Add (Partial)OrdNoBound derive macros (#2256)

This PR is related to
[this](https://github.com/paritytech/polkadot-sdk/issues/154) issue.

The idea is to add `OrdNoBound` and `PartialOrdNoBound` macros to the
substrate `*NoBound` macros.

closes #2198 
✄
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# Description

*Please include a summary of the changes and the related issue. Please
also include relevant motivation and context,
including:*

- What does this PR do?
- Why are these changes needed?
- How were these changes implemented and what do they affect?

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to address any open issues this PR relates to or closes.*

Fixes # (issue number, *if applicable*)

Closes # (issue number, *if applicable*)

# Checklist

- [ ] My PR includes a detailed description as outlined in the
"Description" section above
- [ ] My PR follows the [labeling requirements](CONTRIBUTING.md#Process)
of this project (at minimum one label for `T`
  required)
- [ ] I have made corresponding changes to the documentation (if
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✄
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---------

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>
Co-authored-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>
Co-authored-by: command-bot <>

substrate/frame/src/lib.rs

@@ -307,8 +307,8 @@ pub mod primitives {
 /// This is already part of the [`prelude`].
 pub mod derive {
 	pub use frame_support::{
-		CloneNoBound, DebugNoBound, DefaultNoBound, EqNoBound, PartialEqNoBound,
-		RuntimeDebugNoBound,
+		CloneNoBound, DebugNoBound, DefaultNoBound, EqNoBound, OrdNoBound, PartialEqNoBound,
+		PartialOrdNoBound, RuntimeDebugNoBound,
 	};
 	pub use parity_scale_codec::{Decode, Encode};
 	pub use scale_info::TypeInfo;

substrate/frame/support/procedural/src/lib.rs

@@ -460,7 +460,7 @@ pub fn derive_partial_eq_no_bound(input: TokenStream) -> TokenStream {
 	no_bound::partial_eq::derive_partial_eq_no_bound(input)
 }
 
-/// derive Eq but do no bound any generic. Docs are at `frame_support::EqNoBound`.
+/// Derive [`Eq`] but do no bound any generic. Docs are at `frame_support::EqNoBound`.
 #[proc_macro_derive(EqNoBound)]
 pub fn derive_eq_no_bound(input: TokenStream) -> TokenStream {
 	let input: syn::DeriveInput = match syn::parse(input) {
@@ -479,6 +479,19 @@ pub fn derive_eq_no_bound(input: TokenStream) -> TokenStream {
 	.into()
 }
 
+/// Derive [`PartialOrd`] but do not bound any generic. Docs are at
+/// `frame_support::PartialOrdNoBound`.
+#[proc_macro_derive(PartialOrdNoBound)]
+pub fn derive_partial_ord_no_bound(input: TokenStream) -> TokenStream {
+	no_bound::partial_ord::derive_partial_ord_no_bound(input)
+}
+
+/// Derive [`Ord`] but do no bound any generic. Docs are at `frame_support::OrdNoBound`.
+#[proc_macro_derive(OrdNoBound)]
+pub fn derive_ord_no_bound(input: TokenStream) -> TokenStream {
+	no_bound::ord::derive_ord_no_bound(input)
+}
+
 /// derive `Default` but do no bound any generic. Docs are at `frame_support::DefaultNoBound`.
 #[proc_macro_derive(DefaultNoBound, attributes(default))]
 pub fn derive_default_no_bound(input: TokenStream) -> TokenStream {

substrate/frame/support/procedural/src/no_bound/mod.rs

@@ -20,4 +20,6 @@
 pub mod clone;
 pub mod debug;
 pub mod default;
+pub mod ord;
 pub mod partial_eq;
+pub mod partial_ord;

