1 files changed, 14 insertions, 3 deletions
diff --git a/graph/src/error.rs b/graph/src/error.rs
index 3600005..bf2714b 100644
--- a/graph/src/error.rs
+++ b/graph/src/error.rs
@@ -13,8 +13,11 @@ pub enum Error {
     /// the second component is the current length of nodes.
     IndexOutOfBounds(usize, usize),
     /// The graph does not permit duplicate nodes but encounters a
-    /// repeated node
-    DuplicatedNode,
+    /// repeated node.
+    DuplicatedNode(usize),
+    /// The graph does not permit duplicate edges but encounters a
+    /// repeated edge.
+    DuplicatedEdge(usize, usize),
 }
 
 impl Display for Error {
@@ -23,7 +26,15 @@ impl Display for Error {
             Error::IndexOutOfBounds(index, len) => {
                 write!(f, "index {index} out of bounds {len} ")
             }
-            Error::DuplicatedNode => write!(f, "No duplicate nodes permitted, but found one"),
+            Error::DuplicatedNode(node) => {
+                write!(f, "No duplicate nodes permitted, but found one: {node}")
+            }
+            Error::DuplicatedEdge(source, target) => {
+                write!(
+                    f,
+                    "No duplicate edges permitted, but found one from {source} to {target}"
+                )
+            }
         }
     }
 }