Allow to name the generic for storages in #[pallet::storage] (#8751)

* implement named generic for storages

* fix error message on unexpected name for generic

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

@@ -196,7 +196,7 @@ pub mod pallet {
 		StorageValue<_, <T::AccountId as SomeAssociation2>::_2>;
 
 	#[pallet::storage]
-	pub type Value<T> = StorageValue<_, u32>;
+	pub type Value<T> = StorageValue<Value = u32>;
 
 	#[pallet::type_value]
 	pub fn MyDefault<T: Config>() -> u16
@@ -211,14 +211,19 @@ pub mod pallet {
 		StorageMap<_, Blake2_128Concat, u8, u16, ValueQuery, MyDefault<T>>;
 
 	#[pallet::storage]
-	pub type Map2<T> = StorageMap<_, Twox64Concat, u16, u32, OptionQuery, GetDefault, ConstU32<3>>;
+	pub type Map2<T> = StorageMap<
+		Hasher = Twox64Concat, Key = u16, Value = u32, MaxValues = ConstU32<3>
+	>;
 
 	#[pallet::storage]
 	pub type DoubleMap<T> = StorageDoubleMap<_, Blake2_128Concat, u8, Twox64Concat, u16, u32>;
 
 	#[pallet::storage]
 	pub type DoubleMap2<T> = StorageDoubleMap<
-		_, Twox64Concat, u16, Blake2_128Concat, u32, u64, OptionQuery, GetDefault, ConstU32<5>,
+		Hasher1 = Twox64Concat, Key1 = u16,
+		Hasher2 = Blake2_128Concat, Key2 = u32,
+		Value = u64,
+		MaxValues = ConstU32<5>,
 	>;
 
 	#[pallet::storage]
@@ -228,15 +233,9 @@ pub mod pallet {
 	#[pallet::storage]
 	#[pallet::getter(fn nmap2)]
 	pub type NMap2<T> = StorageNMap<
-		_,
-		(
-			NMapKey<Twox64Concat, u16>,
-			NMapKey<Blake2_128Concat, u32>,
-		),
-		u64,
-		OptionQuery,
-		GetDefault,
-		ConstU32<11>,
+		Key = (NMapKey<Twox64Concat, u16>, NMapKey<Blake2_128Concat, u32>),
+		Value = u64,
+		MaxValues = ConstU32<11>,
 	>;
 
 	#[pallet::storage]

substrate/frame/support/test/tests/pallet_ui/storage_ensure_span_are_ok_on_wrong_gen.rs

@@ -0,0 +1,25 @@
+#[frame_support::pallet]
+mod pallet {
+	use frame_support::pallet_prelude::{Hooks, StorageValue};
+	use frame_system::pallet_prelude::BlockNumberFor;
+
+	#[pallet::config]
+	pub trait Config: frame_system::Config {}
+
+	#[pallet::pallet]
+	pub struct Pallet<T>(core::marker::PhantomData<T>);
+
+	#[pallet::hooks]
+	impl<T: Config> Hooks<BlockNumberFor<T>> for Pallet<T> {}
+
+	#[pallet::call]
+	impl<T: Config> Pallet<T> {}
+
+	struct Bar;
+
+	#[pallet::storage]
+	type Foo<T> = StorageValue<Value = Bar>;
+}
+
+fn main() {
+}

substrate/frame/support/test/tests/pallet_ui/storage_ensure_span_are_ok_on_wrong_gen.stderr

