Bug Report

Error happens only when:

• MyInterface extends type alias which represents named array tuple
• MyInterface is generic
• MyType is NAMED tuple
• MyType has ...rest

🔎 Search Terms

type alias, named tuple, interface

🕗 Version & Regression Information

Typescript v4.9.3

⏯ Playground Link

Playground link with relevant code

💻 Code

The following code throws that error:

type MyType = [
  name1:string,
  name2: number,
  ...rest:any[]
]

interface MyInterface<T> extends MyType {
}

// "Interface 'MyInterface<T>' incorrectly extends interface '[name1: string, name2: number, ...rest: any[]]'.

All of the following below works fine:

type MyType = [
  name1:string,
  name2: number,
  ...rest:any[]
]

interface MyInterface extends MyType { //MyInterface is not generic => works
}

// ----------- OR -------------

type MyType = [ // MyType does not have ...rest => works fine
  name1:string,
  name2: number
]

interface MyInterface<T> extends MyType {
}

// ------------ OR ------------
type MyType = [ // MyType typle elements are not named => works fine
  string,
  number,
  ...any[]
]

interface MyInterface<T> extends MyType {
}

🙁 Actual behavior

TSC throws error:

Interface 'MyInterface<T>' incorrectly extends interface '[name1: string, name2: number, ...rest: any[]]'.

🙂 Expected behavior

Successfull compilation