1 files changed, 13 insertions, 5 deletions
diff --git a/nfa/src/error.rs b/nfa/src/error.rs
index ad75077..7160555 100644
--- a/nfa/src/error.rs
+++ b/nfa/src/error.rs
@@ -1,6 +1,6 @@
 //! This file implements the error type for the crate.
 
-use graph::error::Error as GError;
+use graph::error::Error as GraphError;
 
 use core::fmt::{Display, Formatter};
 
@@ -17,7 +17,7 @@ pub enum Error {
     /// There is no root in the underlying regular expression.
     NoRoot,
     /// This error comes from some underlying graph operation.
-    Graph(GError),
+    Graph(GraphError),
     /// A cycle is found when constructing regular expressions.
     Cycle,
 }
@@ -34,10 +34,18 @@ impl Display for Error {
     }
 }
 
-impl std::error::Error for Error {}
+impl std::error::Error for Error {
+    fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
+        if let Self::Graph(gerr) = self {
+            Some(gerr)
+        } else {
+            None
+        }
+    }
+}
 
-impl From<GError> for Error {
-    fn from(e: GError) -> Self {
+impl From<GraphError> for Error {
+    fn from(e: GraphError) -> Self {
         Self::Graph(e)
     }
 }