Namespaced ES6 classes are not recognized as types

[zeule]

• VSCode Version: 1.33.1
• OS Version: Linux x64

MWE:
jsconfig.json

{
    "compilerOptions": {
        "target": "es2018",
        "checkJs": true
    },
    "files": [
        "mwe.js",
        "mwe.d.ts"
    ]
}

mwe.js:

class T {
	constructor() {
		this.x = 1.23;
	}
}

var NS = {}

NS.T = class {
	constructor() {
		this.x = 1.23;
	}
}

mwe.d.ts:

function f1(x: T): void;
function f2(x: NS.T): void;

The problem: the type of parameter for f2 is shown as any and no type checking is done.

Does this issue occur when all extensions are disabled?: Yes