Revert "Codify linting toolchain (linera-io#1251)"

This reverts commit 7ec6f67.

.github/workflows/rust.yml

@@ -103,11 +103,11 @@ jobs:
       run: >
         find linera-* -name '*.rs' -a -not -wholename '*/target/*' -print0
         | xargs -0 -L1 ./scripts/target/release/check_copyright_header
-    - name: Put lint toolchain file in place
-      run: |
-        ln -sf rust-toolchain.lint.toml rust-toolchain.toml
     - uses: Twey/setup-rust-toolchain@v1
-      working-directory: toolchains/lint
+      with:
+        toolchain: nightly-2023-10-22
+        target: wasm32-unknown-unknown
+        components: clippy rustfmt
     - name: Install cargo-machete
       run: |
         cargo install cargo-machete --locked

flake.nix

@@ -26,10 +26,12 @@
           pkg-config
           nodejs
         ];
-        rustBuildToolchain = (pkgs.rust-bin.fromRustupToolchainFile
-          ./toolchains/build/rust-toolchain.toml);
-        rustLintToolchain = (pkgs.rust-bin.fromRustupToolchainFile
-          ./toolchains/lint/rust-toolchain.toml);
+        rustToolchain = (pkgs.rust-bin.fromRustupToolchainFile
+          ./rust-toolchain.toml);
+        rustPlatform = pkgs.makeRustPlatform {
+          rustc = rustToolchain;
+          cargo = rustToolchain;
+        };
       in {
         _module.args.pkgs = import inputs.nixpkgs {
           inherit system;
@@ -43,21 +45,17 @@
           ];
           shellHook = ''
             # For rust-analyzer 'hover' tooltips to work.
-            export RUST_SRC_PATH=${rustBuildToolchain.availableComponents.rust-src}
+            export RUST_SRC_PATH=${rustToolchain.availableComponents.rust-src}
             export LIBCLANG_PATH=${pkgs.libclang.lib}/lib
             export PATH=$PWD/target/release:~/.cargo/bin:$PATH
           '';
           buildInputs = nonRustDeps;
           nativeBuildInputs = with pkgs; [
-            rustBuildToolchain
+            rustToolchain
             rust-analyzer
           ];
         };
 
-        devShells.lint = pkgs.mkShell {
-          nativeBuildInputs = [ rustLintToolchain ];
-        };
-
         # Add your auto-formatters here.
         # cf. https://numtide.github.io/treefmt/
         treefmt.config = {

rust-toolchain.toml

@@ -0,0 +1,5 @@
+[toolchain]
+channel = "1.73.0"
+components = [ "clippy", "rustfmt", "rust-src" ]
+targets = [ "wasm32-unknown-unknown" ]
+profile = "minimal"