Improve error when not enabling any features

impl/src/lib.rs

@@ -72,6 +72,10 @@ mod unwrap;
 // the derives. A derive can generally be infallible and
 // return a TokenStream, or it can be fallible and return
 // a Result<TokenStream, syn::parse::Error>.
+//
+// This trait can be unused if no feature is enabled. We already error in that case but this
+// warning distracts from the actual error.
+#[allow(dead_code)]
 trait Output {
     fn process(self) -> TokenStream;
 }

src/lib.rs

@@ -70,6 +70,9 @@ pub mod __private {
 ///
 /// Use it in your import paths, if you don't want to import traits, but only macros.
 pub mod derive {
+    // This can be unused if no feature is enabled. We already error in that case, but this warning
+    // distracts from that error. So we suppress the warning.
+    #[allow(unused_imports)]
     #[doc(inline)]
     pub use derive_more_impl::*;
 }
@@ -443,5 +446,5 @@ pub use derive_more_impl::*;
     feature = "unwrap",
 )))]
 compile_error!(
-    "at least one derive feature must be enabled (or the \"full\" one enabling all the derives)"
+    "at least one derive feature must be enabled (or the \"full\" feature enabling all the derives)"
 );