fuse imports and filter_map prepare_extrinsics_input_inner fold.

primitives/arithmetic/src/biguint.rs

@@ -18,7 +18,7 @@
 //! Infinite precision unsigned integer for substrate runtime.
 
 use num_traits::Zero;
-use sp_std::{cmp::Ordering, ops, prelude::*, cell::RefCell, convert::TryFrom, vec};
+use sp_std::{cmp::Ordering, ops, prelude::*, cell::RefCell, convert::TryFrom};
 
 // A sensible value for this would be half of the dword size of the host machine. Since the
 // runtime is compiled to 32bit webassembly, using 32 and 64 for single and double respectively

primitives/externalities/Cargo.toml

@@ -14,7 +14,7 @@ targets = ["x86_64-unknown-linux-gnu"]
 
 [dependencies]
 sp-storage = { version = "2.0.0-rc6", path = "../storage", default-features = false }
-sp-std = { version = "2.0.0-rc5", path = "../std", default-features = false }
+sp-std = { version = "2.0.0-rc6", path = "../std", default-features = false }
 environmental = { version = "1.1.1", default-features = false }
 codec = { package = "parity-scale-codec", version = "1.3.1", default-features = false }
 

primitives/externalities/src/extensions.rs

@@ -22,8 +22,8 @@
 //!
 //! It is required that each extension implements the [`Extension`] trait.
 
-use sp_std::collections::btree_map::{BTreeMap, Entry};
-use sp_std::{any::{Any, TypeId}, ops::DerefMut, boxed::Box};
+use sp_std::{collections::btree_map::{BTreeMap, Entry}, any::{Any, TypeId},
+	ops::DerefMut, boxed::Box};
 use crate::Error;
 
 /// Marker trait for types that should be registered as [`Externalities`](crate::Externalities) extension.

primitives/externalities/src/lib.rs

@@ -25,9 +25,7 @@
 //!
 //! This crate exposes the main [`Externalities`] trait.
 
-use sp_std::any::{Any, TypeId};
-use sp_std::vec::Vec;
-use sp_std::boxed::Box;
+use sp_std::{any::{Any, TypeId}, vec::Vec, boxed::Box};
 
 use sp_storage::{ChildInfo, TrackedStorageKey};
 

primitives/state-machine/Cargo.toml

@@ -26,7 +26,7 @@ num-traits = { version = "0.2.8", default-features = false }
 rand = { version = "0.7.2", optional = true }
 sp-externalities = { version = "0.8.0-rc6", path = "../externalities", default-features = false }
 smallvec = "1.4.1"
-sp-std = { version = "2.0.0-rc5", default-features = false, path = "../std" }
+sp-std = { version = "2.0.0-rc6", default-features = false, path = "../std" }
 
 [dev-dependencies]
 hex-literal = "0.3.1"

