Compiler Assertion when comparing `null` with `undefined`

[dsiu]

Happens in rescript@v12.0.0-alpha.6 but NOT in rescript@v11.1.6

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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[zth]

Works in alpha4, but not 5 or 6.

[shulhi]

Works in alpha4, but not 5 or 6.

I run git bisect, it points to this commit 6a30fa2

[cristianoc]

There's a leftover assert false to remove.