Pass in rust-overlay for creating rust-bin.

flake.nix

@@ -96,6 +96,7 @@
                 bindgenTarget ? null,
               }:
               (organicScope.callPackage ./nix/package.nix {
+                inherit rust-overlay;
                 targetBins = [
                   "wasm"
                 ];
@@ -128,18 +129,24 @@
                 );
           in
           {
-            library = (organicScope.callPackage ./nix/package.nix { buildLib = true; }).overrideAttrs (
-              old:
-              let
-              in
-              {
-                installPhase = ''
-                  mkdir -p $out/lib
-                  cp target/*/release/liborganic.rlib $out/lib/
-                '';
-              }
-            );
+            library =
+              (organicScope.callPackage ./nix/package.nix {
+                inherit rust-overlay;
+                buildLib = true;
+              }).overrideAttrs
+                (
+                  old:
+                  let
+                  in
+                  {
+                    installPhase = ''
+                      mkdir -p $out/lib
+                      cp target/*/release/liborganic.rlib $out/lib/
+                    '';
+                  }
+                );
             devTools = organicScope.callPackage ./nix/package.nix {
+              inherit rust-overlay;
               targetBins = [
                 "parse"
                 "compare"

nix/package.nix

@@ -1,8 +1,8 @@
 {
   hello,
   lib,
-  makeRustPlatform,
-  rust-bin,
+  pkgs,
+  rust-overlay,
 
   targetBins ? [ ],
   features ? [ ],
@@ -12,34 +12,41 @@
 }:
 let
   cargoToml = (lib.importTOML ../Cargo.toml);
-  rustToolchain = (rust-bin.fromRustupToolchainFile ../rust-toolchain.toml).override (
-    if cargoBuildTarget != null then
-      {
-        targets = [ cargoBuildTarget ];
-      }
-    else
-      { }
-  );
-  baseRustPlatform = (
-    makeRustPlatform {
-      cargo = rustToolchain;
-      rustc = rustToolchain;
-    }
-  );
-  rustPlatform =
-    if cargoBuildTarget != null then
-      baseRustPlatform.overrideScope (
-        final: prev: {
-          cargoBuildHook = prev.cargoBuildHook.overrideDerivation (_: {
-            rustcTargetSpec = cargoBuildTarget;
-          });
-          cargoInstallHook = hello;
+  rustPlatformFor =
+    pkgs:
+    let
+      rust-bin = rust-overlay.lib.mkRustBin { } pkgs;
+      rustToolchain = (rust-bin.fromRustupToolchainFile ../rust-toolchain.toml).override (
+        if cargoBuildTarget != null then
+          {
+            targets = [ cargoBuildTarget ];
+          }
+        else
+          { }
+      );
+      baseRustPlatform = (
+        pkgs.makeRustPlatform {
+          cargo = rustToolchain;
+          rustc = rustToolchain;
         }
-      )
-    else
-      baseRustPlatform;
+      );
+      rustPlatform =
+        if cargoBuildTarget != null then
+          baseRustPlatform.overrideScope (
+            final: prev: {
+              cargoBuildHook = prev.cargoBuildHook.overrideDerivation (_: {
+                rustcTargetSpec = cargoBuildTarget;
+              });
+              cargoInstallHook = hello;
+            }
+          )
+        else
+          baseRustPlatform;
+    in
+    rustPlatform;
 in
-rustPlatform.buildRustPackage (
+(rustPlatformFor pkgs).buildRustPackage (
+  # rustPlatform.buildRustPackage (
   {
     pname = "organic";
     version = cargoToml.package.version;