diff --git a/nixide/src/errors/context.rs b/nixide/src/errors/context.rs
index 9056d82..f04a10e 100644
--- a/nixide/src/errors/context.rs
+++ b/nixide/src/errors/context.rs
@@ -119,7 +119,6 @@ impl Into<NixideResult<()>> for &ErrorContext {
             },
 
             sys::NixErr::Unknown => NixError::Unknown,
-            err => NixError::Undocumented(err),
         };
 
         Err(new_nixide_error!(NixError, inner, err, msg))
diff --git a/nixide/src/errors/error.rs b/nixide/src/errors/error.rs
index b0bb66a..95c8379 100644
--- a/nixide/src/errors/error.rs
+++ b/nixide/src/errors/error.rs
@@ -86,7 +86,7 @@ pub(crate) use new_nixide_error;
 macro_rules! retrace_nixide_error {
     ($x:expr) => {{ crate::errors::new_nixide_error!($x.err) }};
 }
-pub(crate) use retrace_nixide_error;
+// pub(crate) use retrace_nixide_error;
 
 impl std::error::Error for NixideError {}
 
diff --git a/nixide/src/errors/mod.rs b/nixide/src/errors/mod.rs
index 4ab5ca5..c194728 100644
--- a/nixide/src/errors/mod.rs
+++ b/nixide/src/errors/mod.rs
@@ -4,6 +4,6 @@ mod context;
 mod nix_error;
 
 pub(crate) use context::ErrorContext;
-pub(crate) use error::{new_nixide_error, retrace_nixide_error};
+pub(crate) use error::new_nixide_error;
 pub use error::{NixideError, NixideResult};
 pub use nix_error::NixError;
diff --git a/nixide/src/expr/eval_state.rs b/nixide/src/expr/eval_state.rs
index 10644fb..7cee8e4 100644
--- a/nixide/src/expr/eval_state.rs
+++ b/nixide/src/expr/eval_state.rs
@@ -15,6 +15,7 @@ use crate::{NixideResult, Store};
 ///
 /// This provides the main interface for evaluating Nix expressions
 /// and creating values.
+#[derive(Clone)]
 pub struct EvalState {
     inner: Rc<RefCell<NonNull<sys::EvalState>>>,
 
diff --git a/nixide/src/expr/eval_state_builder.rs b/nixide/src/expr/eval_state_builder.rs
index e1265db..f1a09e6 100644
--- a/nixide/src/expr/eval_state_builder.rs
+++ b/nixide/src/expr/eval_state_builder.rs
@@ -106,8 +106,8 @@ impl EvalStateBuilder {
     }
 
     pub fn set_lookup_path<P: AsRef<str>>(self, paths: Vec<P>) -> NixideResult<Self> {
-        let paths_len = paths.len();
-        let paths_capacity = paths.capacity();
+        // let paths_len = paths.len();
+        // let paths_capacity = paths.capacity();
 
         // XXX: TODO: use the `AsCArray` trait instead
         let mut ptrs: Vec<*const c_char> = paths