add derive macro for trait Unsigned

Author: tdelabro

src/lib.rs

@@ -992,3 +992,21 @@ pub fn signed(input: TokenStream) -> TokenStream {
 
     import.wrap("Signed", &name, impl_).into()
 }
+
+/// Derives [`num_traits::Unsigned`][unsigned].  The inner type must already implement
+/// `Unsigned`.
+///
+/// [unsigned]: https://docs.rs/num/latest/num/traits/trait.Unsigned.html
+#[proc_macro_derive(Unsigned, attributes(num_traits))]
+pub fn unsigned(input: TokenStream) -> TokenStream {
+    let ast = parse!(input as syn::DeriveInput);
+    let name = &ast.ident;
+
+    let import = NumTraits::new(&ast);
+
+    let impl_ = quote! {
+        impl #import::Unsigned for #name {}
+    };
+
+    import.wrap("Unsigned", &name, impl_).into()
+}

tests/newtype.rs

@@ -2,9 +2,22 @@ extern crate num as num_renamed;
 #[macro_use]
 extern crate num_derive;
 
-use crate::num_renamed::{Float, FromPrimitive, Num, NumCast, One, Signed, ToPrimitive, Zero};
+use crate::num_renamed::{
+    Float, FromPrimitive, Num, NumCast, One, Signed, ToPrimitive, Unsigned, Zero,
+};
 use std::ops::Neg;
 
+#[derive(PartialEq, Zero, One, NumOps, Num, Unsigned)]
+struct MyNum(u32);
+
+#[test]
+fn test_derive_unsingned_works() {
+    fn do_nothing_on_unsigned(_input: impl Unsigned) {}
+
+    let x = MyNum(42);
+    do_nothing_on_unsigned(x);
+}
+
 #[derive(
     Debug,
     Clone,