substrate/frame/support/procedural/src/no_bound/ord.rs

@@ -0,0 +1,75 @@
+// This file is part of Substrate.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use syn::spanned::Spanned;
+
+/// Derive Ord but do not bound any generic.
+pub fn derive_ord_no_bound(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
+	let input: syn::DeriveInput = match syn::parse(input) {
+		Ok(input) => input,
+		Err(e) => return e.to_compile_error().into(),
+	};
+
+	let name = &input.ident;
+	let (impl_generics, ty_generics, where_clause) = input.generics.split_for_impl();
+
+	let impl_ = match input.data {
+		syn::Data::Struct(struct_) => match struct_.fields {
+			syn::Fields::Named(named) => {
+				let fields = named
+					.named
+					.iter()
+					.map(|i| &i.ident)
+					.map(|i| quote::quote_spanned!(i.span() => self.#i.cmp(&other.#i) ));
+
+				quote::quote!( core::cmp::Ordering::Equal #( .then_with(|| #fields) )* )
+			},
+			syn::Fields::Unnamed(unnamed) => {
+				let fields = unnamed
+					.unnamed
+					.iter()
+					.enumerate()
+					.map(|(i, _)| syn::Index::from(i))
+					.map(|i| quote::quote_spanned!(i.span() => self.#i.cmp(&other.#i) ));
+
+				quote::quote!( core::cmp::Ordering::Equal #( .then_with(|| #fields) )* )
+			},
+			syn::Fields::Unit => {
+				quote::quote!(core::cmp::Ordering::Equal)
+			},
+		},
+		syn::Data::Enum(_) => {
+			let msg = "Enum type not supported by `derive(OrdNoBound)`";
+			return syn::Error::new(input.span(), msg).to_compile_error().into()
+		},
+		syn::Data::Union(_) => {
+			let msg = "Union type not supported by `derive(OrdNoBound)`";
+			return syn::Error::new(input.span(), msg).to_compile_error().into()
+		},
+	};
+
+	quote::quote!(
+		const _: () = {
+			impl #impl_generics core::cmp::Ord for #name #ty_generics #where_clause {
+				fn cmp(&self, other: &Self) -> core::cmp::Ordering {
+					#impl_
+				}
+			}
+		};
+	)
+	.into()
+}

substrate/frame/support/procedural/src/no_bound/partial_ord.rs

@@ -0,0 +1,89 @@
+// This file is part of Substrate.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use syn::spanned::Spanned;
+
+/// Derive PartialOrd but do not bound any generic.
+pub fn derive_partial_ord_no_bound(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
+	let input: syn::DeriveInput = match syn::parse(input) {
+		Ok(input) => input,
+		Err(e) => return e.to_compile_error().into(),
+	};
+
+	let name = &input.ident;
+	let (impl_generics, ty_generics, where_clause) = input.generics.split_for_impl();
+
+	let impl_ = match input.data {
+		syn::Data::Struct(struct_) =>
+			match struct_.fields {
+				syn::Fields::Named(named) => {
+					let fields =
+						named.named.iter().map(|i| &i.ident).map(
+							|i| quote::quote_spanned!(i.span() => self.#i.partial_cmp(&other.#i)),
+						);
+
+					quote::quote!(
+						Some(core::cmp::Ordering::Equal)
+							#(
+								.and_then(|order| {
+									let next_order = #fields?;
+									Some(order.then(next_order))
+								})
+							)*
+					)
+				},
+				syn::Fields::Unnamed(unnamed) => {
+					let fields =
+						unnamed.unnamed.iter().enumerate().map(|(i, _)| syn::Index::from(i)).map(
+							|i| quote::quote_spanned!(i.span() => self.#i.partial_cmp(&other.#i)),
+						);
+
+					quote::quote!(
+						Some(core::cmp::Ordering::Equal)
+							#(
+								.and_then(|order| {
+									let next_order = #fields?;
+									Some(order.then(next_order))
+								})
+							)*
+					)
+				},
+				syn::Fields::Unit => {
+					quote::quote!(Some(core::cmp::Ordering::Equal))
+				},
+			},
+		syn::Data::Enum(_) => {
+			let msg = "Enum type not supported by `derive(PartialOrdNoBound)`";
+			return syn::Error::new(input.span(), msg).to_compile_error().into()
+		},
+		syn::Data::Union(_) => {
+			let msg = "Union type not supported by `derive(PartialOrdNoBound)`";
+			return syn::Error::new(input.span(), msg).to_compile_error().into()
+		},
+	};
+
+	quote::quote!(
+		const _: () = {
+			impl #impl_generics core::cmp::PartialOrd for #name #ty_generics #where_clause {
+				fn partial_cmp(&self, other: &Self) -> Option<core::cmp::Ordering> {
+					#impl_
+				}
+			}
+		};
+	)
+	.into()
+}

substrate/frame/support/src/lib.rs

@@ -557,6 +557,42 @@ pub use frame_support_procedural::EqNoBound;
 /// ```
 pub use frame_support_procedural::PartialEqNoBound;
 
