wrong css :is selector result

[neves]

What version of Bun is running?

1.2.18

What platform is your computer?

Darwin 23.6.0 arm64 arm

What steps can reproduce the bug?

CORRECT

style.css

.foo:is(input) {
   color: red;
 }

bun build --watch ./style.css

output

/* style.css */
.foo:-webkit-any(input) {
  color: red;
}

.foo:-moz-any(input) {
  color: red;
}

.foo:is(input) {
  color: red;
}

WRONG

If I add any modifier to the input selector (id, class, pseudo, ...)

style.css

.foo:is(input:checked) {
   color: red;
 }

bun build --watch ./style.css

output

It collapse together .foo with the inner selector.

/* style.css */
.fooinput:checked {
  color: red;
}

It works fine if I change :is with :where
It also works if I use a list like:

.foo:is(input:checked, input:valid) {
   color: red;
 }

What is the expected behavior?

valid css

What do you see instead?

invalid css

No response

Additional information

No response

[linear]

ENG-19670 wrong css :is selector result