hdl.dsl: py3.12+: turn off heuristic warning on ~True and ~False.

There is now an upstream deprecation warning for the same.
We don't have to duplicate it.

Author: whitequark

amaranth/hdl/dsl.py

@@ -3,6 +3,7 @@
 from functools import wraps
 from enum import Enum
 import warnings
+import sys
 
 from .._utils import flatten, bits_for
 from .. import tracer
@@ -210,7 +211,8 @@ def _set_ctrl(self, name, data):
 
     def _check_signed_cond(self, cond):
         cond = Value.cast(cond)
-        if cond.shape().signed:
+        if sys.version_info < (3, 12, 0) and cond.shape().signed:
+            # TODO(py3.11): remove; ~True is a warning in 3.12+, finally!
             warnings.warn("Signed values in If/Elif conditions usually result from inverting "
                           "Python booleans with ~, which leads to unexpected results. "
                           "Replace `~flag` with `not flag`. (If this is a false positive, "

tests/test_hdl_dsl.py

@@ -1,5 +1,6 @@
 # amaranth: UnusedElaboratable=no
 
+import sys
 from collections import OrderedDict
 
 from amaranth.hdl.ast import *
@@ -324,27 +325,28 @@ def test_If_wide(self):
         )
         """)
 
-    def test_If_signed_suspicious(self):
-        m = Module()
-        with self.assertWarnsRegex(SyntaxWarning,
-                (r"^Signed values in If\/Elif conditions usually result from inverting Python "
+    if sys.version_info < (3, 12): # upstream warning in 3.12!
+        def test_If_signed_suspicious(self):
+            m = Module()
+            with self.assertWarnsRegex(SyntaxWarning,
+                    r"^Signed values in If\/Elif conditions usually result from inverting Python "
                     r"booleans with ~, which leads to unexpected results\. Replace `~flag` with "
                     r"`not flag`\. \(If this is a false positive, silence this warning with "
-                    r"`m\.If\(x\)` → `m\.If\(x\.bool\(\)\)`\.\)$")):
-            with m.If(~True):
-                pass
+                    r"`m\.If\(x\)` → `m\.If\(x\.bool\(\)\)`\.\)$"):
+                with m.If(~True):
+                    pass
 
-    def test_Elif_signed_suspicious(self):
-        m = Module()
-        with m.If(0):
-            pass
-        with self.assertWarnsRegex(SyntaxWarning,
-                (r"^Signed values in If\/Elif conditions usually result from inverting Python "
+        def test_Elif_signed_suspicious(self):
+            m = Module()
+            with m.If(0):
+                pass
+            with self.assertWarnsRegex(SyntaxWarning,
+                    r"^Signed values in If\/Elif conditions usually result from inverting Python "
                     r"booleans with ~, which leads to unexpected results\. Replace `~flag` with "
                     r"`not flag`\. \(If this is a false positive, silence this warning with "
-                    r"`m\.If\(x\)` → `m\.If\(x\.bool\(\)\)`\.\)$")):
-            with m.Elif(~True):
-                pass
+                    r"`m\.If\(x\)` → `m\.If\(x\.bool\(\)\)`\.\)$"):
+                with m.Elif(~True):
+                    pass
 
     def test_if_If_Elif_Else(self):
         m = Module()