Bump MSRV to Rust version 1.56.1

Rust version 1.56.0 introduced edition 2021. Shortly afterwards, on
October 21 2021 Rust version 1.56.1 was released.

Debian stable is currently shipping `rustc 1.63.0`.

Our stated MSRV policy is: In Debian stable and at least 2 years old.

Therefore our MSRV policy is met by Rust version 1.56.1 and we can strat
to bump our MSRV org wide.

Start by bumping the `rust-bitcoin` and `hashes` MSRV to Rust 1.56.1,
includes:

- Update docs.
- Update CI and remove pinning.
- Update the build files and remove now stale cfg attributes rust_v_1_x
  for values less than the new MSRV.
- Use new `IntoIterator` for arrays so we no longer need to allocate a
  vector to iterate.

Links:

- https://blog.rust-lang.org/2021/11/01/Rust-1.56.1.html
- https://blog.rust-lang.org/2021/10/21/Rust-1.56.0.html
- https://packages.debian.org/stable/rust/rustc

.github/workflows/rust.yml

@@ -66,7 +66,7 @@ jobs:
         run: ./contrib/test.sh
 
   MSRV:
-    name: Test - 1.48.0 toolchain
+    name: Test - 1.56.1 toolchain
     runs-on: ubuntu-latest
     strategy:
       fail-fast: false
@@ -76,7 +76,7 @@ jobs:
       - name: Checkout Toolchain
         uses: dtolnay/rust-toolchain@stable
         with:
-          toolchain: "1.48.0"
+          toolchain: "1.56.1"
       - name: Running test script
         env:
           DO_FEATURE_MATRIX: true

README.md

@@ -12,7 +12,7 @@
     <a href="https://github.com/rust-bitcoin/rust-bitcoin/blob/master/LICENSE"><img alt="CC0 1.0 Universal Licensed" src="https://img.shields.io/badge/license-CC0--1.0-blue.svg"/></a>
     <a href="https://github.com/rust-bitcoin/rust-bitcoin/actions?query=workflow%3AContinuous%20integration"><img alt="CI Status" src="https://github.com/rust-bitcoin/rust-bitcoin/workflows/Continuous%20integration/badge.svg"></a>
     <a href="https://docs.rs/bitcoin"><img alt="API Docs" src="https://img.shields.io/badge/docs.rs-bitcoin-green"/></a>
-    <a href="https://blog.rust-lang.org/2020/02/27/Rust-1.48.0.html"><img alt="Rustc Version 1.48.0+" src="https://img.shields.io/badge/rustc-1.48.0%2B-lightgrey.svg"/></a>
+    <a href="https://blog.rust-lang.org/2020/02/27/Rust-1.56.1.html"><img alt="Rustc Version 1.56.1+" src="https://img.shields.io/badge/rustc-1.56.1%2B-lightgrey.svg"/></a>
     <a href="https://gnusha.org/bitcoin-rust/"><img alt="Chat on IRC" src="https://img.shields.io/badge/irc-%23bitcoin--rust%20on%20libera.chat-blue"></a>
     <a href="https://github.com/model-checking/kani"><imp alt="kani" src="https://github.com/rust-bitcoin/rust-bitcoin/actions/workflows/kani.yaml/badge.svg"></a>
   </p>
@@ -69,7 +69,7 @@ For more information please see `./CONTRIBUTING.md`.
 
 ## Minimum Supported Rust Version (MSRV)
 
-This library should always compile with any combination of features on **Rust 1.48.0**.
+This library should always compile with any combination of features on **Rust 1.56.1**.
 
 To build with the MSRV you will likely need to pin a bunch of dependencies, see `./contrib/test.sh`
 for the current list.

bitcoin/CHANGELOG.md

@@ -1,3 +1,7 @@
+# unreleased
+
+- Bump MSRV to Rust 1.56.1
+
 # 0.31.1 - 2023-10-18
 
 - Bump MSRV to Rust 1.48.0 [#1729](https://github.com/rust-bitcoin/rust-bitcoin/pull/1729)

bitcoin/build.rs

@@ -1,4 +1,4 @@
-const MSRV_MINOR: u64 = 48;
+const MSRV_MINOR: u64 = 56;
 
 fn main() {
     let rustc = std::env::var_os("RUSTC");

bitcoin/src/blockdata/script/borrowed.rs

@@ -2,9 +2,9 @@
 
 use core::convert::{TryFrom, TryInto};
 use core::fmt;
-#[cfg(rust_v_1_53)]
+use core::ops::{
-use core::ops::Bound;
+    Bound, Index, Range, RangeFrom, RangeFull, RangeInclusive, RangeTo, RangeToInclusive,
-use core::ops::{Index, Range, RangeFrom, RangeFull, RangeInclusive, RangeTo, RangeToInclusive};
+};
 
