Do not set host if url cannot be a base.

Author: o0Ignition0o

src/quirks.rs

@@ -102,6 +102,11 @@ pub fn set_host(url: &mut Url, new_host: &str) -> Result<(), ()> {
     let host;
     let opt_port;
     {
+        // If context object’s url’s cannot-be-a-base-URL flag is set, then return.
+        if url.cannot_be_a_base() {
+            return Err(());
+        }
+
         let scheme = url.scheme();
         let result = Parser::parse_host(Input::new(new_host), SchemeType::from(scheme));
         match result {