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/frame/support/procedural/src/construct_runtime/expand/call.rs

@@ -178,7 +178,7 @@ pub fn expand_outer_dispatch(
 			type PostInfo = #scrate::dispatch::PostDispatchInfo;
 			fn dispatch(self, origin: RuntimeOrigin) -> #scrate::dispatch::DispatchResultWithPostInfo {
 				if !<Self::RuntimeOrigin as #scrate::traits::OriginTrait>::filter_call(&origin, &self) {
-					return #scrate::__private::sp_std::result::Result::Err(
+					return ::core::result::Result::Err(
 						#system_path::Error::<#runtime>::CallFiltered.into()
 					);
 				}

substrate/frame/support/procedural/src/construct_runtime/expand/outer_enums.rs

@@ -134,7 +134,6 @@ pub fn expand_outer_enum(
 			enum_ty,
 		));
 		enum_conversions.extend(expand_enum_conversion(
-			scrate,
 			pallet_decl,
 			&pallet_enum,
 			&enum_name_ident,
@@ -220,7 +219,6 @@ fn expand_enum_variant(
 }
 
 fn expand_enum_conversion(
-	scrate: &TokenStream,
 	pallet: &Pallet,
 	pallet_enum: &TokenStream,
 	enum_name_ident: &Ident,
@@ -247,7 +245,7 @@ fn expand_enum_conversion(
 		impl TryInto<#pallet_enum> for #enum_name_ident {
 			type Error = ();
 
-			fn try_into(self) -> #scrate::__private::sp_std::result::Result<#pallet_enum, Self::Error> {
+			fn try_into(self) -> ::core::result::Result<#pallet_enum, Self::Error> {
 				match self {
 					Self::#variant_name(evt) => Ok(evt),
 					_ => Err(()),

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

@@ -304,7 +304,7 @@ pub fn expand_call(def: &mut Def) -> proc_macro2::TokenStream {
 			#[doc(hidden)]
 			#[codec(skip)]
 			__Ignore(
-				#frame_support::__private::sp_std::marker::PhantomData<(#type_use_gen,)>,
+				::core::marker::PhantomData<(#type_use_gen,)>,
 				#frame_support::Never,
 			),
 			#(

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

@@ -87,7 +87,7 @@ pub fn expand_event(def: &mut Def) -> proc_macro2::TokenStream {
 			#[doc(hidden)]
 			#[codec(skip)]
 			__Ignore(
-				#frame_support::__private::sp_std::marker::PhantomData<(#event_use_gen)>,
+				::core::marker::PhantomData<(#event_use_gen)>,
 				#frame_support::Never,
 			)
 		);

substrate/frame/support/procedural/src/pallet/parse/composite.rs

@@ -171,7 +171,7 @@ impl CompositeDef {
 				#[doc(hidden)]
 				#[codec(skip)]
 				__Ignore(
-					#scrate::__private::sp_std::marker::PhantomData<I>,
+					::core::marker::PhantomData<I>,
 				)
 			});
 		}

substrate/frame/support/procedural/src/storage_alias.rs

@@ -623,7 +623,7 @@ fn generate_storage_instance(
 
 		quote! {
 			#visibility struct #counter_name< #impl_generics >(
-				#crate_::__private::sp_std::marker::PhantomData<(#type_generics)>
+				::core::marker::PhantomData<(#type_generics)>
 			) #where_clause;
 
 			impl<#impl_generics> #crate_::traits::StorageInstance
@@ -653,7 +653,7 @@ fn generate_storage_instance(
 	let code = quote! {
 		#[allow(non_camel_case_types)]
 		#visibility struct #name< #impl_generics >(
-			#crate_::__private::sp_std::marker::PhantomData<(#type_generics)>
+			::core::marker::PhantomData<(#type_generics)>
 		) #where_clause;
 
 		impl<#impl_generics> #crate_::traits::StorageInstance

substrate/frame/support/src/tests/mod.rs

@@ -171,7 +171,7 @@ pub mod frame_system {
 		pub data: Vec<(u32, u64)>,
 		pub test_config: Vec<(u32, u32, u64)>,
 		#[serde(skip)]
-		pub _config: sp_std::marker::PhantomData<T>,
+		pub _config: core::marker::PhantomData<T>,
 	}
 
 	impl<T: Config> Default for GenesisConfig<T> {

substrate/frame/support/src/traits/dispatch.rs

@@ -19,11 +19,11 @@
 
 use crate::dispatch::{DispatchResultWithPostInfo, Parameter, RawOrigin};
 use codec::MaxEncodedLen;
+use core::{cmp::Ordering, marker::PhantomData};
 use sp_runtime::{
 	traits::{BadOrigin, Get, Member, Morph, TryMorph},
 	Either,
 };
-use sp_std::{cmp::Ordering, marker::PhantomData};
 
 use super::misc;
 
@@ -85,7 +85,7 @@ pub trait EnsureOrigin<OuterOrigin> {
 /// ```rust
 /// # use frame_support::traits::{EnsureOriginEqualOrHigherPrivilege, PrivilegeCmp, EnsureOrigin as _};
 /// # use sp_runtime::traits::{parameter_types, Get};
-/// # use sp_std::cmp::Ordering;
+/// # use core::cmp::Ordering;
 ///
 /// #[derive(Eq, PartialEq, Debug)]
 /// pub enum Origin {
@@ -124,7 +124,7 @@ pub trait EnsureOrigin<OuterOrigin> {
 /// assert!(EnsureOrigin::ensure_origin(Origin::NormalUser).is_err());
 /// ```
 pub struct EnsureOriginEqualOrHigherPrivilege<Origin, PrivilegeCmp>(
-	sp_std::marker::PhantomData<(Origin, PrivilegeCmp)>,
+	core::marker::PhantomData<(Origin, PrivilegeCmp)>,
 );
 
 impl<OuterOrigin, Origin, PrivilegeCmp> EnsureOrigin<OuterOrigin>
@@ -218,7 +218,7 @@ macro_rules! impl_ensure_origin_with_arg_ignoring_arg {
 }
 
