bin/auto-classify

 #!/usr/bin/env python3
 #
-# Copyright © 2020-2021 Chris Lamb <lamby@debian.org>
+# Copyright © 2020-2022 Chris Lamb <lamby@debian.org>
 #
 # diffoscope is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -122,6 +122,9 @@ def walk_json(elem):
         if "qt_resource_data" in diff:
             yield "timestamps_in_source_generated_by_rcc"
 
+        if v.startswith("ghc --show-iface") and "ABI hash" in diff:
+            yield "haskell_abi_hash_differences"
+
         if v.endswith(".html") and "/build/1st/" in diff and "Doxygen" in diff:
             yield "absolute_build_dir_in_docs_generated_by_doxygen_ref"
 

issues.yml

@@ -2422,3 +2422,8 @@ nondeterministic_ids_in_html_output_generated_by_python_sphinx_panels:
     python3-sphinx-panels generates unique identifiers using uuid4, resulting
     in documentation that is not reproducible.
   url: https://bugs.debian.org/1017475
+haskell_abi_hash_differences:
+  description: |
+    the interface/abi hash in .hi files differs between builds. Curiously, the
+    order of these fields appears to differ too, but that might be downstream
+    of the former issue.