rlp_derive: cleanup (#11446)

* rlp_derive: update syn & co

* rlp_derive: remove dummy_const

* rlp_derive: remove unused attirubutes

* rlp-derive: change authors

Cargo.lock

@@ -4078,10 +4078,10 @@ dependencies = [
 name = "rlp_derive"
 version = "0.1.0"
 dependencies = [
- "proc-macro2 0.4.20 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "quote 0.6.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "rlp 0.4.4 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.26 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]

util/rlp-derive/Cargo.toml

@@ -1,16 +1,17 @@
 [package]
 name = "rlp_derive"
 version = "0.1.0"
-authors = ["debris <marek.kotewicz@gmail.com>"]
+authors = ["Parity Technologies <admin@parity.io>"]
+edition = "2018"
 
 [lib]
 name = "rlp_derive"
 proc-macro = true
 
 [dependencies]
-syn = "0.15"
+syn = "1.0.14"
-quote = "0.6"
+quote = "1.0.2"
-proc-macro2 = "0.4"
+proc-macro2 = "1.0.8"
 
 [dev-dependencies]
 rlp = "0.4.0"

util/rlp-derive/src/de.rs

@@ -14,8 +14,8 @@
 // You should have received a copy of the GNU General Public License
 // along with Parity Ethereum.  If not, see <http://www.gnu.org/licenses/>.
 
-use syn;
+use proc_macro2::TokenStream;
-use proc_macro2::{TokenStream, Span};
+use quote::quote;
 
 struct ParseQuotes {
 	single: TokenStream,
@@ -45,10 +45,14 @@ pub fn impl_decodable(ast: &syn::DeriveInput) -> TokenStream {
 		_ => panic!("#[derive(RlpDecodable)] is only defined for structs."),
 	};
 
-	let stmts: Vec<_> = body.fields.iter().enumerate().map(decodable_field_map).collect();
+	let stmts: Vec<_> = body
+		.fields
+		.iter()
+		.enumerate()
+		.map(decodable_field_map)
+		.collect();
 	let name = &ast.ident;
 
-	let dummy_const = syn::Ident::new(&format!("_IMPL_RLP_DECODABLE_FOR_{}", name), Span::call_site());
 	let impl_block = quote! {
 		impl rlp::Decodable for #name {
 			fn decode(rlp: &rlp::Rlp) -> Result<Self, rlp::DecoderError> {
@@ -62,8 +66,7 @@ pub fn impl_decodable(ast: &syn::DeriveInput) -> TokenStream {
 	};
 
 	quote! {
-		#[allow(non_upper_case_globals, unused_attributes, unused_qualifications)]
+		const _: () = {
-		const #dummy_const: () = {
 			extern crate rlp;
 			#impl_block
 		};
@@ -88,7 +91,6 @@ pub fn impl_decodable_wrapper(ast: &syn::DeriveInput) -> TokenStream {
 
 	let name = &ast.ident;
 
-	let dummy_const = syn::Ident::new(&format!("_IMPL_RLP_DECODABLE_FOR_{}", name), Span::call_site());
 	let impl_block = quote! {
 		impl rlp::Decodable for #name {
 			fn decode(rlp: &rlp::Rlp) -> Result<Self, rlp::DecoderError> {
@@ -102,8 +104,7 @@ pub fn impl_decodable_wrapper(ast: &syn::DeriveInput) -> TokenStream {
 	};
 
 	quote! {
-		#[allow(non_upper_case_globals, unused_attributes, unused_qualifications)]
+		const _: () = {
-		const #dummy_const: () = {
 			extern crate rlp;
 			#impl_block
 		};
@@ -130,7 +131,12 @@ fn decodable_field(index: usize, field: &syn::Field, quotes: ParseQuotes) -> Tok
 
 	match field.ty {
 		syn::Type::Path(ref path) => {
-			let ident = &path.path.segments.first().expect("there must be at least 1 segment").value().ident;
+			let ident = &path
+				.path
+				.segments
+				.first()
+				.expect("there must be at least 1 segment")
+				.ident;
 			if &ident.to_string() == "Vec" {
 				if quotes.takes_index {
 					quote! { #id: #list(#index)?, }
@@ -144,7 +150,7 @@ fn decodable_field(index: usize, field: &syn::Field, quotes: ParseQuotes) -> Tok
 					quote! { #id: #single()?, }
 				}
 			}
-		},
+		}
 		_ => panic!("rlp_derive not supported"),
 	}
 }

util/rlp-derive/src/en.rs

@@ -14,8 +14,8 @@
 // You should have received a copy of the GNU General Public License
 // along with Parity Ethereum.  If not, see <http://www.gnu.org/licenses/>.
 
