diff --git a/.version b/.version
index 6a6900382..bcec02eeb 100644
--- a/.version
+++ b/.version
@@ -1 +1 @@
-2.30.0
+2.30.1
diff --git a/docker.nix b/docker.nix
index ac047b4d6..ca7a81c1f 100644
--- a/docker.nix
+++ b/docker.nix
@@ -184,11 +184,14 @@ let
       } " = ";
     };
 
-  nixConfContents = toConf {
-    sandbox = false;
-    build-users-group = "nixbld";
-    trusted-public-keys = [ "cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY=" ];
-  };
+  nixConfContents = toConf (
+    {
+      sandbox = false;
+      build-users-group = "nixbld";
+      trusted-public-keys = [ "cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY=" ];
+    }
+    // nixConf
+  );
 
   userHome = if uid == 0 then "/root" else "/home/${uname}";
 
diff --git a/scripts/install-multi-user.sh b/scripts/install-multi-user.sh
index f051ccc46..e9ddfc014 100644
--- a/scripts/install-multi-user.sh
+++ b/scripts/install-multi-user.sh
@@ -834,8 +834,13 @@ install_from_extracted_nix() {
     (
         cd "$EXTRACTED_NIX_PATH"
 
-        _sudo "to copy the basic Nix files to the new store at $NIX_ROOT/store" \
-              cp -RPp ./store/* "$NIX_ROOT/store/"
+        if is_os_darwin; then
+            _sudo "to copy the basic Nix files to the new store at $NIX_ROOT/store" \
+                  cp -RPp ./store/* "$NIX_ROOT/store/"
+        else
+            _sudo "to copy the basic Nix files to the new store at $NIX_ROOT/store" \
+                  cp -RP --preserve=ownership,timestamps ./store/* "$NIX_ROOT/store/"
+        fi
 
         _sudo "to make the new store non-writable at $NIX_ROOT/store" \
               chmod -R ugo-w "$NIX_ROOT/store/"
diff --git a/scripts/install-nix-from-tarball.sh b/scripts/install-nix-from-tarball.sh
index 8d127a9c5..ec3264793 100644
--- a/scripts/install-nix-from-tarball.sh
+++ b/scripts/install-nix-from-tarball.sh
@@ -167,7 +167,11 @@ for i in $(cd "$self/store" >/dev/null && echo ./*); do
         rm -rf "$i_tmp"
     fi
     if ! [ -e "$dest/store/$i" ]; then
-        cp -RPp "$self/store/$i" "$i_tmp"
+        if [ "$(uname -s)" = "Darwin" ]; then
+            cp -RPp "$self/store/$i" "$i_tmp"
+        else
+            cp -RP --preserve=ownership,timestamps "$self/store/$i" "$i_tmp"
+        fi
         chmod -R a-w "$i_tmp"
         chmod +w "$i_tmp"
         mv "$i_tmp" "$dest/store/$i"
diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc
index 054b51564..2baed9bca 100644
--- a/src/libexpr/eval.cc
+++ b/src/libexpr/eval.cc
@@ -1609,7 +1609,7 @@ void EvalState::callFunction(Value & fun, std::span<Value *> args, Value & vRes,
                                              symbols[i.name])
                                     .atPos(lambda.pos)
                                     .withTrace(pos, "from call site")
-                                    .withFrame(*fun.lambda().env, lambda)
+                                    .withFrame(*vCur.lambda().env, lambda)
                                     .debugThrow();
                         }
                         env2.values[displ++] = i.def->maybeThunk(*this, env2);
@@ -1636,7 +1636,7 @@ void EvalState::callFunction(Value & fun, std::span<Value *> args, Value & vRes,
                                 .atPos(lambda.pos)
                                 .withTrace(pos, "from call site")
                                 .withSuggestions(suggestions)
-                                .withFrame(*fun.lambda().env, lambda)
+                                .withFrame(*vCur.lambda().env, lambda)
                                 .debugThrow();
                         }
                     unreachable();
diff --git a/src/libexpr/primops/fetchClosure.cc b/src/libexpr/primops/fetchClosure.cc
index fb17d71b9..e74c8484d 100644
--- a/src/libexpr/primops/fetchClosure.cc
+++ b/src/libexpr/primops/fetchClosure.cc
@@ -124,7 +124,7 @@ static void prim_fetchClosure(EvalState & state, const PosIdx pos, Value * * arg
     for (auto & attr : *args[0]->attrs()) {
         const auto & attrName = state.symbols[attr.name];
         auto attrHint = [&]() -> std::string {
-            return "while evaluating the '" + attrName + "' attribute passed to builtins.fetchClosure";
+            return fmt("while evaluating the attribute '%s' passed to builtins.fetchClosure", attrName);
         };
 
