SC9001 ICE: `bytesNew source of kind union` when `Buffer.from(union)` is inside a function used as a value (`.map` callback)

[somarlyonks]

Summary

Buffer.from() on a union narrowed to its object arm crashes when the enclosing function is used as a value (e.g. as an Array.prototype.map callback):

error SC9001: internal compiler error: in encodeParam: bytesNew source of kind union — please report this

Reproduction

type SqlParam = string | number | boolean | null | Uint8Array

function encodeParam (param: SqlParam): string | number | boolean | null | {$hex: string} {
    if (param !== null && typeof param === 'object') {
        return {$hex: Buffer.from(param).toString('hex')}
    }
    return param
}

function encodeParams (params: SqlParam[]): string {
    return JSON.stringify(params.map(encodeParam))
}

console.log(encodeParams(['a', 1, true, null, new Uint8Array([0xde, 0xad])]))

Actual

repro.ts:4:23 - error SC9001: internal compiler error: in encodeParam: bytesNew source of kind union — please report this

Expected

Compiles - param is narrowed to Uint8Array by the typeof param === 'object' guard.

Notes

• Calling encodeParam(...) directly (not through .map) compiles; the crash appears when the function is used as a value/callback.
• The same call flow compiled under 0.0.36.

Workaround

Bind the narrowed value to an explicitly typed local first:

if (param !== null && typeof param === 'object') {
    const bytes: Uint8Array = param
    return {$hex: Buffer.from(bytes).toString('hex')}
}

Environment

• scriptc 0.1.4
• Node v24.14.0
• macOS (Darwin arm64)