@@ -0,0 +1,33 @@
+error[E0277]: the trait bound `Bar: WrapperTypeDecode` is not satisfied
+  --> $DIR/storage_ensure_span_are_ok_on_wrong_gen.rs:20:12
+   |
+20 |     #[pallet::storage]
+   |               ^^^^^^^ the trait `WrapperTypeDecode` is not implemented for `Bar`
+   |
+   = note: required because of the requirements on the impl of `Decode` for `Bar`
+   = note: required because of the requirements on the impl of `FullCodec` for `Bar`
+   = note: required because of the requirements on the impl of `StorageValueMetadata` for `frame_support::pallet_prelude::StorageValue<_GeneratedPrefixForStorageFoo<T>, Bar>`
+   = note: required by `frame_support::storage::types::StorageValueMetadata::NAME`
+
+error[E0277]: the trait bound `Bar: EncodeLike` is not satisfied
+  --> $DIR/storage_ensure_span_are_ok_on_wrong_gen.rs:20:12
+   |
+20 |     #[pallet::storage]
+   |               ^^^^^^^ the trait `EncodeLike` is not implemented for `Bar`
+   |
+   = note: required because of the requirements on the impl of `FullEncode` for `Bar`
+   = note: required because of the requirements on the impl of `FullCodec` for `Bar`
+   = note: required because of the requirements on the impl of `StorageValueMetadata` for `frame_support::pallet_prelude::StorageValue<_GeneratedPrefixForStorageFoo<T>, Bar>`
+   = note: required by `frame_support::storage::types::StorageValueMetadata::NAME`
+
+error[E0277]: the trait bound `Bar: WrapperTypeEncode` is not satisfied
+  --> $DIR/storage_ensure_span_are_ok_on_wrong_gen.rs:20:12
+   |
+20 |     #[pallet::storage]
+   |               ^^^^^^^ the trait `WrapperTypeEncode` is not implemented for `Bar`
+   |
+   = note: required because of the requirements on the impl of `pallet::_::_parity_scale_codec::Encode` for `Bar`
+   = note: required because of the requirements on the impl of `FullEncode` for `Bar`
+   = note: required because of the requirements on the impl of `FullCodec` for `Bar`
+   = note: required because of the requirements on the impl of `StorageValueMetadata` for `frame_support::pallet_prelude::StorageValue<_GeneratedPrefixForStorageFoo<T>, Bar>`
+   = note: required by `frame_support::storage::types::StorageValueMetadata::NAME`

substrate/frame/support/test/tests/pallet_ui/storage_ensure_span_are_ok_on_wrong_gen_unnamed.rs

@@ -0,0 +1,25 @@
+#[frame_support::pallet]
+mod pallet {
+	use frame_support::pallet_prelude::{Hooks, StorageValue};
+	use frame_system::pallet_prelude::BlockNumberFor;
+
+	#[pallet::config]
+	pub trait Config: frame_system::Config {}
+
+	#[pallet::pallet]
+	pub struct Pallet<T>(core::marker::PhantomData<T>);
+
+	#[pallet::hooks]
+	impl<T: Config> Hooks<BlockNumberFor<T>> for Pallet<T> {}
+
+	#[pallet::call]
+	impl<T: Config> Pallet<T> {}
+
+	struct Bar;
+
+	#[pallet::storage]
+	type Foo<T> = StorageValue<_, Bar>;
+}
+
+fn main() {
+}

substrate/frame/support/test/tests/pallet_ui/storage_ensure_span_are_ok_on_wrong_gen_unnamed.stderr