primitives/state-machine/src/changes_trie/build.rs

@@ -132,52 +132,57 @@ fn prepare_extrinsics_input_inner<'a, B, H, Number>(
 	block: &Number,
 	overlay: &'a OverlayedChanges,
 	child_info: Option<ChildInfo>,
-	mut changes: impl Iterator<Item=(&'a StorageKey, &'a OverlayedValue)>
+	changes: impl Iterator<Item=(&'a StorageKey, &'a OverlayedValue)>
 ) -> Result<impl Iterator<Item=InputPair<Number>> + 'a, String>
 	where
 		B: Backend<H>,
 		H: Hasher,
 		Number: BlockNumber,
 {
 	changes
-		.try_fold(BTreeMap::new(), |mut map: BTreeMap<&[u8], (ExtrinsicIndex<Number>, Vec<u32>)>, (k, v)| {
+		.filter_map(|(k, v)| {
 			let extrinsics = v.extrinsics();
 			if !extrinsics.is_empty() {
-				match map.entry(k) {
-					Entry::Vacant(entry) => {
-						// ignore temporary values (values that have null value at the end of operation
-						// AND are not in storage at the beginning of operation
-						if let Some(child_info) = child_info.as_ref() {
-							if !overlay.child_storage(child_info, k).map(|v| v.is_some()).unwrap_or_default() {
-								if !backend.exists_child_storage(&child_info, k)
-									.map_err(|e| format!("{}", e))? {
-									return Ok(map);
-								}
+				Some((k, extrinsics))
+			} else {
+				None
+			}
+		})
+		.try_fold(BTreeMap::new(), |mut map: BTreeMap<&[u8], (ExtrinsicIndex<Number>, Vec<u32>)>, (k, extrinsics)| {
+			match map.entry(k) {
+				Entry::Vacant(entry) => {
+					// ignore temporary values (values that have null value at the end of operation
+					// AND are not in storage at the beginning of operation
+					if let Some(child_info) = child_info.as_ref() {
+						if !overlay.child_storage(child_info, k).map(|v| v.is_some()).unwrap_or_default() {
+							if !backend.exists_child_storage(&child_info, k)
+								.map_err(|e| format!("{}", e))? {
+								return Ok(map);
 							}
-						} else {
-							if !overlay.storage(k).map(|v| v.is_some()).unwrap_or_default() {
-								if !backend.exists_storage(k).map_err(|e| format!("{}", e))? {
-									return Ok(map);
-								}
+						}
+					} else {
+						if !overlay.storage(k).map(|v| v.is_some()).unwrap_or_default() {
+							if !backend.exists_storage(k).map_err(|e| format!("{}", e))? {
+								return Ok(map);
 							}
-						};
-
-						let extrinsics = extrinsics.into_iter().collect();
-						entry.insert((ExtrinsicIndex {
-							block: block.clone(),
-							key: k.to_vec(),
-						}, extrinsics));
-					},
-					Entry::Occupied(mut entry) => {
-						// we do not need to check for temporary values here, because entry is Occupied
-						// AND we are checking it before insertion
-						let entry_extrinsics = &mut entry.get_mut().1;
-						entry_extrinsics.extend(
-							extrinsics.into_iter()
-						);
-						entry_extrinsics.sort();
-					},
-				}
+						}
+					};
+
+					let extrinsics = extrinsics.into_iter().collect();
+					entry.insert((ExtrinsicIndex {
+						block: block.clone(),
+						key: k.to_vec(),
+					}, extrinsics));
+				},
+				Entry::Occupied(mut entry) => {
+					// we do not need to check for temporary values here, because entry is Occupied
+					// AND we are checking it before insertion
+					let entry_extrinsics = &mut entry.get_mut().1;
+					entry_extrinsics.extend(
+						extrinsics.into_iter()
+					);
+					entry_extrinsics.sort();
+				},
 			}
 
 			Ok(map)

primitives/state-machine/src/lib.rs

@@ -46,7 +46,6 @@ pub use std_reexport::*;
 #[cfg(feature = "std")]
 pub use execution::*;
 
-
 #[cfg(feature = "std")]
 pub use log::{debug, warn, trace, error as log_error};
 
@@ -102,7 +101,7 @@ macro_rules! log_error {
 	);
 }
 
-/// Default rror type to use with state machine trie backend.
+/// Default error type to use with state machine trie backend.
 #[cfg(feature = "std")]
 pub type DefaultError = String;
 /// Error type to use with state machine trie backend.
@@ -113,7 +112,7 @@ pub struct DefaultError;
 #[cfg(not(feature = "std"))]
 impl sp_std::fmt::Display for DefaultError {
 	fn fmt(&self, f: &mut sp_std::fmt::Formatter) -> sp_std::fmt::Result {
-		write!(f, "Default Error")
+		write!(f, "DefaultError")
 	}
 }
 

primitives/state-machine/src/overlayed_changes/mod.rs

@@ -81,7 +81,7 @@ impl Extrinsics {
 		}
 	}
 
-	/// Merge two extrinsics sets.
+	/// Extend `self` with `other`.
 	fn extend(&mut self, other: Self) {
 		self.0.extend(other.0.into_iter());
 	}

primitives/state-machine/src/trie_backend_essence.rs

@@ -20,7 +20,7 @@
 
 #[cfg(feature = "std")]
 use std::sync::Arc;
-use sp_std::ops::Deref;
+use sp_std::{ops::Deref, boxed::Box, vec::Vec};
 use crate::{warn, debug};
 use hash_db::{self, Hasher, Prefix};
 use sp_trie::{Trie, MemoryDB, PrefixedMemoryDB, DBValue,
@@ -30,8 +30,6 @@ use sp_trie::trie_types::{TrieDB, TrieError, Layout};
 use crate::{backend::Consolidate, StorageKey, StorageValue};
 use sp_core::storage::ChildInfo;
 use codec::Encode;
-use sp_std::boxed::Box;
-use sp_std::vec::Vec;
 
 #[cfg(not(feature = "std"))]
 macro_rules! format {