TypeScript 4.7 beta compile errors #647
Description
🐛 Bug report
This is a separate issue from #644, not related to ESM compatibility (as far as I can tell).
Current Behavior
io-ts fails to compile under the new TypeScript 4.7 beta.
Expected behavior
io-ts compiles without emitting any errors.
Reproducible example
package.json:
{
"name": "example",
"scripts": {
"build": "tsc"
},
"dependencies": {
"fp-ts": "^2.12.1",
"io-ts": "^2.2.16"
},
"devDependencies": {
"typescript": "^4.7.0-beta"
}
}tsconfig.json:
{
"compilerOptions": {
"strict": true
}
}index.ts:
import * as t from "io-ts"
const thing = t.type({ foo: t.string })
console.log(thing.is(5))
console.log(thing.is({ foo: "wow" }))% npm run build
> [email protected] build
> tsc
node_modules/io-ts/lib/index.d.ts:1387:29 - error TS2344: Type 'O' does not satisfy the constraint 'Exact<O, O>'.
Type 'O' is not assignable to type '{ [K in ({ [K in keyof O]: K; } & { [K in keyof O]: never; } & { [key: string]: never; })[keyof O]]?: undefined; }'.
1387 OO extends Exact<O, OO> = O,
~
node_modules/io-ts/lib/index.d.ts:1383:34
1383 export declare function alias<A, O, P, I>(
~
This type parameter probably needs an `extends object` constraint.
node_modules/io-ts/lib/index.d.ts:1388:29 - error TS2344: Type 'P' does not satisfy the constraint 'Exact<P, P>'.
Type 'P' is not assignable to type '{ [K in ({ [K in keyof P]: K; } & { [K in keyof P]: never; } & { [key: string]: never; })[keyof P]]?: undefined; }'.
1388 PP extends Exact<P, PP> = P,
~
node_modules/io-ts/lib/index.d.ts:1383:37
1383 export declare function alias<A, O, P, I>(
~
This type parameter probably needs an `extends object` constraint.
node_modules/io-ts/lib/index.d.ts:1395:29 - error TS2344: Type 'O' does not satisfy the constraint 'Exact<O, O>'.
Type 'O' is not assignable to type '{ [K in ({ [K in keyof O]: K; } & { [K in keyof O]: never; } & { [key: string]: never; })[keyof O]]?: undefined; }'.
1395 OO extends Exact<O, OO> = O,
~
node_modules/io-ts/lib/index.d.ts:1391:34
1391 export declare function alias<A, O, P, I>(
~
This type parameter probably needs an `extends object` constraint.
node_modules/io-ts/lib/index.d.ts:1396:29 - error TS2344: Type 'P' does not satisfy the constraint 'Exact<P, P>'.
Type 'P' is not assignable to type '{ [K in ({ [K in keyof P]: K; } & { [K in keyof P]: never; } & { [key: string]: never; })[keyof P]]?: undefined; }'.
1396 PP extends Exact<P, PP> = P,
~
node_modules/io-ts/lib/index.d.ts:1391:37
1391 export declare function alias<A, O, P, I>(
~
This type parameter probably needs an `extends object` constraint.
node_modules/io-ts/lib/index.d.ts:1403:29 - error TS2344: Type 'O' does not satisfy the constraint 'Exact<O, O>'.
Type 'O' is not assignable to type '{ [K in ({ [K in keyof O]: K; } & { [K in keyof O]: never; } & { [key: string]: never; })[keyof O]]?: undefined; }'.
1403 OO extends Exact<O, OO> = O,
~
node_modules/io-ts/lib/index.d.ts:1399:34
1399 export declare function alias<A, O, P, I>(
~
This type parameter probably needs an `extends object` constraint.
node_modules/io-ts/lib/index.d.ts:1404:29 - error TS2344: Type 'P' does not satisfy the constraint 'Exact<P, P>'.
Type 'P' is not assignable to type '{ [K in ({ [K in keyof P]: K; } & { [K in keyof P]: never; } & { [key: string]: never; })[keyof P]]?: undefined; }'.
1404 PP extends Exact<P, PP> = P,
~
node_modules/io-ts/lib/index.d.ts:1399:37
1399 export declare function alias<A, O, P, I>(
~
This type parameter probably needs an `extends object` constraint.
Found 6 errors in the same file, starting at: node_modules/io-ts/lib/index.d.ts:1387
Suggested solution(s)
The errors show a couple suggestions but I don't understand them very well.
Additional context
Your environment
Which versions of io-ts are affected by this issue? Did this work in previous versions of io-ts?
| Software | Version(s) |
|---|---|
| io-ts | 2.2.16 |
| fp-ts | 2.12.1 |
| TypeScript | 4.7.0-beta |