diff --git a/libgit2-sys/lib.rs b/libgit2-sys/lib.rs
index 383db6c37e..32c2af9f92 100644
--- a/libgit2-sys/lib.rs
+++ b/libgit2-sys/lib.rs
@@ -741,8 +741,9 @@ git_enum! {
     }
 }
 
-pub type git_treewalk_cb =
-    Option<extern "C" fn(*const c_char, *const git_tree_entry, *mut c_void) -> c_int>;
+pub type git_treewalk_inner_cb =
+    extern "C" fn(*const c_char, *const git_tree_entry, *mut c_void) -> c_int;
+pub type git_treewalk_cb = Option<git_treewalk_inner_cb>;
 pub type git_treebuilder_filter_cb =
     Option<extern "C" fn(*const git_tree_entry, *mut c_void) -> c_int>;
 
diff --git a/src/call.rs b/src/call.rs
index a18f05da91..57aaa26dbd 100644
--- a/src/call.rs
+++ b/src/call.rs
@@ -116,6 +116,17 @@ mod impls {
         }
     }
 
+    impl Convert<raw::git_treewalk_mode> for crate::TreeWalkMode {
+        #[cfg(target_env = "msvc")]
+        fn convert(&self) -> raw::git_treewalk_mode {
+            *self as i32
+        }
+        #[cfg(not(target_env = "msvc"))]
+        fn convert(&self) -> raw::git_treewalk_mode {
+            *self as u32
+        }
+    }
+
     impl Convert<raw::git_direction> for Direction {
         fn convert(&self) -> raw::git_direction {
             match *self {
diff --git a/src/tree.rs b/src/tree.rs
index ae8fe3b4c5..a509852025 100644
--- a/src/tree.rs
+++ b/src/tree.rs
@@ -36,6 +36,7 @@ pub struct TreeIter<'tree> {
 
 /// A binary indicator of whether a tree walk should be performed in pre-order
 /// or post-order.
+#[derive(Clone, Copy)]
 pub enum TreeWalkMode {
     /// Runs the traversal in pre-order.
     PreOrder = 0,
@@ -60,17 +61,6 @@ impl Into<i32> for TreeWalkResult {
     }
 }
 
-impl Into<raw::git_treewalk_mode> for TreeWalkMode {
-    #[cfg(target_env = "msvc")]
-    fn into(self) -> raw::git_treewalk_mode {
-        self as i32
-    }
-    #[cfg(not(target_env = "msvc"))]
-    fn into(self) -> raw::git_treewalk_mode {
-        self as u32
-    }
-}
-
 impl<'repo> Tree<'repo> {
     /// Get the id (SHA1) of a repository object
     pub fn id(&self) -> Oid {
@@ -126,12 +116,12 @@ impl<'repo> Tree<'repo> {
             let mut data = TreeWalkCbData {
                 callback: &mut callback,
             };
-            raw::git_tree_walk(
+            try_call!(raw::git_tree_walk(
                 self.raw(),
-                mode.into(),
-                Some(treewalk_cb::<T>),
-                &mut data as *mut _ as *mut c_void,
-            );
+                mode,
+                Some(treewalk_cb::<T> as raw::git_treewalk_inner_cb),
+                &mut data as *mut _ as *mut c_void
+            ));
             Ok(())
         }
     }
@@ -599,4 +589,18 @@ mod tests {
         .unwrap();
         assert_eq!(ct, 8);
     }
+
+    #[test]
+    fn tree_walk_error() {
+        let (td, repo) = crate::test::repo_init();
+
+        setup_repo(&td, &repo);
+
+        let head = repo.head().unwrap();
+        let target = head.target().unwrap();
+        let commit = repo.find_commit(target).unwrap();
+        let tree = repo.find_tree(commit.tree_id()).unwrap();
+
+        assert!(tree.walk(TreeWalkMode::PreOrder, |_, _| { -1 }).is_err());
+    }
 }