sp-std -> core (#3199)

First in a series of PRs that reduces our use of sp-std with a view to
deprecating it.

This is just looking at /substrate and moving some of the references
from `sp-std` to `core`.
These particular changes should be uncontroversial.

Where macros are used `::core` should be used to remove any ambiguity.

part of https://github.com/paritytech/polkadot-sdk/issues/2101

substrate/primitives/api/proc-macro/src/impl_runtime_apis.rs

@@ -243,7 +243,7 @@ fn generate_wasm_interface(impls: &[ItemImpl]) -> Result<TokenStream> {
 								&[0u8; 0]
 							} else {
 								unsafe {
-									#c::slice::from_raw_parts(input_data, input_len)
+									::core::slice::from_raw_parts(input_data, input_len)
 								}
 							};
 
@@ -345,7 +345,7 @@ fn generate_runtime_api_base_structures() -> Result<TokenStream> {
 					&self,
 					backend: &B,
 					parent_hash: Block::Hash,
-				) -> core::result::Result<
+				) -> ::core::result::Result<
 					#crate_::StorageChanges<Block>,
 				String
 					> where Self: Sized {

substrate/primitives/arithmetic/src/helpers_128bit.rs

@@ -22,7 +22,7 @@
 //! multiplication implementation provided there.
 
 use crate::{biguint, Rounding};
-use sp_std::cmp::{max, min};
+use core::cmp::{max, min};
 
 /// Helper gcd function used in Rational128 implementation.
 pub fn gcd(a: u128, b: u128) -> u128 {

substrate/primitives/arithmetic/src/traits.rs

@@ -18,6 +18,9 @@
 //! Primitive traits for the runtime arithmetic.
 
 use codec::HasCompact;
+use core::ops::{
+	Add, AddAssign, Div, DivAssign, Mul, MulAssign, Rem, RemAssign, Shl, Shr, Sub, SubAssign,
+};
 pub use ensure::{
 	ensure_pow, Ensure, EnsureAdd, EnsureAddAssign, EnsureDiv, EnsureDivAssign,
 	EnsureFixedPointNumber, EnsureFrom, EnsureInto, EnsureMul, EnsureMulAssign, EnsureOp,
@@ -28,9 +31,6 @@ pub use num_traits::{
 	checked_pow, Bounded, CheckedAdd, CheckedDiv, CheckedMul, CheckedNeg, CheckedRem, CheckedShl,
 	CheckedShr, CheckedSub, One, Signed, Unsigned, Zero,
 };
-use sp_std::ops::{
-	Add, AddAssign, Div, DivAssign, Mul, MulAssign, Rem, RemAssign, Shl, Shr, Sub, SubAssign,
-};
 
 use crate::MultiplyRational;
 
@@ -262,7 +262,7 @@ pub trait Saturating {
 		Self: One,
 	{
 		let mut o = Self::one();
-		sp_std::mem::swap(&mut o, self);
+		core::mem::swap(&mut o, self);
 		*self = o.saturating_add(One::one());
 	}
 
@@ -272,7 +272,7 @@ pub trait Saturating {
 		Self: One,
 	{
 		let mut o = Self::one();
-		sp_std::mem::swap(&mut o, self);
+		core::mem::swap(&mut o, self);
 		*self = o.saturating_sub(One::one());
 	}
 
@@ -282,7 +282,7 @@ pub trait Saturating {
 		Self: One,
 	{
 		let mut o = Self::one();
-		sp_std::mem::swap(&mut o, self);
+		core::mem::swap(&mut o, self);
 		*self = o.saturating_add(amount);
 	}
 
@@ -292,7 +292,7 @@ pub trait Saturating {
 		Self: One,
 	{
 		let mut o = Self::one();
-		sp_std::mem::swap(&mut o, self);
+		core::mem::swap(&mut o, self);
 		*self = o.saturating_sub(amount);
 	}
 }
@@ -949,7 +949,7 @@ mod ensure {
 			}
 		}
 
-		impl sp_std::ops::Mul for Signum {
+		impl core::ops::Mul for Signum {
 			type Output = Self;
 
 			fn mul(self, rhs: Self) -> Self {

substrate/primitives/consensus/aura/src/inherents.rs

@@ -69,7 +69,7 @@ impl InherentDataProvider {
 }
 
 #[cfg(feature = "std")]
-impl sp_std::ops::Deref for InherentDataProvider {
+impl core::ops::Deref for InherentDataProvider {
 	type Target = InherentType;
 
 	fn deref(&self) -> &Self::Target {

substrate/primitives/consensus/babe/src/inherents.rs

@@ -17,8 +17,8 @@
 
 //! Inherents for BABE
 
+use core::result::Result;
 use sp_inherents::{Error, InherentData, InherentIdentifier};
-use sp_std::result::Result;
 
