diff --git a/hy/lex/__init__.py b/hy/lex/__init__.py
index 8153aa8..f1a74aa 100644
--- a/hy/lex/__init__.py
+++ b/hy/lex/__init__.py
@@ -35,3 +35,7 @@ def tokenize(buf):
         pos = e.getsourcepos()
         raise LexException("Could not identify the next token.",
                            pos.lineno, pos.colno)
+    except LexException as e:
+        if e.source is None:
+            e.source = buf
+        raise