add .#nightly devshell

flake.lock

@@ -1,5 +1,26 @@
 {
   "nodes": {
+    "fenix": {
+      "inputs": {
+        "nixpkgs": [
+          "nixpkgs"
+        ],
+        "rust-analyzer-src": "rust-analyzer-src"
+      },
+      "locked": {
+        "lastModified": 1774682177,
+        "narHash": "sha256-OVbuJnJLlbHE28eRMudjtA6NXz/ifuXSho79gvh6GHY=",
+        "owner": "nix-community",
+        "repo": "fenix",
+        "rev": "e0f515387df77b9fdbaaf81e7f866f0365474c18",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-community",
+        "repo": "fenix",
+        "type": "github"
+      }
+    },
     "nixpkgs": {
       "locked": {
         "lastModified": 1773222311,
@@ -18,10 +39,28 @@
     },
     "root": {
       "inputs": {
+        "fenix": "fenix",
         "nixpkgs": "nixpkgs",
         "systems": "systems"
       }
     },
+    "rust-analyzer-src": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1774569884,
+        "narHash": "sha256-E8iWEPzg7OnE0XXXjo75CX7xFauqzJuGZ5wSO9KS8Ek=",
+        "owner": "rust-lang",
+        "repo": "rust-analyzer",
+        "rev": "443ddcddd0c73b07b799d052f5ef3b448c2f3508",
+        "type": "github"
+      },
+      "original": {
+        "owner": "rust-lang",
+        "ref": "nightly",
+        "repo": "rust-analyzer",
+        "type": "github"
+      }
+    },
     "systems": {
       "locked": {
         "lastModified": 1681028828,

flake.nix

@@ -4,6 +4,11 @@
   inputs = {
     nixpkgs.url = "github:NixOS/nixpkgs/nixos-25.11";
     systems.url = "github:nix-systems/default";
+
+    fenix = {
+      url = "github:nix-community/fenix";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
   };
 
   outputs = {
@@ -29,8 +34,11 @@
           pkgs = mkPkgs system nixpkgs;
         });
   in {
-    overlays.default = self: super: {
-      libclang = super.llvmPackages_21.libclang;
+    overlays = {
+      default = self: super: {
+        libclang = super.llvmPackages_21.libclang;
+      };
+      fenix = inputs.fenix.overlays.default;
     };
 
     devShells = forAllSystems (
@@ -107,6 +115,91 @@
 
             shellHook = postConfigure;
 
+            env = let
+              inherit (llvmPackages) llvm libclang;
+            in {
+              LD_LIBRARY_PATH = builtins.toString (lib.makeLibraryPath buildInputs);
+              LIBCLANG_PATH = "${libclang.lib}/lib";
+
+              RUST_SRC_PATH = "${pkgs.rustPlatform.rustLibSrc}";
+              BINDGEN_EXTRA_CLANG_ARGS = "--sysroot=${pkgs.glibc.dev}";
+
+              # `cargo-llvm-cov` reads these environment variables to find these binaries,
+              # which are needed to run the tests
+              LLVM_COV = "${llvm}/bin/llvm-cov";
+              LLVM_PROFDATA = "${llvm}/bin/llvm-profdata";
+            };
+          };
+
+        nightly = let
+          nixForBindings = pkgs.nixVersions.nix_2_32;
+          inherit (pkgs.rustc) llvmPackages;
+        in
+          pkgs.mkShell rec {
+            name = "nixide";
+            shell = "${pkgs.bash}/bin/bash";
+            strictDeps = true;
+
+            # packages we need at runtime
+            packages = with pkgs; [
+              llvmPackages.lld
+              lldb
+              (pkgs.fenix.complete.withComponents [
+                "cargo"
+                "clippy"
+                "rust-src"
+                "rustc"
+                "rustfmt"
+              ])
+              rust-analyzer-nightly
+
+              # cargo-c
+              # cargo-llvm-cov
+              # cargo-nextest
+            ];
+
+            # packages we need at build time
+            nativeBuildInputs = with pkgs; [
+              pkg-config
+              glibc.dev
+              nixForBindings.dev
+
+              rustPlatform.bindgenHook
+            ];
+
+            # packages we link against
+            buildInputs = with pkgs; [
+              stdenv.cc
+
+              nixForBindings
+            ];
+
+            # bindgen uses clang to generate bindings, but it doesn't know where to
+            # find our stdenv cc's headers, so when it's gcc, we need to tell it.
+            postConfigure = lib.optionalString pkgs.stdenv.cc.isGNU ''
+              #!/usr/bin/env bash
+              # REF: https://github.com/nixops4/nix-bindings-rust/blob/main/bindgen-gcc.sh
+              # Rust bindgen uses Clang to generate bindings, but that means that it can't
+              # find the "system" or compiler headers when the stdenv compiler is GCC.
+              # This script tells it where to find them.
+
+              echo "Extending BINDGEN_EXTRA_CLANG_ARGS with system include paths..." 2>&1
+              BINDGEN_EXTRA_CLANG_ARGS="$${BINDGEN_EXTRA_CLANG_ARGS:-}"
+              export BINDGEN_EXTRA_CLANG_ARGS
+              include_paths=$(
+                echo | $NIX_CC_UNWRAPPED -v -E -x c - 2>&1 \
+                | awk '/#include <...> search starts here:/{flag=1;next} \
+                      /End of search list./{flag=0} \
+                      flag==1 {print $1}'
+              )
+              for path in $include_paths; do
+                echo " - $path" 2>&1
+                BINDGEN_EXTRA_CLANG_ARGS="$BINDGEN_EXTRA_CLANG_ARGS -I$path"
+              done
+            '';
+
+            shellHook = postConfigure;
+
             env = let
               inherit (llvmPackages) llvm libclang;
             in {