Bump MSRV to 1.56.1

Closes zcash/halo2#482.

.github/workflows/ci.yml

@@ -14,7 +14,7 @@ jobs:
       - uses: actions/checkout@v2
       - uses: actions-rs/toolchain@v1
         with:
-          toolchain: 1.51.0
+          toolchain: 1.56.1
           override: true
       - name: Run tests
         uses: actions-rs/cargo@v1
@@ -35,7 +35,7 @@ jobs:
       - uses: actions/checkout@v2
       - uses: actions-rs/toolchain@v1
         with:
-          toolchain: 1.51.0
+          toolchain: 1.56.1
           override: true
       - name: Add target
         run: rustup target add ${{ matrix.target }}
@@ -53,7 +53,7 @@ jobs:
       - uses: actions/checkout@v2
       - uses: actions-rs/toolchain@v1
         with:
-          toolchain: 1.51.0
+          toolchain: 1.56.1
           override: true
       # Build benchmarks to prevent bitrot
       - name: Build benchmarks
@@ -69,7 +69,7 @@ jobs:
       - uses: actions/checkout@v2
       - uses: actions-rs/toolchain@v1
         with:
-          toolchain: 1.51.0
+          toolchain: 1.56.1
           override: true
       - name: cargo build
         uses: actions-rs/cargo@v1
@@ -114,7 +114,7 @@ jobs:
       - uses: actions/checkout@v2
       - uses: actions-rs/toolchain@v1
         with:
-          toolchain: 1.51.0
+          toolchain: 1.56.1
           override: true
       - name: cargo fetch
         uses: actions-rs/cargo@v1
@@ -137,7 +137,7 @@ jobs:
       - uses: actions/checkout@v2
       - uses: actions-rs/toolchain@v1
         with:
-          toolchain: 1.51.0
+          toolchain: 1.56.1
           override: true
       - run: rustup component add rustfmt
       - uses: actions-rs/cargo@v1

.github/workflows/lints-stable.yml

@@ -5,7 +5,7 @@ on: pull_request
 
 jobs:
   clippy:
-    name: Clippy (1.51.0)
+    name: Clippy (1.56.1)
     timeout-minutes: 30
     runs-on: ubuntu-latest
 
@@ -13,12 +13,12 @@ jobs:
       - uses: actions/checkout@v2
       - uses: actions-rs/toolchain@v1
         with:
-          toolchain: 1.51.0
+          toolchain: 1.56.1
           components: clippy
           override: true
       - name: Run clippy
         uses: actions-rs/clippy-check@v1
         with:
-          name: Clippy (1.51.0)
+          name: Clippy (1.56.1)
           token: ${{ secrets.GITHUB_TOKEN }}
           args: --all-features --all-targets -- -D warnings

README.md

@@ -6,7 +6,7 @@
 
 ## Minimum Supported Rust Version
 
-Requires Rust **1.51** or higher.
+Requires Rust **1.56.1** or higher.
 
 Minimum supported Rust version can be changed in the future, but it will be done with a
 minor version bump.

halo2/Cargo.toml

@@ -5,6 +5,7 @@ authors = [
     "Jack Grigg <jack@electriccoin.co>",
 ]
 edition = "2018"
+rust-version = "1.56.1"
 description = "[BETA] Fast zero-knowledge proof-carrying data implementation with no trusted setup"
 license-file = "../COPYING"
 repository = "https://github.com/zcash/halo2"

halo2_gadgets/Cargo.toml

@@ -9,6 +9,7 @@ authors = [
     "Kris Nuttycombe <kris@electriccoin.co>",
 ]
 edition = "2018"
+rust-version = "1.56.1"
 description = "[BETA] Reusable gadgets and chip implementations for Halo 2"
 license-file = "../COPYING"
 repository = "https://github.com/zcash/halo2"

halo2_gadgets/rust-toolchain

@@ -1 +0,0 @@
-1.51.0

halo2_proofs/Cargo.toml

@@ -8,6 +8,7 @@ authors = [
     "Jack Grigg <jack@electriccoin.co>",
 ]
 edition = "2018"
+rust-version = "1.56.1"
 description = """
 [BETA] Fast PLONK-based zero-knowledge proving system with no trusted setup
 """

rust-toolchain

@@ -1 +1 @@
-1.51.0
+1.56.1