From ee17363d96c46171f063677d87155f03c521284c Mon Sep 17 00:00:00 2001
From: Yuval Kogman <nothingmuch@woobling.org>
Date: Thu, 28 May 2026 18:18:23 +0000
Subject: [PATCH 1/2] nix: deny unused lint group in dedicated flake check

Catches stale #[allow(dead_code)] annotations when the code they guard
becomes live.
---
 nix/checks.nix | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/nix/checks.nix b/nix/checks.nix
index 6b25e06..38cf40a 100644
--- a/nix/checks.nix
+++ b/nix/checks.nix
@@ -100,6 +100,19 @@
               mkdir -p $out
             '';
 
+        unused-lints = toolchains.nightly.mkCargoDerivation (
+          commonArgs
+          // {
+            cargoArtifacts = cargoArtifactsDev;
+            CARGO_PROFILE = "dev";
+            pnameSuffix = "-unused-lints";
+            buildPhaseCargoCommand = ''
+              RUSTFLAGS="''${RUSTFLAGS:-} -D unused" cargo check --all-targets --all-features
+            '';
+            installPhase = "mkdir -p $out";
+          }
+        );
+
         no-todo-comments = pkgs.runCommand "no-todo-comments-${rev}" { inherit src; } ''
           if grep -rn --exclude-dir=contrib 'TO[D]O\|FIX[M]E' $src/ 2>/dev/null; then
             echo "FAIL: unresolved work-item markers found"
@@ -124,6 +137,7 @@
             checks.cargo-sort
             checks.clippy
             checks.doc
+            checks.unused-lints
             checks.no-todo-comments
           ];
         };

From 355c67206bca213e473f85d447c03ec68704c8ac Mon Sep 17 00:00:00 2001
From: Yuval Kogman <nothingmuch@woobling.org>
Date: Fri, 29 May 2026 18:19:35 +0200
Subject: [PATCH 2/2] nix: trivial readability refactor

---
 nix/checks.nix | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/nix/checks.nix b/nix/checks.nix
index 38cf40a..fd340f9 100644
--- a/nix/checks.nix
+++ b/nix/checks.nix
@@ -126,19 +126,19 @@
       checks = checks // {
         quick = pkgs.symlinkJoin {
           name = "quick-checks-${rev}";
-          paths = [
-            checks.tests-nightly-dev
-            checks.clippy
+          paths = with checks; [
+            tests-nightly-dev
+            clippy
           ];
         };
         lint = pkgs.symlinkJoin {
           name = "lint-checks-${rev}";
-          paths = [
-            checks.cargo-sort
-            checks.clippy
-            checks.doc
-            checks.unused-lints
-            checks.no-todo-comments
+          paths = with checks; [
+            cargo-sort
+            clippy
+            doc
+            unused-lints
+            no-todo-comments
           ];
         };
         nightly = pkgs.symlinkJoin {