fix: SetterError is no_std friendly

Now passes `just all`

Author: alexpovel

examples/simple.rs

@@ -1,13 +1,22 @@
 use ada_url::Url;
 
 fn main() -> Result<(), Box<dyn std::error::Error>> {
-    let mut u = Url::parse("http://www.google:8080/love#drug", None).expect("bad url");
-    println!("port: {:?}", u.port());
-    println!("hash: {:?}", u.hash());
-    println!("pathname: {:?}", u.pathname());
-    println!("href: {:?}", u.href());
-    u.set_port(Some("9999"))?;
-    println!("href: {:?}", u.href());
+    let url = Url::parse("http://www.google:8080/love#drug", None).expect("bad url");
+
+    println!("port: {:?}", url.port());
+    println!("hash: {:?}", url.hash());
+    println!("pathname: {:?}", url.pathname());
+    println!("href: {:?}", url.href());
+
+    let mut url = url;
+
+    #[cfg(feature = "std")]
+    url.set_port(Some("9999"))?;
+
+    #[cfg(not(feature = "std"))]
+    url.set_port(Some("9999")).unwrap();
+
+    println!("href: {:?}", url.href());
 
     Ok(())
 }

src/lib.rs

@@ -180,10 +180,9 @@ impl From<*mut ffi::ada_url> for Url {
 }
 
 #[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Default, Display)]
+#[cfg_attr(feature = "std", derive(derive_more::Error))] // error still requires std: https://github.com/rust-lang/rust/issues/103765
 pub struct SetterError;
 
-impl std::error::Error for SetterError {}
-
 type SetterResult = Result<(), SetterError>;
 
 #[inline]