diff --git a/src/libexpr/eval-gc.cc b/src/libexpr/eval-gc.cc
index 07ce05a2c73..de0b53865f1 100644
--- a/src/libexpr/eval-gc.cc
+++ b/src/libexpr/eval-gc.cc
@@ -101,7 +101,7 @@ void initGC()
 #endif
 
     // NIX_PATH must override the regular setting
-    // See the comment in applyConfig
+    // See the XXX comment in `applyConfig()`
     if (auto nixPathEnv = getEnv("NIX_PATH")) {
         globalConfig.set("nix-path", concatStringsSep(" ", EvalSettings::parseNixPath(nixPathEnv.value())));
     }
diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc
index 2420f15c19a..345acb6d25d 100644
--- a/src/libexpr/eval.cc
+++ b/src/libexpr/eval.cc
@@ -341,6 +341,7 @@ EvalState::EvalState(
         for (auto & i : settings.nixPath.get()) {
             lookupPath.elements.emplace_back(LookupPath::Elem::parse(i));
         }
+        // TODO: only set if nothing else is
         if (!settings.restrictEval) {
             for (auto & i : EvalSettings::getDefaultNixPath()) {
                 lookupPath.elements.emplace_back(LookupPath::Elem::parse(i));
diff --git a/tests/functional/nix_path.sh b/tests/functional/nix_path.sh
index 90cba1f0c9c..51d22967f49 100755
--- a/tests/functional/nix_path.sh
+++ b/tests/functional/nix_path.sh
@@ -42,6 +42,19 @@ done
 # finding something that's not in any of the default paths fails
 ( ! $(nix-instantiate --find-file test) )
 
+# XXX: we can't manipulate $NIX_STATE_DIR contents on NixOS
+# TODO: port to NixOS somehow; ideally we'd run the test suite in a non-NixOS VM
+if [[ ! isTestOnNixOS ]]; then
+    mkdir -p $NIX_STATE_DIR/profiles/per-user/root/channels/nixpkgs
+    # check that the default values are set
+    [[ $(nix-instantiate --eval -E 'with builtins; length nixPath') = 2 ]]
+    # setting anything overrides the default paths
+    # this ensures we can force an empty search path
+    [[ $(NIX_PATH= nix-instantiate --eval -E 'with builtins; length nixPath') = 0 ]]
+    [[ $(nix-instantiate --nix-path "" --eval -E 'with builtins; length nixPath') = 0 ]]
+    [[ $(nix-instantiate -I "" --eval -E 'with builtins; length nixPath') = 1 ]]
+fi
+
 echo "nix-path = test=$TEST_ROOT/from-nix-path-file" >> "$test_nix_conf"
 
 # Use nix.conf in absence of NIX_PATH