cfg: replace std feature gate alloc imports with extern crate alloc (#10861)

crates/ethereum-forks/src/display.rs

@@ -1,12 +1,10 @@
-#[cfg(not(feature = "std"))]
+use crate::{hardforks::Hardforks, ForkCondition};
 use alloc::{
     format,
     string::{String, ToString},
     vec::Vec,
 };
 
-use crate::{hardforks::Hardforks, ForkCondition};
-
 /// A container to pretty-print a hardfork.
 ///
 /// The fork is formatted depending on its fork condition:

crates/ethereum-forks/src/forkid.rs

@@ -3,7 +3,6 @@
 //! Previously version of Apache licenced [`ethereum-forkid`](https://crates.io/crates/ethereum-forkid).
 
 use crate::Head;
-#[cfg(not(feature = "std"))]
 use alloc::{
     collections::{BTreeMap, BTreeSet},
     vec::Vec,
@@ -22,8 +21,6 @@ use crc::*;
 use proptest_derive::Arbitrary as PropTestArbitrary;
 #[cfg(feature = "serde")]
 use serde::{Deserialize, Serialize};
-#[cfg(feature = "std")]
-use std::collections::{BTreeMap, BTreeSet};
 
 const CRC_32_IEEE: Crc<u32> = Crc::<u32>::new(&CRC_32_ISO_HDLC);
 const TIMESTAMP_BEFORE_ETHEREUM_MAINNET: u64 = 1_300_000_000;

crates/ethereum-forks/src/hardfork/dev.rs

@@ -1,10 +1,8 @@
 use crate::{ChainHardforks, EthereumHardfork, ForkCondition};
+use alloc::vec;
 use alloy_primitives::U256;
 use once_cell::sync::Lazy;
 
-#[cfg(not(feature = "std"))]
-use alloc::vec;
-
 /// Dev hardforks
 pub static DEV_HARDFORKS: Lazy<ChainHardforks> = Lazy::new(|| {
     ChainHardforks::new(vec![

crates/ethereum-forks/src/hardfork/ethereum.rs

@@ -1,4 +1,5 @@
 use crate::{hardfork, ChainHardforks, ForkCondition, Hardfork};
+use alloc::{boxed::Box, format, string::String};
 use alloy_chains::Chain;
 use alloy_primitives::{uint, U256};
 use core::{
@@ -9,9 +10,6 @@ use core::{
 #[cfg(feature = "serde")]
 use serde::{Deserialize, Serialize};
 
-#[cfg(not(feature = "std"))]
-use alloc::{boxed::Box, format, string::String};
-
 hardfork!(
     /// The name of an Ethereum hardfork.
     EthereumHardfork {

crates/ethereum-forks/src/hardfork/optimism.rs

@@ -1,4 +1,3 @@
-#[cfg(not(feature = "std"))]
 use alloc::{boxed::Box, format, string::String, vec};
 use core::{
     any::Any,

crates/ethereum-forks/src/lib.rs

@@ -15,7 +15,6 @@
 #![cfg_attr(docsrs, feature(doc_cfg, doc_auto_cfg))]
 #![cfg_attr(not(feature = "std"), no_std)]
 
-#[cfg(not(feature = "std"))]
 extern crate alloc;
 
 mod display;