 use hashes::Hash;
 use secp256k1::{Secp256k1, Verification};
@@ -653,7 +653,6 @@ delegate_index!(
     RangeTo<usize>,
     RangeFull,
     RangeInclusive<usize>,
-    RangeToInclusive<usize>
+    RangeToInclusive<usize>,
+    (Bound<usize>, Bound<usize>)
 );
-#[cfg(rust_v_1_53)]
-delegate_index!((Bound<usize>, Bound<usize>));

bitcoin/src/blockdata/script/push_bytes.rs

@@ -16,10 +16,8 @@ pub use self::primitive::*;
 /// break invariants. Therefore auditing this module should be sufficient.
 mod primitive {
     use core::convert::{TryFrom, TryInto};
-    #[cfg(rust_v_1_53)]
-    use core::ops::Bound;
     use core::ops::{
-        Index, Range, RangeFrom, RangeFull, RangeInclusive, RangeTo, RangeToInclusive,
+        Bound, Index, Range, RangeFrom, RangeFull, RangeInclusive, RangeTo, RangeToInclusive,
     };
 
     use super::PushBytesError;
@@ -105,10 +103,9 @@ mod primitive {
         RangeTo<usize>,
         RangeFull,
         RangeInclusive<usize>,
-        RangeToInclusive<usize>
+        RangeToInclusive<usize>,
+        (Bound<usize>, Bound<usize>)
     );
-    #[cfg(rust_v_1_53)]
-    delegate_index!((Bound<usize>, Bound<usize>));
 
     impl Index<usize> for PushBytes {
         type Output = u8;

bitcoin/src/taproot.rs

@@ -1845,7 +1845,7 @@ mod test {
         let tree_info = builder.finalize(&secp, internal_key).unwrap();
         let output_key = tree_info.output_key();
 
-        for script in vec![a, b, c, d, e] {
+        for script in [a, b, c, d, e] {
             let ver_script = (script, LeafVersion::TapScript);
             let ctrl_block = tree_info.control_block(&ver_script).unwrap();
             assert!(ctrl_block.verify_taproot_commitment(

clippy.toml

@@ -1,2 +1,2 @@
-msrv = "1.48.0"
+msrv = "1.56.1"
 too-many-arguments-threshold = 13

contrib/test.sh

@@ -4,22 +4,6 @@ set -ex
 
 CRATES="bitcoin hashes internals fuzz"
 DEPS="recent minimal"
-MSRV="1\.48\.0"
-
-# Test pinned versions.
-if cargo --version | grep ${MSRV}; then
-    cargo update -p serde_json --precise 1.0.99
-    cargo update -p serde --precise 1.0.156
-    cargo update -p quote --precise 1.0.30
-    cargo update -p proc-macro2 --precise 1.0.63
-    cargo update -p serde_test --precise 1.0.175
-    cargo update -p schemars --precise 0.8.12
-    # byteorder 1.5.0 uses edition 2021
-    cargo update -p byteorder --precise 1.4.3
-
-    # Build MSRV with pinned versions.
-    cargo check --all-features --all-targets
-fi
 
 for dep in $DEPS
 do

hashes/README.md

@@ -9,7 +9,7 @@ since these are needed to display hashes anway.
 
 ## Minimum Supported Rust Version (MSRV)
 
-This library should always compile with any combination of features on **Rust 1.48.0**.
+This library should always compile with any combination of features on **Rust 1.56.1**.
 
 
 To build with the MSRV you will need to pin `serde` (if you have either the `serde` or the

internals/build.rs

@@ -1,4 +1,4 @@
-const MSRV_MINOR: u64 = 48;
+const MSRV_MINOR: u64 = 56;
 
 fn main() {
     let rustc = std::env::var_os("RUSTC");

internals/src/serde.rs

@@ -47,7 +47,6 @@ mod impls {
             })
         }
 
-        #[cfg(rust_v_1_55)]
         fn try_into_de_error<E>(self, expected: Option<&dyn de::Expected>) -> Result<E, Self>
         where
             E: de::Error,
@@ -61,13 +60,5 @@ mod impls {
                 _ => Err(self),
             }
         }
-
-        #[cfg(not(rust_v_1_55))]
-        fn try_into_de_error<E>(self, _expected: Option<&dyn de::Expected>) -> Result<E, Self>
-        where
-            E: de::Error,
-        {
-            Err(self)
-        }
     }
 }