IntegrityTest implementation should be feature gated (#13094)

* `IntegrityTest` implementation should be feature gated

The initial implementation for the old declarative macros is still feature gating the
implementation. As we only call this in a test, there is no need to have this compiled for wasm.

* Don't assume that all "consumers" have a `std` feature

substrate/frame/support/procedural/src/pallet/expand/hooks.rs

@@ -191,16 +191,19 @@ pub fn expand_hooks(def: &mut Def) -> proc_macro2::TokenStream {
 			}
 		}
 
-		impl<#type_impl_gen>
+		// Integrity tests are only required for when `std` is enabled.
-			#frame_support::traits::IntegrityTest
+		#frame_support::std_enabled! {
+			impl<#type_impl_gen>
+				#frame_support::traits::IntegrityTest
 			for #pallet_ident<#type_use_gen> #where_clause
-		{
+			{
-			fn integrity_test() {
+				fn integrity_test() {
-				<
+					<
-					Self as #frame_support::traits::Hooks<
+						Self as #frame_support::traits::Hooks<
 						<T as #frame_system::Config>::BlockNumber
-					>
+						>
-				>::integrity_test()
+						>::integrity_test()
+				}
 			}
 		}
 

substrate/frame/support/src/lib.rs

@@ -2744,3 +2744,6 @@ pub mod pallet_macros {
 		type_value, unbounded, validate_unsigned, weight, whitelist_storage,
 	};
 }
+
+// Generate a macro that will enable/disable code based on `std` feature being active.
+sp_core::generate_feature_enabled_macro!(std_enabled, feature = "std", $);

substrate/frame/system/benches/bench.rs

@@ -16,10 +16,7 @@
 // limitations under the License.
 
 use criterion::{black_box, criterion_group, criterion_main, Criterion};
-use frame_support::{
+use frame_support::traits::{ConstU32, ConstU64};
-	traits::{ConstU32, ConstU64},
-	weights::Weight,
-};
 use sp_core::H256;
 use sp_runtime::{
 	testing::Header,