+/// Derive [`Ord`] but do not bound any generic.
+///
+/// This is useful for type generic over runtime:
+/// ```
+/// # use frame_support::{OrdNoBound, PartialOrdNoBound, EqNoBound, PartialEqNoBound};
+/// trait Config {
+/// 		type C: Ord;
+/// }
+///
+/// // Foo implements [`Ord`] because `C` bounds [`Ord`].
+/// // Otherwise compilation will fail with an output telling `c` doesn't implement [`Ord`].
+/// #[derive(EqNoBound, OrdNoBound, PartialEqNoBound, PartialOrdNoBound)]
+/// struct Foo<T: Config> {
+/// 		c: T::C,
+/// }
+/// ```
+pub use frame_support_procedural::OrdNoBound;
+
+/// Derive [`PartialOrd`] but do not bound any generic.
+///
+/// This is useful for type generic over runtime:
+/// ```
+/// # use frame_support::{OrdNoBound, PartialOrdNoBound, EqNoBound, PartialEqNoBound};
+/// trait Config {
+/// 		type C: PartialOrd;
+/// }
+///
+/// // Foo implements [`PartialOrd`] because `C` bounds [`PartialOrd`].
+/// // Otherwise compilation will fail with an output telling `c` doesn't implement [`PartialOrd`].
+/// #[derive(PartialOrdNoBound, PartialEqNoBound, EqNoBound)]
+/// struct Foo<T: Config> {
+/// 		c: T::C,
+/// }
+/// ```
+pub use frame_support_procedural::PartialOrdNoBound;
+
 /// Derive [`Debug`] but do not bound any generic.
 ///
 /// This is useful for type generic over runtime:

substrate/frame/support/test/tests/derive_no_bound.rs

@@ -15,11 +15,12 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-//! Tests for DebugNoBound, CloneNoBound, EqNoBound, PartialEqNoBound, DefaultNoBound, and
-//! RuntimeDebugNoBound
+//! Tests for DebugNoBound, CloneNoBound, EqNoBound, PartialEqNoBound, DefaultNoBound,
+//! RuntimeDebugNoBound, PartialOrdNoBound and OrdNoBound
 
 use frame_support::{
-	CloneNoBound, DebugNoBound, DefaultNoBound, EqNoBound, PartialEqNoBound, RuntimeDebugNoBound,
+	CloneNoBound, DebugNoBound, DefaultNoBound, EqNoBound, OrdNoBound, PartialEqNoBound,
+	PartialOrdNoBound, RuntimeDebugNoBound,
 };
 
 #[derive(RuntimeDebugNoBound)]
@@ -32,7 +33,7 @@ fn runtime_debug_no_bound_display_correctly() {
 }
 
 trait Config {
-	type C: std::fmt::Debug + Clone + Eq + PartialEq + Default;
+	type C: std::fmt::Debug + Clone + Eq + PartialEq + Default + PartialOrd + Ord;
 }
 
 struct Runtime;
@@ -42,7 +43,15 @@ impl Config for Runtime {
 	type C = u32;
 }
 
-#[derive(DebugNoBound, CloneNoBound, EqNoBound, PartialEqNoBound, DefaultNoBound)]
+#[derive(
+	DebugNoBound,
+	CloneNoBound,
+	EqNoBound,
+	PartialEqNoBound,
+	DefaultNoBound,
+	PartialOrdNoBound,
+	OrdNoBound,
+)]
 struct StructNamed<T: Config, U, V> {
 	a: u32,
 	b: u64,
@@ -96,9 +105,18 @@ fn test_struct_named() {
 	};
 
 	assert!(b != a_1);
+	assert!(b > a_1);
 }
 
-#[derive(DebugNoBound, CloneNoBound, EqNoBound, PartialEqNoBound, DefaultNoBound)]
+#[derive(
+	DebugNoBound,
+	CloneNoBound,
+	EqNoBound,
+	PartialEqNoBound,
+	DefaultNoBound,
+	PartialOrdNoBound,
+	OrdNoBound,
+)]
 struct StructUnnamed<T: Config, U, V>(u32, u64, T::C, core::marker::PhantomData<(U, V)>);
 
