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Wrong type narrowing with Boolean(expression) #37770

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@Felix-Indoing

Description

@Felix-Indoing

TypeScript Version: 3.8.3

Search Terms: Boolean type narrowing

Code

    const x: {test: string} | null | undefined = something()

    // this works
    if (!!x) {
        console.log(x.test)
    }

    // this can not work
    if (Boolean(x)) {
        console.log(x.test)
    }

Expected behavior:
Expression inside the second if statement should work.

Actual behavior:
The second if statement gives the following error:

TS2533: Object is possibly 'null' or 'undefined'.

Related Issues: None

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