Unsupported expando pattern in commonjs prevents parent function from being called

Bug Report

From npm@7, repros at least in 4.1 and 4.3-dev. It's likely to have been around since late 3.* at least

💻 Code

// @checkjs: true
// @filename: mod1.js
module.exports.json = fetchJSON
function fetchJSON () {
}

module.exports.json.stream = fetchJSONStream
function fetchJSONStream () {
}

// @filename: test.js
const npmFetch = require('./mod1')
let u2 = npmFetch.json()

🙁 Actual behavior

Error: 'typeof json' has no call signatures.

BUT quick info for json is:

module json
(alias) function json(): void
import json

🙂 Expected behavior

no error and u2: void

Inlining fetchJSON to be module.exports.json = function fetchJSON() { } fixes the problem because it's correctly treated as a expando.

Start by running the supplied checkjs repro using mod1.js and test.js, then inspect how CommonJS export assignments and expandos are analyzed. The fix is complete when the call to npmFetch.json() produces no error and u2 is typed as void.