[omerta pants (kwlzn/pantsd_invalidation_test)]$ gd | cat
diff --git a/src/python/pants/engine/legacy/structs.py b/src/python/pants/engine/legacy/structs.py
index 097fba1..6216963 100644
--- a/src/python/pants/engine/legacy/structs.py
+++ b/src/python/pants/engine/legacy/structs.py
@@ -85,8 +85,14 @@ class SourcesField(datatype('SourcesField', ['address', 'arg', 'filespecs', 'pat
   :param path_globs: A PathGlobs describing included files.
   """
 
+  def __eq__(self, other):
+    return type(self) == type(other) and self.address == other.address and self.arg == other.arg
+
+  def __ne__(self, other):
+    return not (self == other)
+
   def __hash__(self):
-    return hash((self.address, self.arg))
+    return hash(self.address)
 
   def __repr__(self):
     return str(self)