 /// [`EnsureOrigin`] implementation that always fails.
-pub struct NeverEnsureOrigin<Success>(sp_std::marker::PhantomData<Success>);
+pub struct NeverEnsureOrigin<Success>(core::marker::PhantomData<Success>);
 impl<OO, Success> EnsureOrigin<OO> for NeverEnsureOrigin<Success> {
 	type Success = Success;
 	fn try_origin(o: OO) -> Result<Success, OO> {
@@ -235,7 +235,7 @@ impl_ensure_origin_with_arg_ignoring_arg! {
 	{}
 }
 
-pub struct AsEnsureOriginWithArg<EO>(sp_std::marker::PhantomData<EO>);
+pub struct AsEnsureOriginWithArg<EO>(core::marker::PhantomData<EO>);
 impl<OuterOrigin, Argument, EO: EnsureOrigin<OuterOrigin>>
 	EnsureOriginWithArg<OuterOrigin, Argument> for AsEnsureOriginWithArg<EO>
 {
@@ -353,7 +353,7 @@ impl<
 /// Origin check will pass if `L` or `R` origin check passes. `L` is tested first.
 ///
 /// Successful origin is derived from the left side.
-pub struct EitherOfDiverse<L, R>(sp_std::marker::PhantomData<(L, R)>);
+pub struct EitherOfDiverse<L, R>(core::marker::PhantomData<(L, R)>);
 impl<OuterOrigin, L: EnsureOrigin<OuterOrigin>, R: EnsureOrigin<OuterOrigin>>
 	EnsureOrigin<OuterOrigin> for EitherOfDiverse<L, R>
 {
@@ -402,7 +402,7 @@ pub type EnsureOneOf<L, R> = EitherOfDiverse<L, R>;
 /// Origin check will pass if `L` or `R` origin check passes. `L` is tested first.
 ///
 /// Successful origin is derived from the left side.
-pub struct EitherOf<L, R>(sp_std::marker::PhantomData<(L, R)>);
+pub struct EitherOf<L, R>(core::marker::PhantomData<(L, R)>);
 impl<
 		OuterOrigin,
 		L: EnsureOrigin<OuterOrigin>,

substrate/frame/support/src/traits/error.rs

@@ -17,7 +17,7 @@
 
 //! Traits for describing and constraining pallet error types.
 use codec::{Compact, Decode, Encode};
-use sp_std::marker::PhantomData;
+use core::marker::PhantomData;
 
 /// Trait indicating that the implementing type is going to be included as a field in a variant of
 /// the `#[pallet::error]` enum type.

substrate/frame/support/src/traits/stored_map.rs

@@ -81,7 +81,7 @@ pub trait StoredMap<K, T: Default> {
 /// be the default value), or where the account is being removed or reset back to the default value
 /// where previously it did exist (though may have been in a default state). This works well with
 /// system module's `CallOnCreatedAccount` and `CallKillAccount`.
-pub struct StorageMapShim<S, K, T>(sp_std::marker::PhantomData<(S, K, T)>);
+pub struct StorageMapShim<S, K, T>(core::marker::PhantomData<(S, K, T)>);
 impl<S: StorageMap<K, T, Query = T>, K: FullCodec, T: FullCodec + Default> StoredMap<K, T>
 	for StorageMapShim<S, K, T>
 {

substrate/frame/support/src/traits/tokens/currency.rs

@@ -211,7 +211,7 @@ pub trait Currency<AccountId> {
 
 /// A non-const `Get` implementation parameterised by a `Currency` impl which provides the result
 /// of `total_issuance`.
-pub struct TotalIssuanceOf<C: Currency<A>, A>(sp_std::marker::PhantomData<(C, A)>);
+pub struct TotalIssuanceOf<C: Currency<A>, A>(core::marker::PhantomData<(C, A)>);
 impl<C: Currency<A>, A> Get<C::Balance> for TotalIssuanceOf<C, A> {
 	fn get() -> C::Balance {
 		C::total_issuance()
@@ -220,7 +220,7 @@ impl<C: Currency<A>, A> Get<C::Balance> for TotalIssuanceOf<C, A> {
 
 /// A non-const `Get` implementation parameterised by a `Currency` impl which provides the result
 /// of `active_issuance`.
-pub struct ActiveIssuanceOf<C: Currency<A>, A>(sp_std::marker::PhantomData<(C, A)>);
+pub struct ActiveIssuanceOf<C: Currency<A>, A>(core::marker::PhantomData<(C, A)>);
 impl<C: Currency<A>, A> Get<C::Balance> for ActiveIssuanceOf<C, A> {
 	fn get() -> C::Balance {
 		C::active_issuance()

substrate/frame/support/src/traits/tokens/imbalance.rs

@@ -19,8 +19,8 @@
 //! with unbalanced operations.
 
 use crate::traits::misc::{SameOrOther, TryDrop};
+use core::ops::Div;
 use sp_runtime::traits::Saturating;
-use sp_std::ops::Div;
 
 mod on_unbalanced;
 mod signed_imbalance;