[Fix] parameter_types! dead code errors (paritytech#12340)

* [Fix] parameter_types! dead code errors

* mark the whole impl allow(unused)

Author: ruseinov

frame/support/src/lib.rs

@@ -361,9 +361,9 @@ macro_rules! parameter_types {
 		}
 	};
 	(IMPL_STORAGE $name:ident, $type:ty, $value:expr $(, $ty_params:ident)*) => {
+		#[allow(unused)]
 		impl< $($ty_params),* > $name< $($ty_params),* > {
 			/// Returns the key for this parameter type.
-			#[allow(unused)]
 			pub fn key() -> [u8; 16] {
 				$crate::sp_core_hashing_proc_macro::twox_128!(b":", $name, b":")
 			}
@@ -372,7 +372,6 @@ macro_rules! parameter_types {
 			///
 			/// This needs to be executed in an externalities provided
 			/// environment.
-			#[allow(unused)]
 			pub fn set(value: &$type) {
 				$crate::storage::unhashed::put(&Self::key(), value);
 			}
@@ -448,6 +447,7 @@ macro_rules! parameter_types_impl_thread_local {
 					}
 
 					/// Mutate the internal value in place.
+					#[allow(unused)]
 					pub fn mutate<R, F: FnOnce(&mut $type) -> R>(mutate: F) -> R{
 						let mut current = Self::get();
 						let result = mutate(&mut current);
@@ -456,6 +456,7 @@ macro_rules! parameter_types_impl_thread_local {
 					}
 
 					/// Get current value and replace with initial value of the parameter type.
+					#[allow(unused)]
 					pub fn take() -> $type {
 						let current = Self::get();
 						Self::set($value);