 /// The BABE inherent identifier.
 pub const INHERENT_IDENTIFIER: InherentIdentifier = *b"babeslot";
@@ -75,7 +75,7 @@ impl InherentDataProvider {
 }
 
 #[cfg(feature = "std")]
-impl sp_std::ops::Deref for InherentDataProvider {
+impl core::ops::Deref for InherentDataProvider {
 	type Target = InherentType;
 
 	fn deref(&self) -> &Self::Target {

substrate/primitives/consensus/slots/src/lib.rs

@@ -155,9 +155,9 @@ impl SlotDuration {
 
 #[cfg(feature = "std")]
 impl SlotDuration {
-	/// Returns `self` as [`sp_std::time::Duration`].
-	pub const fn as_duration(&self) -> sp_std::time::Duration {
-		sp_std::time::Duration::from_millis(self.0)
+	/// Returns `self` as [`core::time::Duration`].
+	pub const fn as_duration(&self) -> core::time::Duration {
+		core::time::Duration::from_millis(self.0)
 	}
 }
 

substrate/primitives/core/src/testing.rs

@@ -89,7 +89,7 @@ macro_rules! wasm_export_functions {
 				&[0u8; 0]
 			} else {
 				unsafe {
-					$crate::sp_std::slice::from_raw_parts(input_data, input_len)
+					::core::slice::from_raw_parts(input_data, input_len)
 				}
 			};
 
@@ -117,7 +117,7 @@ macro_rules! wasm_export_functions {
 				&[0u8; 0]
 			} else {
 				unsafe {
-					$crate::sp_std::slice::from_raw_parts(input_data, input_len)
+					::core::slice::from_raw_parts(input_data, input_len)
 				}
 			};
 

substrate/primitives/runtime-interface/src/util.rs

@@ -21,7 +21,7 @@
 pub fn pack_ptr_and_len(ptr: u32, len: u32) -> u64 {
 	// The static assertions from above are changed into a runtime check.
 	#[cfg(all(not(feature = "std"), feature = "disable_target_static_assertions"))]
-	assert_eq!(4, sp_std::mem::size_of::<usize>());
+	assert_eq!(4, core::mem::size_of::<usize>());
 
 	(u64::from(len) << 32) | u64::from(ptr)
 }
@@ -34,7 +34,7 @@ pub fn pack_ptr_and_len(ptr: u32, len: u32) -> u64 {
 pub fn unpack_ptr_and_len(val: u64) -> (u32, u32) {
 	// The static assertions from above are changed into a runtime check.
 	#[cfg(all(not(feature = "std"), feature = "disable_target_static_assertions"))]
-	assert_eq!(4, sp_std::mem::size_of::<usize>());
+	assert_eq!(4, core::mem::size_of::<usize>());
 
 	let ptr = (val & (!0u32 as u64)) as u32;
 	let len = (val >> 32) as u32;

substrate/primitives/runtime-interface/src/wasm.rs

@@ -19,7 +19,7 @@
 
 use crate::RIType;
 
-use sp_std::cell::Cell;
+use core::cell::Cell;
 
 /// Something that can be created from a ffi value.
 ///

substrate/primitives/runtime/src/generic/header.rs

@@ -133,7 +133,7 @@ where
 impl<Number, Hash> Header<Number, Hash>
 where
 	Number: Member
-		+ sp_std::hash::Hash
+		+ core::hash::Hash
 		+ Copy
 		+ MaybeDisplay
 		+ AtLeast32BitUnsigned

substrate/primitives/runtime/src/offchain/storage_lock.rs

@@ -66,9 +66,9 @@ use crate::{
 	traits::BlockNumberProvider,
 };
 use codec::{Codec, Decode, Encode};
+use core::fmt;
 use sp_core::offchain::{Duration, Timestamp};
 use sp_io::offchain;
-use sp_std::fmt;
 
 /// Default expiry duration for time based locks in milliseconds.
 const STORAGE_LOCK_DEFAULT_EXPIRY_DURATION: Duration = Duration::from_millis(20_000);

substrate/primitives/state-machine/src/error.rs

@@ -16,7 +16,7 @@
 // limitations under the License.
 
