Happens in [email protected] but NOT in [email protected]

let a = null
let b = undefined
let res = a != b

yields

Unexpected Error

File "compiler/core/js_exp_make.ml", line 1756, characters 12-18: Assertion failed

Playgound link

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• Is it a bug? Usage questions should often be asked in the forum instead.
• Concise, focused, friendly issue title & description.
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