From 0521890dbc19f97922ca1a9ab68fb3c13df9654a Mon Sep 17 00:00:00 2001
From: Geoff Romer <gromer@google.com>
Date: Wed, 8 Sep 2021 11:36:16 -0700
Subject: [PATCH] Clarify the copy semantics of continuations (#816)

---
 executable_semantics/README.md                |  3 +++
 executable_semantics/test_list.bzl            |  1 -
 .../experimental_continuation8.carbon         | 27 -------------------
 .../experimental_continuation8.golden         |  1 -
 4 files changed, 3 insertions(+), 29 deletions(-)
 delete mode 100644 executable_semantics/testdata/experimental_continuation8.carbon
 delete mode 100644 executable_semantics/testdata/experimental_continuation8.golden

diff --git a/executable_semantics/README.md b/executable_semantics/README.md
index 1557c1a1b006..c18ea63e0981 100644
--- a/executable_semantics/README.md
+++ b/executable_semantics/README.md
@@ -198,6 +198,9 @@ the continuation. After the first `__run`, the control state is just after the
 `__await`. After the second `__run`, the control state is at the end of the
 continuation.
 
+Continuation variables are currently copyable, but that operation is "shallow":
+the two values are aliases for the same underlying continuation object.
+
 The delimited continuation feature described here is based on the
 `shift`/`reset` style of delimited continuations created by Danvy and Filinsky
 (Abstracting control, ACM Conference on Lisp and Functional Programming, 1990).
diff --git a/executable_semantics/test_list.bzl b/executable_semantics/test_list.bzl
index 038ad64bc5a4..3d0cfbb701b7 100644
--- a/executable_semantics/test_list.bzl
+++ b/executable_semantics/test_list.bzl
@@ -25,7 +25,6 @@ TEST_LIST = [
     "experimental_continuation5",
     "experimental_continuation6",
     "experimental_continuation7",
-    "experimental_continuation8",
     "experimental_continuation9",
     "fun1",
     "fun2",
diff --git a/executable_semantics/testdata/experimental_continuation8.carbon b/executable_semantics/testdata/experimental_continuation8.carbon
deleted file mode 100644
index aad639c2fe62..000000000000
--- a/executable_semantics/testdata/experimental_continuation8.carbon
+++ /dev/null
@@ -1,27 +0,0 @@
-// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
-// Exceptions. See /LICENSE for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-
-package ExecutableSemanticsTest api;
-
-// Test the way in which copying of continuations interacts with data
-// on the stack such as the variable `x`. In this example the copy
-// happens before the variable `x` is created, so each continuation
-// creates a different `x`.
-
-var y: i32 = 0;
-
-fn main() -> i32 {
-  __continuation k1 {
-    var x: i32 = 0;
-    x = x + 1;
-    __await;
-    y = x;
-  }
-  var k2: __Continuation = k1;
-  __run k1;
-  __run k2;
-  __run k1;
-  __run k2;
-  return y;
-}
diff --git a/executable_semantics/testdata/experimental_continuation8.golden b/executable_semantics/testdata/experimental_continuation8.golden
deleted file mode 100644
index 0c204052cb21..000000000000
--- a/executable_semantics/testdata/experimental_continuation8.golden
+++ /dev/null
@@ -1 +0,0 @@
-result: 1