Block comment removed from function signature when using unit

[funnyboy-roks]

When I write a function like one of the following

fn foo() -> (/* some comment */) {}
fn bar(x: (/* some comment */)) {}
fn baz() -> Result<(/* some comment */), ()> {}

The comment inside the unit in the return/parameter type gets removed:

fn foo() -> () {}
fn bar(x: ()) {}
fn baz() -> Result<(), ()> {}

This does not happen inside of the function body itself:

fn qux() {
    (/* comment */) // this is fine
}