Move MaxBoundedLen into its own crate

Cargo.toml

@@ -90,6 +90,8 @@ members = [
 	"frame/im-online",
 	"frame/indices",
 	"frame/lottery",
+	"frame/max-encoded-len",
+	"frame/max-encoded-len/derive",
 	"frame/membership",
 	"frame/merkle-mountain-range",
 	"frame/merkle-mountain-range/primitives",

bin/node/runtime/Cargo.toml

@@ -87,6 +87,8 @@ pallet-transaction-payment = { version = "3.0.0", default-features = false, path
 pallet-transaction-payment-rpc-runtime-api = { version = "3.0.0", default-features = false, path = "../../../frame/transaction-payment/rpc/runtime-api/" }
 pallet-vesting = { version = "3.0.0", default-features = false, path = "../../../frame/vesting" }
 
+max-encoded-len = { version = "3.0.0", default-features = false, path = "../../../frame/max-encoded-len", features = [ "derive" ] }
+
 [build-dependencies]
 substrate-wasm-builder = { version = "4.0.0", path = "../../../utils/wasm-builder" }
 
@@ -159,6 +161,7 @@ std = [
 	"log/std",
 	"frame-try-runtime/std",
 	"sp-npos-elections/std",
+	"max-encoded-len/std",
 ]
 runtime-benchmarks = [
 	"frame-benchmarking",

bin/node/runtime/src/lib.rs

@@ -33,7 +33,7 @@ use frame_support::{
 	},
 	traits::{
 		Currency, Imbalance, KeyOwnerProofSystem, OnUnbalanced, LockIdentifier,
-		U128CurrencyToVote,
+		U128CurrencyToVote, MaxEncodedLen,
 	},
 };
 use frame_system::{
@@ -252,7 +252,7 @@ parameter_types! {
 }
 
 /// The type used to represent the kinds of proxying allowed.
-#[derive(Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Encode, Decode, RuntimeDebug)]
+#[derive(Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Encode, Decode, RuntimeDebug, MaxEncodedLen)]
 pub enum ProxyType {
 	Any,
 	NonTransfer,

frame/assets/Cargo.toml

@@ -22,6 +22,7 @@ frame-support = { version = "3.0.0", default-features = false, path = "../suppor
 # `system` module provides us with all sorts of useful stuff and macros depend on it being around.
 frame-system = { version = "3.0.0", default-features = false, path = "../system" }
 frame-benchmarking = { version = "3.1.0", default-features = false, path = "../benchmarking", optional = true }
+max-encoded-len = { version = "3.0.0", default-features = false, path = "../max-encoded-len", features = [ "derive" ] }
 
 [dev-dependencies]
 sp-core = { version = "3.0.0", path = "../../primitives/core" }
@@ -38,6 +39,7 @@ std = [
 	"frame-support/std",
 	"frame-system/std",
 	"frame-benchmarking/std",
+	"max-encoded-len/std",
 ]
 runtime-benchmarks = [
 	"frame-benchmarking",

frame/balances/Cargo.toml

@@ -20,6 +20,7 @@ frame-benchmarking = { version = "3.1.0", default-features = false, path = "../b
 frame-support = { version = "3.0.0", default-features = false, path = "../support" }
 frame-system = { version = "3.0.0", default-features = false, path = "../system" }
 log = { version = "0.4.14", default-features = false }
+max-encoded-len = { version = "3.0.0", default-features = false, path = "../max-encoded-len", features = [ "derive" ] }
 
 [dev-dependencies]
 sp-io = { version = "3.0.0", path = "../../primitives/io" }
@@ -36,6 +37,7 @@ std = [
 	"frame-support/std",
 	"frame-system/std",
 	"log/std",
+	"max-encoded-len/std",
 ]
 runtime-benchmarks = ["frame-benchmarking"]
 try-runtime = ["frame-support/try-runtime"]

frame/max-encoded-len/Cargo.toml

@@ -0,0 +1,35 @@
+[package]
+name = "max-encoded-len"
+version = "3.0.0"
+authors = ["Parity Technologies <admin@parity.io>"]
+edition = "2018"
+license = "Apache-2.0"
+homepage = "https://substrate.dev"
+repository = "https://github.com/paritytech/substrate/"
+description = "Trait MaxEncodedLen bounds the max encoded length of an item."
+
+
+[dependencies]
+codec = { package = "parity-scale-codec", version = "2.0.0", default-features = false }
+impl-trait-for-tuples = "0.2.1"
+max-encoded-len-derive = { package = "max-encoded-len-derive", version = "3.0.0", path = "derive", default-features = false, optional = true }
+primitive-types = { version = "0.9.0", default-features = false, features = ["codec"] }
+
+[dev-dependencies]
+codec = { package = "parity-scale-codec", version = "2.0.0", default-features = false, features = [ "derive" ] }
+rustversion = "1.0.4"
+trybuild = "1.0.42"
+
+[features]
+default = [
+	"derive",
+	"std",
+]
+derive = [
+	"max-encoded-len-derive",
+]
+std = [
+	"codec/std",
+	"max-encoded-len-derive/std",
+	"primitive-types/std",
+]