@@ -0,0 +1,33 @@
+error[E0277]: the trait bound `Bar: WrapperTypeDecode` is not satisfied
+  --> $DIR/storage_ensure_span_are_ok_on_wrong_gen_unnamed.rs:20:12
+   |
+20 |     #[pallet::storage]
+   |               ^^^^^^^ the trait `WrapperTypeDecode` is not implemented for `Bar`
+   |
+   = note: required because of the requirements on the impl of `Decode` for `Bar`
+   = note: required because of the requirements on the impl of `FullCodec` for `Bar`
+   = note: required because of the requirements on the impl of `StorageValueMetadata` for `frame_support::pallet_prelude::StorageValue<_GeneratedPrefixForStorageFoo<T>, Bar>`
+   = note: required by `frame_support::storage::types::StorageValueMetadata::NAME`
+
+error[E0277]: the trait bound `Bar: EncodeLike` is not satisfied
+  --> $DIR/storage_ensure_span_are_ok_on_wrong_gen_unnamed.rs:20:12
+   |
+20 |     #[pallet::storage]
+   |               ^^^^^^^ the trait `EncodeLike` is not implemented for `Bar`
+   |
+   = note: required because of the requirements on the impl of `FullEncode` for `Bar`
+   = note: required because of the requirements on the impl of `FullCodec` for `Bar`
+   = note: required because of the requirements on the impl of `StorageValueMetadata` for `frame_support::pallet_prelude::StorageValue<_GeneratedPrefixForStorageFoo<T>, Bar>`
+   = note: required by `frame_support::storage::types::StorageValueMetadata::NAME`
+
+error[E0277]: the trait bound `Bar: WrapperTypeEncode` is not satisfied
+  --> $DIR/storage_ensure_span_are_ok_on_wrong_gen_unnamed.rs:20:12
+   |
+20 |     #[pallet::storage]
+   |               ^^^^^^^ the trait `WrapperTypeEncode` is not implemented for `Bar`
+   |
+   = note: required because of the requirements on the impl of `pallet::_::_parity_scale_codec::Encode` for `Bar`
+   = note: required because of the requirements on the impl of `FullEncode` for `Bar`
+   = note: required because of the requirements on the impl of `FullCodec` for `Bar`
+   = note: required because of the requirements on the impl of `StorageValueMetadata` for `frame_support::pallet_prelude::StorageValue<_GeneratedPrefixForStorageFoo<T>, Bar>`
+   = note: required by `frame_support::storage::types::StorageValueMetadata::NAME`

substrate/frame/support/test/tests/pallet_ui/storage_invalid_first_generic.stderr

@@ -1,4 +1,4 @@
-error: Invalid use of `#[pallet::storage]`, the type first generic argument must be `_`, the final argument is automatically set by macro.
+error: Invalid pallet::storage, for unnamed generic arguments the type first generic argument must be `_`, the argument is then replaced by macro.
   --> $DIR/storage_invalid_first_generic.rs:19:29
    |
 19 |     type Foo<T> = StorageValue<u8, u8>;

substrate/frame/support/test/tests/pallet_ui/storage_not_storage_type.stderr

@@ -1,4 +1,4 @@
-error: Invalid pallet::storage, expected ident: `StorageValue` or `StorageMap` or `StorageDoubleMap` or `StorageNMap` in order to expand metadata, found `u8`
+error: Invalid pallet::storage, expected ident: `StorageValue` or `StorageMap` or `StorageDoubleMap` or `StorageNMap` in order to expand metadata, found `u8`.
   --> $DIR/storage_not_storage_type.rs:19:16
    |
 19 |     type Foo<T> = u8;

substrate/frame/support/test/tests/pallet_ui/storage_value_duplicate_named_generic.rs

@@ -0,0 +1,23 @@
+#[frame_support::pallet]
+mod pallet {
+	use frame_support::pallet_prelude::{Hooks, StorageValue};
+	use frame_system::pallet_prelude::BlockNumberFor;
+
+	#[pallet::config]
+	pub trait Config: frame_system::Config {}
+
+	#[pallet::pallet]
+	pub struct Pallet<T>(core::marker::PhantomData<T>);
+
+	#[pallet::hooks]
+	impl<T: Config> Hooks<BlockNumberFor<T>> for Pallet<T> {}
+
+	#[pallet::call]
+	impl<T: Config> Pallet<T> {}
+
+	#[pallet::storage]
+	type Foo<T> = StorageValue<Value = u32, Value = u32>;
+}
+
+fn main() {
+}

substrate/frame/support/test/tests/pallet_ui/storage_value_duplicate_named_generic.stderr

@@ -0,0 +1,11 @@
+error: Invalid pallet::storage, Duplicated named generic
+  --> $DIR/storage_value_duplicate_named_generic.rs:19:42
+   |
+19 |     type Foo<T> = StorageValue<Value = u32, Value = u32>;
+   |                                             ^^^^^
+
+error: Invalid pallet::storage, Duplicated named generic
+  --> $DIR/storage_value_duplicate_named_generic.rs:19:29
+   |
+19 |     type Foo<T> = StorageValue<Value = u32, Value = u32>;
+   |                                ^^^^^

substrate/frame/support/test/tests/pallet_ui/storage_value_generic_named_and_unnamed.rs

