The type of bitwise operations on 'any' operands should be 'number | bigint'

Bug Report

🔎 Search Terms

• bigint
• bitwise

🕗 Version & Regression Information

• This is the behavior in every version I tried, and I reviewed the FAQ for entries about bigint.

⏯ Playground Link

Workbench Repro

💻 Code

//@target: ES2020
const v1 = 1n as any;
const v2 = 2n as never;
const v3 = v1 | v2; // v3 should be typed (number | bigint), but is number

🙁 Actual behavior

The result of the bitwise operations &, |, ^ and ~ is assumed to be a number when all the operands have unspecified type, like any or never.

🙂 Expected behavior

The result of bitwise operations with unspecified type operands should be number | bigint.

[fasttime]

Clearly TypeScript thinks that certain operators can produce nothing but a number, which used to be true (i.e. -value), but no longer holds in times of bigint.

[serbanghita]

Here is a relevant recent example:

// This works
type Bitmask = number | bigint;

export function toggleAllBits(bitmask: any): Bitmask {
    const oneBit = (typeof bitmask === "bigint" ? 1n : 1) as typeof bitmask;
    let start = oneBit;
    while(start <= bitmask) {
        bitmask ^= start;
        start = start << oneBit;
    }
    return bitmask;
}

// Change the function's  signature to:
export function toggleAllBits(bitmask: Bitmask): Bitmask {
// throws TS2365: Operator '^=' cannot be applied to types 'number | bigint' and 'number | bigint'.