From 53b7d59b6a1e86ad3bff2d910779a21188b1615e Mon Sep 17 00:00:00 2001
From: whitequark <whitequark@whitequark.org>
Date: Mon, 21 Nov 2016 13:21:32 +0000
Subject: [PATCH] analyses.constness: fix false positive on x[...].

---
 artiq/compiler/analyses/constness.py | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/artiq/compiler/analyses/constness.py b/artiq/compiler/analyses/constness.py
index 4fab07ea4..add1f7fac 100644
--- a/artiq/compiler/analyses/constness.py
+++ b/artiq/compiler/analyses/constness.py
@@ -17,6 +17,12 @@ class Constness(algorithm.Visitor):
         self.visit(node.targets)
         self.in_assign = False
 
+    def visit_SubscriptT(self, node):
+        old_in_assign, self.in_assign = self.in_assign, False
+        self.visit(node.value)
+        self.visit(node.slice)
+        self.in_assign = old_in_assign
+
     def visit_AttributeT(self, node):
         self.generic_visit(node)
         if self.in_assign: