[isTypeReadonly] Unions are always marked as readonly

- [x] I have tried restarting my IDE and the issue persists.
- [x] I have updated to the latest version of the packages.
- [x] I have [read the FAQ](https://github.com/typescript-eslint/typescript-eslint/blob/master/docs/getting-started/linting/FAQ.md) and my problem is not listed.

**Repro**



```TS
type TestType = string[] | number[]
```

```TS
isTypeReadonly(checker, type, {})
```

**Expected Result**



`isTypeReadonly` should return `false`

**Actual Result**



`isTypeReadonly` returns `true` for any union

**Additional Info**

Predicate always return `true`:

https://github.com/typescript-eslint/typescript-eslint/blob/97c0e8606705dc0b4ef8b4ee5206111276c8a170/packages/type-utils/src/isTypeReadonly.ts#L193-L196



**Versions**

| package                         | version |
| ------------------------------- | ------- |
| `@typescript-eslint/type-utils` | `5.9.0` |
| `@typescript-eslint/type-utils` | `5.9.0` |
| `TypeScript`                    | `4.5.4` |
| `node`                          | `17.1.0` |

Also note the error in the template in **Versions**: `@typescript-eslint/type-utils`'s version is requested twice. I assume there is supposed to be only one or one is supposed to be `@typescript-eslint/experimental-utils`

	t =>
	seenTypes.has(t) \|\|
	isTypeReadonlyRecurser(checker, t, options, seenTypes),
	);

package	version
`@typescript-eslint/type-utils`	`5.9.0`
`@typescript-eslint/type-utils`	`5.9.0`
`TypeScript`	`4.5.4`
`node`	`17.1.0`

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Uh oh!

Uh oh!

[isTypeReadonly] Unions are always marked as readonly #4418

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

Pfad - The Proxy pFad of © 2024 Garber Painting. All rights reserved.

Uh oh!

[isTypeReadonly] Unions are always marked as readonly #4418

Description

Metadata

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

Issue actions

Pfad - The Proxy pFad of © 2024 Garber Painting. All rights reserved.