@@ -0,0 +1,23 @@
+#[frame_support::pallet]
+mod pallet {
+	use frame_support::pallet_prelude::{Hooks, StorageValue, OptionQuery};
+	use frame_system::pallet_prelude::BlockNumberFor;
+
+	#[pallet::config]
+	pub trait Config: frame_system::Config {}
+
+	#[pallet::pallet]
+	pub struct Pallet<T>(core::marker::PhantomData<T>);
+
+	#[pallet::hooks]
+	impl<T: Config> Hooks<BlockNumberFor<T>> for Pallet<T> {}
+
+	#[pallet::call]
+	impl<T: Config> Pallet<T> {}
+
+	#[pallet::storage]
+	type Foo<T> = StorageValue<u32, QueryKind = OptionQuery>;
+}
+
+fn main() {
+}

substrate/frame/support/test/tests/pallet_ui/storage_value_generic_named_and_unnamed.stderr

@@ -0,0 +1,5 @@
+error: Invalid pallet::storage, invalid generic declaration for storage. Expect only type generics or binding generics, e.g. `<Name1 = Gen1, Name2 = Gen2, ..>` or `<Gen1, Gen2, ..>`.
+  --> $DIR/storage_value_generic_named_and_unnamed.rs:19:16
+   |
+19 |     type Foo<T> = StorageValue<u32, QueryKind = OptionQuery>;
+   |                   ^^^^^^^^^^^^

substrate/frame/support/test/tests/pallet_ui/storage_value_no_generic.stderr

@@ -1,4 +1,4 @@
-error: pallet::storage unexpected number of generic argument, expected at least 2 args, found none
+error: Invalid pallet::storage, invalid number of generic generic arguments, expect more that 0 generic arguments.
   --> $DIR/storage_value_no_generic.rs:19:16
    |
 19 |     type Foo<T> = StorageValue;

substrate/frame/support/test/tests/pallet_ui/storage_value_unexpected_named_generic.rs

@@ -0,0 +1,23 @@
+#[frame_support::pallet]
+mod pallet {
+	use frame_support::pallet_prelude::{Hooks, StorageValue};
+	use frame_system::pallet_prelude::BlockNumberFor;
+
+	#[pallet::config]
+	pub trait Config: frame_system::Config {}
+
+	#[pallet::pallet]
+	pub struct Pallet<T>(core::marker::PhantomData<T>);
+
+	#[pallet::hooks]
+	impl<T: Config> Hooks<BlockNumberFor<T>> for Pallet<T> {}
+
+	#[pallet::call]
+	impl<T: Config> Pallet<T> {}
+
+	#[pallet::storage]
+	type Foo<T> = StorageValue<P = u32>;
+}
+
+fn main() {
+}

substrate/frame/support/test/tests/pallet_ui/storage_value_unexpected_named_generic.stderr

@@ -0,0 +1,11 @@
+error: Invalid pallet::storage, Unexpected generic `P` for `StorageValue`. `StorageValue` expect generics `Value`, and optional generics `QueryKind`, `OnEmpty`.
+  --> $DIR/storage_value_unexpected_named_generic.rs:19:29
+   |
+19 |     type Foo<T> = StorageValue<P = u32>;
+   |                                ^
+
+error: Invalid pallet::storage, cannot find `Value` generic, required for `StorageValue`.
+  --> $DIR/storage_value_unexpected_named_generic.rs:19:28
+   |
+19 |     type Foo<T> = StorageValue<P = u32>;
+   |                               ^

substrate/frame/support/test/tests/pallet_ui/storage_wrong_item.stderr

@@ -1,4 +1,4 @@
-error: Invalid pallet::storage, expected item type
+error: Invalid pallet::storage, expect item type.
   --> $DIR/storage_wrong_item.rs:19:2
    |
 19 |     impl Foo {}