         if (attrName == "fromPath") {
diff --git a/tests/functional/lang/eval-fail-missing-arg-import.err.exp b/tests/functional/lang/eval-fail-missing-arg-import.err.exp
new file mode 100644
index 000000000..45774f003
--- /dev/null
+++ b/tests/functional/lang/eval-fail-missing-arg-import.err.exp
@@ -0,0 +1,12 @@
+error:
+       … from call site
+         at /pwd/lang/eval-fail-missing-arg-import.nix:1:1:
+            1| import ./non-eval-trivial-lambda-formals.nix { }
+             | ^
+            2|
+
+       error: function 'anonymous lambda' called without required argument 'a'
+       at /pwd/lang/non-eval-trivial-lambda-formals.nix:1:1:
+            1| { a }: a
+             | ^
+            2|
diff --git a/tests/functional/lang/eval-fail-missing-arg-import.nix b/tests/functional/lang/eval-fail-missing-arg-import.nix
new file mode 100644
index 000000000..7cb33f2b5
--- /dev/null
+++ b/tests/functional/lang/eval-fail-missing-arg-import.nix
@@ -0,0 +1 @@
+import ./non-eval-trivial-lambda-formals.nix { }
diff --git a/tests/functional/lang/eval-fail-undeclared-arg-import.err.exp b/tests/functional/lang/eval-fail-undeclared-arg-import.err.exp
new file mode 100644
index 000000000..ca797d3ec
--- /dev/null
+++ b/tests/functional/lang/eval-fail-undeclared-arg-import.err.exp
@@ -0,0 +1,13 @@
+error:
+       … from call site
+         at /pwd/lang/eval-fail-undeclared-arg-import.nix:1:1:
+            1| import ./non-eval-trivial-lambda-formals.nix {
+             | ^
+            2|   a = "a";
+
+       error: function 'anonymous lambda' called with unexpected argument 'b'
+       at /pwd/lang/non-eval-trivial-lambda-formals.nix:1:1:
+            1| { a }: a
+             | ^
+            2|
+       Did you mean a?
diff --git a/tests/functional/lang/eval-fail-undeclared-arg-import.nix b/tests/functional/lang/eval-fail-undeclared-arg-import.nix
new file mode 100644
index 000000000..e8454c725
--- /dev/null
+++ b/tests/functional/lang/eval-fail-undeclared-arg-import.nix
@@ -0,0 +1,4 @@
+import ./non-eval-trivial-lambda-formals.nix {
+  a = "a";
+  b = "b";
+}
diff --git a/tests/functional/lang/non-eval-trivial-lambda-formals.nix b/tests/functional/lang/non-eval-trivial-lambda-formals.nix
new file mode 100644
index 000000000..46a7ea4f4
--- /dev/null
+++ b/tests/functional/lang/non-eval-trivial-lambda-formals.nix
@@ -0,0 +1 @@
+{ a }: a
diff --git a/tests/nixos/github-flakes.nix b/tests/nixos/github-flakes.nix
index b93e35074..67e2d41e9 100644
--- a/tests/nixos/github-flakes.nix
+++ b/tests/nixos/github-flakes.nix
@@ -81,7 +81,7 @@ let
     mkdir -p $out/archive
 
     dir=NixOS-nixpkgs-${nixpkgs.shortRev}
-    cp -prd ${nixpkgs} $dir
+    cp -rd --preserve=ownership,timestamps ${nixpkgs} $dir
     # Set the correct timestamp in the tarball.
     find $dir -print0 | xargs -0 touch -h -t ${builtins.substring 0 12 nixpkgs.lastModifiedDate}.${
       builtins.substring 12 2 nixpkgs.lastModifiedDate
diff --git a/tests/nixos/sourcehut-flakes.nix b/tests/nixos/sourcehut-flakes.nix
index ff9a42dcd..5b40866d1 100644
--- a/tests/nixos/sourcehut-flakes.nix
+++ b/tests/nixos/sourcehut-flakes.nix
@@ -48,7 +48,7 @@ let
 
   nixpkgs-repo = pkgs.runCommand "nixpkgs-flake" { } ''
     dir=NixOS-nixpkgs-${nixpkgs.shortRev}
-    cp -prd ${nixpkgs} $dir
+    cp -rd --preserve=ownership,timestamps ${nixpkgs} $dir
 
     # Set the correct timestamp in the tarball.
     find $dir -print0 | xargs -0 touch -h -t ${builtins.substring 0 12 nixpkgs.lastModifiedDate}.${
diff --git a/tests/nixos/tarball-flakes.nix b/tests/nixos/tarball-flakes.nix
index fc2c5fe38..a68d64bfd 100644
--- a/tests/nixos/tarball-flakes.nix
+++ b/tests/nixos/tarball-flakes.nix
@@ -13,7 +13,7 @@ let
 
     set -x
     dir=nixpkgs-${nixpkgs.shortRev}
-    cp -prd ${nixpkgs} $dir
+    cp -rd --preserve=ownership,timestamps ${nixpkgs} $dir
     # Set the correct timestamp in the tarball.
     find $dir -print0 | xargs -0 touch -h -t ${builtins.substring 0 12 nixpkgs.lastModifiedDate}.${
       builtins.substring 12 2 nixpkgs.lastModifiedDate