Merge rust-bitcoin/rust-bitcoin#2543: hashes: Default to `no_std`

ba124757c4 hashes: Default to no_std (Tobin C. Harding)
6a4e219c55 hashes: embedded: Remove unused import (Tobin C. Harding)
915c9627f6 Put feature gate attribute under test attribute (Tobin C. Harding)

Pull request description:

  `hashes` is `no_std` ready, lets default to `no_std`.

  Done as part of #2413

ACKs for top commit:
  apoelstra:
    ACK ba124757c419aef38019ee7825c32af540b9dcd0; successfully ran local tests

Tree-SHA512: 14a69d32c7e1fe8303d53944fa274acfe6a509407b8d69312d693102588a1f59a56a815370d6d4dfe15fa68678ef67faa1c313967a7caaba01db97065e634b7b

bitcoin/src/blockdata/transaction.rs

@@ -1361,8 +1361,8 @@ mod tests {
     }
 
     // We temporarily abuse `Transaction` for testing consensus serde adapter.
-    #[cfg(feature = "serde")]
     #[test]
+    #[cfg(feature = "serde")]
     fn consensus_serde() {
         use crate::consensus::serde as con_serde;
         let json = "\"010000000001010000000000000000000000000000000000000000000000000000000000000000ffffffff3603da1b0e00045503bd5704c7dd8a0d0ced13bb5785010800000000000a636b706f6f6c122f4e696e6a61506f6f6c2f5345475749542fffffffff02b4e5a212000000001976a914876fbb82ec05caa6af7a3b5e5a983aae6c6cc6d688ac0000000000000000266a24aa21a9edf91c46b49eb8a29089980f02ee6b57e7d63d33b18b4fddac2bcd7db2a39837040120000000000000000000000000000000000000000000000000000000000000000000000000\"";

bitcoin/src/crypto/key.rs

@@ -1222,8 +1222,8 @@ mod tests {
         assert!(upk.wpubkey_hash().is_err());
     }
 
-    #[cfg(feature = "serde")]
     #[test]
+    #[cfg(feature = "serde")]
     fn test_key_serde() {
         use serde_test::{assert_tokens, Configure, Token};
 

bitcoin/src/network/mod.rs

@@ -490,8 +490,8 @@ mod tests {
         }
     }
 
-    #[cfg(feature = "serde")]
     #[test]
+    #[cfg(feature = "serde")]
     fn serde_as_core_arg() {
         #[derive(Serialize, Deserialize, PartialEq, Debug)]
         struct T {

bitcoin/src/pow.rs

@@ -1643,8 +1643,8 @@ mod tests {
         assert_eq!(got, want);
     }
 
-    #[cfg(feature = "serde")]
     #[test]
+    #[cfg(feature = "serde")]
     fn u256_serde() {
         let check = |uint, hex| {
             let json = format!("\"{}\"", hex);
@@ -1932,8 +1932,8 @@ mod tests {
         assert_eq!(back, target)
     }
 
-    #[cfg(feature = "std")]
     #[test]
+    #[cfg(feature = "std")]
     fn work_log2() {
         // Compare work log2 to historical Bitcoin Core values found in Core logs.
         let tests: &[(u128, f64)] = &[

hashes/embedded/src/main.rs

@@ -11,7 +11,6 @@ extern crate bitcoin_hashes;
 
 use bitcoin_hashes::{sha256, HashEngine};
 use bitcoin_io::Write;
-use core::str::FromStr;
 use cortex_m_rt::entry;
 use cortex_m_semihosting::{debug, hprintln};
 use panic_halt as _;

hashes/src/hash160.rs

@@ -101,8 +101,8 @@ mod tests {
         }
     }
 
-    #[cfg(feature = "serde")]
     #[test]
+    #[cfg(feature = "serde")]
     fn ripemd_serde() {
         use serde_test::{assert_tokens, Configure, Token};
 

hashes/src/hmac.rs

@@ -289,8 +289,8 @@ mod tests {
         }
     }
 
-    #[cfg(feature = "serde")]
     #[test]
+    #[cfg(feature = "serde")]
     fn hmac_sha512_serde() {
         use serde_test::{assert_tokens, Configure, Token};
 

hashes/src/lib.rs

@@ -50,7 +50,7 @@
 //! # }
 //! ```
 
-#![cfg_attr(not(feature = "std"), no_std)]
+#![no_std]
 // Experimental features we need.
 #![cfg_attr(docsrs, feature(doc_auto_cfg))]
 #![cfg_attr(bench, feature(test))]
@@ -70,6 +70,9 @@ extern crate alloc;
 
 extern crate core;
 
+#[cfg(feature = "std")]
+extern crate std;
+
 #[cfg(feature = "bitcoin-io")]
 extern crate bitcoin_io as io;
 

hashes/src/ripemd160.rs

@@ -493,8 +493,8 @@ mod tests {
         }
     }
 
-    #[cfg(feature = "serde")]
     #[test]
+    #[cfg(feature = "serde")]
     fn ripemd_serde() {
         use serde_test::{assert_tokens, Configure, Token};
 

hashes/src/sha1.rs

@@ -197,8 +197,8 @@ mod tests {
         }
     }
 
-    #[cfg(feature = "serde")]
     #[test]
+    #[cfg(feature = "serde")]
     fn sha1_serde() {
         use serde_test::{assert_tokens, Configure, Token};
 

hashes/src/sha256.rs

@@ -491,10 +491,10 @@ impl HashEngine {
     fn process_block(&mut self) {
         #[cfg(all(feature = "std", any(target_arch = "x86", target_arch = "x86_64")))]
         {
-            if is_x86_feature_detected!("sse4.1")
-                && is_x86_feature_detected!("sha")
-                && is_x86_feature_detected!("sse2")
-                && is_x86_feature_detected!("ssse3")
+            if std::is_x86_feature_detected!("sse4.1")
+                && std::is_x86_feature_detected!("sha")
+                && std::is_x86_feature_detected!("sse2")
+                && std::is_x86_feature_detected!("ssse3")
             {
                 return unsafe { self.process_block_simd_x86_intrinsics() };
             }
@@ -1063,8 +1063,8 @@ mod tests {
         assert_eq!(got, want);
     }
 
-    #[cfg(feature = "serde")]
     #[test]
+    #[cfg(feature = "serde")]
     fn sha256_serde() {
         use serde_test::{assert_tokens, Configure, Token};
 

hashes/src/sha256d.rs

@@ -107,8 +107,8 @@ mod tests {
         assert_eq!(rinsed, hash)
     }
 
-    #[cfg(feature = "serde")]
     #[test]
+    #[cfg(feature = "serde")]
     fn sha256_serde() {
         use serde_test::{assert_tokens, Configure, Token};
 

hashes/src/sha512.rs

@@ -384,8 +384,8 @@ mod tests {
         }
     }
 
-    #[cfg(feature = "serde")]
     #[test]
+    #[cfg(feature = "serde")]
     fn sha512_serde() {
         use serde_test::{assert_tokens, Configure, Token};