Typescript: Unexpected TS2365: Operator '!==' cannot be applied to types '"string" | "number" | "boolean" | "symbol" | "undefined" | "object" | "function"' and '"String"'.

[RandallFlagg]

TypeScript Version: 2.2.2

Code
Maybe the same as https://github.com/Microsoft/TypeScript/issues/12794

export function convertAllFloat2Int<T>(json: any): T {
        if (typeof json !== "String") {
            json = JSON.stringify(json);
        }

        json = JSON.parse(json, function (key: any, value: any) {
            let result = value;
            if ($.isNumeric(value)) {
                result = ~~value;
            }

            return result;
        });

        return json;
    }
// A *self-contained* demonstration of the problem follows...

Expected behavior:
No compile error as this is a valid JS code or a hint how to solve this issue
Actual behavior:
The following error message on this line 'if (typeof json !== "String") {' :
Operator '!==' cannot be applied to types '"string" | "number" | "boolean" | "symbol" | "undefined" | "object" | "function"' and '"String"'.

[gcnew]

Did you mean typeof json !== "string"? Notice that typeof operator returns string without a capital letter.

The error basically tells you that this comparison is always true, because the return value of typeof is never the string you compare it to.