Promise.catch `null` vs `null as null`

# Bug Report



### 🔎 Search Terms



### 🕗 Version & Regression Information


- This is a crash
- This changed between versions ______ and _______
- This is the behavior in every version I tried, and I reviewed the FAQ for entries about _________
- I was unable to test this on prior versions because _______

### ⏯ Playground Link


[Playground link with relevant code](https://www.typescriptlang.org/play?#code/PTAEFkE9QYwewCYFNQHM5IM6gBZIE5JA)

### 💻 Code

> Version 4.4.0-dev.20210705

![image](https://user-images.githubusercontent.com/167966/124636135-c8423e80-deba-11eb-91f5-735464db76ac.png)



```ts
export function f1()
{
	return Promise.resolve(1).catch(e => null)
}

export function f2()
{
	return Promise.resolve(1).catch(e => null as null)
}

// @ts-expect-error
f1().then(v => v.split('')) // <====== should is `number` but `any`

// @ts-expect-error
f2().then(v => v.split(''))

```

```
{
  "compilerOptions": {
    "module": "commonjs",
    "target": "es2019",
    "jsx": "preserve",
    "moduleResolution": "node",
    "allowJs": false,
    "allowUmdGlobalAccess": false,
    "sourceMap": true,
    "inlineSourceMap": false,
    "inlineSources": true,
    "declaration": true,
    "experimentalDecorators": true,
    "emitDecoratorMetadata": true,
    "allowSyntheticDefaultImports": true,
    "resolveJsonModule": true,
    "strict": false,
    "strictBindCallApply": true,
    "strictNullChecks": false,
    "strictFunctionTypes": true,
    "noImplicitThis": true,
    "noImplicitOverride": true,
    "preserveConstEnums": true,
    "forceConsistentCasingInFileNames": true,
    "incremental": true,
    "noErrorTruncation": true,
    "removeComments": true,
    "traceResolution": false,
    "newLine": "lf",
    "esModuleInterop": true,
    "importHelpers": true
  }
}

```

### 🙁 Actual behavior



```
// @ts-expect-error
f1().then(v => v.split('')) // <====== should is `number` but `any`
```

### 🙂 Expected behavior



```
// @ts-expect-error
f1().then(v => v.split('')) // <====== should is `number`
```

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Promise.catch `null` vs `null as null` #44913

Bug Report

🔎 Search Terms

🕗 Version & Regression Information

⏯ Playground Link

💻 Code

🙁 Actual behavior

🙂 Expected behavior

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Promise.catch null vs null as null #44913

Description

Bug Report

🔎 Search Terms

🕗 Version & Regression Information

⏯ Playground Link

💻 Code

🙁 Actual behavior

🙂 Expected behavior

Metadata

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

Issue actions

Promise.catch `null` vs `null as null` #44913