 /// State Machine Errors
-use sp_std::fmt;
+use core::fmt;
 
 /// State Machine Error bound.
 ///

substrate/primitives/state-machine/src/in_memory_backend.rs

@@ -79,7 +79,7 @@ where
 
 	/// Apply the given transaction to this backend and set the root to the given value.
 	pub fn apply_transaction(&mut self, root: H::Out, transaction: PrefixedMemoryDB<H>) {
-		let mut storage = sp_std::mem::take(self).into_storage();
+		let mut storage = core::mem::take(self).into_storage();
 
 		storage.consolidate(transaction);
 		*self = TrieBackendBuilder::new(storage, root).build();

substrate/primitives/state-machine/src/stats.rs

@@ -17,7 +17,7 @@
 
 //! Usage statistics for state db
 
-use sp_std::cell::RefCell;
+use core::cell::RefCell;
 #[cfg(feature = "std")]
 use std::time::{Duration, Instant};
 

substrate/primitives/timestamp/src/lib.rs

@@ -20,8 +20,8 @@
 #![cfg_attr(not(feature = "std"), no_std)]
 
 use codec::{Decode, Encode};
+use core::time::Duration;
 use sp_inherents::{InherentData, InherentIdentifier, IsFatalError};
-use sp_std::time::Duration;
 
 /// The identifier for the `timestamp` inherent.
 pub const INHERENT_IDENTIFIER: InherentIdentifier = *b"timstap0";
@@ -69,7 +69,7 @@ impl Timestamp {
 	}
 }
 
-impl sp_std::ops::Deref for Timestamp {
+impl core::ops::Deref for Timestamp {
 	type Target = u64;
 
 	fn deref(&self) -> &Self::Target {
@@ -219,7 +219,7 @@ impl InherentDataProvider {
 }
 
 #[cfg(feature = "std")]
-impl sp_std::ops::Deref for InherentDataProvider {
+impl core::ops::Deref for InherentDataProvider {
 	type Target = InherentType;
 
 	fn deref(&self) -> &Self::Target {

substrate/primitives/trie/src/node_header.rs

@@ -19,7 +19,7 @@
 
 use crate::trie_constants;
 use codec::{Decode, Encode, Input, Output};
-use sp_std::iter::once;
+use core::iter::once;
 
 /// A node header
 #[derive(Copy, Clone, PartialEq, Eq, sp_core::RuntimeDebug)]
@@ -118,7 +118,7 @@ pub(crate) fn size_and_prefix_iterator(
 	prefix_mask: usize,
 ) -> impl Iterator<Item = u8> {
 	let max_value = 255u8 >> prefix_mask;
-	let l1 = sp_std::cmp::min((max_value as usize).saturating_sub(1), size);
+	let l1 = core::cmp::min((max_value as usize).saturating_sub(1), size);
 	let (first_byte, mut rem) = if size == l1 {
 		(once(prefix + l1 as u8), 0)
 	} else {
@@ -138,7 +138,7 @@ pub(crate) fn size_and_prefix_iterator(
 			None
 		}
 	};
-	first_byte.chain(sp_std::iter::from_fn(next_bytes))
+	first_byte.chain(core::iter::from_fn(next_bytes))
 }
 
 /// Encodes size and prefix to a stream output.

substrate/primitives/weights/src/lib.rs

@@ -235,7 +235,7 @@ where
 }
 
 /// Implementor of `WeightToFee` that maps one unit of weight to one unit of fee.
-pub struct IdentityFee<T>(sp_std::marker::PhantomData<T>);
+pub struct IdentityFee<T>(core::marker::PhantomData<T>);
 
 impl<T> WeightToFee for IdentityFee<T>
 where
@@ -249,7 +249,7 @@ where
 }
 
 /// Implementor of [`WeightToFee`] such that it maps any unit of weight to a fixed fee.
-pub struct FixedFee<const F: u32, T>(sp_std::marker::PhantomData<T>);
+pub struct FixedFee<const F: u32, T>(core::marker::PhantomData<T>);
 
 impl<const F: u32, T> WeightToFee for FixedFee<F, T>
 where
@@ -275,7 +275,7 @@ pub type NoFee<T> = FixedFee<0, T>;
 /// // Results in a multiplier of 10 for each unit of weight (or length)
 /// type LengthToFee = ConstantMultiplier::<u128, ConstU128<10u128>>;
 /// ```
-pub struct ConstantMultiplier<T, M>(sp_std::marker::PhantomData<(T, M)>);
+pub struct ConstantMultiplier<T, M>(core::marker::PhantomData<(T, M)>);
 
 impl<T, M> WeightToFee for ConstantMultiplier<T, M>
 where