-use syn;
+use proc_macro2::TokenStream;
-use proc_macro2::{TokenStream, Span};
+use quote::quote;
 
 pub fn impl_encodable(ast: &syn::DeriveInput) -> TokenStream {
 	let body = match ast.data {
@@ -23,12 +23,16 @@ pub fn impl_encodable(ast: &syn::DeriveInput) -> TokenStream {
 		_ => panic!("#[derive(RlpEncodable)] is only defined for structs."),
 	};
 
-	let stmts: Vec<_> = body.fields.iter().enumerate().map(encodable_field_map).collect();
+	let stmts: Vec<_> = body
+		.fields
+		.iter()
+		.enumerate()
+		.map(encodable_field_map)
+		.collect();
 	let name = &ast.ident;
 
 	let stmts_len = stmts.len();
 	let stmts_len = quote! { #stmts_len };
-	let dummy_const = syn::Ident::new(&format!("_IMPL_RLP_ENCODABLE_FOR_{}", name), Span::call_site());
 	let impl_block = quote! {
 		impl rlp::Encodable for #name {
 			fn rlp_append(&self, stream: &mut rlp::RlpStream) {
@@ -39,8 +43,7 @@ pub fn impl_encodable(ast: &syn::DeriveInput) -> TokenStream {
 	};
 
 	quote! {
-		#[allow(non_upper_case_globals, unused_attributes, unused_qualifications)]
+		const _: () = {
-		const #dummy_const: () = {
 			extern crate rlp;
 			#impl_block
 		};
@@ -65,7 +68,6 @@ pub fn impl_encodable_wrapper(ast: &syn::DeriveInput) -> TokenStream {
 
 	let name = &ast.ident;
 
-	let dummy_const = syn::Ident::new(&format!("_IMPL_RLP_ENCODABLE_FOR_{}", name), Span::call_site());
 	let impl_block = quote! {
 		impl rlp::Encodable for #name {
 			fn rlp_append(&self, stream: &mut rlp::RlpStream) {
@@ -75,8 +77,7 @@ pub fn impl_encodable_wrapper(ast: &syn::DeriveInput) -> TokenStream {
 	};
 
 	quote! {
-		#[allow(non_upper_case_globals, unused_attributes, unused_qualifications)]
+		const _: () = {
-		const #dummy_const: () = {
 			extern crate rlp;
 			#impl_block
 		};
@@ -100,24 +101,38 @@ fn encodable_field(index: usize, field: &syn::Field) -> TokenStream {
 
 	match field.ty {
 		syn::Type::Path(ref path) => {
-			let top_segment = path.path.segments.first().expect("there must be at least 1 segment");
+			let top_segment = path
-			let ident = &top_segment.value().ident;
+				.path
+				.segments
+				.first()
+				.expect("there must be at least 1 segment");
+			let ident = &top_segment.ident;
 			if &ident.to_string() == "Vec" {
-				let inner_ident = match top_segment.value().arguments {
+				let inner_ident = match top_segment.arguments {
 					syn::PathArguments::AngleBracketed(ref angle) => {
-						let ty = angle.args.first().expect("Vec has only one angle bracketed type; qed");
+						let ty = angle
-						match **ty.value() {
+							.args
-							syn::GenericArgument::Type(syn::Type::Path(ref path)) => &path.path.segments.first().expect("there must be at least 1 segment").value().ident,
+							.first()
+							.expect("Vec has only one angle bracketed type; qed");
+						match *ty {
+							syn::GenericArgument::Type(syn::Type::Path(ref path)) => {
+								&path
+									.path
+									.segments
+									.first()
+									.expect("there must be at least 1 segment")
+									.ident
+							}
 							_ => panic!("rlp_derive not supported"),
 						}
-					},
+					}
 					_ => unreachable!("Vec has only one angle bracketed type; qed"),
 				};
 				quote! { stream.append_list::<#inner_ident, _>(&#id); }
 			} else {
 				quote! { stream.append(&#id); }
 			}
-		},
+		}
 		_ => panic!("rlp_derive not supported"),
 	}
 }

util/rlp-derive/src/lib.rs

@@ -15,17 +15,13 @@
 // along with Parity Ethereum.  If not, see <http://www.gnu.org/licenses/>.
 
 extern crate proc_macro;
-extern crate proc_macro2;
-extern crate syn;
-#[macro_use]
-extern crate quote;
 
-mod en;
 mod de;
+mod en;
 
-use proc_macro::TokenStream;
-use en::{impl_encodable, impl_encodable_wrapper};
 use de::{impl_decodable, impl_decodable_wrapper};
+use en::{impl_encodable, impl_encodable_wrapper};
+use proc_macro::TokenStream;
 
 #[proc_macro_derive(RlpEncodable)]
 pub fn encodable(input: TokenStream) -> TokenStream {

util/rlp-derive/tests/rlp.rs

@@ -14,11 +14,8 @@
 // You should have received a copy of the GNU General Public License
 // along with Parity Ethereum.  If not, see <http://www.gnu.org/licenses/>.
 
-extern crate rlp;
+use rlp::{decode, encode};
-#[macro_use]
+use rlp_derive::{RlpDecodable, RlpDecodableWrapper, RlpEncodable, RlpEncodableWrapper};
-extern crate rlp_derive;
-
-use rlp::{encode, decode};
 
 #[derive(Debug, PartialEq, RlpEncodable, RlpDecodable)]
 struct Foo {
@@ -32,9 +29,7 @@ struct FooWrapper {
 
 #[test]
 fn test_encode_foo() {
-	let foo = Foo {
+	let foo = Foo { a: "cat".into() };
-		a: "cat".into(),
-	};
 
 	let expected = vec![0xc4, 0x83, b'c', b'a', b't'];
 	let out = encode(&foo);
@@ -46,9 +41,7 @@ fn test_encode_foo() {
 
 #[test]
 fn test_encode_foo_wrapper() {
-	let foo = FooWrapper {
+	let foo = FooWrapper { a: "cat".into() };
-		a: "cat".into(),
-	};
 
 	let expected = vec![0x83, b'c', b'a', b't'];
 	let out = encode(&foo);