Nested assignment to untyped imports in JS results in error

[sandersn]

Since the "JS require is alias" PR went in, in JS:

Prerequisite: install shelljs but NOT @types/shelljs.

const sh = require('shelljs') // no types, so `sh` is implicitly any
sh.config.fatal = true        // assignment is interpreted as assignment declaration
sh.exec('npm pack')           // `sh` is no longer properly `any`, so error that `exec` is not found.

Expected behavior:

No error, like typescript:

import sh = require('shelljs')
sh.config.fatal = true // ok, whatever, it's any
sh.exec('npm pack') // still any!

Actual behavior:

Property exec doesn't exist on type typeof shell.

Workaround:

Install @types/shelljs.

The best probable fix is to disable assignment declarations to JS aliases. It doesn't make sense to me. However, this might not happen enough to be worth fixing.

[sandersn]

Accessing arbitrary properties on a class that extends an alias of an untyped module is also now disallowed, although this is the same as TS:

class K extends sh {
    constructor() {
        super()
        this.whatever() // now there's an error here, same as in TS
    }
}