From f8d15069227298492ce539d793cfedfd8a80874c Mon Sep 17 00:00:00 2001
From: David Nadlinger <code@klickverbot.at>
Date: Tue, 28 Jul 2020 00:33:28 +0100
Subject: [PATCH] compiler: Fix lifetime tracking for function call return
 values

GitHub: Fixes #1497.
---
 artiq/compiler/validators/escape.py |  2 +-
 artiq/test/lit/escape/error_call.py | 14 ++++++++++++++
 2 files changed, 15 insertions(+), 1 deletion(-)
 create mode 100644 artiq/test/lit/escape/error_call.py

diff --git a/artiq/compiler/validators/escape.py b/artiq/compiler/validators/escape.py
index 000c3ee5b..5aae58e51 100644
--- a/artiq/compiler/validators/escape.py
+++ b/artiq/compiler/validators/escape.py
@@ -103,7 +103,7 @@ class RegionOf(algorithm.Visitor):
             # The cache is borrow checked dynamically
             return Global()
         else:
-            self.visit_sometimes_allocating(node)
+            return self.visit_sometimes_allocating(node)
 
     # Value lives as long as the object/container, if it's mutable,
     # or else forever
diff --git a/artiq/test/lit/escape/error_call.py b/artiq/test/lit/escape/error_call.py
new file mode 100644
index 000000000..8bbc7992f
--- /dev/null
+++ b/artiq/test/lit/escape/error_call.py
@@ -0,0 +1,14 @@
+# RUN: %python -m artiq.compiler.testbench.embedding +diag %s 2>%t
+# RUN: OutputCheck %s --file-to-check=%t
+
+from artiq.experiment import *
+
+@kernel
+def leak(a):
+    return a
+
+@kernel
+def entrypoint():
+    # CHECK-L: ${LINE:+2}: error: cannot return an allocated value that does not live forever
+    # CHECK-L: ${LINE:+1}: note: ... to this point
+    return leak([1, 2, 3])