From 77334757d7e3908b247bd3072d38d5d025f20e3a Mon Sep 17 00:00:00 2001
From: Eman Resu <78693624+quatquatt@users.noreply.github.com>
Date: Thu, 14 May 2026 19:28:43 -0400
Subject: [PATCH 1/2] lib.isFunction: save an attribute lookup

---
 lib/trivial.nix | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/lib/trivial.nix b/lib/trivial.nix
index fcd9a8791dcf..9a7305d500e1 100644
--- a/lib/trivial.nix
+++ b/lib/trivial.nix
@@ -1123,7 +1123,11 @@ in
     isFunction : Any -> Bool
     ```
   */
-  isFunction = f: builtins.isFunction f || (f ? __functor && isFunction (f.__functor f));
+  isFunction =
+    let
+      isFunction = builtins.isFunction;
+    in
+    f: isFunction f || (f ? __functor && isFunction (f.__functor f));
 
   /**
     `mirrorFunctionArgs f g` creates a new function `g'` with the same behavior as `g` (`g' x == g x`)

From bb71feaec136824966ae51c5007d11ae2b544c57 Mon Sep 17 00:00:00 2001
From: Eman Resu <78693624+quatquatt@users.noreply.github.com>
Date: Thu, 14 May 2026 19:29:25 -0400
Subject: [PATCH 2/2] lib.functionArgs: save a function call on every lookup

---
 lib/trivial.nix | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/lib/trivial.nix b/lib/trivial.nix
index 9a7305d500e1..fd48a0456b66 100644
--- a/lib/trivial.nix
+++ b/lib/trivial.nix
@@ -1101,11 +1101,10 @@ in
     ```
   */
   functionArgs =
-    f:
-    if f ? __functor then
-      f.__functionArgs or (functionArgs (f.__functor f))
-    else
-      builtins.functionArgs f;
+    let
+      functionArgs = builtins.functionArgs;
+    in
+    f: if f ? __functor then f.__functionArgs or (functionArgs (f.__functor f)) else functionArgs f;
 
   /**
     Check whether something is a function or something