back.rtlil: support slicing on Parts

Fixes #605.

diff --git a/nmigen/back/rtlil.py b/nmigen/back/rtlil.py
index 0802b367e6d73dd3f8124528ef8f0b4c48ec2ae6..0990e42d5a31da42719acb6bc7336a5421e29f26 100644 (file)
--- a/nmigen/back/rtlil.py
+++ b/nmigen/back/rtlil.py
@@ -664,7 +664,7 @@ class _LHSValueCompiler(_ValueCompiler):
         return wire_next or wire_curr
 
     def _prepare_value_for_Slice(self, value):
-        assert isinstance(value, (ast.Signal, ast.Slice, ast.Cat))
+        assert isinstance(value, (ast.Signal, ast.Slice, ast.Cat, ast.Part))
         return self(value)
 
     def on_Part(self, value):