frame/max-encoded-len/derive/Cargo.toml

@@ -0,0 +1,25 @@
+[package]
+name = "max-encoded-len-derive"
+version = "3.0.0"
+authors = ["Parity Technologies <admin@parity.io>"]
+edition = "2018"
+license = "Apache-2.0"
+homepage = "https://substrate.dev"
+repository = "https://github.com/paritytech/substrate/"
+description = "Derive support for MaxEncodedLen"
+
+[package.metadata.docs.rs]
+targets = ["x86_64-unknown-linux-gnu"]
+
+[lib]
+proc-macro = true
+
+[dependencies]
+frame-support-procedural-tools = { version = "3.0.0", path = "../../support/procedural/tools" }
+proc-macro2 = "1.0.6"
+quote = "1.0.3"
+syn = { version = "1.0.58", features = ["full"] }
+
+[features]
+default = ["std"]
+std = []

frame/support/procedural/src/max_encoded_len.rs → frame/max-encoded-len/derive/src/lib.rs

@@ -22,7 +22,9 @@ use syn::{
 	parse_quote, spanned::Spanned,
 };
 
-/// impl for `#[derive(MaxEncodedLen)]`
+
+/// Derive `MaxEncodedLen`.
+#[proc_macro_derive(MaxEncodedLen)]
 pub fn derive_max_encoded_len(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
 	let input: DeriveInput = match syn::parse(input) {
 		Ok(input) => input,
@@ -53,8 +55,8 @@ pub fn derive_max_encoded_len(input: proc_macro::TokenStream) -> proc_macro::Tok
 }
 
 fn max_encoded_len_trait() -> syn::Result<TraitBound> {
-	let frame_support = generate_crate_access_2018("frame-support")?;
-	Ok(parse_quote!(#frame_support::traits::MaxEncodedLen))
+	let mel = generate_crate_access_2018("max-encoded-len")?;
+	Ok(parse_quote!(#mel::MaxEncodedLen))
 }
 
 // Add a bound `T: MaxEncodedLen` to every type parameter T.

frame/support/src/traits/max_encoded_len.rs → frame/max-encoded-len/src/lib.rs

@@ -1,6 +1,6 @@
 // This file is part of Substrate.
 
-// Copyright (C) 2019-2021 Parity Technologies (UK) Ltd.
+// Copyright (C) 2021 Parity Technologies (UK) Ltd.
 // SPDX-License-Identifier: Apache-2.0
 
 // Licensed under the Apache License, Version 2.0 (the "License");
@@ -15,10 +15,17 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+//! `trait MaxEncodedLen` bounds the max encoded length of items.
+
+#![cfg_attr(not(feature = "std"), no_std)]
+
 use codec::{Compact, Encode};
 use impl_trait_for_tuples::impl_for_tuples;
-use sp_std::{mem, marker::PhantomData};
-use sp_core::{H160, H256, H512};
+use core::{mem, marker::PhantomData};
+use primitive_types::{H160, H256, H512};
+
+#[cfg(feature = "derive")]
+pub use max_encoded_len_derive::MaxEncodedLen;
 
 /// Items implementing `MaxEncodedLen` have a statically known maximum encoded size.
 ///

frame/support/test/tests/max_encoded_len.rs → frame/max-encoded-len/tests/max_encoded_len.rs

@@ -17,7 +17,9 @@
 
 //! Tests for MaxEncodedLen derive macro
 
-use frame_support::traits::MaxEncodedLen;
+#![cfg(feature = "derive")]
+
+use max_encoded_len::MaxEncodedLen;
 use codec::{Compact, Encode};
 
 // These structs won't even compile if the macro isn't working right.

frame/support/test/tests/max_encoded_len_ui.rs → frame/max-encoded-len/tests/max_encoded_len_ui.rs

@@ -15,6 +15,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+#[cfg(feature = "derive")]
 #[rustversion::attr(not(stable), ignore)]
 #[test]
 fn derive_no_bound_ui() {

frame/support/test/tests/max_encoded_len_ui/not_encode.rs → frame/max-encoded-len/tests/max_encoded_len_ui/not_encode.rs

@@ -1,4 +1,4 @@
-use frame_support::traits::MaxEncodedLen;
+use max_encoded_len::MaxEncodedLen;
 
