Make sure docs given to decl_module! are passed to the module struct (#4526)

substrate/frame/support/src/dispatch.rs

@@ -1075,7 +1075,6 @@ macro_rules! decl_module {
 
 	// Declare a `Call` variant parameter that should be encoded `compact`.
 	(@create_call_enum
-		$( #[$attr:meta] )*
 		$call_type:ident;
 		<$trait_instance:ident: $trait_name:ident$(<I>, $instance:ident: $instantiable:path $(= $module_default_instance:path)?)?>
 		{ $( $other_where_bounds:tt )* }
@@ -1089,7 +1088,6 @@ macro_rules! decl_module {
 	) => {
 		$crate::decl_module! {
 			@create_call_enum
-			$( #[$attr] )*
 			$call_type;
 			<$trait_instance: $trait_name $(<I>, $instance: $instantiable $(= $module_default_instance)? )?>
 			{ $( $other_where_bounds )* }
@@ -1107,7 +1105,6 @@ macro_rules! decl_module {
 
 	// Declare a `Call` variant parameter.
 	(@create_call_enum
-		$( #[$attr:meta] )*
 		$call_type:ident;
 		<$trait_instance:ident: $trait_name:ident$(<I>, $instance:ident: $instantiable:path $(= $module_default_instance:path)?)?>
 		{ $( $other_where_bounds:tt )* }
@@ -1120,7 +1117,6 @@ macro_rules! decl_module {
 	) => {
 		$crate::decl_module! {
 			@create_call_enum
-			$( #[$attr] )*
 			$call_type;
 			<$trait_instance: $trait_name $(<I>, $instance: $instantiable $(= $module_default_instance)? )?>
 			{ $( $other_where_bounds )* }
@@ -1136,7 +1132,6 @@ macro_rules! decl_module {
 	};
 
 	(@create_call_enum
-		$( #[$attr:meta] )*
 		$call_type:ident;
 		<$trait_instance:ident: $trait_name:ident$(<I>, $instance:ident: $instantiable:path $(= $module_default_instance:path)?)?>
 		{ $( $other_where_bounds:tt )* }
@@ -1151,7 +1146,6 @@ macro_rules! decl_module {
 	) => {
 		$crate::decl_module! {
 			@create_call_enum
-			$( #[$attr] )*
 			$call_type;
 			<$trait_instance: $trait_name $(<I>, $instance: $instantiable $(= $module_default_instance)? )?>
 			{ $( $other_where_bounds )* }
@@ -1172,15 +1166,16 @@ macro_rules! decl_module {
 	};
 
 	(@create_call_enum
-		$( #[$attr:meta] )*
 		$call_type:ident;
 		<$trait_instance:ident: $trait_name:ident$(<I>, $instance:ident: $instantiable:path $(= $module_default_instance:path)?)?>
 		{ $( $other_where_bounds:tt )* }
 		{ $( $generated_variants:tt )* }
 		{}
 	) => {
+		/// Dispatchable calls.
+		///
+		/// Each variant of this enum maps to a dispatchable function from the associated module.
 		#[derive($crate::codec::Encode, $crate::codec::Decode)]
-		$( #[$attr] )*
 		pub enum $call_type<$trait_instance: $trait_name$(<I>, $instance: $instantiable $( = $module_default_instance)?)?>
 			where $( $other_where_bounds )*
 		{
@@ -1221,6 +1216,7 @@ macro_rules! decl_module {
 
 		// Workaround for https://github.com/rust-lang/rust/issues/26925 . Remove when sorted.
 		#[derive(Clone, Copy, PartialEq, Eq, $crate::RuntimeDebug)]
+		$( #[$attr] )*
 		pub struct $mod_type<
 			$trait_instance: $trait_name
 			$(<I>, $instance: $instantiable $( = $module_default_instance)?)?
@@ -1286,7 +1282,6 @@ macro_rules! decl_module {
 
 		$crate::decl_module! {
 			@create_call_enum
-			$( #[$attr] )*
 			$call_type;
 			<$trait_instance: $trait_name $(<I>, $instance: $instantiable $(= $module_default_instance)? )?>
 			{ $( $other_where_bounds )* }

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

@@ -16,3 +16,20 @@
 
 //! Test crate for frame_support. Allow to make use of `frame_support::decl_storage`.
 //! See tests directory.
+
+// Make sure we fail compilation on warnings
+#![warn(missing_docs)]
+#![deny(warnings)]
+
+/// The configuration trait
+pub trait Trait {
+	/// The runtime origin type.
+	type Origin;
+	/// The block number type.
+	type BlockNumber;
+}
+
+frame_support::decl_module! {
+	/// Some test module
+	pub struct Module<T: Trait> for enum Call where origin: T::Origin {}
+}

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

@@ -1,3 +1,19 @@
+// Copyright 2019 Parity Technologies (UK) Ltd.
+// This file is part of Substrate.
+
+// Substrate is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Substrate is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
+
 use frame_support::codec::{Encode, Decode, EncodeLike};
 
 pub trait Trait: 'static + Eq + Clone {
@@ -12,13 +28,11 @@ pub trait Trait: 'static + Eq + Clone {
 }
 
 frame_support::decl_module! {
-	pub struct Module<T: Trait> for enum Call where origin: T::Origin {
-	}
+	pub struct Module<T: Trait> for enum Call where origin: T::Origin {}
 }
 
 impl<T: Trait> Module<T> {
-	pub fn deposit_event(_event: impl Into<T::Event>) {
-	}
+	pub fn deposit_event(_event: impl Into<T::Event>) {}
 }
 
 frame_support::decl_event!(