From bf8faea51e92364564562cd02bf6e9743289e679 Mon Sep 17 00:00:00 2001
From: Wanda <wanda@phinode.net>
Date: Sat, 13 Jan 2024 13:39:02 +0100
Subject: [PATCH] hdl.ast: raise a sensible error for `xxx in Value`

---
 amaranth/hdl/ast.py   | 3 +++
 tests/test_hdl_ast.py | 5 +++++
 2 files changed, 8 insertions(+)

diff --git a/amaranth/hdl/ast.py b/amaranth/hdl/ast.py
index 26be377..7f7dfc7 100644
--- a/amaranth/hdl/ast.py
+++ b/amaranth/hdl/ast.py
@@ -377,6 +377,9 @@ class Value(metaclass=ABCMeta):
         else:
             raise TypeError(f"Cannot index value with {key!r}")
 
+    def __contains__(self, other):
+        raise TypeError("Cannot use 'in' with an Amaranth value")
+
     def as_unsigned(self):
         """Conversion to unsigned.
 
diff --git a/tests/test_hdl_ast.py b/tests/test_hdl_ast.py
index 4e52c6b..81ba518 100644
--- a/tests/test_hdl_ast.py
+++ b/tests/test_hdl_ast.py
@@ -750,6 +750,11 @@ class OperatorTestCase(FHDLTestCase):
         """)
         self.assertEqual(abs(s).shape(), unsigned(4))
 
+    def test_contains(self):
+        with self.assertRaisesRegex(TypeError,
+                r"^Cannot use 'in' with an Amaranth value$"):
+            1 in Signal(3)
+
 
 class SliceTestCase(FHDLTestCase):
     def test_shape(self):