Inheritance messes with comparison to primitive

[CALICAWESOME]

Bug Report

Typescript version 4.6.2
VSCode version 1.65.0

🔎 Search Terms

#202
#25642

💻 Code

1 type Foo = String & { bar: 'baz' }
2
3 function qux(quux: Foo) {
4   const quuz = '';
5   quux === quuz;
6 }
7
8 qux('');

🙁 Actual behavior

Line 5:
This condition will always return 'false' since the types 'string' and 'Foo' have no overlap.

🙂 Expected behavior

No compiler error

[Josh-Cena]

String is a wrapper type of string, and in general String ≠ string, because typeof new String("foo") === "object" while typeof "foo" === "string".

FYI, there's the TS-ESLint rule ban-types that bans the String type because of this confusion.

[CALICAWESOME]

Wow. Thanks for the quick response! That did it.