SubtleCrypto methods return PromiseLike instead of Promise

[taymonbeal]

TypeScript Version: 3.9.0-dev.20200328

Search Terms:
WebCrypto, web crypto, SubtleCrypto, subtle, PromiseLike

Expected behavior:
Should compile with no errors.

Actual behavior:

Type 'PromiseLike<CryptoKey>' is missing the following properties from type 'Promise<CryptoKey>': catch, [Symbol.toStringTag]

Related Issues:
microsoft/TypeScript-DOM-lib-generator#843 (pull request that should fix this)
microsoft/TypeScript-DOM-lib-generator#60
microsoft/TypeScript-DOM-lib-generator#47

Code

const keyPromise: Promise<CryptoKey> = crypto.subtle.generateKey({name: 'AES-GCM', length: 256}, true, ['encrypt']);

Output

"use strict";
const keyPromise = crypto.subtle.generateKey({ name: 'AES-GCM', length: 256 }, true, ['encrypt']);

Compiler Options

{
  "compilerOptions": {
    "noImplicitAny": true,
    "strictNullChecks": true,
    "strictFunctionTypes": true,
    "strictPropertyInitialization": true,
    "strictBindCallApply": true,
    "noImplicitThis": true,
    "noImplicitReturns": true,
    "alwaysStrict": true,
    "esModuleInterop": true,
    "declaration": true,
    "experimentalDecorators": true,
    "emitDecoratorMetadata": true,
    "moduleResolution": 2,
    "target": "ES2017",
    "jsx": "React",
    "module": "ESNext"
  }
}

Playground Link: Provided

[taymonbeal]

I've already sent a PR to fix this at microsoft/TypeScript-DOM-lib-generator#843. It just needs to be reviewed.

[jakebailey]

This was fixed in #39052.