3 files changed, 13 insertions, 1 deletions
diff --git a/tvix/eval/src/builtins/mod.rs b/tvix/eval/src/builtins/mod.rs
index 331dcbcd41..b93bbd99f8 100644
--- a/tvix/eval/src/builtins/mod.rs
+++ b/tvix/eval/src/builtins/mod.rs
@@ -898,7 +898,7 @@ mod pure_builtins {
     fn builtin_tail(_: &mut VM, list: Value) -> Result<Value, ErrorKind> {
         let xs = list.to_list()?;
 
-        if xs.len() == 0 {
+        if xs.is_empty() {
             Err(ErrorKind::TailEmptyList)
         } else {
             let output = xs.into_iter().skip(1).collect::<Vec<_>>();
diff --git a/tvix/eval/src/value/attrs.rs b/tvix/eval/src/value/attrs.rs
index d413f0073f..6515fb515a 100644
--- a/tvix/eval/src/value/attrs.rs
+++ b/tvix/eval/src/value/attrs.rs
@@ -301,6 +301,14 @@ impl NixAttrs {
         }
     }
 
+    pub fn is_empty(&self) -> bool {
+        match &self.0 {
+            AttrsRep::Im(map) => map.is_empty(),
+            AttrsRep::Empty => true,
+            AttrsRep::KV { .. } => false,
+        }
+    }
+
     /// Select a value from an attribute set by key.
     pub fn select(&self, key: &str) -> Option<&Value> {
         self.0.select(key)
diff --git a/tvix/eval/src/value/list.rs b/tvix/eval/src/value/list.rs
index 70952419ab..6d830b7283 100644
--- a/tvix/eval/src/value/list.rs
+++ b/tvix/eval/src/value/list.rs
@@ -67,6 +67,10 @@ impl NixList {
         self.0.get(i)
     }
 
+    pub fn is_empty(&self) -> bool {
+        self.0.is_empty()
+    }
+
     pub fn construct(count: usize, stack_slice: Vec<Value>) -> Self {
         debug_assert!(
             count == stack_slice.len(),