Fix breaking changes in latest stable and nightly rust (#1375)

### What

Pin the version of nightly in builds and CI, and make a few minor
changes.

### Why

The version is pinned because there's a bug in the next version of
nightly that we can't work around. The bug is:
- rust-lang/rust#131643

The other minor changes that are to prepare for updating to the next
nightly and were required by it when using it.

### Known limitations

N/A

.github/workflows/rust.yml

@@ -131,7 +131,8 @@ jobs:
     steps:
     - uses: actions/checkout@v3
     - uses: stellar/actions/rust-cache@main
-    - run: rustup install nightly
+    # TODO: Unpin nightly version after https://github.com/rust-lang/rust/issues/131643 is fixed.
+    - run: rustup install nightly-2024-10-10
     - uses: stellar/binaries@v15
       with:
         name: cargo-fuzz
@@ -143,15 +144,17 @@ jobs:
     steps:
     - uses: actions/checkout@v3
     - uses: stellar/actions/rust-cache@main
-    - run: rustup install nightly
+    # TODO: Unpin nightly version after https://github.com/rust-lang/rust/issues/131643 is fixed.
+    - run: rustup install nightly-2024-10-10
     - run: make doc
 
   readme:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v3
     - uses: stellar/actions/rust-cache@main
-    - run: rustup install nightly
+    # TODO: Unpin nightly version after https://github.com/rust-lang/rust/issues/131643 is fixed.
+    - run: rustup install nightly-2024-10-10
     - run: make readme
     - run: git add -N . && git diff HEAD --exit-code
 

Makefile

@@ -6,8 +6,8 @@ CARGO_DOC_ARGS?=--open
 
 doc: fmt
 	cargo test --doc -p soroban-sdk -p soroban-sdk-macros --features testutils,hazmat
-    # TODO: Upgrade to latest nightly after problem that was introduced in nightly-2024-02-05 (https://github.com/dalek-cryptography/curve25519-dalek/issues/618) is resolved.
-	cargo +nightly doc -p soroban-sdk --no-deps --all-features $(CARGO_DOC_ARGS)
+	# TODO: Unpin nightly version after https://github.com/rust-lang/rust/issues/131643 is fixed.
+	cargo +nightly-2024-10-10 doc -p soroban-sdk --no-deps --all-features $(CARGO_DOC_ARGS)
 
 test: fmt build
 	cargo hack --feature-powerset --ignore-unknown-features --features testutils --exclude-features docs test
@@ -24,20 +24,22 @@ check: build fmt
 	cargo hack check --release --target wasm32-unknown-unknown
 
 build-fuzz:
-	cd tests/fuzz/fuzz && cargo +nightly fuzz check
+	# TODO: Unpin nightly version after https://github.com/rust-lang/rust/issues/131643 is fixed.
+	cd tests/fuzz/fuzz && cargo +nightly-2024-10-10 fuzz check
 
 readme:
+	# TODO: Unpin nightly version after https://github.com/rust-lang/rust/issues/131643 is fixed.
 	cd soroban-sdk \
-		&& cargo +nightly rustdoc -- -Zunstable-options -wjson \
+		&& cargo +nightly-2024-10-10 rustdoc -- -Zunstable-options -wjson \
 		&& cat ../target/doc/soroban_sdk.json \
-		| jq -r '.index[.root].docs' \
+		| jq -r '.index[.root|tostring].docs' \
 		> README.md
 
 watch:
 	cargo watch --clear --watch-when-idle --shell '$(MAKE)'
 
 watch-doc:
-	cargo +nightly watch --clear --watch-when-idle --shell '$(MAKE) doc CARGO_DOC_ARGS='
+	cargo +nightly-2024-10-10 watch --clear --watch-when-idle --shell '$(MAKE) doc CARGO_DOC_ARGS='
 
 fmt:
 	cargo fmt --all

soroban-sdk/src/crypto.rs

@@ -7,7 +7,7 @@ use crate::{
 };
 
 pub mod bls12_381;
-/// A BytesN<N> generated by a cryptographic hash function.
+/// A `BytesN<N>` generated by a cryptographic hash function.
 ///
 /// The `Hash<N>` type contains a `BytesN<N>` and can only be constructed in
 /// contexts where the value has been generated by a secure cryptographic
@@ -177,7 +177,8 @@ impl Crypto {
         CryptoHazmat::new(env).secp256r1_verify(public_key, &message_digest.0, signature)
     }
 
-    /// Get a [Bls12_381] for accessing the bls12-381 functions.
+    /// Get a [Bls12_381][bls12_381::Bls12_381] for accessing the bls12-381
+    /// functions.
     pub fn bls12_381(&self) -> bls12_381::Bls12_381 {
         bls12_381::Bls12_381::new(self.env())
     }

soroban-sdk/src/ledger.rs

@@ -4,7 +4,7 @@ use crate::{env::internal, unwrap::UnwrapInfallible, BytesN, Env, TryIntoVal};
 /// Ledger retrieves information about the current ledger.
 ///
 /// For more details about the ledger and the ledger header that the values in the Ledger are derived from, see:
-///  - https://developers.stellar.org/docs/learn/encyclopedia/network-configuration/ledger-headers
+///  - <https://developers.stellar.org/docs/learn/encyclopedia/network-configuration/ledger-headers>
 ///
 /// ### Examples
 ///
@@ -83,7 +83,7 @@ impl Ledger {
     /// 00:00:00 UTC.
     ///
     /// For more details see:
-    ///  - https://developers.stellar.org/docs/learn/encyclopedia/network-configuration/ledger-headers#close-time
+    ///  - <https://developers.stellar.org/docs/learn/encyclopedia/network-configuration/ledger-headers#close-time>
     pub fn timestamp(&self) -> u64 {
         internal::Env::get_ledger_timestamp(self.env())
             .unwrap_infallible()