From bb0f35f8a06752ccce5b8d0c5733378cd6afc22f Mon Sep 17 00:00:00 2001
From: Sergei Trofimovich <slyich@gmail.com>
Date: Sun, 20 Sep 2026 20:47:59 +0100
Subject: [PATCH] swift.swiftArch, swift.swiftOs: fix the eval
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Without the chnage the eval fails as:

    $ nix eval 'nixpkgs/staging#swift.swiftArch'
    error:
       … in the left operand of the update (//) operator
         at «github:NixOS/nixpkgs/9cfde996e4f874e9b58a0e9efb5193d565b6daf3»/lib/derivations.nix:265:8:
          264|     drv
          265|     // mapAttrs (_: lib.warn msg) drvToWrap
             |        ^
          266|     // (

       … while calling the 'mapAttrs' builtin
         at «github:NixOS/nixpkgs/9cfde996e4f874e9b58a0e9efb5193d565b6daf3»/lib/derivations.nix:265:8:
          264|     drv
          265|     // mapAttrs (_: lib.warn msg) drvToWrap
             |        ^
          266|     // (

       (stack trace truncated; use '--show-trace' to show the full, detailed trace)

       error: expected a set but found a string: "x86_64"
---
 pkgs/development/compilers/swift/by-name/sw/swift/package.nix | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/pkgs/development/compilers/swift/by-name/sw/swift/package.nix b/pkgs/development/compilers/swift/by-name/sw/swift/package.nix
index 5d9d5eabcdc2..bc96a9cd7f91 100644
--- a/pkgs/development/compilers/swift/by-name/sw/swift/package.nix
+++ b/pkgs/development/compilers/swift/by-name/sw/swift/package.nix
@@ -241,9 +241,9 @@ stdenv.mkDerivation (finalAttrs: {
   // lib.optionalAttrs config.allowAliases {
     # Legacy aliases for the old Swift packaging. These should eventually be removed.
     swift = lib.warnOnInstantiate "`swift` is an alias for this (`swift`) package. Just use it directly." finalAttrs.finalPackage;
-    swiftArch = lib.warnOnInstantiate "'swiftArch' is an alias for 'stdenv.hostPlatform.swift.arch'." stdenv.hostPlatform.swift.arch;
+    swiftArch = lib.warn "'swiftArch' is an alias for 'stdenv.hostPlatform.swift.arch'." stdenv.hostPlatform.swift.arch;
     swiftDriver = lib.warnOnInstantiate "'swiftDriver' has been renamed to 'swift-driver'" finalAttrs.passthru.swift-driver;
-    swiftOs = lib.warnOnInstantiate "'swiftOs' is an alias for 'stdenv.hostPlatform.swift.platform'." stdenv.hostPlatform.swift.platform;
+    swiftOs = lib.warn "'swiftOs' is an alias for 'stdenv.hostPlatform.swift.platform'." stdenv.hostPlatform.swift.platform;
   };
 
   meta = {