 #[rustversion::attr(not(stable), ignore)]
@@ -128,9 +146,18 @@ fn test_struct_unnamed() {
 	let b = StructUnnamed::<Runtime, ImplNone, ImplNone>(1, 2, 4, Default::default());
 
 	assert!(b != a_1);
+	assert!(b > a_1);
 }
 
-#[derive(DebugNoBound, CloneNoBound, EqNoBound, PartialEqNoBound, DefaultNoBound)]
+#[derive(
+	DebugNoBound,
+	CloneNoBound,
+	EqNoBound,
+	PartialEqNoBound,
+	DefaultNoBound,
+	PartialOrdNoBound,
+	OrdNoBound,
+)]
 struct StructNoGenerics {
 	field1: u32,
 	field2: u64,
@@ -254,3 +281,63 @@ fn test_enum() {
 	assert!(variant_2.clone() == variant_2);
 	assert!(variant_3.clone() == variant_3);
 }
+
+// Return all the combinations of (0, 0, 0), (0, 0, 1), (0, 1, 0), ...
+// Used to test all the possible struct orderings
+fn combinations() -> Vec<(u32, u64, u32)> {
+	let mut v = vec![];
+
+	for a in 0..=1 {
+		for b in 0..=1 {
+			for c in 0..=1 {
+				v.push((a, b, c));
+			}
+		}
+	}
+
+	v
+}
+
+// Ensure that the PartialOrdNoBound follows the same rules as the native PartialOrd
+#[derive(Debug, Clone, Eq, PartialEq, Default, PartialOrd, Ord)]
+struct StructNamedRust {
+	a: u32,
+	b: u64,
+	c: u32,
+	phantom: core::marker::PhantomData<(ImplNone, ImplNone)>,
+}
+
+#[derive(Debug, Clone, Eq, PartialEq, Default, PartialOrd, Ord)]
+struct StructUnnamedRust(u32, u64, u32, core::marker::PhantomData<(ImplNone, ImplNone)>);
+
+#[test]
+fn struct_named_same_as_native_rust() {
+	for (a, b, c) in combinations() {
+		let a_1 =
+			StructNamed::<Runtime, ImplNone, ImplNone> { a, b, c, phantom: Default::default() };
+		let b_1 = StructNamedRust { a, b, c, phantom: Default::default() };
+		for (a, b, c) in combinations() {
+			let a_2 =
+				StructNamed::<Runtime, ImplNone, ImplNone> { a, b, c, phantom: Default::default() };
+			let b_2 = StructNamedRust { a, b, c, phantom: Default::default() };
+			assert_eq!(a_1.partial_cmp(&a_2), b_1.partial_cmp(&b_2));
+			assert_eq!(a_1.cmp(&a_2), b_1.cmp(&b_2));
+			assert_eq!(a_1.eq(&a_2), b_1.eq(&b_2));
+		}
+	}
+}
+
+#[test]
+fn struct_unnamed_same_as_native_rust() {
+	for (a, b, c) in combinations() {
+		let a_1 = StructUnnamed::<Runtime, ImplNone, ImplNone>(a, b, c, Default::default());
+		let b_1 = StructUnnamedRust(a, b, c, Default::default());
+		for (a, b, c) in combinations() {
+			let a_2 = StructUnnamed::<Runtime, ImplNone, ImplNone>(a, b, c, Default::default());
+			let b_2 = StructUnnamedRust(a, b, c, Default::default());
+			assert_eq!(a_1.partial_cmp(&a_2), b_1.partial_cmp(&b_2));
+			assert_eq!(a_1.cmp(&a_2), b_1.cmp(&b_2));
+			assert_eq!(a_1.eq(&a_2), b_1.eq(&b_2));
+		}
+	}
+}

