}

class SadPerson extends Person {
  sadness: number
  constructor(p: {name: string}, sadness: number) {
    super(p)
    this.sadness = sadness
  }
  cry() {
    console.log("crying")
  }
}

class HappyPerson extends Person {
  happiness: number
  constructor(p: SadPerson)
  constructor(p: {name: string}, happiness: number)
  constructor(p: SadPerson | {name: string}, happiness?: number) {
    super(p)
    this.happiness = p instanceof SadPerson ? -p.sadness : happiness!
  }
  smile() {
    console.log("smiling")
  }
}

Expected behavior:
super(p) in HappyPerson's constructor should compile successfully.
Actual behavior:
ts complains "No overload matches this call."

Though it can be fixed by replacing super(p) with

if (p instanceof Person) {
  super(p)
} else {
  super(p)
}

But this feels strictly redundant.

I'm pretty sure there is already some ticket that described this, but I couldn't find it using the search term. Hope someone could link to it and I will close this one as a duplicate.

Playground Link:
https://www.typescriptlang.org/play?#code/IYIwzgLgTsDGEAJYBthjAgCgUymA9gHYIDeAUAgocALbYBcCA2pFAJaEDmANAqx5wC6ZCkiKsArvHxQAFAAdGOPEQCUo2OOhSIMhYxLU6jflwC+6ypsKTpcxVlwFiAH1JGGfaAIulRlNgAzBAUEDkhgQlhsfGDlZ1U-SmSECAALNjAAOg8EAF4EeRzabH8EMwRsZDBsJJSEZGxEeWAoCAwCoo8ssHlkNghZAHoAHTAAaiHLevTM4rp85ha2sCYABkEEFzcAIh3eZfamAEZN7YQ94RSzURubshQ0DABlYAATeKJKgA8IbEI3hhPsRyJQwO9CNh0IxCBIaCBcBotFAdHoHIYSiZvOZeOC3pDoVQ4QioIlQckwBJ5LgFNNKLNsniCR0+BCoWBbhooABPWRksrWAiNLLIfCcWQ7WA8gQ7aZ3ESPdAIAASwHk8m5wJ+fwBQKcX3JaTV8g47JhxMRVmRqPsjFeH31hGmgu0dn07kxXnYOIQRvVpsJsPhuGd1rdDntWrcGOMXp8vD9JuZAH5zcHSXUwVSafI6akMtlEwGWfIwjYIJForEEJHHQhkwgALRFJnshCMIvMgCEnLBNDYjT5mbENnwwtF4p2YH7-S4ss5ZiAA

Related Issues:

[hgl]

Also, having to use happiness! doesn't feel right, since it should be possible to deduce from the overloads that since p is a SadPerson, happiness can't be undefined.

Not sure if it relates to #22609, since this one is about optional parameters.

[MartinJohns]

Your issue is completely unrelated to polymorphism, but instead to overloads. Duplicate of #40827.

[hgl]

Thanks. You're correct. If I replace constructor(p: SadPerson) with constructor(p: Person), ts complains with the same error.

This ultimately links to #1805, also from @MartinJohns.