Adds ability to use default hasher in dev_mode for explicit key binding (#14164)

* Initial setup

* Minor update

* Minor update

* Addresses review comments

* Addresses review comments

* Updates doc

* ".git/.scripts/commands/fmt/fmt.sh"

* Renames file

* Updates path in test

---------

Co-authored-by: command-bot <>

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

@@ -0,0 +1,33 @@
+#![cfg_attr(not(feature = "std"), no_std)]
+
+pub use pallet::*;
+
+#[frame_support::pallet]
+pub mod pallet {
+	use frame_support::pallet_prelude::*;
+
+	// The struct on which we build all of our Pallet logic.
+	#[pallet::pallet]
+	pub struct Pallet<T>(_);
+
+	// Your Pallet's configuration trait, representing custom external types and interfaces.
+	#[pallet::config]
+	pub trait Config: frame_system::Config {}
+
+	#[pallet::storage]
+	type MyStorage<T: Config> = StorageValue<_, Vec<u8>>;
+
+	#[pallet::storage]
+	type MyStorageMap<T: Config> = StorageMap<Key = u32, Value = u64>;
+
+	#[pallet::storage]
+	type MyStorageDoubleMap<T: Config> = StorageDoubleMap<Key1 = u32, Key2 = u64, Value = u64>;
+
+	#[pallet::storage]
+	type MyCountedStorageMap<T: Config> = CountedStorageMap<Key = u32, Value = u64>;
+
+	// Your Pallet's internal functions.
+	impl<T: Config> Pallet<T> {}
+}
+
+fn main() {}

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

@@ -0,0 +1,11 @@
+error: Invalid pallet::storage, cannot find `Hasher` generic, required for `StorageMap`.
+  --> tests/pallet_ui/non_dev_mode_storage_map_explicit_key_default_hasher.rs:21:43
+   |
+21 |     type MyStorageMap<T: Config> = StorageMap<Key = u32, Value = u64>;
+   |                                              ^
+
+error[E0432]: unresolved import `pallet`
+ --> tests/pallet_ui/non_dev_mode_storage_map_explicit_key_default_hasher.rs:3:9
+  |
+3 | pub use pallet::*;
+  |         ^^^^^^ help: a similar path exists: `test_pallet::pallet`

substrate/frame/support/test/tests/pallet_ui/pass/dev_mode_valid.rs

@@ -35,6 +35,15 @@ pub mod pallet {
 	#[pallet::storage]
 	type MyCountedStorageMap<T: Config> = CountedStorageMap<_, _, u32, u64>;
 
+	#[pallet::storage]
+	pub type MyStorageMap2<T: Config> = StorageMap<Key = u32, Value = u64>;
+
+	#[pallet::storage]
+	type MyStorageDoubleMap2<T: Config> = StorageDoubleMap<Key1 = u32, Key2 = u64, Value = u64>;
+
+	#[pallet::storage]
+	type MyCountedStorageMap2<T: Config> = CountedStorageMap<Key = u32, Value = u64>;
+
 	// Your Pallet's callable functions.
 	#[pallet::call]
 	impl<T: Config> Pallet<T> {