substrate/frame/support/test/tests/derive_no_bound_ui/ord.rs

@@ -0,0 +1,27 @@
+// This file is part of Substrate.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+trait Config {
+	type C;
+}
+
+#[derive(frame_support::OrdNoBound, frame_support::EqNoBound)]
+struct Foo<T: Config> {
+	c: T::C,
+}
+
+fn main() {}

substrate/frame/support/test/tests/derive_no_bound_ui/ord.stderr

@@ -0,0 +1,25 @@
+error[E0277]: can't compare `Foo<T>` with `Foo<T>`
+  --> tests/derive_no_bound_ui/ord.rs:23:8
+   |
+23 | struct Foo<T: Config> {
+   |        ^^^^^^^^^^^^^^ no implementation for `Foo<T> < Foo<T>` and `Foo<T> > Foo<T>`
+   |
+   = help: the trait `PartialOrd` is not implemented for `Foo<T>`
+note: required by a bound in `Ord`
+  --> $RUST/core/src/cmp.rs
+   |
+   | pub trait Ord: Eq + PartialOrd<Self> {
+   |                     ^^^^^^^^^^^^^^^^ required by this bound in `Ord`
+
+error[E0277]: can't compare `Foo<T>` with `Foo<T>`
+  --> tests/derive_no_bound_ui/ord.rs:23:8
+   |
+23 | struct Foo<T: Config> {
+   |        ^^^^^^^^^^^^^^ no implementation for `Foo<T> == Foo<T>`
+   |
+   = help: the trait `PartialEq` is not implemented for `Foo<T>`
+note: required by a bound in `std::cmp::Eq`
+  --> $RUST/core/src/cmp.rs
+   |
+   | pub trait Eq: PartialEq<Self> {
+   |               ^^^^^^^^^^^^^^^ required by this bound in `Eq`

substrate/frame/support/test/tests/derive_no_bound_ui/partial_ord.rs

@@ -0,0 +1,27 @@
+// This file is part of Substrate.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+trait Config {
+	type C;
+}
+
+#[derive(frame_support::PartialOrdNoBound, frame_support::PartialEqNoBound)]
+struct Foo<T: Config> {
+	c: T::C,
+}
+
+fn main() {}

substrate/frame/support/test/tests/derive_no_bound_ui/partial_ord.stderr

@@ -0,0 +1,15 @@
+error[E0599]: `<T as Config>::C` is not an iterator
+  --> tests/derive_no_bound_ui/partial_ord.rs:24:2
+   |
+24 |     c: T::C,
+   |     ^ `<T as Config>::C` is not an iterator
+   |
+   = note: the following trait bounds were not satisfied:
+           `<T as Config>::C: Iterator`
+           which is required by `&mut <T as Config>::C: Iterator`
+
+error[E0369]: binary operation `==` cannot be applied to type `<T as Config>::C`
+  --> tests/derive_no_bound_ui/partial_ord.rs:24:2
+   |
+24 |     c: T::C,
+   |     ^

substrate/frame/support/test/tests/pallet.rs

@@ -28,6 +28,7 @@ use frame_support::{
 		UnfilteredDispatchable,
 	},
 	weights::{RuntimeDbWeight, Weight},
+	OrdNoBound, PartialOrdNoBound,
 };
 use scale_info::{meta_type, TypeInfo};
 use sp_io::{
@@ -467,6 +468,8 @@ pub mod pallet {
 		RuntimeDebugNoBound,
 		CloneNoBound,
 		PartialEqNoBound,
+		PartialOrdNoBound,
+		OrdNoBound,
 		Encode,
 		Decode,
 		TypeInfo,

substrate/frame/support/test/tests/pallet_instance.rs

@@ -26,6 +26,7 @@ use frame_support::{
 		UnfilteredDispatchable,
 	},
 	weights::Weight,
+	OrdNoBound, PartialOrdNoBound,
 };
 use sp_io::{
 	hashing::{blake2_128, twox_128, twox_64},
@@ -208,6 +209,8 @@ pub mod pallet {
 		RuntimeDebugNoBound,
 		CloneNoBound,
 		PartialEqNoBound,
+		PartialOrdNoBound,
+		OrdNoBound,
 		Encode,
 		Decode,
 		scale_info::TypeInfo,