null checks not working with &&false

[whizsid]

Bug Report

I have a project that enabled allowUnreachableCode option. I wanted to bypass a large condition. So I appended &&false at the end of the condition. But now I can not compile the project due to null check errors.

🔎 Search Terms

• null check false
• null check boolean
• null guard boolean

⏯ Playground Link

Playground link with relevant code

💻 Code

let anExampleVariable: string|null = "Hello World"

if(anExampleVariable!=null&&false) {
    let anotherVariable: string = anExampleVariable;
    //   ^^^^^^^^^^^^^^^ Type 'string | null' is not assignable to type 'string'. Type 'null' is not assignable to type 'string'.
}

🙁 Actual behavior

Getting Type 'string | null' is not assignable to type 'string'. Type 'null' is not assignable to type 'string'. error.

🙂 Expected behavior

null checks should work as before.

[MartinJohns]

Duplicate of #26914.

[typescript-bot]

This issue has been marked as a 'Duplicate' and has seen no recent activity. It has been automatically closed for house-keeping purposes.