Make Substrate compile with latest nightly (#7381)

* Try to get it compiling

* One more

* Make stable happy

* Make stable even more happy ;)

* Update shell.nix

substrate/frame/grandpa/src/benchmarking.rs

@@ -65,8 +65,8 @@ benchmarks! {
 	}
 
 	note_stalled {
-		let delay = 1000.into();
-		let best_finalized_block_number = 1.into();
+		let delay = 1000u32.into();
+		let best_finalized_block_number = 1u32.into();
 
 	}: _(RawOrigin::Root, delay, best_finalized_block_number)
 	verify {

substrate/frame/grandpa/src/lib.rs

@@ -446,7 +446,7 @@ impl<T: Trait> Module<T> {
 
 				// only allow the next forced change when twice the window has passed since
 				// this one.
-				<NextForced<T>>::put(scheduled_at + in_blocks * 2.into());
+				<NextForced<T>>::put(scheduled_at + in_blocks * 2u32.into());
 			}
 
 			<PendingChange<T>>::put(StoredPendingChange {