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unexpected behaviour when use Omit with Insection Types #39359
Description
TypeScript Version: 3.9.2
Search Terms:
omit, insection types
Code
interface User {
type: 'user';
name: string;
age: number;
occupation: string;
}
interface Admin {
type: 'admin';
name: string;
age: number;
role: string;
}
type PowerUser = Omit<User & Admin, 'type'> & {
type: 'powerUser'
};
let p: PowerUser = {
type: 'powerUser',
name: 'hello',
age: 123,
occupation: '123',
role: '123'
}
console.log(p)Expected behavior:
no error
Actual behavior:
test.ts:21:3 - error TS2322: Type 'string' is not assignable to type 'never'.
21 name: 'hello',
~~~~
test.ts:22:3 - error TS2322: Type 'number' is not assignable to type 'never'.
22 age: 123,
~~~
test.ts:23:3 - error TS2322: Type 'string' is not assignable to type 'never'.
23 occupation: '123',
~~~~~~~~~~
test.ts:24:3 - error TS2322: Type 'string' is not assignable to type 'never'.
24 role: '123'
~~~~
Activity
dragomirtitian commentedon Jul 1, 2020
This is related to a recent change in behavior from #36696, where intersection resulting in a field of type
neverare reduced tonever.You can change your types to this:
Playground Link
RyanCavanaugh commentedon Jul 7, 2020
Titian Cernicova-Dragomir (@dragomirtitian) has it right 👆
typescript-bot commentedon Jul 10, 2020
This issue has been marked 'Working as Intended' and has seen no recent activity. It has been automatically closed for house-keeping purposes.