 #[derive(MaxEncodedLen)]
 struct NotEncode;

frame/support/test/tests/max_encoded_len_ui/not_encode.stderr → frame/max-encoded-len/tests/max_encoded_len_ui/not_encode.stderr

@@ -1,13 +1,13 @@
-error[E0277]: the trait bound `NotEncode: WrapperTypeEncode` is not satisfied
+error[E0277]: the trait bound `NotEncode: parity_scale_codec::codec::WrapperTypeEncode` is not satisfied
   --> $DIR/not_encode.rs:3:10
    |
 3  | #[derive(MaxEncodedLen)]
-   |          ^^^^^^^^^^^^^ the trait `WrapperTypeEncode` is not implemented for `NotEncode`
+   |          ^^^^^^^^^^^^^ the trait `parity_scale_codec::codec::WrapperTypeEncode` is not implemented for `NotEncode`
    |
-  ::: $WORKSPACE/frame/support/src/traits/max_encoded_len.rs
+  ::: $WORKSPACE/frame/max-encoded-len/src/lib.rs
    |
    | pub trait MaxEncodedLen: Encode {
    |                          ------ required by this bound in `MaxEncodedLen`
    |
-   = note: required because of the requirements on the impl of `frame_support::dispatch::Encode` for `NotEncode`
+   = note: required because of the requirements on the impl of `parity_scale_codec::codec::Encode` for `NotEncode`
    = note: this error originates in a derive macro (in Nightly builds, run with -Z macro-backtrace for more info)

frame/support/test/tests/max_encoded_len_ui/not_mel.rs → frame/max-encoded-len/tests/max_encoded_len_ui/not_mel.rs

@@ -1,5 +1,5 @@
 use codec::Encode;
-use frame_support::traits::MaxEncodedLen;
+use max_encoded_len::MaxEncodedLen;
 
 #[derive(Encode)]
 struct NotMel;

frame/support/test/tests/max_encoded_len_ui/union.rs → frame/max-encoded-len/tests/max_encoded_len_ui/union.rs

@@ -1,5 +1,5 @@
 use codec::Encode;
-use frame_support::traits::MaxEncodedLen;
+use max_encoded_len::MaxEncodedLen;
 
 #[derive(Encode, MaxEncodedLen)]
 union Union {

frame/support/test/tests/max_encoded_len_ui/unsupported_variant.rs → frame/max-encoded-len/tests/max_encoded_len_ui/unsupported_variant.rs

@@ -1,5 +1,5 @@
 use codec::Encode;
-use frame_support::traits::MaxEncodedLen;
+use max_encoded_len::MaxEncodedLen;
 
 #[derive(Encode)]
 struct NotMel;

frame/proxy/Cargo.toml

@@ -20,6 +20,7 @@ sp-core = { version = "3.0.0", default-features = false, path = "../../primitive
 sp-io = { version = "3.0.0", default-features = false, path = "../../primitives/io" }
 sp-runtime = { version = "3.0.0", default-features = false, path = "../../primitives/runtime" }
 sp-std = { version = "3.0.0", default-features = false, path = "../../primitives/std" }
+max-encoded-len = { version = "3.0.0", default-features = false, path = "../max-encoded-len", features = [ "derive" ] }
 
 frame-benchmarking = { version = "3.1.0", default-features = false, path = "../benchmarking", optional = true }
 
@@ -36,7 +37,8 @@ std = [
 	"frame-support/std",
 	"frame-system/std",
 	"sp-std/std",
-	"sp-io/std"
+	"sp-io/std",
+	"max-encoded-len/std",
 ]
 runtime-benchmarks = [
 	"frame-benchmarking",

frame/support/Cargo.toml

@@ -16,6 +16,7 @@ targets = ["x86_64-unknown-linux-gnu"]
 serde = { version = "1.0.101", optional = true, features = ["derive"] }
 codec = { package = "parity-scale-codec", version = "2.0.0", default-features = false, features = ["derive"] }
 frame-metadata = { version = "13.0.0", default-features = false, path = "../metadata" }
+max-encoded-len = { version = "3.0.0", default-features = false, path = "../max-encoded-len", features = [ "derive" ] }
 sp-std = { version = "3.0.0", default-features = false, path = "../../primitives/std" }
 sp-io = { version = "3.0.0", default-features = false, path = "../../primitives/io" }
 sp-runtime = { version = "3.0.0", default-features = false, path = "../../primitives/runtime" }
@@ -55,6 +56,7 @@ std = [
 	"sp-state-machine",
 	"frame-support-procedural/std",
 	"log/std",
+	"max-encoded-len/std",
 ]
 runtime-benchmarks = []
 try-runtime = []